From acaf6a97d623af123314c2f8ce4cf7254f6b2fc1 Mon Sep 17 00:00:00 2001
From: James Hogan <james.hogan@imgtec.com>
Date: Wed, 25 Feb 2015 13:08:05 +0000
Subject: MIPS: lose_fpu(): Disable FPU when MSA enabled

The lose_fpu() function only disables the FPU in CP0_Status.CU1 if the
FPU is in use and MSA isn't enabled.

This isn't necessarily a problem because KSTK_STATUS(current), the
version of CP0_Status stored on the kernel stack on entry from user
mode, does always get updated and gets restored when returning to user
mode, but I don't think it was intended, and it is inconsistent with the
case of only the FPU being in use. Sometimes leaving the FPU enabled may
also mask kernel bugs where FPU operations are executed when the FPU
might not be enabled.

So lets disable the FPU in the MSA case too.

Fixes: 33c771ba5c5d ("MIPS: save/disable MSA in lose_fpu")
Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Paul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/9323/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
---
 arch/mips/include/asm/fpu.h | 1 +
 1 file changed, 1 insertion(+)

diff --git a/arch/mips/include/asm/fpu.h b/arch/mips/include/asm/fpu.h
index dd083e999b08..9f26b079cc6a 100644
--- a/arch/mips/include/asm/fpu.h
+++ b/arch/mips/include/asm/fpu.h
@@ -170,6 +170,7 @@ static inline void lose_fpu(int save)
 		}
 		disable_msa();
 		clear_thread_flag(TIF_USEDMSA);
+		__disable_fpu();
 	} else if (is_fpu_owner()) {
 		if (save)
 			_save_fp(current);
-- 
cgit v1.2.3


From 631afc65e8f4f845945ef9e90236d10cee601498 Mon Sep 17 00:00:00 2001
From: Paul Burton <paul.burton@imgtec.com>
Date: Fri, 27 Mar 2015 17:00:03 +0000
Subject: MIPS: Push .set mips64r* into the functions needing it

The {save,restore}_fp_context{,32} functions require that the assembler
allows the use of sdc instructions on any FP register, and this is
acomplished by setting the arch to mips64r2 or mips64r6
(using MIPS_ISA_ARCH_LEVEL_RAW).

However this has the effect of enabling the assembler to use mips64
instructions in the expansion of pseudo-instructions. This was done in
the (now-reverted) commit eec43a224cf1 "MIPS: Save/restore MSA context
around signals" which led to my mistakenly believing that there was an
assembler bug, when in reality the assembler was just emitting mips64
instructions. Avoid the issue for future commits which will add code to
r4k_fpu.S by pushing the .set MIPS_ISA_ARCH_LEVEL_RAW directives into
the functions that require it, and remove the spurious assertion
declaring the assembler bug.

Signed-off-by: Paul Burton <paul.burton@imgtec.com>
[james.hogan@imgtec.com: Rebase on v4.0-rc1 and reword commit message to
 reflect use of MIPS_ISA_ARCH_LEVEL_RAW]
Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/9612/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
---
 arch/mips/include/asm/asmmacro.h | 12 ++++--------
 arch/mips/kernel/r4k_fpu.S       |  2 +-
 2 files changed, 5 insertions(+), 9 deletions(-)

diff --git a/arch/mips/include/asm/asmmacro.h b/arch/mips/include/asm/asmmacro.h
index 0cae4595e985..782dde7fed57 100644
--- a/arch/mips/include/asm/asmmacro.h
+++ b/arch/mips/include/asm/asmmacro.h
@@ -326,8 +326,7 @@
 	SET_HARDFLOAT
 	.insn
 	.word	COPY_UW_MSA_INSN | (\n << 16) | (\ws << 11)
-	/* move triggers an assembler bug... */
-	or	\rd, $1, zero
+	move	\rd, $1
 	.set	pop
 	.endm
 
@@ -337,8 +336,7 @@
 	SET_HARDFLOAT
 	.insn
 	.word	COPY_UD_MSA_INSN | (\n << 16) | (\ws << 11)
-	/* move triggers an assembler bug... */
-	or	\rd, $1, zero
+	move	\rd, $1
 	.set	pop
 	.endm
 
@@ -346,8 +344,7 @@
 	.set	push
 	.set	noat
 	SET_HARDFLOAT
-	/* move triggers an assembler bug... */
-	or	$1, \rs, zero
+	move	$1, \rs
 	.word	INSERT_W_MSA_INSN | (\n << 16) | (\wd << 6)
 	.set	pop
 	.endm
@@ -356,8 +353,7 @@
 	.set	push
 	.set	noat
 	SET_HARDFLOAT
-	/* move triggers an assembler bug... */
-	or	$1, \rs, zero
+	move	$1, \rs
 	.word	INSERT_D_MSA_INSN | (\n << 16) | (\wd << 6)
 	.set	pop
 	.endm
diff --git a/arch/mips/kernel/r4k_fpu.S b/arch/mips/kernel/r4k_fpu.S
index 676c5030a953..1d88af26ba82 100644
--- a/arch/mips/kernel/r4k_fpu.S
+++ b/arch/mips/kernel/r4k_fpu.S
@@ -34,7 +34,6 @@
 	.endm
 
 	.set	noreorder
-	.set	MIPS_ISA_ARCH_LEVEL_RAW
 
 LEAF(_save_fp_context)
 	.set	push
@@ -103,6 +102,7 @@ LEAF(_save_fp_context)
 	/* Save 32-bit process floating point context */
 LEAF(_save_fp_context32)
 	.set push
+	.set MIPS_ISA_ARCH_LEVEL_RAW
 	SET_HARDFLOAT
 	cfc1	t1, fcr31
 
-- 
cgit v1.2.3


From f23ce3883a30743a5b779dc6fb90ca8620688a23 Mon Sep 17 00:00:00 2001
From: Paul Burton <paul.burton@imgtec.com>
Date: Fri, 30 Jan 2015 12:09:31 +0000
Subject: MIPS: assume at as source/dest of MSA copy/insert instructions

Assuming at ($1) as the source or destination register of copy or
insert instructions:

  - Simplifies the macros providing those instructions for toolchains
    without MSA support.

  - Avoids an unnecessary move instruction when at is used as the source
    or destination register anyway.

  - Is sufficient for the uses to be introduced in the kernel by a
    subsequent patch.

Note that due to a patch ordering snafu on my part this also fixes the
currently broken build with MSA support enabled. The build has been
broken since commit c9017757c532 "MIPS: init upper 64b of vector
registers when MSA is first used", which this patch should have
preceeded.

Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/9161/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
---
 arch/mips/include/asm/asmmacro.h | 28 ++++++++++++----------------
 1 file changed, 12 insertions(+), 16 deletions(-)

diff --git a/arch/mips/include/asm/asmmacro.h b/arch/mips/include/asm/asmmacro.h
index 782dde7fed57..91df136ddce9 100644
--- a/arch/mips/include/asm/asmmacro.h
+++ b/arch/mips/include/asm/asmmacro.h
@@ -227,35 +227,35 @@
 	.set	pop
 	.endm
 
-	.macro	copy_u_w	rd, ws, n
+	.macro	copy_u_w	ws, n
 	.set	push
 	.set	mips32r2
 	.set	msa
-	copy_u.w \rd, $w\ws[\n]
+	copy_u.w $1, $w\ws[\n]
 	.set	pop
 	.endm
 
-	.macro	copy_u_d	rd, ws, n
+	.macro	copy_u_d	ws, n
 	.set	push
 	.set	mips64r2
 	.set	msa
-	copy_u.d \rd, $w\ws[\n]
+	copy_u.d $1, $w\ws[\n]
 	.set	pop
 	.endm
 
-	.macro	insert_w	wd, n, rs
+	.macro	insert_w	wd, n
 	.set	push
 	.set	mips32r2
 	.set	msa
-	insert.w $w\wd[\n], \rs
+	insert.w $w\wd[\n], $1
 	.set	pop
 	.endm
 
-	.macro	insert_d	wd, n, rs
+	.macro	insert_d	wd, n
 	.set	push
 	.set	mips64r2
 	.set	msa
-	insert.d $w\wd[\n], \rs
+	insert.d $w\wd[\n], $1
 	.set	pop
 	.endm
 #else
@@ -320,40 +320,36 @@
 	.set	pop
 	.endm
 
-	.macro	copy_u_w	rd, ws, n
+	.macro	copy_u_w	ws, n
 	.set	push
 	.set	noat
 	SET_HARDFLOAT
 	.insn
 	.word	COPY_UW_MSA_INSN | (\n << 16) | (\ws << 11)
-	move	\rd, $1
 	.set	pop
 	.endm
 
-	.macro	copy_u_d	rd, ws, n
+	.macro	copy_u_d	ws, n
 	.set	push
 	.set	noat
 	SET_HARDFLOAT
 	.insn
 	.word	COPY_UD_MSA_INSN | (\n << 16) | (\ws << 11)
-	move	\rd, $1
 	.set	pop
 	.endm
 
-	.macro	insert_w	wd, n, rs
+	.macro	insert_w	wd, n
 	.set	push
 	.set	noat
 	SET_HARDFLOAT
-	move	$1, \rs
 	.word	INSERT_W_MSA_INSN | (\n << 16) | (\wd << 6)
 	.set	pop
 	.endm
 
-	.macro	insert_d	wd, n, rs
+	.macro	insert_d	wd, n
 	.set	push
 	.set	noat
 	SET_HARDFLOAT
-	move	$1, \rs
 	.word	INSERT_D_MSA_INSN | (\n << 16) | (\wd << 6)
 	.set	pop
 	.endm
-- 
cgit v1.2.3


From a3a49810c55e3489dfb5d72a9b2e41ab1db9ffb9 Mon Sep 17 00:00:00 2001
From: Paul Burton <paul.burton@imgtec.com>
Date: Fri, 30 Jan 2015 12:09:32 +0000
Subject: MIPS: remove MSA macro recursion

Recursive macros made the code more concise & worked great for the
case where the toolchain doesn't support MSA. However, with toolchains
which do support MSA they lead to build failures such as:

  arch/mips/kernel/r4k_switch.S: Assembler messages:
  arch/mips/kernel/r4k_switch.S:148: Error: invalid operands `insert.w $w(0+1)[2],$1'
  arch/mips/kernel/r4k_switch.S:148: Error: invalid operands `insert.w $w(0+1)[3],$1'
  arch/mips/kernel/r4k_switch.S:148: Error: invalid operands `insert.w $w((0+1)+1)[2],$1'
  arch/mips/kernel/r4k_switch.S:148: Error: invalid operands `insert.w $w((0+1)+1)[3],$1'
  ...

Drop the recursion from msa_init_all_upper invoking the msa_init_upper
macro explicitly for each vector register.

Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/9162/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
---
 arch/mips/include/asm/asmmacro.h | 34 +++++++++++++++++++++++++++++++---
 1 file changed, 31 insertions(+), 3 deletions(-)

diff --git a/arch/mips/include/asm/asmmacro.h b/arch/mips/include/asm/asmmacro.h
index 91df136ddce9..73dec5c2084a 100644
--- a/arch/mips/include/asm/asmmacro.h
+++ b/arch/mips/include/asm/asmmacro.h
@@ -444,9 +444,6 @@
 	insert_w \wd, 2
 	insert_w \wd, 3
 #endif
-	.if	31-\wd
-	msa_init_upper	(\wd+1)
-	.endif
 	.endm
 
 	.macro	msa_init_all_upper
@@ -455,6 +452,37 @@
 	SET_HARDFLOAT
 	not	$1, zero
 	msa_init_upper	0
+	msa_init_upper	1
+	msa_init_upper	2
+	msa_init_upper	3
+	msa_init_upper	4
+	msa_init_upper	5
+	msa_init_upper	6
+	msa_init_upper	7
+	msa_init_upper	8
+	msa_init_upper	9
+	msa_init_upper	10
+	msa_init_upper	11
+	msa_init_upper	12
+	msa_init_upper	13
+	msa_init_upper	14
+	msa_init_upper	15
+	msa_init_upper	16
+	msa_init_upper	17
+	msa_init_upper	18
+	msa_init_upper	19
+	msa_init_upper	20
+	msa_init_upper	21
+	msa_init_upper	22
+	msa_init_upper	23
+	msa_init_upper	24
+	msa_init_upper	25
+	msa_init_upper	26
+	msa_init_upper	27
+	msa_init_upper	28
+	msa_init_upper	29
+	msa_init_upper	30
+	msa_init_upper	31
 	.set	pop
 	.endm
 
-- 
cgit v1.2.3


From e1bebbab1eaecac77d77033010b5e0f51b737e64 Mon Sep 17 00:00:00 2001
From: Paul Burton <paul.burton@imgtec.com>
Date: Fri, 30 Jan 2015 12:09:33 +0000
Subject: MIPS: wrap cfcmsa & ctcmsa accesses for toolchains with MSA support

Uses of the cfcmsa & ctcmsa instructions were not being wrapped by a
macro in the case where the toolchain supports MSA, since the arguments
exactly match a typical use of the instructions. However using current
toolchains this leads to errors such as:

  arch/mips/kernel/genex.S:437: Error: opcode not supported on this processor: mips32r2 (mips32r2) `cfcmsa $5,1'

Thus uses of the instructions must be in the context of a ".set msa"
directive, however doing that from the users of the instructions would
be messy due to the possibility that the toolchain does not support
MSA. Fix this by renaming the macros (prepending an underscore) in order
to avoid recursion when attempting to emit the instructions, and provide
implementations for the TOOLCHAIN_SUPPORTS_MSA case which ".set msa" as
appropriate.

Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/9163/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
---
 arch/mips/include/asm/asmmacro.h | 24 ++++++++++++++++++++----
 1 file changed, 20 insertions(+), 4 deletions(-)

diff --git a/arch/mips/include/asm/asmmacro.h b/arch/mips/include/asm/asmmacro.h
index 73dec5c2084a..a64e424ace16 100644
--- a/arch/mips/include/asm/asmmacro.h
+++ b/arch/mips/include/asm/asmmacro.h
@@ -211,6 +211,22 @@
 	.endm
 
 #ifdef TOOLCHAIN_SUPPORTS_MSA
+	.macro	_cfcmsa	rd, cs
+	.set	push
+	.set	mips32r2
+	.set	msa
+	cfcmsa	\rd, $\cs
+	.set	pop
+	.endm
+
+	.macro	_ctcmsa	cd, rs
+	.set	push
+	.set	mips32r2
+	.set	msa
+	ctcmsa	$\cd, \rs
+	.set	pop
+	.endm
+
 	.macro	ld_d	wd, off, base
 	.set	push
 	.set	mips32r2
@@ -283,7 +299,7 @@
 	/*
 	 * Temporary until all toolchains in use include MSA support.
 	 */
-	.macro	cfcmsa	rd, cs
+	.macro	_cfcmsa	rd, cs
 	.set	push
 	.set	noat
 	SET_HARDFLOAT
@@ -293,7 +309,7 @@
 	.set	pop
 	.endm
 
-	.macro	ctcmsa	cd, rs
+	.macro	_ctcmsa	cd, rs
 	.set	push
 	.set	noat
 	SET_HARDFLOAT
@@ -391,7 +407,7 @@
 	.set	push
 	.set	noat
 	SET_HARDFLOAT
-	cfcmsa	$1, MSA_CSR
+	_cfcmsa	$1, MSA_CSR
 	sw	$1, THREAD_MSA_CSR(\thread)
 	.set	pop
 	.endm
@@ -401,7 +417,7 @@
 	.set	noat
 	SET_HARDFLOAT
 	lw	$1, THREAD_MSA_CSR(\thread)
-	ctcmsa	MSA_CSR, $1
+	_ctcmsa	MSA_CSR, $1
 	.set	pop
 	ld_d	0, THREAD_FPR0, \thread
 	ld_d	1, THREAD_FPR1, \thread
-- 
cgit v1.2.3


From 091be550a70a086c3b4420c6155e733dc410f190 Mon Sep 17 00:00:00 2001
From: Paul Burton <paul.burton@imgtec.com>
Date: Fri, 30 Jan 2015 12:09:34 +0000
Subject: MIPS: clear MSACSR cause bits when handling MSA FP exception

Much like for traditional scalar FP exceptions, the cause bits in the
MSACSR register need to be cleared following an MSA FP exception.
Without doing so the exception will simply be raised again whenever
the kernel restores MSACSR from a tasks saved context, leading to
undesirable spurious exceptions. Clear the cause bits from the
handle_msa_fpe function, mirroring the way handle_fpe clears the
cause bits in FCSR.

Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/9164/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
---
 arch/mips/kernel/genex.S | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/arch/mips/kernel/genex.S b/arch/mips/kernel/genex.S
index 2ebaabe3af15..86e22422d08c 100644
--- a/arch/mips/kernel/genex.S
+++ b/arch/mips/kernel/genex.S
@@ -368,6 +368,15 @@ NESTED(nmi_handler, PT_SIZE, sp)
 	STI
 	.endm
 
+	.macro	__build_clear_msa_fpe
+	_cfcmsa	a1, MSA_CSR
+	li	a2, ~(0x3f << 12)
+	and	a1, a1, a2
+	_ctcmsa	MSA_CSR, a1
+	TRACE_IRQS_ON
+	STI
+	.endm
+
 	.macro	__build_clear_ade
 	MFC0	t0, CP0_BADVADDR
 	PTR_S	t0, PT_BVADDR(sp)
@@ -426,7 +435,7 @@ NESTED(nmi_handler, PT_SIZE, sp)
 	BUILD_HANDLER cpu cpu sti silent		/* #11 */
 	BUILD_HANDLER ov ov sti silent			/* #12 */
 	BUILD_HANDLER tr tr sti silent			/* #13 */
-	BUILD_HANDLER msa_fpe msa_fpe sti silent	/* #14 */
+	BUILD_HANDLER msa_fpe msa_fpe msa_fpe silent	/* #14 */
 	BUILD_HANDLER fpe fpe fpe silent		/* #15 */
 	BUILD_HANDLER ftlb ftlb none silent		/* #16 */
 	BUILD_HANDLER msa msa sti silent		/* #21 */
-- 
cgit v1.2.3


From ad70c13a938daf833cad86830f23865ee37aa5c7 Mon Sep 17 00:00:00 2001
From: Paul Burton <paul.burton@imgtec.com>
Date: Fri, 30 Jan 2015 12:09:35 +0000
Subject: MIPS: Ensure FCSR cause bits are clear after invoking FPU emulator

When running the emulator to handle an instruction that raised an FP
unimplemented operation exception, the FCSR cause bits were being
cleared. This is done to ensure that the kernel does not take an FP
exception when later restoring FP context to registers. However, this
was not being done when the emulator is invoked in response to a
coprocessor unusable exception. This happens in 2 cases:

  - There is no FPU present in the system. In this case things were
    OK, since the FP context is never restored to hardware registers
    and thus no FP exception may be raised when restoring FCSR.

  - The FPU could not be configured to the mode required by the task.
    In this case it would be possible for the emulator to set cause
    bits which are later restored to hardware if the task migrates
    to a CPU whose associated FPU does support its mode requirements,
    or if the tasks FP mode requirements change.

Consistently clear the cause bits after invoking the emulator, by moving
the clearing to process_fpemu_return and ensuring this is always called
before the tasks FP context is restored. This will make it easier to
catch further paths invoking the emulator in future, as will be
introduced in further patches.

Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/9165/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
---
 arch/mips/kernel/traps.c | 17 +++++++++--------
 1 file changed, 9 insertions(+), 8 deletions(-)

diff --git a/arch/mips/kernel/traps.c b/arch/mips/kernel/traps.c
index 33984c04b60b..8943ebe4d154 100644
--- a/arch/mips/kernel/traps.c
+++ b/arch/mips/kernel/traps.c
@@ -701,6 +701,13 @@ asmlinkage void do_ov(struct pt_regs *regs)
 
 int process_fpemu_return(int sig, void __user *fault_addr)
 {
+	/*
+	 * We can't allow the emulated instruction to leave any of the cause
+	 * bits set in FCSR. If they were then the kernel would take an FP
+	 * exception when restoring FP context.
+	 */
+	current->thread.fpu.fcr31 &= ~FPU_CSR_ALL_X;
+
 	if (sig == SIGSEGV || sig == SIGBUS) {
 		struct siginfo si = {0};
 		si.si_addr = fault_addr;
@@ -804,18 +811,12 @@ asmlinkage void do_fpe(struct pt_regs *regs, unsigned long fcr31)
 		sig = fpu_emulator_cop1Handler(regs, &current->thread.fpu, 1,
 					       &fault_addr);
 
-		/*
-		 * We can't allow the emulated instruction to leave any of
-		 * the cause bit set in $fcr31.
-		 */
-		current->thread.fpu.fcr31 &= ~FPU_CSR_ALL_X;
+		/* If something went wrong, signal */
+		process_fpemu_return(sig, fault_addr);
 
 		/* Restore the hardware register state */
 		own_fpu(1);	/* Using the FPU again.	 */
 
-		/* If something went wrong, signal */
-		process_fpemu_return(sig, fault_addr);
-
 		goto out;
 	} else if (fcr31 & FPU_CSR_INV_X)
 		info.si_code = FPE_FLTINV;
-- 
cgit v1.2.3


From ac9ad83bc318635ed7496e9dff30beaa522eaec7 Mon Sep 17 00:00:00 2001
From: Paul Burton <paul.burton@imgtec.com>
Date: Fri, 30 Jan 2015 12:09:36 +0000
Subject: MIPS: prevent FP context set via ptrace being discarded

If a ptracee has not used the FPU and the ptracer sets its FP context
using PTRACE_POKEUSR, PTRACE_SETFPREGS or PTRACE_SETREGSET then that
context will be discarded upon either the ptracee using the FPU or a
further write to the context via ptrace. Prevent this loss by recording
that the task has "used" math once its FP context has been written to.
The context initialisation code that was present for the PTRACE_POKEUSR
case is reused for the other 2 cases to provide consistent behaviour
for the different ptrace requests.

Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/9166/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
---
 arch/mips/kernel/ptrace.c | 30 ++++++++++++++++++++++++------
 1 file changed, 24 insertions(+), 6 deletions(-)

diff --git a/arch/mips/kernel/ptrace.c b/arch/mips/kernel/ptrace.c
index 510452812594..7da6e324dd35 100644
--- a/arch/mips/kernel/ptrace.c
+++ b/arch/mips/kernel/ptrace.c
@@ -46,6 +46,26 @@
 #define CREATE_TRACE_POINTS
 #include <trace/events/syscalls.h>
 
+static void init_fp_ctx(struct task_struct *target)
+{
+	/* If FP has been used then the target already has context */
+	if (tsk_used_math(target))
+		return;
+
+	/* Begin with data registers set to all 1s... */
+	memset(&target->thread.fpu.fpr, ~0, sizeof(target->thread.fpu.fpr));
+
+	/* ...and FCSR zeroed */
+	target->thread.fpu.fcr31 = 0;
+
+	/*
+	 * Record that the target has "used" math, such that the context
+	 * just initialised, and any modifications made by the caller,
+	 * aren't discarded.
+	 */
+	set_stopped_child_used_math(target);
+}
+
 /*
  * Called by kernel/ptrace.c when detaching..
  *
@@ -142,6 +162,7 @@ int ptrace_setfpregs(struct task_struct *child, __u32 __user *data)
 	if (!access_ok(VERIFY_READ, data, 33 * 8))
 		return -EIO;
 
+	init_fp_ctx(child);
 	fregs = get_fpu_regs(child);
 
 	for (i = 0; i < 32; i++) {
@@ -439,6 +460,8 @@ static int fpr_set(struct task_struct *target,
 
 	/* XXX fcr31  */
 
+	init_fp_ctx(target);
+
 	if (sizeof(target->thread.fpu.fpr[i]) == sizeof(elf_fpreg_t))
 		return user_regset_copyin(&pos, &count, &kbuf, &ubuf,
 					  &target->thread.fpu,
@@ -660,12 +683,7 @@ long arch_ptrace(struct task_struct *child, long request,
 		case FPR_BASE ... FPR_BASE + 31: {
 			union fpureg *fregs = get_fpu_regs(child);
 
-			if (!tsk_used_math(child)) {
-				/* FP not yet used  */
-				memset(&child->thread.fpu, ~0,
-				       sizeof(child->thread.fpu));
-				child->thread.fpu.fcr31 = 0;
-			}
+			init_fp_ctx(child);
 #ifdef CONFIG_32BIT
 			if (test_thread_flag(TIF_32BIT_FPREGS)) {
 				/*
-- 
cgit v1.2.3


From 84ab45b33858a87632e1f5e207e302bf48eaf52e Mon Sep 17 00:00:00 2001
From: Paul Burton <paul.burton@imgtec.com>
Date: Fri, 30 Jan 2015 12:09:37 +0000
Subject: MIPS: disable FPU if the mode is unsupported

The expected semantics of __enable_fpu are for the FPU to be enabled
in the given mode if possible, otherwise for the FPU to be left
disabled and SIGFPE returned. The FPU was incorrectly being left
enabled in cases where the desired value for FR was unavailable.
Without ensuring the FPU is disabled in this case, it would be
possible for userland to go on to execute further FP instructions
natively in the incorrect mode, rather than those instructions being
trapped & emulated as they need to be.

Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/9167/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
---
 arch/mips/include/asm/fpu.h | 19 ++++++++++++-------
 1 file changed, 12 insertions(+), 7 deletions(-)

diff --git a/arch/mips/include/asm/fpu.h b/arch/mips/include/asm/fpu.h
index 9f26b079cc6a..b104ad9d655f 100644
--- a/arch/mips/include/asm/fpu.h
+++ b/arch/mips/include/asm/fpu.h
@@ -48,6 +48,12 @@ enum fpu_mode {
 #define FPU_FR_MASK		0x1
 };
 
+#define __disable_fpu()							\
+do {									\
+	clear_c0_status(ST0_CU1);					\
+	disable_fpu_hazard();						\
+} while (0)
+
 static inline int __enable_fpu(enum fpu_mode mode)
 {
 	int fr;
@@ -86,7 +92,12 @@ fr_common:
 		enable_fpu_hazard();
 
 		/* check FR has the desired value */
-		return (!!(read_c0_status() & ST0_FR) == !!fr) ? 0 : SIGFPE;
+		if (!!(read_c0_status() & ST0_FR) == !!fr)
+			return 0;
+
+		/* unsupported FR value */
+		__disable_fpu();
+		return SIGFPE;
 
 	default:
 		BUG();
@@ -95,12 +106,6 @@ fr_common:
 	return SIGFPE;
 }
 
-#define __disable_fpu()							\
-do {									\
-	clear_c0_status(ST0_CU1);					\
-	disable_fpu_hazard();						\
-} while (0)
-
 #define clear_fpu_owner()	clear_thread_flag(TIF_USEDFPU)
 
 static inline int __is_fpu_owner(void)
-- 
cgit v1.2.3


From 466aec5f292be469e15b3dc3d17b731dab93727c Mon Sep 17 00:00:00 2001
From: James Hogan <james.hogan@imgtec.com>
Date: Fri, 30 Jan 2015 12:09:38 +0000
Subject: Revert "MIPS: Don't assume 64-bit FP registers for context switch"

This reverts commit 02987633df7ba2f62967791dda816eb191d1add3.

The basic premise of the patch was incorrect since MSA context
(including FP state) is saved using st.d which stores two consecutive
64-bit words in memory rather than a single 128-bit word. This means
that even with big endian MSA, the FP state is still in the first 64-bit
word.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/9168/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
---
 arch/mips/include/asm/asmmacro-32.h | 128 ++++++++++++++++++------------------
 arch/mips/include/asm/asmmacro.h    | 128 ++++++++++++++++++------------------
 arch/mips/kernel/asm-offsets.c      |  66 -------------------
 3 files changed, 128 insertions(+), 194 deletions(-)

diff --git a/arch/mips/include/asm/asmmacro-32.h b/arch/mips/include/asm/asmmacro-32.h
index cdac7b3eeaf7..80386470d3a4 100644
--- a/arch/mips/include/asm/asmmacro-32.h
+++ b/arch/mips/include/asm/asmmacro-32.h
@@ -16,38 +16,38 @@
 	.set push
 	SET_HARDFLOAT
 	cfc1	\tmp,  fcr31
-	swc1	$f0,  THREAD_FPR0_LS64(\thread)
-	swc1	$f1,  THREAD_FPR1_LS64(\thread)
-	swc1	$f2,  THREAD_FPR2_LS64(\thread)
-	swc1	$f3,  THREAD_FPR3_LS64(\thread)
-	swc1	$f4,  THREAD_FPR4_LS64(\thread)
-	swc1	$f5,  THREAD_FPR5_LS64(\thread)
-	swc1	$f6,  THREAD_FPR6_LS64(\thread)
-	swc1	$f7,  THREAD_FPR7_LS64(\thread)
-	swc1	$f8,  THREAD_FPR8_LS64(\thread)
-	swc1	$f9,  THREAD_FPR9_LS64(\thread)
-	swc1	$f10, THREAD_FPR10_LS64(\thread)
-	swc1	$f11, THREAD_FPR11_LS64(\thread)
-	swc1	$f12, THREAD_FPR12_LS64(\thread)
-	swc1	$f13, THREAD_FPR13_LS64(\thread)
-	swc1	$f14, THREAD_FPR14_LS64(\thread)
-	swc1	$f15, THREAD_FPR15_LS64(\thread)
-	swc1	$f16, THREAD_FPR16_LS64(\thread)
-	swc1	$f17, THREAD_FPR17_LS64(\thread)
-	swc1	$f18, THREAD_FPR18_LS64(\thread)
-	swc1	$f19, THREAD_FPR19_LS64(\thread)
-	swc1	$f20, THREAD_FPR20_LS64(\thread)
-	swc1	$f21, THREAD_FPR21_LS64(\thread)
-	swc1	$f22, THREAD_FPR22_LS64(\thread)
-	swc1	$f23, THREAD_FPR23_LS64(\thread)
-	swc1	$f24, THREAD_FPR24_LS64(\thread)
-	swc1	$f25, THREAD_FPR25_LS64(\thread)
-	swc1	$f26, THREAD_FPR26_LS64(\thread)
-	swc1	$f27, THREAD_FPR27_LS64(\thread)
-	swc1	$f28, THREAD_FPR28_LS64(\thread)
-	swc1	$f29, THREAD_FPR29_LS64(\thread)
-	swc1	$f30, THREAD_FPR30_LS64(\thread)
-	swc1	$f31, THREAD_FPR31_LS64(\thread)
+	swc1	$f0,  THREAD_FPR0(\thread)
+	swc1	$f1,  THREAD_FPR1(\thread)
+	swc1	$f2,  THREAD_FPR2(\thread)
+	swc1	$f3,  THREAD_FPR3(\thread)
+	swc1	$f4,  THREAD_FPR4(\thread)
+	swc1	$f5,  THREAD_FPR5(\thread)
+	swc1	$f6,  THREAD_FPR6(\thread)
+	swc1	$f7,  THREAD_FPR7(\thread)
+	swc1	$f8,  THREAD_FPR8(\thread)
+	swc1	$f9,  THREAD_FPR9(\thread)
+	swc1	$f10, THREAD_FPR10(\thread)
+	swc1	$f11, THREAD_FPR11(\thread)
+	swc1	$f12, THREAD_FPR12(\thread)
+	swc1	$f13, THREAD_FPR13(\thread)
+	swc1	$f14, THREAD_FPR14(\thread)
+	swc1	$f15, THREAD_FPR15(\thread)
+	swc1	$f16, THREAD_FPR16(\thread)
+	swc1	$f17, THREAD_FPR17(\thread)
+	swc1	$f18, THREAD_FPR18(\thread)
+	swc1	$f19, THREAD_FPR19(\thread)
+	swc1	$f20, THREAD_FPR20(\thread)
+	swc1	$f21, THREAD_FPR21(\thread)
+	swc1	$f22, THREAD_FPR22(\thread)
+	swc1	$f23, THREAD_FPR23(\thread)
+	swc1	$f24, THREAD_FPR24(\thread)
+	swc1	$f25, THREAD_FPR25(\thread)
+	swc1	$f26, THREAD_FPR26(\thread)
+	swc1	$f27, THREAD_FPR27(\thread)
+	swc1	$f28, THREAD_FPR28(\thread)
+	swc1	$f29, THREAD_FPR29(\thread)
+	swc1	$f30, THREAD_FPR30(\thread)
+	swc1	$f31, THREAD_FPR31(\thread)
 	sw	\tmp, THREAD_FCR31(\thread)
 	.set pop
 	.endm
@@ -56,38 +56,38 @@
 	.set push
 	SET_HARDFLOAT
 	lw	\tmp, THREAD_FCR31(\thread)
-	lwc1	$f0,  THREAD_FPR0_LS64(\thread)
-	lwc1	$f1,  THREAD_FPR1_LS64(\thread)
-	lwc1	$f2,  THREAD_FPR2_LS64(\thread)
-	lwc1	$f3,  THREAD_FPR3_LS64(\thread)
-	lwc1	$f4,  THREAD_FPR4_LS64(\thread)
-	lwc1	$f5,  THREAD_FPR5_LS64(\thread)
-	lwc1	$f6,  THREAD_FPR6_LS64(\thread)
-	lwc1	$f7,  THREAD_FPR7_LS64(\thread)
-	lwc1	$f8,  THREAD_FPR8_LS64(\thread)
-	lwc1	$f9,  THREAD_FPR9_LS64(\thread)
-	lwc1	$f10, THREAD_FPR10_LS64(\thread)
-	lwc1	$f11, THREAD_FPR11_LS64(\thread)
-	lwc1	$f12, THREAD_FPR12_LS64(\thread)
-	lwc1	$f13, THREAD_FPR13_LS64(\thread)
-	lwc1	$f14, THREAD_FPR14_LS64(\thread)
-	lwc1	$f15, THREAD_FPR15_LS64(\thread)
-	lwc1	$f16, THREAD_FPR16_LS64(\thread)
-	lwc1	$f17, THREAD_FPR17_LS64(\thread)
-	lwc1	$f18, THREAD_FPR18_LS64(\thread)
-	lwc1	$f19, THREAD_FPR19_LS64(\thread)
-	lwc1	$f20, THREAD_FPR20_LS64(\thread)
-	lwc1	$f21, THREAD_FPR21_LS64(\thread)
-	lwc1	$f22, THREAD_FPR22_LS64(\thread)
-	lwc1	$f23, THREAD_FPR23_LS64(\thread)
-	lwc1	$f24, THREAD_FPR24_LS64(\thread)
-	lwc1	$f25, THREAD_FPR25_LS64(\thread)
-	lwc1	$f26, THREAD_FPR26_LS64(\thread)
-	lwc1	$f27, THREAD_FPR27_LS64(\thread)
-	lwc1	$f28, THREAD_FPR28_LS64(\thread)
-	lwc1	$f29, THREAD_FPR29_LS64(\thread)
-	lwc1	$f30, THREAD_FPR30_LS64(\thread)
-	lwc1	$f31, THREAD_FPR31_LS64(\thread)
+	lwc1	$f0,  THREAD_FPR0(\thread)
+	lwc1	$f1,  THREAD_FPR1(\thread)
+	lwc1	$f2,  THREAD_FPR2(\thread)
+	lwc1	$f3,  THREAD_FPR3(\thread)
+	lwc1	$f4,  THREAD_FPR4(\thread)
+	lwc1	$f5,  THREAD_FPR5(\thread)
+	lwc1	$f6,  THREAD_FPR6(\thread)
+	lwc1	$f7,  THREAD_FPR7(\thread)
+	lwc1	$f8,  THREAD_FPR8(\thread)
+	lwc1	$f9,  THREAD_FPR9(\thread)
+	lwc1	$f10, THREAD_FPR10(\thread)
+	lwc1	$f11, THREAD_FPR11(\thread)
+	lwc1	$f12, THREAD_FPR12(\thread)
+	lwc1	$f13, THREAD_FPR13(\thread)
+	lwc1	$f14, THREAD_FPR14(\thread)
+	lwc1	$f15, THREAD_FPR15(\thread)
+	lwc1	$f16, THREAD_FPR16(\thread)
+	lwc1	$f17, THREAD_FPR17(\thread)
+	lwc1	$f18, THREAD_FPR18(\thread)
+	lwc1	$f19, THREAD_FPR19(\thread)
+	lwc1	$f20, THREAD_FPR20(\thread)
+	lwc1	$f21, THREAD_FPR21(\thread)
+	lwc1	$f22, THREAD_FPR22(\thread)
+	lwc1	$f23, THREAD_FPR23(\thread)
+	lwc1	$f24, THREAD_FPR24(\thread)
+	lwc1	$f25, THREAD_FPR25(\thread)
+	lwc1	$f26, THREAD_FPR26(\thread)
+	lwc1	$f27, THREAD_FPR27(\thread)
+	lwc1	$f28, THREAD_FPR28(\thread)
+	lwc1	$f29, THREAD_FPR29(\thread)
+	lwc1	$f30, THREAD_FPR30(\thread)
+	lwc1	$f31, THREAD_FPR31(\thread)
 	ctc1	\tmp, fcr31
 	.set pop
 	.endm
diff --git a/arch/mips/include/asm/asmmacro.h b/arch/mips/include/asm/asmmacro.h
index a64e424ace16..6156ac8c4cfb 100644
--- a/arch/mips/include/asm/asmmacro.h
+++ b/arch/mips/include/asm/asmmacro.h
@@ -60,22 +60,22 @@
 	.set	push
 	SET_HARDFLOAT
 	cfc1	\tmp, fcr31
-	sdc1	$f0,  THREAD_FPR0_LS64(\thread)
-	sdc1	$f2,  THREAD_FPR2_LS64(\thread)
-	sdc1	$f4,  THREAD_FPR4_LS64(\thread)
-	sdc1	$f6,  THREAD_FPR6_LS64(\thread)
-	sdc1	$f8,  THREAD_FPR8_LS64(\thread)
-	sdc1	$f10, THREAD_FPR10_LS64(\thread)
-	sdc1	$f12, THREAD_FPR12_LS64(\thread)
-	sdc1	$f14, THREAD_FPR14_LS64(\thread)
-	sdc1	$f16, THREAD_FPR16_LS64(\thread)
-	sdc1	$f18, THREAD_FPR18_LS64(\thread)
-	sdc1	$f20, THREAD_FPR20_LS64(\thread)
-	sdc1	$f22, THREAD_FPR22_LS64(\thread)
-	sdc1	$f24, THREAD_FPR24_LS64(\thread)
-	sdc1	$f26, THREAD_FPR26_LS64(\thread)
-	sdc1	$f28, THREAD_FPR28_LS64(\thread)
-	sdc1	$f30, THREAD_FPR30_LS64(\thread)
+	sdc1	$f0,  THREAD_FPR0(\thread)
+	sdc1	$f2,  THREAD_FPR2(\thread)
+	sdc1	$f4,  THREAD_FPR4(\thread)
+	sdc1	$f6,  THREAD_FPR6(\thread)
+	sdc1	$f8,  THREAD_FPR8(\thread)
+	sdc1	$f10, THREAD_FPR10(\thread)
+	sdc1	$f12, THREAD_FPR12(\thread)
+	sdc1	$f14, THREAD_FPR14(\thread)
+	sdc1	$f16, THREAD_FPR16(\thread)
+	sdc1	$f18, THREAD_FPR18(\thread)
+	sdc1	$f20, THREAD_FPR20(\thread)
+	sdc1	$f22, THREAD_FPR22(\thread)
+	sdc1	$f24, THREAD_FPR24(\thread)
+	sdc1	$f26, THREAD_FPR26(\thread)
+	sdc1	$f28, THREAD_FPR28(\thread)
+	sdc1	$f30, THREAD_FPR30(\thread)
 	sw	\tmp, THREAD_FCR31(\thread)
 	.set	pop
 	.endm
@@ -84,22 +84,22 @@
 	.set	push
 	.set	mips64r2
 	SET_HARDFLOAT
-	sdc1	$f1,  THREAD_FPR1_LS64(\thread)
-	sdc1	$f3,  THREAD_FPR3_LS64(\thread)
-	sdc1	$f5,  THREAD_FPR5_LS64(\thread)
-	sdc1	$f7,  THREAD_FPR7_LS64(\thread)
-	sdc1	$f9,  THREAD_FPR9_LS64(\thread)
-	sdc1	$f11, THREAD_FPR11_LS64(\thread)
-	sdc1	$f13, THREAD_FPR13_LS64(\thread)
-	sdc1	$f15, THREAD_FPR15_LS64(\thread)
-	sdc1	$f17, THREAD_FPR17_LS64(\thread)
-	sdc1	$f19, THREAD_FPR19_LS64(\thread)
-	sdc1	$f21, THREAD_FPR21_LS64(\thread)
-	sdc1	$f23, THREAD_FPR23_LS64(\thread)
-	sdc1	$f25, THREAD_FPR25_LS64(\thread)
-	sdc1	$f27, THREAD_FPR27_LS64(\thread)
-	sdc1	$f29, THREAD_FPR29_LS64(\thread)
-	sdc1	$f31, THREAD_FPR31_LS64(\thread)
+	sdc1	$f1,  THREAD_FPR1(\thread)
+	sdc1	$f3,  THREAD_FPR3(\thread)
+	sdc1	$f5,  THREAD_FPR5(\thread)
+	sdc1	$f7,  THREAD_FPR7(\thread)
+	sdc1	$f9,  THREAD_FPR9(\thread)
+	sdc1	$f11, THREAD_FPR11(\thread)
+	sdc1	$f13, THREAD_FPR13(\thread)
+	sdc1	$f15, THREAD_FPR15(\thread)
+	sdc1	$f17, THREAD_FPR17(\thread)
+	sdc1	$f19, THREAD_FPR19(\thread)
+	sdc1	$f21, THREAD_FPR21(\thread)
+	sdc1	$f23, THREAD_FPR23(\thread)
+	sdc1	$f25, THREAD_FPR25(\thread)
+	sdc1	$f27, THREAD_FPR27(\thread)
+	sdc1	$f29, THREAD_FPR29(\thread)
+	sdc1	$f31, THREAD_FPR31(\thread)
 	.set	pop
 	.endm
 
@@ -118,22 +118,22 @@
 	.set	push
 	SET_HARDFLOAT
 	lw	\tmp, THREAD_FCR31(\thread)
-	ldc1	$f0,  THREAD_FPR0_LS64(\thread)
-	ldc1	$f2,  THREAD_FPR2_LS64(\thread)
-	ldc1	$f4,  THREAD_FPR4_LS64(\thread)
-	ldc1	$f6,  THREAD_FPR6_LS64(\thread)
-	ldc1	$f8,  THREAD_FPR8_LS64(\thread)
-	ldc1	$f10, THREAD_FPR10_LS64(\thread)
-	ldc1	$f12, THREAD_FPR12_LS64(\thread)
-	ldc1	$f14, THREAD_FPR14_LS64(\thread)
-	ldc1	$f16, THREAD_FPR16_LS64(\thread)
-	ldc1	$f18, THREAD_FPR18_LS64(\thread)
-	ldc1	$f20, THREAD_FPR20_LS64(\thread)
-	ldc1	$f22, THREAD_FPR22_LS64(\thread)
-	ldc1	$f24, THREAD_FPR24_LS64(\thread)
-	ldc1	$f26, THREAD_FPR26_LS64(\thread)
-	ldc1	$f28, THREAD_FPR28_LS64(\thread)
-	ldc1	$f30, THREAD_FPR30_LS64(\thread)
+	ldc1	$f0,  THREAD_FPR0(\thread)
+	ldc1	$f2,  THREAD_FPR2(\thread)
+	ldc1	$f4,  THREAD_FPR4(\thread)
+	ldc1	$f6,  THREAD_FPR6(\thread)
+	ldc1	$f8,  THREAD_FPR8(\thread)
+	ldc1	$f10, THREAD_FPR10(\thread)
+	ldc1	$f12, THREAD_FPR12(\thread)
+	ldc1	$f14, THREAD_FPR14(\thread)
+	ldc1	$f16, THREAD_FPR16(\thread)
+	ldc1	$f18, THREAD_FPR18(\thread)
+	ldc1	$f20, THREAD_FPR20(\thread)
+	ldc1	$f22, THREAD_FPR22(\thread)
+	ldc1	$f24, THREAD_FPR24(\thread)
+	ldc1	$f26, THREAD_FPR26(\thread)
+	ldc1	$f28, THREAD_FPR28(\thread)
+	ldc1	$f30, THREAD_FPR30(\thread)
 	ctc1	\tmp, fcr31
 	.endm
 
@@ -141,22 +141,22 @@
 	.set	push
 	.set	mips64r2
 	SET_HARDFLOAT
-	ldc1	$f1,  THREAD_FPR1_LS64(\thread)
-	ldc1	$f3,  THREAD_FPR3_LS64(\thread)
-	ldc1	$f5,  THREAD_FPR5_LS64(\thread)
-	ldc1	$f7,  THREAD_FPR7_LS64(\thread)
-	ldc1	$f9,  THREAD_FPR9_LS64(\thread)
-	ldc1	$f11, THREAD_FPR11_LS64(\thread)
-	ldc1	$f13, THREAD_FPR13_LS64(\thread)
-	ldc1	$f15, THREAD_FPR15_LS64(\thread)
-	ldc1	$f17, THREAD_FPR17_LS64(\thread)
-	ldc1	$f19, THREAD_FPR19_LS64(\thread)
-	ldc1	$f21, THREAD_FPR21_LS64(\thread)
-	ldc1	$f23, THREAD_FPR23_LS64(\thread)
-	ldc1	$f25, THREAD_FPR25_LS64(\thread)
-	ldc1	$f27, THREAD_FPR27_LS64(\thread)
-	ldc1	$f29, THREAD_FPR29_LS64(\thread)
-	ldc1	$f31, THREAD_FPR31_LS64(\thread)
+	ldc1	$f1,  THREAD_FPR1(\thread)
+	ldc1	$f3,  THREAD_FPR3(\thread)
+	ldc1	$f5,  THREAD_FPR5(\thread)
+	ldc1	$f7,  THREAD_FPR7(\thread)
+	ldc1	$f9,  THREAD_FPR9(\thread)
+	ldc1	$f11, THREAD_FPR11(\thread)
+	ldc1	$f13, THREAD_FPR13(\thread)
+	ldc1	$f15, THREAD_FPR15(\thread)
+	ldc1	$f17, THREAD_FPR17(\thread)
+	ldc1	$f19, THREAD_FPR19(\thread)
+	ldc1	$f21, THREAD_FPR21(\thread)
+	ldc1	$f23, THREAD_FPR23(\thread)
+	ldc1	$f25, THREAD_FPR25(\thread)
+	ldc1	$f27, THREAD_FPR27(\thread)
+	ldc1	$f29, THREAD_FPR29(\thread)
+	ldc1	$f31, THREAD_FPR31(\thread)
 	.set	pop
 	.endm
 
diff --git a/arch/mips/kernel/asm-offsets.c b/arch/mips/kernel/asm-offsets.c
index 750d67ac41e9..3ee1565c5be3 100644
--- a/arch/mips/kernel/asm-offsets.c
+++ b/arch/mips/kernel/asm-offsets.c
@@ -167,72 +167,6 @@ void output_thread_fpu_defines(void)
 	OFFSET(THREAD_FPR30, task_struct, thread.fpu.fpr[30]);
 	OFFSET(THREAD_FPR31, task_struct, thread.fpu.fpr[31]);
 
-	/* the least significant 64 bits of each FP register */
-	OFFSET(THREAD_FPR0_LS64, task_struct,
-	       thread.fpu.fpr[0].val64[FPR_IDX(64, 0)]);
-	OFFSET(THREAD_FPR1_LS64, task_struct,
-	       thread.fpu.fpr[1].val64[FPR_IDX(64, 0)]);
-	OFFSET(THREAD_FPR2_LS64, task_struct,
-	       thread.fpu.fpr[2].val64[FPR_IDX(64, 0)]);
-	OFFSET(THREAD_FPR3_LS64, task_struct,
-	       thread.fpu.fpr[3].val64[FPR_IDX(64, 0)]);
-	OFFSET(THREAD_FPR4_LS64, task_struct,
-	       thread.fpu.fpr[4].val64[FPR_IDX(64, 0)]);
-	OFFSET(THREAD_FPR5_LS64, task_struct,
-	       thread.fpu.fpr[5].val64[FPR_IDX(64, 0)]);
-	OFFSET(THREAD_FPR6_LS64, task_struct,
-	       thread.fpu.fpr[6].val64[FPR_IDX(64, 0)]);
-	OFFSET(THREAD_FPR7_LS64, task_struct,
-	       thread.fpu.fpr[7].val64[FPR_IDX(64, 0)]);
-	OFFSET(THREAD_FPR8_LS64, task_struct,
-	       thread.fpu.fpr[8].val64[FPR_IDX(64, 0)]);
-	OFFSET(THREAD_FPR9_LS64, task_struct,
-	       thread.fpu.fpr[9].val64[FPR_IDX(64, 0)]);
-	OFFSET(THREAD_FPR10_LS64, task_struct,
-	       thread.fpu.fpr[10].val64[FPR_IDX(64, 0)]);
-	OFFSET(THREAD_FPR11_LS64, task_struct,
-	       thread.fpu.fpr[11].val64[FPR_IDX(64, 0)]);
-	OFFSET(THREAD_FPR12_LS64, task_struct,
-	       thread.fpu.fpr[12].val64[FPR_IDX(64, 0)]);
-	OFFSET(THREAD_FPR13_LS64, task_struct,
-	       thread.fpu.fpr[13].val64[FPR_IDX(64, 0)]);
-	OFFSET(THREAD_FPR14_LS64, task_struct,
-	       thread.fpu.fpr[14].val64[FPR_IDX(64, 0)]);
-	OFFSET(THREAD_FPR15_LS64, task_struct,
-	       thread.fpu.fpr[15].val64[FPR_IDX(64, 0)]);
-	OFFSET(THREAD_FPR16_LS64, task_struct,
-	       thread.fpu.fpr[16].val64[FPR_IDX(64, 0)]);
-	OFFSET(THREAD_FPR17_LS64, task_struct,
-	       thread.fpu.fpr[17].val64[FPR_IDX(64, 0)]);
-	OFFSET(THREAD_FPR18_LS64, task_struct,
-	       thread.fpu.fpr[18].val64[FPR_IDX(64, 0)]);
-	OFFSET(THREAD_FPR19_LS64, task_struct,
-	       thread.fpu.fpr[19].val64[FPR_IDX(64, 0)]);
-	OFFSET(THREAD_FPR20_LS64, task_struct,
-	       thread.fpu.fpr[20].val64[FPR_IDX(64, 0)]);
-	OFFSET(THREAD_FPR21_LS64, task_struct,
-	       thread.fpu.fpr[21].val64[FPR_IDX(64, 0)]);
-	OFFSET(THREAD_FPR22_LS64, task_struct,
-	       thread.fpu.fpr[22].val64[FPR_IDX(64, 0)]);
-	OFFSET(THREAD_FPR23_LS64, task_struct,
-	       thread.fpu.fpr[23].val64[FPR_IDX(64, 0)]);
-	OFFSET(THREAD_FPR24_LS64, task_struct,
-	       thread.fpu.fpr[24].val64[FPR_IDX(64, 0)]);
-	OFFSET(THREAD_FPR25_LS64, task_struct,
-	       thread.fpu.fpr[25].val64[FPR_IDX(64, 0)]);
-	OFFSET(THREAD_FPR26_LS64, task_struct,
-	       thread.fpu.fpr[26].val64[FPR_IDX(64, 0)]);
-	OFFSET(THREAD_FPR27_LS64, task_struct,
-	       thread.fpu.fpr[27].val64[FPR_IDX(64, 0)]);
-	OFFSET(THREAD_FPR28_LS64, task_struct,
-	       thread.fpu.fpr[28].val64[FPR_IDX(64, 0)]);
-	OFFSET(THREAD_FPR29_LS64, task_struct,
-	       thread.fpu.fpr[29].val64[FPR_IDX(64, 0)]);
-	OFFSET(THREAD_FPR30_LS64, task_struct,
-	       thread.fpu.fpr[30].val64[FPR_IDX(64, 0)]);
-	OFFSET(THREAD_FPR31_LS64, task_struct,
-	       thread.fpu.fpr[31].val64[FPR_IDX(64, 0)]);
-
 	OFFSET(THREAD_FCR31, task_struct, thread.fpu.fcr31);
 	OFFSET(THREAD_MSA_CSR, task_struct, thread.fpu.msacsr);
 	BLANK();
-- 
cgit v1.2.3


From 1f3a2c6e229ccb8df8115b04d16ad4832767cf3a Mon Sep 17 00:00:00 2001
From: James Hogan <james.hogan@imgtec.com>
Date: Fri, 30 Jan 2015 12:09:39 +0000
Subject: MIPS: MSA: Fix big-endian FPR_IDX implementation

The maximum word size is 64-bits since MSA state is saved using st.d
which stores two 64-bit words, therefore reimplement FPR_IDX using xor,
and only within each 64-bit word.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/9169/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
---
 arch/mips/include/asm/processor.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/mips/include/asm/processor.h b/arch/mips/include/asm/processor.h
index b5dcbee01fd7..9b3b48e21c22 100644
--- a/arch/mips/include/asm/processor.h
+++ b/arch/mips/include/asm/processor.h
@@ -105,7 +105,7 @@ union fpureg {
 #ifdef CONFIG_CPU_LITTLE_ENDIAN
 # define FPR_IDX(width, idx)	(idx)
 #else
-# define FPR_IDX(width, idx)	((FPU_REG_WIDTH / (width)) - 1 - (idx))
+# define FPR_IDX(width, idx)	((idx) ^ ((64 / (width)) - 1))
 #endif
 
 #define BUILD_FPR_ACCESS(width) \
-- 
cgit v1.2.3


From 98119ad53376885819d93dfb8737b6a9a61ca0ba Mon Sep 17 00:00:00 2001
From: James Hogan <james.hogan@imgtec.com>
Date: Fri, 6 Feb 2015 11:11:56 +0000
Subject: MIPS: KVM: Handle MSA Disabled exceptions from guest

Guest user mode can generate a guest MSA Disabled exception on an MSA
capable core by simply trying to execute an MSA instruction. Since this
exception is unknown to KVM it will be passed on to the guest kernel.
However guest Linux kernels prior to v3.15 do not set up an exception
handler for the MSA Disabled exception as they don't support any MSA
capable cores. This results in a guest OS panic.

Since an older processor ID may be being emulated, and MSA support is
not advertised to the guest, the correct behaviour is to generate a
Reserved Instruction exception in the guest kernel so it can send the
guest process an illegal instruction signal (SIGILL), as would happen
with a non-MSA-capable core.

Fix this as minimally as reasonably possible by preventing
kvm_mips_check_privilege() from relaying MSA Disabled exceptions from
guest user mode to the guest kernel, and handling the MSA Disabled
exception by emulating a Reserved Instruction exception in the guest,
via a new handle_msa_disabled() KVM callback.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Paul Burton <paul.burton@imgtec.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Gleb Natapov <gleb@kernel.org>
Cc: linux-mips@linux-mips.org
Cc: kvm@vger.kernel.org
Cc: <stable@vger.kernel.org> # v3.15+
---
 arch/mips/include/asm/kvm_host.h |  2 ++
 arch/mips/kvm/emulate.c          |  1 +
 arch/mips/kvm/mips.c             |  4 ++++
 arch/mips/kvm/trap_emul.c        | 28 ++++++++++++++++++++++++++++
 4 files changed, 35 insertions(+)

diff --git a/arch/mips/include/asm/kvm_host.h b/arch/mips/include/asm/kvm_host.h
index ac4fc716062b..f722b0528c25 100644
--- a/arch/mips/include/asm/kvm_host.h
+++ b/arch/mips/include/asm/kvm_host.h
@@ -322,6 +322,7 @@ enum mips_mmu_types {
 #define T_TRAP			13	/* Trap instruction */
 #define T_VCEI			14	/* Virtual coherency exception */
 #define T_FPE			15	/* Floating point exception */
+#define T_MSADIS		21	/* MSA disabled exception */
 #define T_WATCH			23	/* Watch address reference */
 #define T_VCED			31	/* Virtual coherency data */
 
@@ -578,6 +579,7 @@ struct kvm_mips_callbacks {
 	int (*handle_syscall)(struct kvm_vcpu *vcpu);
 	int (*handle_res_inst)(struct kvm_vcpu *vcpu);
 	int (*handle_break)(struct kvm_vcpu *vcpu);
+	int (*handle_msa_disabled)(struct kvm_vcpu *vcpu);
 	int (*vm_init)(struct kvm *kvm);
 	int (*vcpu_init)(struct kvm_vcpu *vcpu);
 	int (*vcpu_setup)(struct kvm_vcpu *vcpu);
diff --git a/arch/mips/kvm/emulate.c b/arch/mips/kvm/emulate.c
index fb3e8dfd1ff6..838d3a6a5b7d 100644
--- a/arch/mips/kvm/emulate.c
+++ b/arch/mips/kvm/emulate.c
@@ -2176,6 +2176,7 @@ enum emulation_result kvm_mips_check_privilege(unsigned long cause,
 		case T_SYSCALL:
 		case T_BREAK:
 		case T_RES_INST:
+		case T_MSADIS:
 			break;
 
 		case T_COP_UNUSABLE:
diff --git a/arch/mips/kvm/mips.c b/arch/mips/kvm/mips.c
index c9eccf5df912..f5e7ddab02f7 100644
--- a/arch/mips/kvm/mips.c
+++ b/arch/mips/kvm/mips.c
@@ -1119,6 +1119,10 @@ int kvm_mips_handle_exit(struct kvm_run *run, struct kvm_vcpu *vcpu)
 		ret = kvm_mips_callbacks->handle_break(vcpu);
 		break;
 
+	case T_MSADIS:
+		ret = kvm_mips_callbacks->handle_msa_disabled(vcpu);
+		break;
+
 	default:
 		kvm_err("Exception Code: %d, not yet handled, @ PC: %p, inst: 0x%08x  BadVaddr: %#lx Status: %#lx\n",
 			exccode, opc, kvm_get_inst(opc, vcpu), badvaddr,
diff --git a/arch/mips/kvm/trap_emul.c b/arch/mips/kvm/trap_emul.c
index fd7257b70e65..4372cc86650c 100644
--- a/arch/mips/kvm/trap_emul.c
+++ b/arch/mips/kvm/trap_emul.c
@@ -330,6 +330,33 @@ static int kvm_trap_emul_handle_break(struct kvm_vcpu *vcpu)
 	return ret;
 }
 
+static int kvm_trap_emul_handle_msa_disabled(struct kvm_vcpu *vcpu)
+{
+	struct kvm_run *run = vcpu->run;
+	uint32_t __user *opc = (uint32_t __user *) vcpu->arch.pc;
+	unsigned long cause = vcpu->arch.host_cp0_cause;
+	enum emulation_result er = EMULATE_DONE;
+	int ret = RESUME_GUEST;
+
+	/* No MSA supported in guest, guest reserved instruction exception */
+	er = kvm_mips_emulate_ri_exc(cause, opc, run, vcpu);
+
+	switch (er) {
+	case EMULATE_DONE:
+		ret = RESUME_GUEST;
+		break;
+
+	case EMULATE_FAIL:
+		run->exit_reason = KVM_EXIT_INTERNAL_ERROR;
+		ret = RESUME_HOST;
+		break;
+
+	default:
+		BUG();
+	}
+	return ret;
+}
+
 static int kvm_trap_emul_vm_init(struct kvm *kvm)
 {
 	return 0;
@@ -470,6 +497,7 @@ static struct kvm_mips_callbacks kvm_trap_emul_callbacks = {
 	.handle_syscall = kvm_trap_emul_handle_syscall,
 	.handle_res_inst = kvm_trap_emul_handle_res_inst,
 	.handle_break = kvm_trap_emul_handle_break,
+	.handle_msa_disabled = kvm_trap_emul_handle_msa_disabled,
 
 	.vm_init = kvm_trap_emul_vm_init,
 	.vcpu_init = kvm_trap_emul_vcpu_init,
-- 
cgit v1.2.3


From 64bedffe496820dbb6b53302d80dd0f04db33d8e Mon Sep 17 00:00:00 2001
From: James Hogan <james.hogan@imgtec.com>
Date: Tue, 2 Dec 2014 13:44:13 +0000
Subject: MIPS: Clear [MSA]FPE CSR.Cause after notify_die()

When handling floating point exceptions (FPEs) and MSA FPEs the Cause
bits of the appropriate control and status register (FCSR for FPEs and
MSACSR for MSA FPEs) are read and cleared before enabling interrupts,
presumably so that it doesn't have to go through the pain of restoring
those bits if the process is pre-empted, since writing those bits would
cause another immediate exception while still in the kernel.

The bits aren't normally ever restored again, since userland never
expects to see them set.

However for virtualisation it is necessary for the kernel to be able to
restore these Cause bits, as the guest may have been interrupted in an
FP exception handler but before it could read the Cause bits. This can
be done by registering a die notifier, to get notified of the exception
when such a value is restored, and if the PC was at the instruction
which is used to restore the guest state, the handler can step over it
and continue execution. The Cause bits can then remain set without
causing further exceptions.

For this to work safely a few changes are made:
- __build_clear_fpe and __build_clear_msa_fpe no longer clear the Cause
  bits, and now return from exception level with interrupts disabled
  instead of enabled.
- do_fpe() now clears the Cause bits and enables interrupts after
  notify_die() is called, so that the notifier can chose to return from
  exception without this happening.
- do_msa_fpe() acts similarly, but now actually makes use of the second
  argument (msacsr) and calls notify_die() with the new DIE_MSAFP,
  allowing die notifiers to be informed of MSA FPEs too.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Acked-by: Ralf Baechle <ralf@linux-mips.org>
Cc: Paul Burton <paul.burton@imgtec.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Gleb Natapov <gleb@kernel.org>
Cc: linux-mips@linux-mips.org
Cc: kvm@vger.kernel.org
---
 arch/mips/include/asm/kdebug.h |  3 ++-
 arch/mips/kernel/genex.S       | 14 ++++----------
 arch/mips/kernel/traps.c       | 16 +++++++++++++++-
 3 files changed, 21 insertions(+), 12 deletions(-)

diff --git a/arch/mips/include/asm/kdebug.h b/arch/mips/include/asm/kdebug.h
index 6a9af5fcb5d7..cba22ab7ad4d 100644
--- a/arch/mips/include/asm/kdebug.h
+++ b/arch/mips/include/asm/kdebug.h
@@ -10,7 +10,8 @@ enum die_val {
 	DIE_RI,
 	DIE_PAGE_FAULT,
 	DIE_BREAK,
-	DIE_SSTEPBP
+	DIE_SSTEPBP,
+	DIE_MSAFP
 };
 
 #endif /* _ASM_MIPS_KDEBUG_H */
diff --git a/arch/mips/kernel/genex.S b/arch/mips/kernel/genex.S
index 86e22422d08c..af42e7003f12 100644
--- a/arch/mips/kernel/genex.S
+++ b/arch/mips/kernel/genex.S
@@ -360,21 +360,15 @@ NESTED(nmi_handler, PT_SIZE, sp)
 	.set	mips1
 	SET_HARDFLOAT
 	cfc1	a1, fcr31
-	li	a2, ~(0x3f << 12)
-	and	a2, a1
-	ctc1	a2, fcr31
 	.set	pop
-	TRACE_IRQS_ON
-	STI
+	CLI
+	TRACE_IRQS_OFF
 	.endm
 
 	.macro	__build_clear_msa_fpe
 	_cfcmsa	a1, MSA_CSR
-	li	a2, ~(0x3f << 12)
-	and	a1, a1, a2
-	_ctcmsa	MSA_CSR, a1
-	TRACE_IRQS_ON
-	STI
+	CLI
+	TRACE_IRQS_OFF
 	.endm
 
 	.macro	__build_clear_ade
diff --git a/arch/mips/kernel/traps.c b/arch/mips/kernel/traps.c
index 8943ebe4d154..5b4d711f878d 100644
--- a/arch/mips/kernel/traps.c
+++ b/arch/mips/kernel/traps.c
@@ -788,6 +788,11 @@ asmlinkage void do_fpe(struct pt_regs *regs, unsigned long fcr31)
 	if (notify_die(DIE_FP, "FP exception", regs, 0, regs_to_trapnr(regs),
 		       SIGFPE) == NOTIFY_STOP)
 		goto out;
+
+	/* Clear FCSR.Cause before enabling interrupts */
+	write_32bit_cp1_register(CP1_STATUS, fcr31 & ~FPU_CSR_ALL_X);
+	local_irq_enable();
+
 	die_if_kernel("FP exception in kernel code", regs);
 
 	if (fcr31 & FPU_CSR_UNI_X) {
@@ -1393,13 +1398,22 @@ out:
 	exception_exit(prev_state);
 }
 
-asmlinkage void do_msa_fpe(struct pt_regs *regs)
+asmlinkage void do_msa_fpe(struct pt_regs *regs, unsigned int msacsr)
 {
 	enum ctx_state prev_state;
 
 	prev_state = exception_enter();
+	if (notify_die(DIE_MSAFP, "MSA FP exception", regs, 0,
+		       regs_to_trapnr(regs), SIGFPE) == NOTIFY_STOP)
+		goto out;
+
+	/* Clear MSACSR.Cause before enabling interrupts */
+	write_msa_csr(msacsr & ~MSA_CSR_CAUSEF);
+	local_irq_enable();
+
 	die_if_kernel("do_msa_fpe invoked from kernel context!", regs);
 	force_sig(SIGFPE, current);
+out:
 	exception_exit(prev_state);
 }
 
-- 
cgit v1.2.3


From 0a5604272d80c985f87de959f0bb7e36fd53d3c7 Mon Sep 17 00:00:00 2001
From: James Hogan <james.hogan@imgtec.com>
Date: Fri, 6 Feb 2015 16:03:57 +0000
Subject: MIPS: KVM: Handle TRAP exceptions from guest kernel

Trap instructions are used by Linux to implement BUG_ON(), however KVM
doesn't pass trap exceptions on to the guest if they occur in guest
kernel mode, instead triggering an internal error "Exception Code: 13,
not yet handled". The guest kernel then doesn't get a chance to print
the usual BUG message and stack trace.

Implement handling of the trap exception so that it gets passed to the
guest and the user is left with a more useful log message.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Gleb Natapov <gleb@kernel.org>
Cc: kvm@vger.kernel.org
Cc: linux-mips@linux-mips.org
---
 arch/mips/include/asm/kvm_host.h |  8 ++++++++
 arch/mips/kvm/emulate.c          | 36 ++++++++++++++++++++++++++++++++++++
 arch/mips/kvm/mips.c             |  7 +++++++
 arch/mips/kvm/stats.c            |  1 +
 arch/mips/kvm/trap_emul.c        | 19 +++++++++++++++++++
 5 files changed, 71 insertions(+)

diff --git a/arch/mips/include/asm/kvm_host.h b/arch/mips/include/asm/kvm_host.h
index f722b0528c25..8fc3ba2872f0 100644
--- a/arch/mips/include/asm/kvm_host.h
+++ b/arch/mips/include/asm/kvm_host.h
@@ -119,6 +119,7 @@ struct kvm_vcpu_stat {
 	u32 syscall_exits;
 	u32 resvd_inst_exits;
 	u32 break_inst_exits;
+	u32 trap_inst_exits;
 	u32 flush_dcache_exits;
 	u32 halt_successful_poll;
 	u32 halt_wakeup;
@@ -138,6 +139,7 @@ enum kvm_mips_exit_types {
 	SYSCALL_EXITS,
 	RESVD_INST_EXITS,
 	BREAK_INST_EXITS,
+	TRAP_INST_EXITS,
 	FLUSH_DCACHE_EXITS,
 	MAX_KVM_MIPS_EXIT_TYPES
 };
@@ -579,6 +581,7 @@ struct kvm_mips_callbacks {
 	int (*handle_syscall)(struct kvm_vcpu *vcpu);
 	int (*handle_res_inst)(struct kvm_vcpu *vcpu);
 	int (*handle_break)(struct kvm_vcpu *vcpu);
+	int (*handle_trap)(struct kvm_vcpu *vcpu);
 	int (*handle_msa_disabled)(struct kvm_vcpu *vcpu);
 	int (*vm_init)(struct kvm *kvm);
 	int (*vcpu_init)(struct kvm_vcpu *vcpu);
@@ -713,6 +716,11 @@ extern enum emulation_result kvm_mips_emulate_bp_exc(unsigned long cause,
 						     struct kvm_run *run,
 						     struct kvm_vcpu *vcpu);
 
+extern enum emulation_result kvm_mips_emulate_trap_exc(unsigned long cause,
+						       uint32_t *opc,
+						       struct kvm_run *run,
+						       struct kvm_vcpu *vcpu);
+
 extern enum emulation_result kvm_mips_complete_mmio_load(struct kvm_vcpu *vcpu,
 							 struct kvm_run *run);
 
diff --git a/arch/mips/kvm/emulate.c b/arch/mips/kvm/emulate.c
index 838d3a6a5b7d..33e132dc7de8 100644
--- a/arch/mips/kvm/emulate.c
+++ b/arch/mips/kvm/emulate.c
@@ -1970,6 +1970,41 @@ enum emulation_result kvm_mips_emulate_bp_exc(unsigned long cause,
 	return er;
 }
 
+enum emulation_result kvm_mips_emulate_trap_exc(unsigned long cause,
+						uint32_t *opc,
+						struct kvm_run *run,
+						struct kvm_vcpu *vcpu)
+{
+	struct mips_coproc *cop0 = vcpu->arch.cop0;
+	struct kvm_vcpu_arch *arch = &vcpu->arch;
+	enum emulation_result er = EMULATE_DONE;
+
+	if ((kvm_read_c0_guest_status(cop0) & ST0_EXL) == 0) {
+		/* save old pc */
+		kvm_write_c0_guest_epc(cop0, arch->pc);
+		kvm_set_c0_guest_status(cop0, ST0_EXL);
+
+		if (cause & CAUSEF_BD)
+			kvm_set_c0_guest_cause(cop0, CAUSEF_BD);
+		else
+			kvm_clear_c0_guest_cause(cop0, CAUSEF_BD);
+
+		kvm_debug("Delivering TRAP @ pc %#lx\n", arch->pc);
+
+		kvm_change_c0_guest_cause(cop0, (0xff),
+					  (T_TRAP << CAUSEB_EXCCODE));
+
+		/* Set PC to the exception entry point */
+		arch->pc = KVM_GUEST_KSEG0 + 0x180;
+
+	} else {
+		kvm_err("Trying to deliver TRAP when EXL is already set\n");
+		er = EMULATE_FAIL;
+	}
+
+	return er;
+}
+
 /* ll/sc, rdhwr, sync emulation */
 
 #define OPCODE 0xfc000000
@@ -2176,6 +2211,7 @@ enum emulation_result kvm_mips_check_privilege(unsigned long cause,
 		case T_SYSCALL:
 		case T_BREAK:
 		case T_RES_INST:
+		case T_TRAP:
 		case T_MSADIS:
 			break;
 
diff --git a/arch/mips/kvm/mips.c b/arch/mips/kvm/mips.c
index f5e7ddab02f7..399b5517ecb8 100644
--- a/arch/mips/kvm/mips.c
+++ b/arch/mips/kvm/mips.c
@@ -48,6 +48,7 @@ struct kvm_stats_debugfs_item debugfs_entries[] = {
 	{ "syscall",	  VCPU_STAT(syscall_exits),	 KVM_STAT_VCPU },
 	{ "resvd_inst",	  VCPU_STAT(resvd_inst_exits),	 KVM_STAT_VCPU },
 	{ "break_inst",	  VCPU_STAT(break_inst_exits),	 KVM_STAT_VCPU },
+	{ "trap_inst",	  VCPU_STAT(trap_inst_exits),	 KVM_STAT_VCPU },
 	{ "flush_dcache", VCPU_STAT(flush_dcache_exits), KVM_STAT_VCPU },
 	{ "halt_successful_poll", VCPU_STAT(halt_successful_poll), KVM_STAT_VCPU },
 	{ "halt_wakeup",  VCPU_STAT(halt_wakeup),	 KVM_STAT_VCPU },
@@ -1119,6 +1120,12 @@ int kvm_mips_handle_exit(struct kvm_run *run, struct kvm_vcpu *vcpu)
 		ret = kvm_mips_callbacks->handle_break(vcpu);
 		break;
 
+	case T_TRAP:
+		++vcpu->stat.trap_inst_exits;
+		trace_kvm_exit(vcpu, TRAP_INST_EXITS);
+		ret = kvm_mips_callbacks->handle_trap(vcpu);
+		break;
+
 	case T_MSADIS:
 		ret = kvm_mips_callbacks->handle_msa_disabled(vcpu);
 		break;
diff --git a/arch/mips/kvm/stats.c b/arch/mips/kvm/stats.c
index a74d6024c5ad..dd90b0a92181 100644
--- a/arch/mips/kvm/stats.c
+++ b/arch/mips/kvm/stats.c
@@ -25,6 +25,7 @@ char *kvm_mips_exit_types_str[MAX_KVM_MIPS_EXIT_TYPES] = {
 	"System Call",
 	"Reserved Inst",
 	"Break Inst",
+	"Trap Inst",
 	"D-Cache Flushes",
 };
 
diff --git a/arch/mips/kvm/trap_emul.c b/arch/mips/kvm/trap_emul.c
index 4372cc86650c..dc019950e243 100644
--- a/arch/mips/kvm/trap_emul.c
+++ b/arch/mips/kvm/trap_emul.c
@@ -330,6 +330,24 @@ static int kvm_trap_emul_handle_break(struct kvm_vcpu *vcpu)
 	return ret;
 }
 
+static int kvm_trap_emul_handle_trap(struct kvm_vcpu *vcpu)
+{
+	struct kvm_run *run = vcpu->run;
+	uint32_t __user *opc = (uint32_t __user *)vcpu->arch.pc;
+	unsigned long cause = vcpu->arch.host_cp0_cause;
+	enum emulation_result er = EMULATE_DONE;
+	int ret = RESUME_GUEST;
+
+	er = kvm_mips_emulate_trap_exc(cause, opc, run, vcpu);
+	if (er == EMULATE_DONE) {
+		ret = RESUME_GUEST;
+	} else {
+		run->exit_reason = KVM_EXIT_INTERNAL_ERROR;
+		ret = RESUME_HOST;
+	}
+	return ret;
+}
+
 static int kvm_trap_emul_handle_msa_disabled(struct kvm_vcpu *vcpu)
 {
 	struct kvm_run *run = vcpu->run;
@@ -497,6 +515,7 @@ static struct kvm_mips_callbacks kvm_trap_emul_callbacks = {
 	.handle_syscall = kvm_trap_emul_handle_syscall,
 	.handle_res_inst = kvm_trap_emul_handle_res_inst,
 	.handle_break = kvm_trap_emul_handle_break,
+	.handle_trap = kvm_trap_emul_handle_trap,
 	.handle_msa_disabled = kvm_trap_emul_handle_msa_disabled,
 
 	.vm_init = kvm_trap_emul_vm_init,
-- 
cgit v1.2.3


From 1068eaaf2f64ffb44d97fbaa9ff7a4662b76cf9e Mon Sep 17 00:00:00 2001
From: James Hogan <james.hogan@imgtec.com>
Date: Thu, 26 Jun 2014 13:56:52 +0100
Subject: MIPS: KVM: Implement PRid CP0 register access

Implement access to the guest Processor Identification CP0 register
using the KVM_GET_ONE_REG and KVM_SET_ONE_REG ioctls. This allows the
owning process to modify and read back the value that is exposed to the
guest in this register.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Gleb Natapov <gleb@kernel.org>
Cc: linux-mips@linux-mips.org
Cc: kvm@vger.kernel.org
---
 Documentation/virtual/kvm/api.txt | 1 +
 arch/mips/include/asm/kvm_host.h  | 1 +
 arch/mips/kvm/mips.c              | 7 +++++++
 3 files changed, 9 insertions(+)

diff --git a/Documentation/virtual/kvm/api.txt b/Documentation/virtual/kvm/api.txt
index 0d7fc66289a0..9a5f8a482db1 100644
--- a/Documentation/virtual/kvm/api.txt
+++ b/Documentation/virtual/kvm/api.txt
@@ -1967,6 +1967,7 @@ registers, find a list below:
   MIPS  | KVM_REG_MIPS_CP0_STATUS       | 32
   MIPS  | KVM_REG_MIPS_CP0_CAUSE        | 32
   MIPS  | KVM_REG_MIPS_CP0_EPC          | 64
+  MIPS  | KVM_REG_MIPS_CP0_PRID         | 32
   MIPS  | KVM_REG_MIPS_CP0_CONFIG       | 32
   MIPS  | KVM_REG_MIPS_CP0_CONFIG1      | 32
   MIPS  | KVM_REG_MIPS_CP0_CONFIG2      | 32
diff --git a/arch/mips/include/asm/kvm_host.h b/arch/mips/include/asm/kvm_host.h
index 8fc3ba2872f0..26d91b0f3c3c 100644
--- a/arch/mips/include/asm/kvm_host.h
+++ b/arch/mips/include/asm/kvm_host.h
@@ -42,6 +42,7 @@
 #define KVM_REG_MIPS_CP0_STATUS		MIPS_CP0_32(12, 0)
 #define KVM_REG_MIPS_CP0_CAUSE		MIPS_CP0_32(13, 0)
 #define KVM_REG_MIPS_CP0_EPC		MIPS_CP0_64(14, 0)
+#define KVM_REG_MIPS_CP0_PRID		MIPS_CP0_32(15, 0)
 #define KVM_REG_MIPS_CP0_EBASE		MIPS_CP0_64(15, 1)
 #define KVM_REG_MIPS_CP0_CONFIG		MIPS_CP0_32(16, 0)
 #define KVM_REG_MIPS_CP0_CONFIG1	MIPS_CP0_32(16, 1)
diff --git a/arch/mips/kvm/mips.c b/arch/mips/kvm/mips.c
index 399b5517ecb8..fd620cc8a44c 100644
--- a/arch/mips/kvm/mips.c
+++ b/arch/mips/kvm/mips.c
@@ -505,6 +505,7 @@ static u64 kvm_mips_get_one_regs[] = {
 	KVM_REG_MIPS_CP0_STATUS,
 	KVM_REG_MIPS_CP0_CAUSE,
 	KVM_REG_MIPS_CP0_EPC,
+	KVM_REG_MIPS_CP0_PRID,
 	KVM_REG_MIPS_CP0_CONFIG,
 	KVM_REG_MIPS_CP0_CONFIG1,
 	KVM_REG_MIPS_CP0_CONFIG2,
@@ -574,6 +575,9 @@ static int kvm_mips_get_reg(struct kvm_vcpu *vcpu,
 	case KVM_REG_MIPS_CP0_EPC:
 		v = (long)kvm_read_c0_guest_epc(cop0);
 		break;
+	case KVM_REG_MIPS_CP0_PRID:
+		v = (long)kvm_read_c0_guest_prid(cop0);
+		break;
 	case KVM_REG_MIPS_CP0_ERROREPC:
 		v = (long)kvm_read_c0_guest_errorepc(cop0);
 		break;
@@ -687,6 +691,9 @@ static int kvm_mips_set_reg(struct kvm_vcpu *vcpu,
 	case KVM_REG_MIPS_CP0_EPC:
 		kvm_write_c0_guest_epc(cop0, v);
 		break;
+	case KVM_REG_MIPS_CP0_PRID:
+		kvm_write_c0_guest_prid(cop0, v);
+		break;
 	case KVM_REG_MIPS_CP0_ERROREPC:
 		kvm_write_c0_guest_errorepc(cop0, v);
 		break;
-- 
cgit v1.2.3


From e93d4c159caaf746422c1af4c4f09fce9b456f8c Mon Sep 17 00:00:00 2001
From: James Hogan <james.hogan@imgtec.com>
Date: Thu, 26 Jun 2014 13:47:22 +0100
Subject: MIPS: KVM: Sort kvm_mips_get_reg() registers

Sort the registers in the kvm_mips_get_reg() switch by register number,
which puts ERROREPC after the CONFIG registers.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Gleb Natapov <gleb@kernel.org>
Cc: linux-mips@linux-mips.org
Cc: kvm@vger.kernel.org
---
 arch/mips/kvm/mips.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/arch/mips/kvm/mips.c b/arch/mips/kvm/mips.c
index fd620cc8a44c..b909c0046f08 100644
--- a/arch/mips/kvm/mips.c
+++ b/arch/mips/kvm/mips.c
@@ -578,9 +578,6 @@ static int kvm_mips_get_reg(struct kvm_vcpu *vcpu,
 	case KVM_REG_MIPS_CP0_PRID:
 		v = (long)kvm_read_c0_guest_prid(cop0);
 		break;
-	case KVM_REG_MIPS_CP0_ERROREPC:
-		v = (long)kvm_read_c0_guest_errorepc(cop0);
-		break;
 	case KVM_REG_MIPS_CP0_CONFIG:
 		v = (long)kvm_read_c0_guest_config(cop0);
 		break;
@@ -596,6 +593,9 @@ static int kvm_mips_get_reg(struct kvm_vcpu *vcpu,
 	case KVM_REG_MIPS_CP0_CONFIG7:
 		v = (long)kvm_read_c0_guest_config7(cop0);
 		break;
+	case KVM_REG_MIPS_CP0_ERROREPC:
+		v = (long)kvm_read_c0_guest_errorepc(cop0);
+		break;
 	/* registers to be handled specially */
 	case KVM_REG_MIPS_CP0_COUNT:
 	case KVM_REG_MIPS_COUNT_CTL:
-- 
cgit v1.2.3


From 58a115bcec06f2de26923bc13e88cb73b780ae41 Mon Sep 17 00:00:00 2001
From: James Hogan <james.hogan@imgtec.com>
Date: Thu, 26 Jun 2014 15:21:11 +0100
Subject: MIPS: KVM: Drop pr_info messages on init/exit

The information messages when the KVM module is loaded and unloaded are
a bit pointless and out of line with other architectures, so lets drop
them.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Gleb Natapov <gleb@kernel.org>
Cc: linux-mips@linux-mips.org
Cc: kvm@vger.kernel.org
---
 arch/mips/kvm/mips.c | 3 ---
 1 file changed, 3 deletions(-)

diff --git a/arch/mips/kvm/mips.c b/arch/mips/kvm/mips.c
index b909c0046f08..0aab83d894ba 100644
--- a/arch/mips/kvm/mips.c
+++ b/arch/mips/kvm/mips.c
@@ -1191,7 +1191,6 @@ int __init kvm_mips_init(void)
 	kvm_mips_release_pfn_clean = kvm_release_pfn_clean;
 	kvm_mips_is_error_pfn = is_error_pfn;
 
-	pr_info("KVM/MIPS Initialized\n");
 	return 0;
 }
 
@@ -1202,8 +1201,6 @@ void __exit kvm_mips_exit(void)
 	kvm_mips_gfn_to_pfn = NULL;
 	kvm_mips_release_pfn_clean = NULL;
 	kvm_mips_is_error_pfn = NULL;
-
-	pr_info("KVM/MIPS unloaded\n");
 }
 
 module_init(kvm_mips_init);
-- 
cgit v1.2.3


From 7bd4acec42670a18b023392db6f4bfaa4dee179e Mon Sep 17 00:00:00 2001
From: James Hogan <james.hogan@imgtec.com>
Date: Tue, 2 Dec 2014 15:47:04 +0000
Subject: MIPS: KVM: Clean up register definitions a little

Clean up KVM_GET_ONE_REG / KVM_SET_ONE_REG register definitions for
MIPS, to prepare for adding a new group for FPU & MSA vector registers.

Definitions are added for common bits in each group of registers, e.g.
KVM_REG_MIPS_CP0 = KVM_REG_MIPS | 0x10000, for the coprocessor 0
registers.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Gleb Natapov <gleb@kernel.org>
Cc: linux-mips@linux-mips.org
Cc: kvm@vger.kernel.org
---
 arch/mips/include/asm/kvm_host.h |   4 +-
 arch/mips/include/uapi/asm/kvm.h | 119 ++++++++++++++++++++++-----------------
 2 files changed, 68 insertions(+), 55 deletions(-)

diff --git a/arch/mips/include/asm/kvm_host.h b/arch/mips/include/asm/kvm_host.h
index 26d91b0f3c3c..1bd392d3a35b 100644
--- a/arch/mips/include/asm/kvm_host.h
+++ b/arch/mips/include/asm/kvm_host.h
@@ -21,10 +21,10 @@
 
 /* MIPS KVM register ids */
 #define MIPS_CP0_32(_R, _S)					\
-	(KVM_REG_MIPS | KVM_REG_SIZE_U32 | 0x10000 | (8 * (_R) + (_S)))
+	(KVM_REG_MIPS_CP0 | KVM_REG_SIZE_U32 | (8 * (_R) + (_S)))
 
 #define MIPS_CP0_64(_R, _S)					\
-	(KVM_REG_MIPS | KVM_REG_SIZE_U64 | 0x10000 | (8 * (_R) + (_S)))
+	(KVM_REG_MIPS_CP0 | KVM_REG_SIZE_U64 | (8 * (_R) + (_S)))
 
 #define KVM_REG_MIPS_CP0_INDEX		MIPS_CP0_32(0, 0)
 #define KVM_REG_MIPS_CP0_ENTRYLO0	MIPS_CP0_64(2, 0)
diff --git a/arch/mips/include/uapi/asm/kvm.h b/arch/mips/include/uapi/asm/kvm.h
index 2c04b6d9ff85..75d6d8557e57 100644
--- a/arch/mips/include/uapi/asm/kvm.h
+++ b/arch/mips/include/uapi/asm/kvm.h
@@ -52,61 +52,76 @@ struct kvm_fpu {
 
 
 /*
- * For MIPS, we use KVM_SET_ONE_REG and KVM_GET_ONE_REG to access CP0
+ * For MIPS, we use KVM_SET_ONE_REG and KVM_GET_ONE_REG to access various
  * registers.  The id field is broken down as follows:
  *
- *  bits[2..0]   - Register 'sel' index.
- *  bits[7..3]   - Register 'rd'  index.
- *  bits[15..8]  - Must be zero.
- *  bits[31..16] - 1 -> CP0 registers.
- *  bits[51..32] - Must be zero.
  *  bits[63..52] - As per linux/kvm.h
+ *  bits[51..32] - Must be zero.
+ *  bits[31..16] - Register set.
+ *
+ * Register set = 0: GP registers from kvm_regs (see definitions below).
+ *
+ * Register set = 1: CP0 registers.
+ *  bits[15..8]  - Must be zero.
+ *  bits[7..3]   - Register 'rd'  index.
+ *  bits[2..0]   - Register 'sel' index.
+ *
+ * Register set = 2: KVM specific registers (see definitions below).
  *
  * Other sets registers may be added in the future.  Each set would
  * have its own identifier in bits[31..16].
- *
- * The registers defined in struct kvm_regs are also accessible, the
- * id values for these are below.
  */
 
-#define KVM_REG_MIPS_R0 (KVM_REG_MIPS | KVM_REG_SIZE_U64 | 0)
-#define KVM_REG_MIPS_R1 (KVM_REG_MIPS | KVM_REG_SIZE_U64 | 1)
-#define KVM_REG_MIPS_R2 (KVM_REG_MIPS | KVM_REG_SIZE_U64 | 2)
-#define KVM_REG_MIPS_R3 (KVM_REG_MIPS | KVM_REG_SIZE_U64 | 3)
-#define KVM_REG_MIPS_R4 (KVM_REG_MIPS | KVM_REG_SIZE_U64 | 4)
-#define KVM_REG_MIPS_R5 (KVM_REG_MIPS | KVM_REG_SIZE_U64 | 5)
-#define KVM_REG_MIPS_R6 (KVM_REG_MIPS | KVM_REG_SIZE_U64 | 6)
-#define KVM_REG_MIPS_R7 (KVM_REG_MIPS | KVM_REG_SIZE_U64 | 7)
-#define KVM_REG_MIPS_R8 (KVM_REG_MIPS | KVM_REG_SIZE_U64 | 8)
-#define KVM_REG_MIPS_R9 (KVM_REG_MIPS | KVM_REG_SIZE_U64 | 9)
-#define KVM_REG_MIPS_R10 (KVM_REG_MIPS | KVM_REG_SIZE_U64 | 10)
-#define KVM_REG_MIPS_R11 (KVM_REG_MIPS | KVM_REG_SIZE_U64 | 11)
-#define KVM_REG_MIPS_R12 (KVM_REG_MIPS | KVM_REG_SIZE_U64 | 12)
-#define KVM_REG_MIPS_R13 (KVM_REG_MIPS | KVM_REG_SIZE_U64 | 13)
-#define KVM_REG_MIPS_R14 (KVM_REG_MIPS | KVM_REG_SIZE_U64 | 14)
-#define KVM_REG_MIPS_R15 (KVM_REG_MIPS | KVM_REG_SIZE_U64 | 15)
-#define KVM_REG_MIPS_R16 (KVM_REG_MIPS | KVM_REG_SIZE_U64 | 16)
-#define KVM_REG_MIPS_R17 (KVM_REG_MIPS | KVM_REG_SIZE_U64 | 17)
-#define KVM_REG_MIPS_R18 (KVM_REG_MIPS | KVM_REG_SIZE_U64 | 18)
-#define KVM_REG_MIPS_R19 (KVM_REG_MIPS | KVM_REG_SIZE_U64 | 19)
-#define KVM_REG_MIPS_R20 (KVM_REG_MIPS | KVM_REG_SIZE_U64 | 20)
-#define KVM_REG_MIPS_R21 (KVM_REG_MIPS | KVM_REG_SIZE_U64 | 21)
-#define KVM_REG_MIPS_R22 (KVM_REG_MIPS | KVM_REG_SIZE_U64 | 22)
-#define KVM_REG_MIPS_R23 (KVM_REG_MIPS | KVM_REG_SIZE_U64 | 23)
-#define KVM_REG_MIPS_R24 (KVM_REG_MIPS | KVM_REG_SIZE_U64 | 24)
-#define KVM_REG_MIPS_R25 (KVM_REG_MIPS | KVM_REG_SIZE_U64 | 25)
-#define KVM_REG_MIPS_R26 (KVM_REG_MIPS | KVM_REG_SIZE_U64 | 26)
-#define KVM_REG_MIPS_R27 (KVM_REG_MIPS | KVM_REG_SIZE_U64 | 27)
-#define KVM_REG_MIPS_R28 (KVM_REG_MIPS | KVM_REG_SIZE_U64 | 28)
-#define KVM_REG_MIPS_R29 (KVM_REG_MIPS | KVM_REG_SIZE_U64 | 29)
-#define KVM_REG_MIPS_R30 (KVM_REG_MIPS | KVM_REG_SIZE_U64 | 30)
-#define KVM_REG_MIPS_R31 (KVM_REG_MIPS | KVM_REG_SIZE_U64 | 31)
-
-#define KVM_REG_MIPS_HI (KVM_REG_MIPS | KVM_REG_SIZE_U64 | 32)
-#define KVM_REG_MIPS_LO (KVM_REG_MIPS | KVM_REG_SIZE_U64 | 33)
-#define KVM_REG_MIPS_PC (KVM_REG_MIPS | KVM_REG_SIZE_U64 | 34)
-
-/* KVM specific control registers */
+#define KVM_REG_MIPS_GP		(KVM_REG_MIPS | 0x0000000000000000ULL)
+#define KVM_REG_MIPS_CP0	(KVM_REG_MIPS | 0x0000000000010000ULL)
+#define KVM_REG_MIPS_KVM	(KVM_REG_MIPS | 0x0000000000020000ULL)
+
+
+/*
+ * KVM_REG_MIPS_GP - General purpose registers from kvm_regs.
+ */
+
+#define KVM_REG_MIPS_R0		(KVM_REG_MIPS_GP | KVM_REG_SIZE_U64 |  0)
+#define KVM_REG_MIPS_R1		(KVM_REG_MIPS_GP | KVM_REG_SIZE_U64 |  1)
+#define KVM_REG_MIPS_R2		(KVM_REG_MIPS_GP | KVM_REG_SIZE_U64 |  2)
+#define KVM_REG_MIPS_R3		(KVM_REG_MIPS_GP | KVM_REG_SIZE_U64 |  3)
+#define KVM_REG_MIPS_R4		(KVM_REG_MIPS_GP | KVM_REG_SIZE_U64 |  4)
+#define KVM_REG_MIPS_R5		(KVM_REG_MIPS_GP | KVM_REG_SIZE_U64 |  5)
+#define KVM_REG_MIPS_R6		(KVM_REG_MIPS_GP | KVM_REG_SIZE_U64 |  6)
+#define KVM_REG_MIPS_R7		(KVM_REG_MIPS_GP | KVM_REG_SIZE_U64 |  7)
+#define KVM_REG_MIPS_R8		(KVM_REG_MIPS_GP | KVM_REG_SIZE_U64 |  8)
+#define KVM_REG_MIPS_R9		(KVM_REG_MIPS_GP | KVM_REG_SIZE_U64 |  9)
+#define KVM_REG_MIPS_R10	(KVM_REG_MIPS_GP | KVM_REG_SIZE_U64 | 10)
+#define KVM_REG_MIPS_R11	(KVM_REG_MIPS_GP | KVM_REG_SIZE_U64 | 11)
+#define KVM_REG_MIPS_R12	(KVM_REG_MIPS_GP | KVM_REG_SIZE_U64 | 12)
+#define KVM_REG_MIPS_R13	(KVM_REG_MIPS_GP | KVM_REG_SIZE_U64 | 13)
+#define KVM_REG_MIPS_R14	(KVM_REG_MIPS_GP | KVM_REG_SIZE_U64 | 14)
+#define KVM_REG_MIPS_R15	(KVM_REG_MIPS_GP | KVM_REG_SIZE_U64 | 15)
+#define KVM_REG_MIPS_R16	(KVM_REG_MIPS_GP | KVM_REG_SIZE_U64 | 16)
+#define KVM_REG_MIPS_R17	(KVM_REG_MIPS_GP | KVM_REG_SIZE_U64 | 17)
+#define KVM_REG_MIPS_R18	(KVM_REG_MIPS_GP | KVM_REG_SIZE_U64 | 18)
+#define KVM_REG_MIPS_R19	(KVM_REG_MIPS_GP | KVM_REG_SIZE_U64 | 19)
+#define KVM_REG_MIPS_R20	(KVM_REG_MIPS_GP | KVM_REG_SIZE_U64 | 20)
+#define KVM_REG_MIPS_R21	(KVM_REG_MIPS_GP | KVM_REG_SIZE_U64 | 21)
+#define KVM_REG_MIPS_R22	(KVM_REG_MIPS_GP | KVM_REG_SIZE_U64 | 22)
+#define KVM_REG_MIPS_R23	(KVM_REG_MIPS_GP | KVM_REG_SIZE_U64 | 23)
+#define KVM_REG_MIPS_R24	(KVM_REG_MIPS_GP | KVM_REG_SIZE_U64 | 24)
+#define KVM_REG_MIPS_R25	(KVM_REG_MIPS_GP | KVM_REG_SIZE_U64 | 25)
+#define KVM_REG_MIPS_R26	(KVM_REG_MIPS_GP | KVM_REG_SIZE_U64 | 26)
+#define KVM_REG_MIPS_R27	(KVM_REG_MIPS_GP | KVM_REG_SIZE_U64 | 27)
+#define KVM_REG_MIPS_R28	(KVM_REG_MIPS_GP | KVM_REG_SIZE_U64 | 28)
+#define KVM_REG_MIPS_R29	(KVM_REG_MIPS_GP | KVM_REG_SIZE_U64 | 29)
+#define KVM_REG_MIPS_R30	(KVM_REG_MIPS_GP | KVM_REG_SIZE_U64 | 30)
+#define KVM_REG_MIPS_R31	(KVM_REG_MIPS_GP | KVM_REG_SIZE_U64 | 31)
+
+#define KVM_REG_MIPS_HI		(KVM_REG_MIPS_GP | KVM_REG_SIZE_U64 | 32)
+#define KVM_REG_MIPS_LO		(KVM_REG_MIPS_GP | KVM_REG_SIZE_U64 | 33)
+#define KVM_REG_MIPS_PC		(KVM_REG_MIPS_GP | KVM_REG_SIZE_U64 | 34)
+
+
+/*
+ * KVM_REG_MIPS_KVM - KVM specific control registers.
+ */
 
 /*
  * CP0_Count control
@@ -118,8 +133,7 @@ struct kvm_fpu {
  *        safely without losing time or guest timer interrupts.
  * Other: Reserved, do not change.
  */
-#define KVM_REG_MIPS_COUNT_CTL		(KVM_REG_MIPS | KVM_REG_SIZE_U64 | \
-					 0x20000 | 0)
+#define KVM_REG_MIPS_COUNT_CTL	    (KVM_REG_MIPS_KVM | KVM_REG_SIZE_U64 | 0)
 #define KVM_REG_MIPS_COUNT_CTL_DC	0x00000001
 
 /*
@@ -131,15 +145,14 @@ struct kvm_fpu {
  * emulated.
  * Modifications to times in the future are rejected.
  */
-#define KVM_REG_MIPS_COUNT_RESUME	(KVM_REG_MIPS | KVM_REG_SIZE_U64 | \
-					 0x20000 | 1)
+#define KVM_REG_MIPS_COUNT_RESUME   (KVM_REG_MIPS_KVM | KVM_REG_SIZE_U64 | 1)
 /*
  * CP0_Count rate in Hz
  * Specifies the rate of the CP0_Count timer in Hz. Modifications occur without
  * discontinuities in CP0_Count.
  */
-#define KVM_REG_MIPS_COUNT_HZ		(KVM_REG_MIPS | KVM_REG_SIZE_U64 | \
-					 0x20000 | 2)
+#define KVM_REG_MIPS_COUNT_HZ	    (KVM_REG_MIPS_KVM | KVM_REG_SIZE_U64 | 2)
+
 
 /*
  * KVM MIPS specific structures and definitions
-- 
cgit v1.2.3


From 2211ee810ac6fdcdb42b7a126e20d1b4e5c55124 Mon Sep 17 00:00:00 2001
From: James Hogan <james.hogan@imgtec.com>
Date: Wed, 4 Mar 2015 15:56:47 +0000
Subject: MIPS: KVM: Simplify default guest Config registers

Various semi-used definitions exist in kvm_host.h for the default guest
config registers. Remove them and use the appropriate values directly
when initialising the Config registers.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Gleb Natapov <gleb@kernel.org>
Cc: linux-mips@linux-mips.org
Cc: kvm@vger.kernel.org
---
 arch/mips/include/asm/kvm_host.h | 25 -------------------------
 arch/mips/kvm/trap_emul.c        | 15 +++++++++------
 2 files changed, 9 insertions(+), 31 deletions(-)

diff --git a/arch/mips/include/asm/kvm_host.h b/arch/mips/include/asm/kvm_host.h
index 1bd392d3a35b..6996447fd2a7 100644
--- a/arch/mips/include/asm/kvm_host.h
+++ b/arch/mips/include/asm/kvm_host.h
@@ -265,31 +265,6 @@ struct mips_coproc {
 #define CP0C3_SM		1
 #define CP0C3_TL		0
 
-/* Have config1, Cacheable, noncoherent, write-back, write allocate*/
-#define MIPS_CONFIG0						\
-  ((1 << CP0C0_M) | (0x3 << CP0C0_K0))
-
-/* Have config2, no coprocessor2 attached, no MDMX support attached,
-   no performance counters, watch registers present,
-   no code compression, EJTAG present, no FPU, no watch registers */
-#define MIPS_CONFIG1						\
-((1 << CP0C1_M) |						\
- (0 << CP0C1_C2) | (0 << CP0C1_MD) | (0 << CP0C1_PC) |		\
- (0 << CP0C1_WR) | (0 << CP0C1_CA) | (1 << CP0C1_EP) |		\
- (0 << CP0C1_FP))
-
-/* Have config3, no tertiary/secondary caches implemented */
-#define MIPS_CONFIG2						\
-((1 << CP0C2_M))
-
-/* No config4, no DSP ASE, no large physaddr (PABITS),
-   no external interrupt controller, no vectored interrupts,
-   no 1kb pages, no SmartMIPS ASE, no trace logic */
-#define MIPS_CONFIG3						\
-((0 << CP0C3_M) | (0 << CP0C3_DSPP) | (0 << CP0C3_LPA) |	\
- (0 << CP0C3_VEIC) | (0 << CP0C3_VInt) | (0 << CP0C3_SP) |	\
- (0 << CP0C3_SM) | (0 << CP0C3_TL))
-
 /* MMU types, the first four entries have the same layout as the
    CP0C0_MT field.  */
 enum mips_mmu_types {
diff --git a/arch/mips/kvm/trap_emul.c b/arch/mips/kvm/trap_emul.c
index dc019950e243..bffba002d1a4 100644
--- a/arch/mips/kvm/trap_emul.c
+++ b/arch/mips/kvm/trap_emul.c
@@ -396,8 +396,9 @@ static int kvm_trap_emul_vcpu_setup(struct kvm_vcpu *vcpu)
 	 * guest will come up as expected, for now we simulate a MIPS 24kc
 	 */
 	kvm_write_c0_guest_prid(cop0, 0x00019300);
-	kvm_write_c0_guest_config(cop0,
-				  MIPS_CONFIG0 | (0x1 << CP0C0_AR) |
+	/* Have config1, Cacheable, noncoherent, write-back, write allocate */
+	kvm_write_c0_guest_config(cop0, MIPS_CONF_M | (0x3 << CP0C0_K0) |
+				  (0x1 << CP0C0_AR) |
 				  (MMU_TYPE_R4000 << CP0C0_MT));
 
 	/* Read the cache characteristics from the host Config1 Register */
@@ -413,10 +414,12 @@ static int kvm_trap_emul_vcpu_setup(struct kvm_vcpu *vcpu)
 	      (1 << CP0C1_WR) | (1 << CP0C1_CA));
 	kvm_write_c0_guest_config1(cop0, config1);
 
-	kvm_write_c0_guest_config2(cop0, MIPS_CONFIG2);
-	/* MIPS_CONFIG2 | (read_c0_config2() & 0xfff) */
-	kvm_write_c0_guest_config3(cop0, MIPS_CONFIG3 | (0 << CP0C3_VInt) |
-					 (1 << CP0C3_ULRI));
+	/* Have config3, no tertiary/secondary caches implemented */
+	kvm_write_c0_guest_config2(cop0, MIPS_CONF_M);
+	/* MIPS_CONF_M | (read_c0_config2() & 0xfff) */
+
+	/* No config4, UserLocal */
+	kvm_write_c0_guest_config3(cop0, MIPS_CONF3_ULRI);
 
 	/* Set Wait IE/IXMT Ignore in Config7, IAR, AR */
 	kvm_write_c0_guest_config7(cop0, (MIPS_CONF7_WII) | (1 << 10));
-- 
cgit v1.2.3


From c771607af959f282704268a209743560d3264eb3 Mon Sep 17 00:00:00 2001
From: James Hogan <james.hogan@imgtec.com>
Date: Thu, 26 Jun 2014 15:11:29 +0100
Subject: MIPS: KVM: Add Config4/5 and writing of Config registers

Add Config4 and Config5 co-processor 0 registers, and add capability to
write the Config1, Config3, Config4, and Config5 registers using the KVM
API.

Only supported bits can be written, to minimise the chances of the guest
being given a configuration from e.g. QEMU that is inconsistent with
that being emulated, and as such the handling is in trap_emul.c as it
may need to be different for VZ. Currently the only modification
permitted is to make Config4 and Config5 exist via the M bits, but other
bits will be added for FPU and MSA support in future patches.

Care should be taken by userland not to change bits without fully
handling the possible extra state that may then exist and which the
guest may begin to use and depend on.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Gleb Natapov <gleb@kernel.org>
Cc: linux-mips@linux-mips.org
Cc: kvm@vger.kernel.org
---
 Documentation/virtual/kvm/api.txt |  2 ++
 arch/mips/include/asm/kvm_host.h  | 13 ++++++++++
 arch/mips/kvm/emulate.c           | 52 +++++++++++++++++++++++++++++++++++++++
 arch/mips/kvm/mips.c              | 14 +++++++++++
 arch/mips/kvm/trap_emul.c         | 49 ++++++++++++++++++++++++++++++++++--
 5 files changed, 128 insertions(+), 2 deletions(-)

diff --git a/Documentation/virtual/kvm/api.txt b/Documentation/virtual/kvm/api.txt
index 9a5f8a482db1..3f295a04b09f 100644
--- a/Documentation/virtual/kvm/api.txt
+++ b/Documentation/virtual/kvm/api.txt
@@ -1972,6 +1972,8 @@ registers, find a list below:
   MIPS  | KVM_REG_MIPS_CP0_CONFIG1      | 32
   MIPS  | KVM_REG_MIPS_CP0_CONFIG2      | 32
   MIPS  | KVM_REG_MIPS_CP0_CONFIG3      | 32
+  MIPS  | KVM_REG_MIPS_CP0_CONFIG4      | 32
+  MIPS  | KVM_REG_MIPS_CP0_CONFIG5      | 32
   MIPS  | KVM_REG_MIPS_CP0_CONFIG7      | 32
   MIPS  | KVM_REG_MIPS_CP0_ERROREPC     | 64
   MIPS  | KVM_REG_MIPS_COUNT_CTL        | 64
diff --git a/arch/mips/include/asm/kvm_host.h b/arch/mips/include/asm/kvm_host.h
index 6996447fd2a7..3f58ee1ebfab 100644
--- a/arch/mips/include/asm/kvm_host.h
+++ b/arch/mips/include/asm/kvm_host.h
@@ -48,6 +48,8 @@
 #define KVM_REG_MIPS_CP0_CONFIG1	MIPS_CP0_32(16, 1)
 #define KVM_REG_MIPS_CP0_CONFIG2	MIPS_CP0_32(16, 2)
 #define KVM_REG_MIPS_CP0_CONFIG3	MIPS_CP0_32(16, 3)
+#define KVM_REG_MIPS_CP0_CONFIG4	MIPS_CP0_32(16, 4)
+#define KVM_REG_MIPS_CP0_CONFIG5	MIPS_CP0_32(16, 5)
 #define KVM_REG_MIPS_CP0_CONFIG7	MIPS_CP0_32(16, 7)
 #define KVM_REG_MIPS_CP0_XCONTEXT	MIPS_CP0_64(20, 0)
 #define KVM_REG_MIPS_CP0_ERROREPC	MIPS_CP0_64(30, 0)
@@ -209,6 +211,8 @@ struct mips_coproc {
 #define MIPS_CP0_CONFIG1_SEL	1
 #define MIPS_CP0_CONFIG2_SEL	2
 #define MIPS_CP0_CONFIG3_SEL	3
+#define MIPS_CP0_CONFIG4_SEL	4
+#define MIPS_CP0_CONFIG5_SEL	5
 
 /* Config0 register bits */
 #define CP0C0_M			31
@@ -461,11 +465,15 @@ struct kvm_vcpu_arch {
 #define kvm_read_c0_guest_config1(cop0)		(cop0->reg[MIPS_CP0_CONFIG][1])
 #define kvm_read_c0_guest_config2(cop0)		(cop0->reg[MIPS_CP0_CONFIG][2])
 #define kvm_read_c0_guest_config3(cop0)		(cop0->reg[MIPS_CP0_CONFIG][3])
+#define kvm_read_c0_guest_config4(cop0)		(cop0->reg[MIPS_CP0_CONFIG][4])
+#define kvm_read_c0_guest_config5(cop0)		(cop0->reg[MIPS_CP0_CONFIG][5])
 #define kvm_read_c0_guest_config7(cop0)		(cop0->reg[MIPS_CP0_CONFIG][7])
 #define kvm_write_c0_guest_config(cop0, val)	(cop0->reg[MIPS_CP0_CONFIG][0] = (val))
 #define kvm_write_c0_guest_config1(cop0, val)	(cop0->reg[MIPS_CP0_CONFIG][1] = (val))
 #define kvm_write_c0_guest_config2(cop0, val)	(cop0->reg[MIPS_CP0_CONFIG][2] = (val))
 #define kvm_write_c0_guest_config3(cop0, val)	(cop0->reg[MIPS_CP0_CONFIG][3] = (val))
+#define kvm_write_c0_guest_config4(cop0, val)	(cop0->reg[MIPS_CP0_CONFIG][4] = (val))
+#define kvm_write_c0_guest_config5(cop0, val)	(cop0->reg[MIPS_CP0_CONFIG][5] = (val))
 #define kvm_write_c0_guest_config7(cop0, val)	(cop0->reg[MIPS_CP0_CONFIG][7] = (val))
 #define kvm_read_c0_guest_errorepc(cop0)	(cop0->reg[MIPS_CP0_ERROR_PC][0])
 #define kvm_write_c0_guest_errorepc(cop0, val)	(cop0->reg[MIPS_CP0_ERROR_PC][0] = (val))
@@ -735,6 +743,11 @@ enum emulation_result kvm_mips_emulate_load(uint32_t inst,
 					    struct kvm_run *run,
 					    struct kvm_vcpu *vcpu);
 
+unsigned int kvm_mips_config1_wrmask(struct kvm_vcpu *vcpu);
+unsigned int kvm_mips_config3_wrmask(struct kvm_vcpu *vcpu);
+unsigned int kvm_mips_config4_wrmask(struct kvm_vcpu *vcpu);
+unsigned int kvm_mips_config5_wrmask(struct kvm_vcpu *vcpu);
+
 /* Dynamic binary translation */
 extern int kvm_mips_trans_cache_index(uint32_t inst, uint32_t *opc,
 				      struct kvm_vcpu *vcpu);
diff --git a/arch/mips/kvm/emulate.c b/arch/mips/kvm/emulate.c
index 33e132dc7de8..91d5b0e370b4 100644
--- a/arch/mips/kvm/emulate.c
+++ b/arch/mips/kvm/emulate.c
@@ -884,6 +884,58 @@ enum emulation_result kvm_mips_emul_tlbp(struct kvm_vcpu *vcpu)
 	return EMULATE_DONE;
 }
 
+/**
+ * kvm_mips_config1_wrmask() - Find mask of writable bits in guest Config1
+ * @vcpu:	Virtual CPU.
+ *
+ * Finds the mask of bits which are writable in the guest's Config1 CP0
+ * register, by userland (currently read-only to the guest).
+ */
+unsigned int kvm_mips_config1_wrmask(struct kvm_vcpu *vcpu)
+{
+	/* Read-only */
+	return 0;
+}
+
+/**
+ * kvm_mips_config3_wrmask() - Find mask of writable bits in guest Config3
+ * @vcpu:	Virtual CPU.
+ *
+ * Finds the mask of bits which are writable in the guest's Config3 CP0
+ * register, by userland (currently read-only to the guest).
+ */
+unsigned int kvm_mips_config3_wrmask(struct kvm_vcpu *vcpu)
+{
+	/* Config4 is optional */
+	return MIPS_CONF_M;
+}
+
+/**
+ * kvm_mips_config4_wrmask() - Find mask of writable bits in guest Config4
+ * @vcpu:	Virtual CPU.
+ *
+ * Finds the mask of bits which are writable in the guest's Config4 CP0
+ * register, by userland (currently read-only to the guest).
+ */
+unsigned int kvm_mips_config4_wrmask(struct kvm_vcpu *vcpu)
+{
+	/* Config5 is optional */
+	return MIPS_CONF_M;
+}
+
+/**
+ * kvm_mips_config5_wrmask() - Find mask of writable bits in guest Config5
+ * @vcpu:	Virtual CPU.
+ *
+ * Finds the mask of bits which are writable in the guest's Config5 CP0
+ * register, by the guest itself.
+ */
+unsigned int kvm_mips_config5_wrmask(struct kvm_vcpu *vcpu)
+{
+	/* Read-only */
+	return 0;
+}
+
 enum emulation_result kvm_mips_emulate_CP0(uint32_t inst, uint32_t *opc,
 					   uint32_t cause, struct kvm_run *run,
 					   struct kvm_vcpu *vcpu)
diff --git a/arch/mips/kvm/mips.c b/arch/mips/kvm/mips.c
index 0aab83d894ba..73eecc779454 100644
--- a/arch/mips/kvm/mips.c
+++ b/arch/mips/kvm/mips.c
@@ -510,6 +510,8 @@ static u64 kvm_mips_get_one_regs[] = {
 	KVM_REG_MIPS_CP0_CONFIG1,
 	KVM_REG_MIPS_CP0_CONFIG2,
 	KVM_REG_MIPS_CP0_CONFIG3,
+	KVM_REG_MIPS_CP0_CONFIG4,
+	KVM_REG_MIPS_CP0_CONFIG5,
 	KVM_REG_MIPS_CP0_CONFIG7,
 	KVM_REG_MIPS_CP0_ERROREPC,
 
@@ -590,6 +592,12 @@ static int kvm_mips_get_reg(struct kvm_vcpu *vcpu,
 	case KVM_REG_MIPS_CP0_CONFIG3:
 		v = (long)kvm_read_c0_guest_config3(cop0);
 		break;
+	case KVM_REG_MIPS_CP0_CONFIG4:
+		v = (long)kvm_read_c0_guest_config4(cop0);
+		break;
+	case KVM_REG_MIPS_CP0_CONFIG5:
+		v = (long)kvm_read_c0_guest_config5(cop0);
+		break;
 	case KVM_REG_MIPS_CP0_CONFIG7:
 		v = (long)kvm_read_c0_guest_config7(cop0);
 		break;
@@ -701,6 +709,12 @@ static int kvm_mips_set_reg(struct kvm_vcpu *vcpu,
 	case KVM_REG_MIPS_CP0_COUNT:
 	case KVM_REG_MIPS_CP0_COMPARE:
 	case KVM_REG_MIPS_CP0_CAUSE:
+	case KVM_REG_MIPS_CP0_CONFIG:
+	case KVM_REG_MIPS_CP0_CONFIG1:
+	case KVM_REG_MIPS_CP0_CONFIG2:
+	case KVM_REG_MIPS_CP0_CONFIG3:
+	case KVM_REG_MIPS_CP0_CONFIG4:
+	case KVM_REG_MIPS_CP0_CONFIG5:
 	case KVM_REG_MIPS_COUNT_CTL:
 	case KVM_REG_MIPS_COUNT_RESUME:
 	case KVM_REG_MIPS_COUNT_HZ:
diff --git a/arch/mips/kvm/trap_emul.c b/arch/mips/kvm/trap_emul.c
index bffba002d1a4..8e0968428a78 100644
--- a/arch/mips/kvm/trap_emul.c
+++ b/arch/mips/kvm/trap_emul.c
@@ -418,8 +418,14 @@ static int kvm_trap_emul_vcpu_setup(struct kvm_vcpu *vcpu)
 	kvm_write_c0_guest_config2(cop0, MIPS_CONF_M);
 	/* MIPS_CONF_M | (read_c0_config2() & 0xfff) */
 
-	/* No config4, UserLocal */
-	kvm_write_c0_guest_config3(cop0, MIPS_CONF3_ULRI);
+	/* Have config4, UserLocal */
+	kvm_write_c0_guest_config3(cop0, MIPS_CONF_M | MIPS_CONF3_ULRI);
+
+	/* Have config5 */
+	kvm_write_c0_guest_config4(cop0, MIPS_CONF_M);
+
+	/* No config6 */
+	kvm_write_c0_guest_config5(cop0, 0);
 
 	/* Set Wait IE/IXMT Ignore in Config7, IAR, AR */
 	kvm_write_c0_guest_config7(cop0, (MIPS_CONF7_WII) | (1 << 10));
@@ -464,6 +470,7 @@ static int kvm_trap_emul_set_one_reg(struct kvm_vcpu *vcpu,
 {
 	struct mips_coproc *cop0 = vcpu->arch.cop0;
 	int ret = 0;
+	unsigned int cur, change;
 
 	switch (reg->id) {
 	case KVM_REG_MIPS_CP0_COUNT:
@@ -492,6 +499,44 @@ static int kvm_trap_emul_set_one_reg(struct kvm_vcpu *vcpu,
 			kvm_write_c0_guest_cause(cop0, v);
 		}
 		break;
+	case KVM_REG_MIPS_CP0_CONFIG:
+		/* read-only for now */
+		break;
+	case KVM_REG_MIPS_CP0_CONFIG1:
+		cur = kvm_read_c0_guest_config1(cop0);
+		change = (cur ^ v) & kvm_mips_config1_wrmask(vcpu);
+		if (change) {
+			v = cur ^ change;
+			kvm_write_c0_guest_config1(cop0, v);
+		}
+		break;
+	case KVM_REG_MIPS_CP0_CONFIG2:
+		/* read-only for now */
+		break;
+	case KVM_REG_MIPS_CP0_CONFIG3:
+		cur = kvm_read_c0_guest_config3(cop0);
+		change = (cur ^ v) & kvm_mips_config3_wrmask(vcpu);
+		if (change) {
+			v = cur ^ change;
+			kvm_write_c0_guest_config3(cop0, v);
+		}
+		break;
+	case KVM_REG_MIPS_CP0_CONFIG4:
+		cur = kvm_read_c0_guest_config4(cop0);
+		change = (cur ^ v) & kvm_mips_config4_wrmask(vcpu);
+		if (change) {
+			v = cur ^ change;
+			kvm_write_c0_guest_config4(cop0, v);
+		}
+		break;
+	case KVM_REG_MIPS_CP0_CONFIG5:
+		cur = kvm_read_c0_guest_config5(cop0);
+		change = (cur ^ v) & kvm_mips_config5_wrmask(vcpu);
+		if (change) {
+			v = cur ^ change;
+			kvm_write_c0_guest_config5(cop0, v);
+		}
+		break;
 	case KVM_REG_MIPS_COUNT_CTL:
 		ret = kvm_mips_set_count_ctl(vcpu, v);
 		break;
-- 
cgit v1.2.3


From b86ecb3766abd9138289ff2a18381d25b73f4622 Mon Sep 17 00:00:00 2001
From: James Hogan <james.hogan@imgtec.com>
Date: Mon, 9 Feb 2015 16:35:20 +0000
Subject: MIPS: KVM: Add vcpu_get_regs/vcpu_set_regs callback

Add a vcpu_get_regs() and vcpu_set_regs() callbacks for loading and
restoring context which may be in hardware registers. This may include
floating point and MIPS SIMD Architecture (MSA) state which may be
accessed directly by the guest (but restored lazily by the hypervisor),
and also dedicated guest registers as provided by the VZ ASE.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Gleb Natapov <gleb@kernel.org>
Cc: linux-mips@linux-mips.org
Cc: kvm@vger.kernel.org
---
 arch/mips/include/asm/kvm_host.h |  2 ++
 arch/mips/kvm/tlb.c              |  6 ++++++
 arch/mips/kvm/trap_emul.c        | 12 ++++++++++++
 3 files changed, 20 insertions(+)

diff --git a/arch/mips/include/asm/kvm_host.h b/arch/mips/include/asm/kvm_host.h
index 3f58ee1ebfab..fb79d67de192 100644
--- a/arch/mips/include/asm/kvm_host.h
+++ b/arch/mips/include/asm/kvm_host.h
@@ -585,6 +585,8 @@ struct kvm_mips_callbacks {
 			   const struct kvm_one_reg *reg, s64 *v);
 	int (*set_one_reg)(struct kvm_vcpu *vcpu,
 			   const struct kvm_one_reg *reg, s64 v);
+	int (*vcpu_get_regs)(struct kvm_vcpu *vcpu);
+	int (*vcpu_set_regs)(struct kvm_vcpu *vcpu);
 };
 extern struct kvm_mips_callbacks *kvm_mips_callbacks;
 int kvm_mips_emulation_init(struct kvm_mips_callbacks **install_callbacks);
diff --git a/arch/mips/kvm/tlb.c b/arch/mips/kvm/tlb.c
index b6beb0e07b1b..aed0ac2a4972 100644
--- a/arch/mips/kvm/tlb.c
+++ b/arch/mips/kvm/tlb.c
@@ -733,6 +733,9 @@ void kvm_arch_vcpu_load(struct kvm_vcpu *vcpu, int cpu)
 		}
 	}
 
+	/* restore guest state to registers */
+	kvm_mips_callbacks->vcpu_set_regs(vcpu);
+
 	local_irq_restore(flags);
 
 }
@@ -751,6 +754,9 @@ void kvm_arch_vcpu_put(struct kvm_vcpu *vcpu)
 	vcpu->arch.preempt_entryhi = read_c0_entryhi();
 	vcpu->arch.last_sched_cpu = cpu;
 
+	/* save guest state in registers */
+	kvm_mips_callbacks->vcpu_get_regs(vcpu);
+
 	if (((cpu_context(cpu, current->mm) ^ asid_cache(cpu)) &
 	     ASID_VERSION_MASK)) {
 		kvm_debug("%s: Dropping MMU Context:  %#lx\n", __func__,
diff --git a/arch/mips/kvm/trap_emul.c b/arch/mips/kvm/trap_emul.c
index 8e0968428a78..0d2729d202f4 100644
--- a/arch/mips/kvm/trap_emul.c
+++ b/arch/mips/kvm/trap_emul.c
@@ -552,6 +552,16 @@ static int kvm_trap_emul_set_one_reg(struct kvm_vcpu *vcpu,
 	return ret;
 }
 
+static int kvm_trap_emul_vcpu_get_regs(struct kvm_vcpu *vcpu)
+{
+	return 0;
+}
+
+static int kvm_trap_emul_vcpu_set_regs(struct kvm_vcpu *vcpu)
+{
+	return 0;
+}
+
 static struct kvm_mips_callbacks kvm_trap_emul_callbacks = {
 	/* exit handlers */
 	.handle_cop_unusable = kvm_trap_emul_handle_cop_unusable,
@@ -578,6 +588,8 @@ static struct kvm_mips_callbacks kvm_trap_emul_callbacks = {
 	.irq_clear = kvm_mips_irq_clear_cb,
 	.get_one_reg = kvm_trap_emul_get_one_reg,
 	.set_one_reg = kvm_trap_emul_set_one_reg,
+	.vcpu_get_regs = kvm_trap_emul_vcpu_get_regs,
+	.vcpu_set_regs = kvm_trap_emul_vcpu_set_regs,
 };
 
 int kvm_mips_emulation_init(struct kvm_mips_callbacks **install_callbacks)
-- 
cgit v1.2.3


From 98e91b8457d81f53fab990fac6c57e2a43c47627 Mon Sep 17 00:00:00 2001
From: James Hogan <james.hogan@imgtec.com>
Date: Tue, 18 Nov 2014 14:09:12 +0000
Subject: MIPS: KVM: Add base guest FPU support

Add base code for supporting FPU in MIPS KVM guests. The FPU cannot yet
be enabled in the guest, we're just laying the groundwork.

Whether the guest's FPU context is loaded is stored in a bit in the
fpu_inuse vcpu member. This allows the FPU to be disabled when the guest
disables it, but keeping the FPU context loaded so it doesn't have to be
reloaded if the guest re-enables it.

An fpu_enabled vcpu member stores whether userland has enabled the FPU
capability (which will be wired up in a later patch).

New assembly code is added for saving and restoring the FPU context, and
for saving/clearing and restoring FCSR (which can itself cause an FP
exception depending on the value). The FCSR is restored before returning
to the guest if the FPU is already enabled, and a die notifier is
registered to catch the possible FP exception and step over the ctc1
instruction.

The helper function kvm_lose_fpu() is added to save FPU context and
disable the FPU, which is used when saving hardware state before a
context switch or KVM exit (the vcpu_get_regs() callback).

The helper function kvm_own_fpu() is added to enable the FPU and restore
the FPU context if it isn't already loaded, which will be used in a
later patch when the guest attempts to use the FPU for the first time
and triggers a co-processor unusable exception.

The helper function kvm_drop_fpu() is added to discard the FPU context
and disable the FPU, which will be used in a later patch when the FPU
state will become architecturally UNPREDICTABLE (change of FR mode) to
force a reload of [stale] context in the new FR mode.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Paul Burton <paul.burton@imgtec.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Gleb Natapov <gleb@kernel.org>
Cc: linux-mips@linux-mips.org
Cc: kvm@vger.kernel.org
---
 arch/mips/include/asm/kvm_host.h |  27 +++++++++
 arch/mips/kernel/asm-offsets.c   |  38 ++++++++++++
 arch/mips/kvm/Makefile           |   2 +-
 arch/mips/kvm/fpu.S              | 122 +++++++++++++++++++++++++++++++++++++
 arch/mips/kvm/locore.S           |  17 ++++++
 arch/mips/kvm/mips.c             | 126 +++++++++++++++++++++++++++++++++++++++
 arch/mips/kvm/trap_emul.c        |   2 +
 7 files changed, 333 insertions(+), 1 deletion(-)
 create mode 100644 arch/mips/kvm/fpu.S

diff --git a/arch/mips/include/asm/kvm_host.h b/arch/mips/include/asm/kvm_host.h
index fb79d67de192..866edf330e53 100644
--- a/arch/mips/include/asm/kvm_host.h
+++ b/arch/mips/include/asm/kvm_host.h
@@ -357,6 +357,8 @@ struct kvm_mips_tlb {
 	long tlb_lo1;
 };
 
+#define KVM_MIPS_FPU_FPU	0x1
+
 #define KVM_MIPS_GUEST_TLB_SIZE	64
 struct kvm_vcpu_arch {
 	void *host_ebase, *guest_ebase;
@@ -378,6 +380,8 @@ struct kvm_vcpu_arch {
 
 	/* FPU State */
 	struct mips_fpu_struct fpu;
+	/* Which FPU state is loaded (KVM_MIPS_FPU_*) */
+	unsigned int fpu_inuse;
 
 	/* COP0 State */
 	struct mips_coproc *cop0;
@@ -424,6 +428,8 @@ struct kvm_vcpu_arch {
 
 	/* WAIT executed */
 	int wait;
+
+	u8 fpu_enabled;
 };
 
 
@@ -554,6 +560,19 @@ static inline void _kvm_atomic_change_c0_guest_reg(unsigned long *reg,
 	kvm_set_c0_guest_ebase(cop0, ((val) & (change)));		\
 }
 
+/* Helpers */
+
+static inline bool kvm_mips_guest_can_have_fpu(struct kvm_vcpu_arch *vcpu)
+{
+	return (!__builtin_constant_p(cpu_has_fpu) || cpu_has_fpu) &&
+		vcpu->fpu_enabled;
+}
+
+static inline bool kvm_mips_guest_has_fpu(struct kvm_vcpu_arch *vcpu)
+{
+	return kvm_mips_guest_can_have_fpu(vcpu) &&
+		kvm_read_c0_guest_config1(vcpu->cop0) & MIPS_CONF1_FP;
+}
 
 struct kvm_mips_callbacks {
 	int (*handle_cop_unusable)(struct kvm_vcpu *vcpu);
@@ -597,6 +616,14 @@ int kvm_arch_vcpu_dump_regs(struct kvm_vcpu *vcpu);
 /* Trampoline ASM routine to start running in "Guest" context */
 extern int __kvm_mips_vcpu_run(struct kvm_run *run, struct kvm_vcpu *vcpu);
 
+/* FPU context management */
+void __kvm_save_fpu(struct kvm_vcpu_arch *vcpu);
+void __kvm_restore_fpu(struct kvm_vcpu_arch *vcpu);
+void __kvm_restore_fcsr(struct kvm_vcpu_arch *vcpu);
+void kvm_own_fpu(struct kvm_vcpu *vcpu);
+void kvm_drop_fpu(struct kvm_vcpu *vcpu);
+void kvm_lose_fpu(struct kvm_vcpu *vcpu);
+
 /* TLB handling */
 uint32_t kvm_get_kernel_asid(struct kvm_vcpu *vcpu);
 
diff --git a/arch/mips/kernel/asm-offsets.c b/arch/mips/kernel/asm-offsets.c
index 3ee1565c5be3..a12bcf920073 100644
--- a/arch/mips/kernel/asm-offsets.c
+++ b/arch/mips/kernel/asm-offsets.c
@@ -404,6 +404,44 @@ void output_kvm_defines(void)
 	OFFSET(VCPU_LO, kvm_vcpu_arch, lo);
 	OFFSET(VCPU_HI, kvm_vcpu_arch, hi);
 	OFFSET(VCPU_PC, kvm_vcpu_arch, pc);
+	BLANK();
+
+	OFFSET(VCPU_FPR0, kvm_vcpu_arch, fpu.fpr[0]);
+	OFFSET(VCPU_FPR1, kvm_vcpu_arch, fpu.fpr[1]);
+	OFFSET(VCPU_FPR2, kvm_vcpu_arch, fpu.fpr[2]);
+	OFFSET(VCPU_FPR3, kvm_vcpu_arch, fpu.fpr[3]);
+	OFFSET(VCPU_FPR4, kvm_vcpu_arch, fpu.fpr[4]);
+	OFFSET(VCPU_FPR5, kvm_vcpu_arch, fpu.fpr[5]);
+	OFFSET(VCPU_FPR6, kvm_vcpu_arch, fpu.fpr[6]);
+	OFFSET(VCPU_FPR7, kvm_vcpu_arch, fpu.fpr[7]);
+	OFFSET(VCPU_FPR8, kvm_vcpu_arch, fpu.fpr[8]);
+	OFFSET(VCPU_FPR9, kvm_vcpu_arch, fpu.fpr[9]);
+	OFFSET(VCPU_FPR10, kvm_vcpu_arch, fpu.fpr[10]);
+	OFFSET(VCPU_FPR11, kvm_vcpu_arch, fpu.fpr[11]);
+	OFFSET(VCPU_FPR12, kvm_vcpu_arch, fpu.fpr[12]);
+	OFFSET(VCPU_FPR13, kvm_vcpu_arch, fpu.fpr[13]);
+	OFFSET(VCPU_FPR14, kvm_vcpu_arch, fpu.fpr[14]);
+	OFFSET(VCPU_FPR15, kvm_vcpu_arch, fpu.fpr[15]);
+	OFFSET(VCPU_FPR16, kvm_vcpu_arch, fpu.fpr[16]);
+	OFFSET(VCPU_FPR17, kvm_vcpu_arch, fpu.fpr[17]);
+	OFFSET(VCPU_FPR18, kvm_vcpu_arch, fpu.fpr[18]);
+	OFFSET(VCPU_FPR19, kvm_vcpu_arch, fpu.fpr[19]);
+	OFFSET(VCPU_FPR20, kvm_vcpu_arch, fpu.fpr[20]);
+	OFFSET(VCPU_FPR21, kvm_vcpu_arch, fpu.fpr[21]);
+	OFFSET(VCPU_FPR22, kvm_vcpu_arch, fpu.fpr[22]);
+	OFFSET(VCPU_FPR23, kvm_vcpu_arch, fpu.fpr[23]);
+	OFFSET(VCPU_FPR24, kvm_vcpu_arch, fpu.fpr[24]);
+	OFFSET(VCPU_FPR25, kvm_vcpu_arch, fpu.fpr[25]);
+	OFFSET(VCPU_FPR26, kvm_vcpu_arch, fpu.fpr[26]);
+	OFFSET(VCPU_FPR27, kvm_vcpu_arch, fpu.fpr[27]);
+	OFFSET(VCPU_FPR28, kvm_vcpu_arch, fpu.fpr[28]);
+	OFFSET(VCPU_FPR29, kvm_vcpu_arch, fpu.fpr[29]);
+	OFFSET(VCPU_FPR30, kvm_vcpu_arch, fpu.fpr[30]);
+	OFFSET(VCPU_FPR31, kvm_vcpu_arch, fpu.fpr[31]);
+
+	OFFSET(VCPU_FCR31, kvm_vcpu_arch, fpu.fcr31);
+	BLANK();
+
 	OFFSET(VCPU_COP0, kvm_vcpu_arch, cop0);
 	OFFSET(VCPU_GUEST_KERNEL_ASID, kvm_vcpu_arch, guest_kernel_asid);
 	OFFSET(VCPU_GUEST_USER_ASID, kvm_vcpu_arch, guest_user_asid);
diff --git a/arch/mips/kvm/Makefile b/arch/mips/kvm/Makefile
index 401fe027c261..78d7bcd7710a 100644
--- a/arch/mips/kvm/Makefile
+++ b/arch/mips/kvm/Makefile
@@ -7,7 +7,7 @@ EXTRA_CFLAGS += -Ivirt/kvm -Iarch/mips/kvm
 
 kvm-objs := $(common-objs) mips.o emulate.o locore.o \
 	    interrupt.o stats.o commpage.o \
-	    dyntrans.o trap_emul.o
+	    dyntrans.o trap_emul.o fpu.o
 
 obj-$(CONFIG_KVM)	+= kvm.o
 obj-y			+= callback.o tlb.o
diff --git a/arch/mips/kvm/fpu.S b/arch/mips/kvm/fpu.S
new file mode 100644
index 000000000000..531fbf5131c0
--- /dev/null
+++ b/arch/mips/kvm/fpu.S
@@ -0,0 +1,122 @@
+/*
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License.  See the file "COPYING" in the main directory of this archive
+ * for more details.
+ *
+ * FPU context handling code for KVM.
+ *
+ * Copyright (C) 2015 Imagination Technologies Ltd.
+ */
+
+#include <asm/asm.h>
+#include <asm/asm-offsets.h>
+#include <asm/fpregdef.h>
+#include <asm/mipsregs.h>
+#include <asm/regdef.h>
+
+	.set	noreorder
+	.set	noat
+
+LEAF(__kvm_save_fpu)
+	.set	push
+	.set	mips64r2
+	SET_HARDFLOAT
+	mfc0	t0, CP0_STATUS
+	sll     t0, t0, 5			# is Status.FR set?
+	bgez    t0, 1f				# no: skip odd doubles
+	 nop
+	sdc1	$f1,  VCPU_FPR1(a0)
+	sdc1	$f3,  VCPU_FPR3(a0)
+	sdc1	$f5,  VCPU_FPR5(a0)
+	sdc1	$f7,  VCPU_FPR7(a0)
+	sdc1	$f9,  VCPU_FPR9(a0)
+	sdc1	$f11, VCPU_FPR11(a0)
+	sdc1	$f13, VCPU_FPR13(a0)
+	sdc1	$f15, VCPU_FPR15(a0)
+	sdc1	$f17, VCPU_FPR17(a0)
+	sdc1	$f19, VCPU_FPR19(a0)
+	sdc1	$f21, VCPU_FPR21(a0)
+	sdc1	$f23, VCPU_FPR23(a0)
+	sdc1	$f25, VCPU_FPR25(a0)
+	sdc1	$f27, VCPU_FPR27(a0)
+	sdc1	$f29, VCPU_FPR29(a0)
+	sdc1	$f31, VCPU_FPR31(a0)
+1:	sdc1	$f0,  VCPU_FPR0(a0)
+	sdc1	$f2,  VCPU_FPR2(a0)
+	sdc1	$f4,  VCPU_FPR4(a0)
+	sdc1	$f6,  VCPU_FPR6(a0)
+	sdc1	$f8,  VCPU_FPR8(a0)
+	sdc1	$f10, VCPU_FPR10(a0)
+	sdc1	$f12, VCPU_FPR12(a0)
+	sdc1	$f14, VCPU_FPR14(a0)
+	sdc1	$f16, VCPU_FPR16(a0)
+	sdc1	$f18, VCPU_FPR18(a0)
+	sdc1	$f20, VCPU_FPR20(a0)
+	sdc1	$f22, VCPU_FPR22(a0)
+	sdc1	$f24, VCPU_FPR24(a0)
+	sdc1	$f26, VCPU_FPR26(a0)
+	sdc1	$f28, VCPU_FPR28(a0)
+	jr	ra
+	 sdc1	$f30, VCPU_FPR30(a0)
+	.set	pop
+	END(__kvm_save_fpu)
+
+LEAF(__kvm_restore_fpu)
+	.set	push
+	.set	mips64r2
+	SET_HARDFLOAT
+	mfc0	t0, CP0_STATUS
+	sll     t0, t0, 5			# is Status.FR set?
+	bgez    t0, 1f				# no: skip odd doubles
+	 nop
+	ldc1	$f1,  VCPU_FPR1(a0)
+	ldc1	$f3,  VCPU_FPR3(a0)
+	ldc1	$f5,  VCPU_FPR5(a0)
+	ldc1	$f7,  VCPU_FPR7(a0)
+	ldc1	$f9,  VCPU_FPR9(a0)
+	ldc1	$f11, VCPU_FPR11(a0)
+	ldc1	$f13, VCPU_FPR13(a0)
+	ldc1	$f15, VCPU_FPR15(a0)
+	ldc1	$f17, VCPU_FPR17(a0)
+	ldc1	$f19, VCPU_FPR19(a0)
+	ldc1	$f21, VCPU_FPR21(a0)
+	ldc1	$f23, VCPU_FPR23(a0)
+	ldc1	$f25, VCPU_FPR25(a0)
+	ldc1	$f27, VCPU_FPR27(a0)
+	ldc1	$f29, VCPU_FPR29(a0)
+	ldc1	$f31, VCPU_FPR31(a0)
+1:	ldc1	$f0,  VCPU_FPR0(a0)
+	ldc1	$f2,  VCPU_FPR2(a0)
+	ldc1	$f4,  VCPU_FPR4(a0)
+	ldc1	$f6,  VCPU_FPR6(a0)
+	ldc1	$f8,  VCPU_FPR8(a0)
+	ldc1	$f10, VCPU_FPR10(a0)
+	ldc1	$f12, VCPU_FPR12(a0)
+	ldc1	$f14, VCPU_FPR14(a0)
+	ldc1	$f16, VCPU_FPR16(a0)
+	ldc1	$f18, VCPU_FPR18(a0)
+	ldc1	$f20, VCPU_FPR20(a0)
+	ldc1	$f22, VCPU_FPR22(a0)
+	ldc1	$f24, VCPU_FPR24(a0)
+	ldc1	$f26, VCPU_FPR26(a0)
+	ldc1	$f28, VCPU_FPR28(a0)
+	jr	ra
+	 ldc1	$f30, VCPU_FPR30(a0)
+	.set	pop
+	END(__kvm_restore_fpu)
+
+LEAF(__kvm_restore_fcsr)
+	.set	push
+	SET_HARDFLOAT
+	lw	t0, VCPU_FCR31(a0)
+	/*
+	 * The ctc1 must stay at this offset in __kvm_restore_fcsr.
+	 * See kvm_mips_csr_die_notify() which handles t0 containing a value
+	 * which triggers an FP Exception, which must be stepped over and
+	 * ignored since the set cause bits must remain there for the guest.
+	 */
+	ctc1	t0, fcr31
+	jr	ra
+	 nop
+	.set	pop
+	END(__kvm_restore_fcsr)
diff --git a/arch/mips/kvm/locore.S b/arch/mips/kvm/locore.S
index 4a68b176d6e4..f5594049c0c3 100644
--- a/arch/mips/kvm/locore.S
+++ b/arch/mips/kvm/locore.S
@@ -353,6 +353,23 @@ NESTED (MIPSX(GuestException), CALLFRAME_SIZ, ra)
 	LONG_L	k0, VCPU_HOST_EBASE(k1)
 	mtc0	k0,CP0_EBASE
 
+	/*
+	 * If FPU is enabled, save FCR31 and clear it so that later ctc1's don't
+	 * trigger FPE for pending exceptions.
+	 */
+	.set	at
+	and	v1, v0, ST0_CU1
+	beqz	v1, 1f
+	 nop
+	.set	push
+	SET_HARDFLOAT
+	cfc1	t0, fcr31
+	sw	t0, VCPU_FCR31(k1)
+	ctc1	zero,fcr31
+	.set	pop
+	.set	noat
+1:
+
 	/* Now that the new EBASE has been loaded, unset BEV and KSU_USER */
 	.set	at
 	and	v0, v0, ~(ST0_EXL | KSU_USER | ST0_IE)
diff --git a/arch/mips/kvm/mips.c b/arch/mips/kvm/mips.c
index 73eecc779454..b26a48d81467 100644
--- a/arch/mips/kvm/mips.c
+++ b/arch/mips/kvm/mips.c
@@ -11,6 +11,7 @@
 
 #include <linux/errno.h>
 #include <linux/err.h>
+#include <linux/kdebug.h>
 #include <linux/module.h>
 #include <linux/vmalloc.h>
 #include <linux/fs.h>
@@ -1178,12 +1179,133 @@ skip_emul:
 		}
 	}
 
+	if (ret == RESUME_GUEST) {
+		/*
+		 * If FPU is enabled (i.e. the guest's FPU context is live),
+		 * restore FCR31.
+		 *
+		 * This should be before returning to the guest exception
+		 * vector, as it may well cause an FP exception if there are
+		 * pending exception bits unmasked. (see
+		 * kvm_mips_csr_die_notifier() for how that is handled).
+		 */
+		if (kvm_mips_guest_has_fpu(&vcpu->arch) &&
+		    read_c0_status() & ST0_CU1)
+			__kvm_restore_fcsr(&vcpu->arch);
+	}
+
 	/* Disable HTW before returning to guest or host */
 	htw_stop();
 
 	return ret;
 }
 
+/* Enable FPU for guest and restore context */
+void kvm_own_fpu(struct kvm_vcpu *vcpu)
+{
+	struct mips_coproc *cop0 = vcpu->arch.cop0;
+	unsigned int sr, cfg5;
+
+	preempt_disable();
+
+	/*
+	 * Enable FPU for guest
+	 * We set FR and FRE according to guest context
+	 */
+	sr = kvm_read_c0_guest_status(cop0);
+	change_c0_status(ST0_CU1 | ST0_FR, sr);
+	if (cpu_has_fre) {
+		cfg5 = kvm_read_c0_guest_config5(cop0);
+		change_c0_config5(MIPS_CONF5_FRE, cfg5);
+	}
+	enable_fpu_hazard();
+
+	/* If guest FPU state not active, restore it now */
+	if (!(vcpu->arch.fpu_inuse & KVM_MIPS_FPU_FPU)) {
+		__kvm_restore_fpu(&vcpu->arch);
+		vcpu->arch.fpu_inuse |= KVM_MIPS_FPU_FPU;
+	}
+
+	preempt_enable();
+}
+
+/* Drop FPU without saving it */
+void kvm_drop_fpu(struct kvm_vcpu *vcpu)
+{
+	preempt_disable();
+	if (vcpu->arch.fpu_inuse & KVM_MIPS_FPU_FPU) {
+		clear_c0_status(ST0_CU1 | ST0_FR);
+		vcpu->arch.fpu_inuse &= ~KVM_MIPS_FPU_FPU;
+	}
+	preempt_enable();
+}
+
+/* Save and disable FPU */
+void kvm_lose_fpu(struct kvm_vcpu *vcpu)
+{
+	/*
+	 * FPU gets disabled in root context (hardware) when it is disabled in
+	 * guest context (software), but the register state in the hardware may
+	 * still be in use. This is why we explicitly re-enable the hardware
+	 * before saving.
+	 */
+
+	preempt_disable();
+	if (vcpu->arch.fpu_inuse & KVM_MIPS_FPU_FPU) {
+		set_c0_status(ST0_CU1);
+		enable_fpu_hazard();
+
+		__kvm_save_fpu(&vcpu->arch);
+		vcpu->arch.fpu_inuse &= ~KVM_MIPS_FPU_FPU;
+
+		/* Disable FPU */
+		clear_c0_status(ST0_CU1 | ST0_FR);
+	}
+	preempt_enable();
+}
+
+/*
+ * Step over a specific ctc1 to FCSR which is used to restore guest FCSR state
+ * and may trigger a "harmless" FP exception if cause bits are set in the value
+ * being written.
+ */
+static int kvm_mips_csr_die_notify(struct notifier_block *self,
+				   unsigned long cmd, void *ptr)
+{
+	struct die_args *args = (struct die_args *)ptr;
+	struct pt_regs *regs = args->regs;
+	unsigned long pc;
+
+	/* Only interested in FPE */
+	if (cmd != DIE_FP)
+		return NOTIFY_DONE;
+
+	/* Return immediately if guest context isn't active */
+	if (!(current->flags & PF_VCPU))
+		return NOTIFY_DONE;
+
+	/* Should never get here from user mode */
+	BUG_ON(user_mode(regs));
+
+	pc = instruction_pointer(regs);
+	switch (cmd) {
+	case DIE_FP:
+		/* match 2nd instruction in __kvm_restore_fcsr */
+		if (pc != (unsigned long)&__kvm_restore_fcsr + 4)
+			return NOTIFY_DONE;
+		break;
+	}
+
+	/* Move PC forward a little and continue executing */
+	instruction_pointer(regs) += 4;
+
+	return NOTIFY_STOP;
+}
+
+static struct notifier_block kvm_mips_csr_die_notifier = {
+	.notifier_call = kvm_mips_csr_die_notify,
+};
+
 int __init kvm_mips_init(void)
 {
 	int ret;
@@ -1193,6 +1315,8 @@ int __init kvm_mips_init(void)
 	if (ret)
 		return ret;
 
+	register_die_notifier(&kvm_mips_csr_die_notifier);
+
 	/*
 	 * On MIPS, kernel modules are executed from "mapped space", which
 	 * requires TLBs. The TLB handling code is statically linked with
@@ -1215,6 +1339,8 @@ void __exit kvm_mips_exit(void)
 	kvm_mips_gfn_to_pfn = NULL;
 	kvm_mips_release_pfn_clean = NULL;
 	kvm_mips_is_error_pfn = NULL;
+
+	unregister_die_notifier(&kvm_mips_csr_die_notifier);
 }
 
 module_init(kvm_mips_init);
diff --git a/arch/mips/kvm/trap_emul.c b/arch/mips/kvm/trap_emul.c
index 0d2729d202f4..408af244aed2 100644
--- a/arch/mips/kvm/trap_emul.c
+++ b/arch/mips/kvm/trap_emul.c
@@ -554,6 +554,8 @@ static int kvm_trap_emul_set_one_reg(struct kvm_vcpu *vcpu,
 
 static int kvm_trap_emul_vcpu_get_regs(struct kvm_vcpu *vcpu)
 {
+	kvm_lose_fpu(vcpu);
+
 	return 0;
 }
 
-- 
cgit v1.2.3


From 6cdc65e31d4f70561d71eeaf34a2a70ab68bf146 Mon Sep 17 00:00:00 2001
From: James Hogan <james.hogan@imgtec.com>
Date: Tue, 3 Feb 2015 13:59:38 +0000
Subject: MIPS: KVM: Emulate FPU bits in COP0 interface

Emulate FPU related parts of COP0 interface so that the guest will be
able to enable/disable the following once the FPU capability has been
wired up:
- The FPU (Status.CU1)
- 64-bit FP register mode (Status.FR)
- Hybrid FP register mode (Config5.FRE)

Changing Status.CU1 has no immediate effect if the FPU state isn't live,
as the FPU state is restored lazily on first use. After that, changes
take place immediately in the host Status.CU1, so that the guest can
start getting coprocessor unusable exceptions right away for guest FPU
operations if it is disabled. The FPU state is saved lazily too, as the
FPU may get re-enabled in the near future anyway.

Any change to Status.FR causes the FPU state to be discarded and FPU
disabled, as the register state is architecturally UNPREDICTABLE after
such a change. This should also ensure that the FPU state is fully
initialised (with stale state, but that's fine) when it is next used in
the new FP mode.

Any change to the Config5.FRE bit is immediately updated in the host
state so that the guest can get the relevant exceptions right away for
single-precision FPU operations.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Paul Burton <paul.burton@imgtec.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Gleb Natapov <gleb@kernel.org>
Cc: linux-mips@linux-mips.org
Cc: kvm@vger.kernel.org
---
 arch/mips/kvm/emulate.c | 111 +++++++++++++++++++++++++++++++++++++++++++-----
 1 file changed, 100 insertions(+), 11 deletions(-)

diff --git a/arch/mips/kvm/emulate.c b/arch/mips/kvm/emulate.c
index 91d5b0e370b4..3511bb20fe0e 100644
--- a/arch/mips/kvm/emulate.c
+++ b/arch/mips/kvm/emulate.c
@@ -893,8 +893,13 @@ enum emulation_result kvm_mips_emul_tlbp(struct kvm_vcpu *vcpu)
  */
 unsigned int kvm_mips_config1_wrmask(struct kvm_vcpu *vcpu)
 {
-	/* Read-only */
-	return 0;
+	unsigned int mask = 0;
+
+	/* Permit FPU to be present if FPU is supported */
+	if (kvm_mips_guest_can_have_fpu(&vcpu->arch))
+		mask |= MIPS_CONF1_FP;
+
+	return mask;
 }
 
 /**
@@ -932,8 +937,19 @@ unsigned int kvm_mips_config4_wrmask(struct kvm_vcpu *vcpu)
  */
 unsigned int kvm_mips_config5_wrmask(struct kvm_vcpu *vcpu)
 {
-	/* Read-only */
-	return 0;
+	unsigned int mask = 0;
+
+	/*
+	 * Permit guest FPU mode changes if FPU is enabled and the relevant
+	 * feature exists according to FIR register.
+	 */
+	if (kvm_mips_guest_has_fpu(&vcpu->arch)) {
+		if (cpu_has_fre)
+			mask |= MIPS_CONF5_FRE;
+		/* We don't support UFR or UFE */
+	}
+
+	return mask;
 }
 
 enum emulation_result kvm_mips_emulate_CP0(uint32_t inst, uint32_t *opc,
@@ -1073,18 +1089,91 @@ enum emulation_result kvm_mips_emulate_CP0(uint32_t inst, uint32_t *opc,
 				kvm_mips_write_compare(vcpu,
 						       vcpu->arch.gprs[rt]);
 			} else if ((rd == MIPS_CP0_STATUS) && (sel == 0)) {
-				kvm_write_c0_guest_status(cop0,
-							  vcpu->arch.gprs[rt]);
+				unsigned int old_val, val, change;
+
+				old_val = kvm_read_c0_guest_status(cop0);
+				val = vcpu->arch.gprs[rt];
+				change = val ^ old_val;
+
+				/* Make sure that the NMI bit is never set */
+				val &= ~ST0_NMI;
+
+				/*
+				 * Don't allow CU1 or FR to be set unless FPU
+				 * capability enabled and exists in guest
+				 * configuration.
+				 */
+				if (!kvm_mips_guest_has_fpu(&vcpu->arch))
+					val &= ~(ST0_CU1 | ST0_FR);
+
+				/*
+				 * Also don't allow FR to be set if host doesn't
+				 * support it.
+				 */
+				if (!(current_cpu_data.fpu_id & MIPS_FPIR_F64))
+					val &= ~ST0_FR;
+
+
+				/* Handle changes in FPU mode */
+				preempt_disable();
+
 				/*
-				 * Make sure that CU1 and NMI bits are
-				 * never set
+				 * FPU and Vector register state is made
+				 * UNPREDICTABLE by a change of FR, so don't
+				 * even bother saving it.
 				 */
-				kvm_clear_c0_guest_status(cop0,
-							  (ST0_CU1 | ST0_NMI));
+				if (change & ST0_FR)
+					kvm_drop_fpu(vcpu);
+
+				/*
+				 * Propagate CU1 (FPU enable) changes
+				 * immediately if the FPU context is already
+				 * loaded. When disabling we leave the context
+				 * loaded so it can be quickly enabled again in
+				 * the near future.
+				 */
+				if (change & ST0_CU1 &&
+				    vcpu->arch.fpu_inuse & KVM_MIPS_FPU_FPU)
+					change_c0_status(ST0_CU1, val);
+
+				preempt_enable();
+
+				kvm_write_c0_guest_status(cop0, val);
 
 #ifdef CONFIG_KVM_MIPS_DYN_TRANS
-				kvm_mips_trans_mtc0(inst, opc, vcpu);
+				/*
+				 * If FPU present, we need CU1/FR bits to take
+				 * effect fairly soon.
+				 */
+				if (!kvm_mips_guest_has_fpu(&vcpu->arch))
+					kvm_mips_trans_mtc0(inst, opc, vcpu);
 #endif
+			} else if ((rd == MIPS_CP0_CONFIG) && (sel == 5)) {
+				unsigned int old_val, val, change, wrmask;
+
+				old_val = kvm_read_c0_guest_config5(cop0);
+				val = vcpu->arch.gprs[rt];
+
+				/* Only a few bits are writable in Config5 */
+				wrmask = kvm_mips_config5_wrmask(vcpu);
+				change = (val ^ old_val) & wrmask;
+				val = old_val ^ change;
+
+
+				/* Handle changes in FPU modes */
+				preempt_disable();
+
+				/*
+				 * Propagate FRE changes immediately if the FPU
+				 * context is already loaded.
+				 */
+				if (change & MIPS_CONF5_FRE &&
+				    vcpu->arch.fpu_inuse & KVM_MIPS_FPU_FPU)
+					change_c0_config5(MIPS_CONF5_FRE, val);
+
+				preempt_enable();
+
+				kvm_write_c0_guest_config5(cop0, val);
 			} else if ((rd == MIPS_CP0_CAUSE) && (sel == 0)) {
 				uint32_t old_cause, new_cause;
 
-- 
cgit v1.2.3


From 1c0cd66adbac8aa339b9521eceb18b00d1b0699e Mon Sep 17 00:00:00 2001
From: James Hogan <james.hogan@imgtec.com>
Date: Fri, 6 Feb 2015 10:56:27 +0000
Subject: MIPS: KVM: Add FP exception handling

Add guest exception handling for floating point exceptions and
coprocessor 1 unusable exceptions.

Floating point exceptions from the guest need passing to the guest
kernel, so for these a guest FPE is emulated.

Also, coprocessor 1 unusable exceptions are normally passed straight
through to the guest (because no guest FPU was supported), but the
hypervisor can now handle them if the guest has its FPU enabled by
restoring the guest FPU context and enabling the FPU.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Paul Burton <paul.burton@imgtec.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Gleb Natapov <gleb@kernel.org>
Cc: linux-mips@linux-mips.org
Cc: kvm@vger.kernel.org
---
 arch/mips/include/asm/kvm_host.h |  8 ++++++++
 arch/mips/kvm/emulate.c          | 36 ++++++++++++++++++++++++++++++++++++
 arch/mips/kvm/mips.c             |  7 +++++++
 arch/mips/kvm/stats.c            |  1 +
 arch/mips/kvm/trap_emul.c        | 39 ++++++++++++++++++++++++++++++++++++---
 5 files changed, 88 insertions(+), 3 deletions(-)

diff --git a/arch/mips/include/asm/kvm_host.h b/arch/mips/include/asm/kvm_host.h
index 866edf330e53..fb264d8695e4 100644
--- a/arch/mips/include/asm/kvm_host.h
+++ b/arch/mips/include/asm/kvm_host.h
@@ -123,6 +123,7 @@ struct kvm_vcpu_stat {
 	u32 resvd_inst_exits;
 	u32 break_inst_exits;
 	u32 trap_inst_exits;
+	u32 fpe_exits;
 	u32 flush_dcache_exits;
 	u32 halt_successful_poll;
 	u32 halt_wakeup;
@@ -143,6 +144,7 @@ enum kvm_mips_exit_types {
 	RESVD_INST_EXITS,
 	BREAK_INST_EXITS,
 	TRAP_INST_EXITS,
+	FPE_EXITS,
 	FLUSH_DCACHE_EXITS,
 	MAX_KVM_MIPS_EXIT_TYPES
 };
@@ -585,6 +587,7 @@ struct kvm_mips_callbacks {
 	int (*handle_res_inst)(struct kvm_vcpu *vcpu);
 	int (*handle_break)(struct kvm_vcpu *vcpu);
 	int (*handle_trap)(struct kvm_vcpu *vcpu);
+	int (*handle_fpe)(struct kvm_vcpu *vcpu);
 	int (*handle_msa_disabled)(struct kvm_vcpu *vcpu);
 	int (*vm_init)(struct kvm *kvm);
 	int (*vcpu_init)(struct kvm_vcpu *vcpu);
@@ -734,6 +737,11 @@ extern enum emulation_result kvm_mips_emulate_trap_exc(unsigned long cause,
 						       struct kvm_run *run,
 						       struct kvm_vcpu *vcpu);
 
+extern enum emulation_result kvm_mips_emulate_fpe_exc(unsigned long cause,
+						      uint32_t *opc,
+						      struct kvm_run *run,
+						      struct kvm_vcpu *vcpu);
+
 extern enum emulation_result kvm_mips_complete_mmio_load(struct kvm_vcpu *vcpu,
 							 struct kvm_run *run);
 
diff --git a/arch/mips/kvm/emulate.c b/arch/mips/kvm/emulate.c
index 3511bb20fe0e..fbf169fb63df 100644
--- a/arch/mips/kvm/emulate.c
+++ b/arch/mips/kvm/emulate.c
@@ -2146,6 +2146,41 @@ enum emulation_result kvm_mips_emulate_trap_exc(unsigned long cause,
 	return er;
 }
 
+enum emulation_result kvm_mips_emulate_fpe_exc(unsigned long cause,
+					       uint32_t *opc,
+					       struct kvm_run *run,
+					       struct kvm_vcpu *vcpu)
+{
+	struct mips_coproc *cop0 = vcpu->arch.cop0;
+	struct kvm_vcpu_arch *arch = &vcpu->arch;
+	enum emulation_result er = EMULATE_DONE;
+
+	if ((kvm_read_c0_guest_status(cop0) & ST0_EXL) == 0) {
+		/* save old pc */
+		kvm_write_c0_guest_epc(cop0, arch->pc);
+		kvm_set_c0_guest_status(cop0, ST0_EXL);
+
+		if (cause & CAUSEF_BD)
+			kvm_set_c0_guest_cause(cop0, CAUSEF_BD);
+		else
+			kvm_clear_c0_guest_cause(cop0, CAUSEF_BD);
+
+		kvm_debug("Delivering FPE @ pc %#lx\n", arch->pc);
+
+		kvm_change_c0_guest_cause(cop0, (0xff),
+					  (T_FPE << CAUSEB_EXCCODE));
+
+		/* Set PC to the exception entry point */
+		arch->pc = KVM_GUEST_KSEG0 + 0x180;
+
+	} else {
+		kvm_err("Trying to deliver FPE when EXL is already set\n");
+		er = EMULATE_FAIL;
+	}
+
+	return er;
+}
+
 /* ll/sc, rdhwr, sync emulation */
 
 #define OPCODE 0xfc000000
@@ -2353,6 +2388,7 @@ enum emulation_result kvm_mips_check_privilege(unsigned long cause,
 		case T_BREAK:
 		case T_RES_INST:
 		case T_TRAP:
+		case T_FPE:
 		case T_MSADIS:
 			break;
 
diff --git a/arch/mips/kvm/mips.c b/arch/mips/kvm/mips.c
index b26a48d81467..dd0833833bea 100644
--- a/arch/mips/kvm/mips.c
+++ b/arch/mips/kvm/mips.c
@@ -50,6 +50,7 @@ struct kvm_stats_debugfs_item debugfs_entries[] = {
 	{ "resvd_inst",	  VCPU_STAT(resvd_inst_exits),	 KVM_STAT_VCPU },
 	{ "break_inst",	  VCPU_STAT(break_inst_exits),	 KVM_STAT_VCPU },
 	{ "trap_inst",	  VCPU_STAT(trap_inst_exits),	 KVM_STAT_VCPU },
+	{ "fpe",	  VCPU_STAT(fpe_exits),		 KVM_STAT_VCPU },
 	{ "flush_dcache", VCPU_STAT(flush_dcache_exits), KVM_STAT_VCPU },
 	{ "halt_successful_poll", VCPU_STAT(halt_successful_poll), KVM_STAT_VCPU },
 	{ "halt_wakeup",  VCPU_STAT(halt_wakeup),	 KVM_STAT_VCPU },
@@ -1148,6 +1149,12 @@ int kvm_mips_handle_exit(struct kvm_run *run, struct kvm_vcpu *vcpu)
 		ret = kvm_mips_callbacks->handle_trap(vcpu);
 		break;
 
+	case T_FPE:
+		++vcpu->stat.fpe_exits;
+		trace_kvm_exit(vcpu, FPE_EXITS);
+		ret = kvm_mips_callbacks->handle_fpe(vcpu);
+		break;
+
 	case T_MSADIS:
 		ret = kvm_mips_callbacks->handle_msa_disabled(vcpu);
 		break;
diff --git a/arch/mips/kvm/stats.c b/arch/mips/kvm/stats.c
index dd90b0a92181..3843828f3b91 100644
--- a/arch/mips/kvm/stats.c
+++ b/arch/mips/kvm/stats.c
@@ -26,6 +26,7 @@ char *kvm_mips_exit_types_str[MAX_KVM_MIPS_EXIT_TYPES] = {
 	"Reserved Inst",
 	"Break Inst",
 	"Trap Inst",
+	"FPE",
 	"D-Cache Flushes",
 };
 
diff --git a/arch/mips/kvm/trap_emul.c b/arch/mips/kvm/trap_emul.c
index 408af244aed2..421d5b815f24 100644
--- a/arch/mips/kvm/trap_emul.c
+++ b/arch/mips/kvm/trap_emul.c
@@ -39,16 +39,30 @@ static gpa_t kvm_trap_emul_gva_to_gpa_cb(gva_t gva)
 
 static int kvm_trap_emul_handle_cop_unusable(struct kvm_vcpu *vcpu)
 {
+	struct mips_coproc *cop0 = vcpu->arch.cop0;
 	struct kvm_run *run = vcpu->run;
 	uint32_t __user *opc = (uint32_t __user *) vcpu->arch.pc;
 	unsigned long cause = vcpu->arch.host_cp0_cause;
 	enum emulation_result er = EMULATE_DONE;
 	int ret = RESUME_GUEST;
 
-	if (((cause & CAUSEF_CE) >> CAUSEB_CE) == 1)
-		er = kvm_mips_emulate_fpu_exc(cause, opc, run, vcpu);
-	else
+	if (((cause & CAUSEF_CE) >> CAUSEB_CE) == 1) {
+		/* FPU Unusable */
+		if (!kvm_mips_guest_has_fpu(&vcpu->arch) ||
+		    (kvm_read_c0_guest_status(cop0) & ST0_CU1) == 0) {
+			/*
+			 * Unusable/no FPU in guest:
+			 * deliver guest COP1 Unusable Exception
+			 */
+			er = kvm_mips_emulate_fpu_exc(cause, opc, run, vcpu);
+		} else {
+			/* Restore FPU state */
+			kvm_own_fpu(vcpu);
+			er = EMULATE_DONE;
+		}
+	} else {
 		er = kvm_mips_emulate_inst(cause, opc, run, vcpu);
+	}
 
 	switch (er) {
 	case EMULATE_DONE:
@@ -348,6 +362,24 @@ static int kvm_trap_emul_handle_trap(struct kvm_vcpu *vcpu)
 	return ret;
 }
 
+static int kvm_trap_emul_handle_fpe(struct kvm_vcpu *vcpu)
+{
+	struct kvm_run *run = vcpu->run;
+	uint32_t __user *opc = (uint32_t __user *)vcpu->arch.pc;
+	unsigned long cause = vcpu->arch.host_cp0_cause;
+	enum emulation_result er = EMULATE_DONE;
+	int ret = RESUME_GUEST;
+
+	er = kvm_mips_emulate_fpe_exc(cause, opc, run, vcpu);
+	if (er == EMULATE_DONE) {
+		ret = RESUME_GUEST;
+	} else {
+		run->exit_reason = KVM_EXIT_INTERNAL_ERROR;
+		ret = RESUME_HOST;
+	}
+	return ret;
+}
+
 static int kvm_trap_emul_handle_msa_disabled(struct kvm_vcpu *vcpu)
 {
 	struct kvm_run *run = vcpu->run;
@@ -576,6 +608,7 @@ static struct kvm_mips_callbacks kvm_trap_emul_callbacks = {
 	.handle_res_inst = kvm_trap_emul_handle_res_inst,
 	.handle_break = kvm_trap_emul_handle_break,
 	.handle_trap = kvm_trap_emul_handle_trap,
+	.handle_fpe = kvm_trap_emul_handle_fpe,
 	.handle_msa_disabled = kvm_trap_emul_handle_msa_disabled,
 
 	.vm_init = kvm_trap_emul_vm_init,
-- 
cgit v1.2.3


From 379245cdf1d1efc1eccc38bf0cc985dae232123d Mon Sep 17 00:00:00 2001
From: James Hogan <james.hogan@imgtec.com>
Date: Tue, 2 Dec 2014 15:48:24 +0000
Subject: MIPS: KVM: Expose FPU registers

Add KVM register numbers for the MIPS FPU registers, and implement
access to them with the KVM_GET_ONE_REG / KVM_SET_ONE_REG ioctls when
the FPU capability is enabled (exposed in a later patch) and present in
the guest according to its Config1.FP bit.

The registers are accessible in the current mode of the guest, with each
sized access showing what the guest would see with an equivalent access,
and like the architecture they may become UNPREDICTABLE if the FR mode
is changed. When FR=0, odd doubles are inaccessible as they do not exist
in that mode.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
Cc: Paul Burton <paul.burton@imgtec.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Gleb Natapov <gleb@kernel.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: linux-mips@linux-mips.org
Cc: kvm@vger.kernel.org
Cc: linux-api@vger.kernel.org
Cc: linux-doc@vger.kernel.org
---
 Documentation/virtual/kvm/api.txt | 16 +++++++++
 arch/mips/include/uapi/asm/kvm.h  | 37 ++++++++++++++------
 arch/mips/kvm/mips.c              | 72 ++++++++++++++++++++++++++++++++++++++-
 3 files changed, 114 insertions(+), 11 deletions(-)

diff --git a/Documentation/virtual/kvm/api.txt b/Documentation/virtual/kvm/api.txt
index 3f295a04b09f..f3c198360785 100644
--- a/Documentation/virtual/kvm/api.txt
+++ b/Documentation/virtual/kvm/api.txt
@@ -1979,6 +1979,10 @@ registers, find a list below:
   MIPS  | KVM_REG_MIPS_COUNT_CTL        | 64
   MIPS  | KVM_REG_MIPS_COUNT_RESUME     | 64
   MIPS  | KVM_REG_MIPS_COUNT_HZ         | 64
+  MIPS  | KVM_REG_MIPS_FPR_32(0..31)    | 32
+  MIPS  | KVM_REG_MIPS_FPR_64(0..31)    | 64
+  MIPS  | KVM_REG_MIPS_FCR_IR           | 32
+  MIPS  | KVM_REG_MIPS_FCR_CSR          | 32
 
 ARM registers are mapped using the lower 32 bits.  The upper 16 of that
 is the register group type, or coprocessor number:
@@ -2032,6 +2036,18 @@ patterns depending on whether they're 32-bit or 64-bit registers:
 MIPS KVM control registers (see above) have the following id bit patterns:
   0x7030 0000 0002 <reg:16>
 
+MIPS FPU registers (see KVM_REG_MIPS_FPR_{32,64}() above) have the following
+id bit patterns depending on the size of the register being accessed. They are
+always accessed according to the current guest FPU mode (Status.FR and
+Config5.FRE), i.e. as the guest would see them, and they become unpredictable
+if the guest FPU mode is changed:
+  0x7020 0000 0003 00 <0:3> <reg:5> (32-bit FPU registers)
+  0x7030 0000 0003 00 <0:3> <reg:5> (64-bit FPU registers)
+
+MIPS FPU control registers (see KVM_REG_MIPS_FCR_{IR,CSR} above) have the
+following id bit patterns:
+  0x7020 0000 0003 01 <0:3> <reg:5>
+
 
 4.69 KVM_GET_ONE_REG
 
diff --git a/arch/mips/include/uapi/asm/kvm.h b/arch/mips/include/uapi/asm/kvm.h
index 75d6d8557e57..401e6a6f8bb8 100644
--- a/arch/mips/include/uapi/asm/kvm.h
+++ b/arch/mips/include/uapi/asm/kvm.h
@@ -36,18 +36,8 @@ struct kvm_regs {
 
 /*
  * for KVM_GET_FPU and KVM_SET_FPU
- *
- * If Status[FR] is zero (32-bit FPU), the upper 32-bits of the FPRs
- * are zero filled.
  */
 struct kvm_fpu {
-	__u64 fpr[32];
-	__u32 fir;
-	__u32 fccr;
-	__u32 fexr;
-	__u32 fenr;
-	__u32 fcsr;
-	__u32 pad;
 };
 
 
@@ -68,6 +58,8 @@ struct kvm_fpu {
  *
  * Register set = 2: KVM specific registers (see definitions below).
  *
+ * Register set = 3: FPU registers (see definitions below).
+ *
  * Other sets registers may be added in the future.  Each set would
  * have its own identifier in bits[31..16].
  */
@@ -75,6 +67,7 @@ struct kvm_fpu {
 #define KVM_REG_MIPS_GP		(KVM_REG_MIPS | 0x0000000000000000ULL)
 #define KVM_REG_MIPS_CP0	(KVM_REG_MIPS | 0x0000000000010000ULL)
 #define KVM_REG_MIPS_KVM	(KVM_REG_MIPS | 0x0000000000020000ULL)
+#define KVM_REG_MIPS_FPU	(KVM_REG_MIPS | 0x0000000000030000ULL)
 
 
 /*
@@ -154,6 +147,30 @@ struct kvm_fpu {
 #define KVM_REG_MIPS_COUNT_HZ	    (KVM_REG_MIPS_KVM | KVM_REG_SIZE_U64 | 2)
 
 
+/*
+ * KVM_REG_MIPS_FPU - Floating Point registers.
+ *
+ *  bits[15..8]  - Register subset (see definitions below).
+ *  bits[7..5]   - Must be zero.
+ *  bits[4..0]   - Register number within register subset.
+ */
+
+#define KVM_REG_MIPS_FPR	(KVM_REG_MIPS_FPU | 0x0000000000000000ULL)
+#define KVM_REG_MIPS_FCR	(KVM_REG_MIPS_FPU | 0x0000000000000100ULL)
+
+/*
+ * KVM_REG_MIPS_FPR - Floating point / Vector registers.
+ */
+#define KVM_REG_MIPS_FPR_32(n)	(KVM_REG_MIPS_FPR | KVM_REG_SIZE_U32  | (n))
+#define KVM_REG_MIPS_FPR_64(n)	(KVM_REG_MIPS_FPR | KVM_REG_SIZE_U64  | (n))
+
+/*
+ * KVM_REG_MIPS_FCR - Floating point control registers.
+ */
+#define KVM_REG_MIPS_FCR_IR	(KVM_REG_MIPS_FCR | KVM_REG_SIZE_U32 |  0)
+#define KVM_REG_MIPS_FCR_CSR	(KVM_REG_MIPS_FCR | KVM_REG_SIZE_U32 | 31)
+
+
 /*
  * KVM MIPS specific structures and definitions
  *
diff --git a/arch/mips/kvm/mips.c b/arch/mips/kvm/mips.c
index dd0833833bea..5e41afe15ae8 100644
--- a/arch/mips/kvm/mips.c
+++ b/arch/mips/kvm/mips.c
@@ -526,10 +526,13 @@ static int kvm_mips_get_reg(struct kvm_vcpu *vcpu,
 			    const struct kvm_one_reg *reg)
 {
 	struct mips_coproc *cop0 = vcpu->arch.cop0;
+	struct mips_fpu_struct *fpu = &vcpu->arch.fpu;
 	int ret;
 	s64 v;
+	unsigned int idx;
 
 	switch (reg->id) {
+	/* General purpose registers */
 	case KVM_REG_MIPS_R0 ... KVM_REG_MIPS_R31:
 		v = (long)vcpu->arch.gprs[reg->id - KVM_REG_MIPS_R0];
 		break;
@@ -543,6 +546,38 @@ static int kvm_mips_get_reg(struct kvm_vcpu *vcpu,
 		v = (long)vcpu->arch.pc;
 		break;
 
+	/* Floating point registers */
+	case KVM_REG_MIPS_FPR_32(0) ... KVM_REG_MIPS_FPR_32(31):
+		if (!kvm_mips_guest_has_fpu(&vcpu->arch))
+			return -EINVAL;
+		idx = reg->id - KVM_REG_MIPS_FPR_32(0);
+		/* Odd singles in top of even double when FR=0 */
+		if (kvm_read_c0_guest_status(cop0) & ST0_FR)
+			v = get_fpr32(&fpu->fpr[idx], 0);
+		else
+			v = get_fpr32(&fpu->fpr[idx & ~1], idx & 1);
+		break;
+	case KVM_REG_MIPS_FPR_64(0) ... KVM_REG_MIPS_FPR_64(31):
+		if (!kvm_mips_guest_has_fpu(&vcpu->arch))
+			return -EINVAL;
+		idx = reg->id - KVM_REG_MIPS_FPR_64(0);
+		/* Can't access odd doubles in FR=0 mode */
+		if (idx & 1 && !(kvm_read_c0_guest_status(cop0) & ST0_FR))
+			return -EINVAL;
+		v = get_fpr64(&fpu->fpr[idx], 0);
+		break;
+	case KVM_REG_MIPS_FCR_IR:
+		if (!kvm_mips_guest_has_fpu(&vcpu->arch))
+			return -EINVAL;
+		v = boot_cpu_data.fpu_id;
+		break;
+	case KVM_REG_MIPS_FCR_CSR:
+		if (!kvm_mips_guest_has_fpu(&vcpu->arch))
+			return -EINVAL;
+		v = fpu->fcr31;
+		break;
+
+	/* Co-processor 0 registers */
 	case KVM_REG_MIPS_CP0_INDEX:
 		v = (long)kvm_read_c0_guest_index(cop0);
 		break;
@@ -636,7 +671,9 @@ static int kvm_mips_set_reg(struct kvm_vcpu *vcpu,
 			    const struct kvm_one_reg *reg)
 {
 	struct mips_coproc *cop0 = vcpu->arch.cop0;
-	u64 v;
+	struct mips_fpu_struct *fpu = &vcpu->arch.fpu;
+	s64 v;
+	unsigned int idx;
 
 	if ((reg->id & KVM_REG_SIZE_MASK) == KVM_REG_SIZE_U64) {
 		u64 __user *uaddr64 = (u64 __user *)(long)reg->addr;
@@ -655,6 +692,7 @@ static int kvm_mips_set_reg(struct kvm_vcpu *vcpu,
 	}
 
 	switch (reg->id) {
+	/* General purpose registers */
 	case KVM_REG_MIPS_R0:
 		/* Silently ignore requests to set $0 */
 		break;
@@ -671,6 +709,38 @@ static int kvm_mips_set_reg(struct kvm_vcpu *vcpu,
 		vcpu->arch.pc = v;
 		break;
 
+	/* Floating point registers */
+	case KVM_REG_MIPS_FPR_32(0) ... KVM_REG_MIPS_FPR_32(31):
+		if (!kvm_mips_guest_has_fpu(&vcpu->arch))
+			return -EINVAL;
+		idx = reg->id - KVM_REG_MIPS_FPR_32(0);
+		/* Odd singles in top of even double when FR=0 */
+		if (kvm_read_c0_guest_status(cop0) & ST0_FR)
+			set_fpr32(&fpu->fpr[idx], 0, v);
+		else
+			set_fpr32(&fpu->fpr[idx & ~1], idx & 1, v);
+		break;
+	case KVM_REG_MIPS_FPR_64(0) ... KVM_REG_MIPS_FPR_64(31):
+		if (!kvm_mips_guest_has_fpu(&vcpu->arch))
+			return -EINVAL;
+		idx = reg->id - KVM_REG_MIPS_FPR_64(0);
+		/* Can't access odd doubles in FR=0 mode */
+		if (idx & 1 && !(kvm_read_c0_guest_status(cop0) & ST0_FR))
+			return -EINVAL;
+		set_fpr64(&fpu->fpr[idx], 0, v);
+		break;
+	case KVM_REG_MIPS_FCR_IR:
+		if (!kvm_mips_guest_has_fpu(&vcpu->arch))
+			return -EINVAL;
+		/* Read-only */
+		break;
+	case KVM_REG_MIPS_FCR_CSR:
+		if (!kvm_mips_guest_has_fpu(&vcpu->arch))
+			return -EINVAL;
+		fpu->fcr31 = v;
+		break;
+
+	/* Co-processor 0 registers */
 	case KVM_REG_MIPS_CP0_INDEX:
 		kvm_write_c0_guest_index(cop0, v);
 		break;
-- 
cgit v1.2.3


From 5fafd8748b366105e08c198892e9fe02ef15c021 Mon Sep 17 00:00:00 2001
From: James Hogan <james.hogan@imgtec.com>
Date: Mon, 8 Dec 2014 23:07:56 +0000
Subject: MIPS: KVM: Wire up FPU capability

Now that the code is in place for KVM to support FPU in MIPS KVM guests,
wire up the new KVM_CAP_MIPS_FPU capability.

For backwards compatibility, the capability must be explicitly enabled
in order to detect or make use of the FPU from the guest.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Gleb Natapov <gleb@kernel.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: linux-mips@linux-mips.org
Cc: kvm@vger.kernel.org
Cc: linux-api@vger.kernel.org
Cc: linux-doc@vger.kernel.org
---
 Documentation/virtual/kvm/api.txt | 13 +++++++++++++
 arch/mips/kvm/mips.c              | 37 +++++++++++++++++++++++++++++++++++++
 include/uapi/linux/kvm.h          |  1 +
 3 files changed, 51 insertions(+)

diff --git a/Documentation/virtual/kvm/api.txt b/Documentation/virtual/kvm/api.txt
index f3c198360785..a1e9bfa5fe9e 100644
--- a/Documentation/virtual/kvm/api.txt
+++ b/Documentation/virtual/kvm/api.txt
@@ -3312,6 +3312,19 @@ Parameters: none
 This capability enables the in-kernel irqchip for s390. Please refer to
 "4.24 KVM_CREATE_IRQCHIP" for details.
 
+6.9 KVM_CAP_MIPS_FPU
+
+Architectures: mips
+Target: vcpu
+Parameters: args[0] is reserved for future use (should be 0).
+
+This capability allows the use of the host Floating Point Unit by the guest. It
+allows the Config1.FP bit to be set to enable the FPU in the guest. Once this is
+done the KVM_REG_MIPS_FPR_* and KVM_REG_MIPS_FCR_* registers can be accessed
+(depending on the current guest FPU register mode), and the Status.FR,
+Config5.FRE bits are accessible via the KVM API and also from the guest,
+depending on them being supported by the FPU.
+
 7. Capabilities that can be enabled on VMs
 ------------------------------------------
 
diff --git a/arch/mips/kvm/mips.c b/arch/mips/kvm/mips.c
index 5e41afe15ae8..7f86cb73d05d 100644
--- a/arch/mips/kvm/mips.c
+++ b/arch/mips/kvm/mips.c
@@ -797,6 +797,30 @@ static int kvm_mips_set_reg(struct kvm_vcpu *vcpu,
 	return 0;
 }
 
+static int kvm_vcpu_ioctl_enable_cap(struct kvm_vcpu *vcpu,
+				     struct kvm_enable_cap *cap)
+{
+	int r = 0;
+
+	if (!kvm_vm_ioctl_check_extension(vcpu->kvm, cap->cap))
+		return -EINVAL;
+	if (cap->flags)
+		return -EINVAL;
+	if (cap->args[0])
+		return -EINVAL;
+
+	switch (cap->cap) {
+	case KVM_CAP_MIPS_FPU:
+		vcpu->arch.fpu_enabled = true;
+		break;
+	default:
+		r = -EINVAL;
+		break;
+	}
+
+	return r;
+}
+
 long kvm_arch_vcpu_ioctl(struct file *filp, unsigned int ioctl,
 			 unsigned long arg)
 {
@@ -854,6 +878,15 @@ long kvm_arch_vcpu_ioctl(struct file *filp, unsigned int ioctl,
 			r = kvm_vcpu_ioctl_interrupt(vcpu, &irq);
 			break;
 		}
+	case KVM_ENABLE_CAP: {
+		struct kvm_enable_cap cap;
+
+		r = -EFAULT;
+		if (copy_from_user(&cap, argp, sizeof(cap)))
+			goto out;
+		r = kvm_vcpu_ioctl_enable_cap(vcpu, &cap);
+		break;
+	}
 	default:
 		r = -ENOIOCTLCMD;
 	}
@@ -962,11 +995,15 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext)
 
 	switch (ext) {
 	case KVM_CAP_ONE_REG:
+	case KVM_CAP_ENABLE_CAP:
 		r = 1;
 		break;
 	case KVM_CAP_COALESCED_MMIO:
 		r = KVM_COALESCED_MMIO_PAGE_OFFSET;
 		break;
+	case KVM_CAP_MIPS_FPU:
+		r = !!cpu_has_fpu;
+		break;
 	default:
 		r = 0;
 		break;
diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h
index 1162ef7a3fa1..ce49688976d2 100644
--- a/include/uapi/linux/kvm.h
+++ b/include/uapi/linux/kvm.h
@@ -802,6 +802,7 @@ struct kvm_ppc_smmu_info {
 #define KVM_CAP_S390_MEM_OP 108
 #define KVM_CAP_S390_USER_STSI 109
 #define KVM_CAP_S390_SKEYS 110
+#define KVM_CAP_MIPS_FPU 111
 
 #ifdef KVM_CAP_IRQ_ROUTING
 
-- 
cgit v1.2.3


From 539cb89fbdfe082d00be6f83d0f2140b7802151c Mon Sep 17 00:00:00 2001
From: James Hogan <james.hogan@imgtec.com>
Date: Thu, 5 Mar 2015 11:43:36 +0000
Subject: MIPS: KVM: Add base guest MSA support

Add base code for supporting the MIPS SIMD Architecture (MSA) in MIPS
KVM guests. MSA cannot yet be enabled in the guest, we're just laying
the groundwork.

As with the FPU, whether the guest's MSA context is loaded is stored in
another bit in the fpu_inuse vcpu member. This allows MSA to be disabled
when the guest disables it, but keeping the MSA context loaded so it
doesn't have to be reloaded if the guest re-enables it.

New assembly code is added for saving and restoring the MSA context,
restoring only the upper half of the MSA context (for if the FPU context
is already loaded) and for saving/clearing and restoring MSACSR (which
can itself cause an MSA FP exception depending on the value). The MSACSR
is restored before returning to the guest if MSA is already enabled, and
the existing FP exception die notifier is extended to catch the possible
MSA FP exception and step over the ctcmsa instruction.

The helper function kvm_own_msa() is added to enable MSA and restore
the MSA context if it isn't already loaded, which will be used in a
later patch when the guest attempts to use MSA for the first time and
triggers an MSA disabled exception.

The existing FPU helpers are extended to handle MSA. kvm_lose_fpu()
saves the full MSA context if it is loaded (which includes the FPU
context) and both kvm_lose_fpu() and kvm_drop_fpu() disable MSA.

kvm_own_fpu() also needs to lose any MSA context if FR=0, since there
would be a risk of getting reserved instruction exceptions if CU1 is
enabled and we later try and save the MSA context. We shouldn't usually
hit this case since it will be handled when emulating CU1 changes,
however there's nothing to stop the guest modifying the Status register
directly via the comm page, which will cause this case to get hit.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Paul Burton <paul.burton@imgtec.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Gleb Natapov <gleb@kernel.org>
Cc: linux-mips@linux-mips.org
Cc: kvm@vger.kernel.org
---
 arch/mips/include/asm/kvm_host.h |  21 ++++-
 arch/mips/kernel/asm-offsets.c   |   1 +
 arch/mips/kvm/Makefile           |   6 +-
 arch/mips/kvm/locore.S           |  21 +++++
 arch/mips/kvm/mips.c             | 132 ++++++++++++++++++++++++++++----
 arch/mips/kvm/msa.S              | 161 +++++++++++++++++++++++++++++++++++++++
 6 files changed, 323 insertions(+), 19 deletions(-)
 create mode 100644 arch/mips/kvm/msa.S

diff --git a/arch/mips/include/asm/kvm_host.h b/arch/mips/include/asm/kvm_host.h
index fb264d8695e4..1dc0dca15cbd 100644
--- a/arch/mips/include/asm/kvm_host.h
+++ b/arch/mips/include/asm/kvm_host.h
@@ -360,6 +360,7 @@ struct kvm_mips_tlb {
 };
 
 #define KVM_MIPS_FPU_FPU	0x1
+#define KVM_MIPS_FPU_MSA	0x2
 
 #define KVM_MIPS_GUEST_TLB_SIZE	64
 struct kvm_vcpu_arch {
@@ -432,6 +433,7 @@ struct kvm_vcpu_arch {
 	int wait;
 
 	u8 fpu_enabled;
+	u8 msa_enabled;
 };
 
 
@@ -576,6 +578,18 @@ static inline bool kvm_mips_guest_has_fpu(struct kvm_vcpu_arch *vcpu)
 		kvm_read_c0_guest_config1(vcpu->cop0) & MIPS_CONF1_FP;
 }
 
+static inline bool kvm_mips_guest_can_have_msa(struct kvm_vcpu_arch *vcpu)
+{
+	return (!__builtin_constant_p(cpu_has_msa) || cpu_has_msa) &&
+		vcpu->msa_enabled;
+}
+
+static inline bool kvm_mips_guest_has_msa(struct kvm_vcpu_arch *vcpu)
+{
+	return kvm_mips_guest_can_have_msa(vcpu) &&
+		kvm_read_c0_guest_config3(vcpu->cop0) & MIPS_CONF3_MSA;
+}
+
 struct kvm_mips_callbacks {
 	int (*handle_cop_unusable)(struct kvm_vcpu *vcpu);
 	int (*handle_tlb_mod)(struct kvm_vcpu *vcpu);
@@ -619,11 +633,16 @@ int kvm_arch_vcpu_dump_regs(struct kvm_vcpu *vcpu);
 /* Trampoline ASM routine to start running in "Guest" context */
 extern int __kvm_mips_vcpu_run(struct kvm_run *run, struct kvm_vcpu *vcpu);
 
-/* FPU context management */
+/* FPU/MSA context management */
 void __kvm_save_fpu(struct kvm_vcpu_arch *vcpu);
 void __kvm_restore_fpu(struct kvm_vcpu_arch *vcpu);
 void __kvm_restore_fcsr(struct kvm_vcpu_arch *vcpu);
+void __kvm_save_msa(struct kvm_vcpu_arch *vcpu);
+void __kvm_restore_msa(struct kvm_vcpu_arch *vcpu);
+void __kvm_restore_msa_upper(struct kvm_vcpu_arch *vcpu);
+void __kvm_restore_msacsr(struct kvm_vcpu_arch *vcpu);
 void kvm_own_fpu(struct kvm_vcpu *vcpu);
+void kvm_own_msa(struct kvm_vcpu *vcpu);
 void kvm_drop_fpu(struct kvm_vcpu *vcpu);
 void kvm_lose_fpu(struct kvm_vcpu *vcpu);
 
diff --git a/arch/mips/kernel/asm-offsets.c b/arch/mips/kernel/asm-offsets.c
index a12bcf920073..e59fd7cfac9e 100644
--- a/arch/mips/kernel/asm-offsets.c
+++ b/arch/mips/kernel/asm-offsets.c
@@ -440,6 +440,7 @@ void output_kvm_defines(void)
 	OFFSET(VCPU_FPR31, kvm_vcpu_arch, fpu.fpr[31]);
 
 	OFFSET(VCPU_FCR31, kvm_vcpu_arch, fpu.fcr31);
+	OFFSET(VCPU_MSA_CSR, kvm_vcpu_arch, fpu.msacsr);
 	BLANK();
 
 	OFFSET(VCPU_COP0, kvm_vcpu_arch, cop0);
diff --git a/arch/mips/kvm/Makefile b/arch/mips/kvm/Makefile
index 78d7bcd7710a..637ebbebd549 100644
--- a/arch/mips/kvm/Makefile
+++ b/arch/mips/kvm/Makefile
@@ -1,11 +1,13 @@
 # Makefile for KVM support for MIPS
 #
 
-common-objs = $(addprefix ../../../virt/kvm/, kvm_main.o coalesced_mmio.o)
+common-objs-y = $(addprefix ../../../virt/kvm/, kvm_main.o coalesced_mmio.o)
 
 EXTRA_CFLAGS += -Ivirt/kvm -Iarch/mips/kvm
 
-kvm-objs := $(common-objs) mips.o emulate.o locore.o \
+common-objs-$(CONFIG_CPU_HAS_MSA) += msa.o
+
+kvm-objs := $(common-objs-y) mips.o emulate.o locore.o \
 	    interrupt.o stats.o commpage.o \
 	    dyntrans.o trap_emul.o fpu.o
 
diff --git a/arch/mips/kvm/locore.S b/arch/mips/kvm/locore.S
index f5594049c0c3..c567240386a0 100644
--- a/arch/mips/kvm/locore.S
+++ b/arch/mips/kvm/locore.S
@@ -36,6 +36,8 @@
 #define PT_HOST_USERLOCAL   PT_EPC
 
 #define CP0_DDATA_LO        $28,3
+#define CP0_CONFIG3         $16,3
+#define CP0_CONFIG5         $16,5
 #define CP0_EBASE           $15,1
 
 #define CP0_INTCTL          $12,1
@@ -370,6 +372,25 @@ NESTED (MIPSX(GuestException), CALLFRAME_SIZ, ra)
 	.set	noat
 1:
 
+#ifdef CONFIG_CPU_HAS_MSA
+	/*
+	 * If MSA is enabled, save MSACSR and clear it so that later
+	 * instructions don't trigger MSAFPE for pending exceptions.
+	 */
+	mfc0	t0, CP0_CONFIG3
+	ext	t0, t0, 28, 1 /* MIPS_CONF3_MSAP */
+	beqz	t0, 1f
+	 nop
+	mfc0	t0, CP0_CONFIG5
+	ext	t0, t0, 27, 1 /* MIPS_CONF5_MSAEN */
+	beqz	t0, 1f
+	 nop
+	_cfcmsa	t0, MSA_CSR
+	sw	t0, VCPU_MSA_CSR(k1)
+	_ctcmsa	MSA_CSR, zero
+1:
+#endif
+
 	/* Now that the new EBASE has been loaded, unset BEV and KSU_USER */
 	.set	at
 	and	v0, v0, ~(ST0_EXL | KSU_USER | ST0_IE)
diff --git a/arch/mips/kvm/mips.c b/arch/mips/kvm/mips.c
index 7f86cb73d05d..a17f21015a0b 100644
--- a/arch/mips/kvm/mips.c
+++ b/arch/mips/kvm/mips.c
@@ -1295,17 +1295,21 @@ skip_emul:
 
 	if (ret == RESUME_GUEST) {
 		/*
-		 * If FPU is enabled (i.e. the guest's FPU context is live),
-		 * restore FCR31.
+		 * If FPU / MSA are enabled (i.e. the guest's FPU / MSA context
+		 * is live), restore FCR31 / MSACSR.
 		 *
 		 * This should be before returning to the guest exception
-		 * vector, as it may well cause an FP exception if there are
-		 * pending exception bits unmasked. (see
+		 * vector, as it may well cause an [MSA] FP exception if there
+		 * are pending exception bits unmasked. (see
 		 * kvm_mips_csr_die_notifier() for how that is handled).
 		 */
 		if (kvm_mips_guest_has_fpu(&vcpu->arch) &&
 		    read_c0_status() & ST0_CU1)
 			__kvm_restore_fcsr(&vcpu->arch);
+
+		if (kvm_mips_guest_has_msa(&vcpu->arch) &&
+		    read_c0_config5() & MIPS_CONF5_MSAEN)
+			__kvm_restore_msacsr(&vcpu->arch);
 	}
 
 	/* Disable HTW before returning to guest or host */
@@ -1322,11 +1326,26 @@ void kvm_own_fpu(struct kvm_vcpu *vcpu)
 
 	preempt_disable();
 
+	sr = kvm_read_c0_guest_status(cop0);
+
+	/*
+	 * If MSA state is already live, it is undefined how it interacts with
+	 * FR=0 FPU state, and we don't want to hit reserved instruction
+	 * exceptions trying to save the MSA state later when CU=1 && FR=1, so
+	 * play it safe and save it first.
+	 *
+	 * In theory we shouldn't ever hit this case since kvm_lose_fpu() should
+	 * get called when guest CU1 is set, however we can't trust the guest
+	 * not to clobber the status register directly via the commpage.
+	 */
+	if (cpu_has_msa && sr & ST0_CU1 && !(sr & ST0_FR) &&
+	    vcpu->arch.fpu_inuse & KVM_MIPS_FPU_MSA)
+		kvm_lose_fpu(vcpu);
+
 	/*
 	 * Enable FPU for guest
 	 * We set FR and FRE according to guest context
 	 */
-	sr = kvm_read_c0_guest_status(cop0);
 	change_c0_status(ST0_CU1 | ST0_FR, sr);
 	if (cpu_has_fre) {
 		cfg5 = kvm_read_c0_guest_config5(cop0);
@@ -1343,10 +1362,73 @@ void kvm_own_fpu(struct kvm_vcpu *vcpu)
 	preempt_enable();
 }
 
-/* Drop FPU without saving it */
+#ifdef CONFIG_CPU_HAS_MSA
+/* Enable MSA for guest and restore context */
+void kvm_own_msa(struct kvm_vcpu *vcpu)
+{
+	struct mips_coproc *cop0 = vcpu->arch.cop0;
+	unsigned int sr, cfg5;
+
+	preempt_disable();
+
+	/*
+	 * Enable FPU if enabled in guest, since we're restoring FPU context
+	 * anyway. We set FR and FRE according to guest context.
+	 */
+	if (kvm_mips_guest_has_fpu(&vcpu->arch)) {
+		sr = kvm_read_c0_guest_status(cop0);
+
+		/*
+		 * If FR=0 FPU state is already live, it is undefined how it
+		 * interacts with MSA state, so play it safe and save it first.
+		 */
+		if (!(sr & ST0_FR) &&
+		    (vcpu->arch.fpu_inuse & (KVM_MIPS_FPU_FPU |
+				KVM_MIPS_FPU_MSA)) == KVM_MIPS_FPU_FPU)
+			kvm_lose_fpu(vcpu);
+
+		change_c0_status(ST0_CU1 | ST0_FR, sr);
+		if (sr & ST0_CU1 && cpu_has_fre) {
+			cfg5 = kvm_read_c0_guest_config5(cop0);
+			change_c0_config5(MIPS_CONF5_FRE, cfg5);
+		}
+	}
+
+	/* Enable MSA for guest */
+	set_c0_config5(MIPS_CONF5_MSAEN);
+	enable_fpu_hazard();
+
+	switch (vcpu->arch.fpu_inuse & (KVM_MIPS_FPU_FPU | KVM_MIPS_FPU_MSA)) {
+	case KVM_MIPS_FPU_FPU:
+		/*
+		 * Guest FPU state already loaded, only restore upper MSA state
+		 */
+		__kvm_restore_msa_upper(&vcpu->arch);
+		vcpu->arch.fpu_inuse |= KVM_MIPS_FPU_MSA;
+		break;
+	case 0:
+		/* Neither FPU or MSA already active, restore full MSA state */
+		__kvm_restore_msa(&vcpu->arch);
+		vcpu->arch.fpu_inuse |= KVM_MIPS_FPU_MSA;
+		if (kvm_mips_guest_has_fpu(&vcpu->arch))
+			vcpu->arch.fpu_inuse |= KVM_MIPS_FPU_FPU;
+		break;
+	default:
+		break;
+	}
+
+	preempt_enable();
+}
+#endif
+
+/* Drop FPU & MSA without saving it */
 void kvm_drop_fpu(struct kvm_vcpu *vcpu)
 {
 	preempt_disable();
+	if (cpu_has_msa && vcpu->arch.fpu_inuse & KVM_MIPS_FPU_MSA) {
+		disable_msa();
+		vcpu->arch.fpu_inuse &= ~KVM_MIPS_FPU_MSA;
+	}
 	if (vcpu->arch.fpu_inuse & KVM_MIPS_FPU_FPU) {
 		clear_c0_status(ST0_CU1 | ST0_FR);
 		vcpu->arch.fpu_inuse &= ~KVM_MIPS_FPU_FPU;
@@ -1354,18 +1436,29 @@ void kvm_drop_fpu(struct kvm_vcpu *vcpu)
 	preempt_enable();
 }
 
-/* Save and disable FPU */
+/* Save and disable FPU & MSA */
 void kvm_lose_fpu(struct kvm_vcpu *vcpu)
 {
 	/*
-	 * FPU gets disabled in root context (hardware) when it is disabled in
-	 * guest context (software), but the register state in the hardware may
-	 * still be in use. This is why we explicitly re-enable the hardware
+	 * FPU & MSA get disabled in root context (hardware) when it is disabled
+	 * in guest context (software), but the register state in the hardware
+	 * may still be in use. This is why we explicitly re-enable the hardware
 	 * before saving.
 	 */
 
 	preempt_disable();
-	if (vcpu->arch.fpu_inuse & KVM_MIPS_FPU_FPU) {
+	if (cpu_has_msa && vcpu->arch.fpu_inuse & KVM_MIPS_FPU_MSA) {
+		set_c0_config5(MIPS_CONF5_MSAEN);
+		enable_fpu_hazard();
+
+		__kvm_save_msa(&vcpu->arch);
+
+		/* Disable MSA & FPU */
+		disable_msa();
+		if (vcpu->arch.fpu_inuse & KVM_MIPS_FPU_FPU)
+			clear_c0_status(ST0_CU1 | ST0_FR);
+		vcpu->arch.fpu_inuse &= ~(KVM_MIPS_FPU_FPU | KVM_MIPS_FPU_MSA);
+	} else if (vcpu->arch.fpu_inuse & KVM_MIPS_FPU_FPU) {
 		set_c0_status(ST0_CU1);
 		enable_fpu_hazard();
 
@@ -1379,9 +1472,9 @@ void kvm_lose_fpu(struct kvm_vcpu *vcpu)
 }
 
 /*
- * Step over a specific ctc1 to FCSR which is used to restore guest FCSR state
- * and may trigger a "harmless" FP exception if cause bits are set in the value
- * being written.
+ * Step over a specific ctc1 to FCSR and a specific ctcmsa to MSACSR which are
+ * used to restore guest FCSR/MSACSR state and may trigger a "harmless" FP/MSAFP
+ * exception if cause bits are set in the value being written.
  */
 static int kvm_mips_csr_die_notify(struct notifier_block *self,
 				   unsigned long cmd, void *ptr)
@@ -1390,8 +1483,8 @@ static int kvm_mips_csr_die_notify(struct notifier_block *self,
 	struct pt_regs *regs = args->regs;
 	unsigned long pc;
 
-	/* Only interested in FPE */
-	if (cmd != DIE_FP)
+	/* Only interested in FPE and MSAFPE */
+	if (cmd != DIE_FP && cmd != DIE_MSAFP)
 		return NOTIFY_DONE;
 
 	/* Return immediately if guest context isn't active */
@@ -1408,6 +1501,13 @@ static int kvm_mips_csr_die_notify(struct notifier_block *self,
 		if (pc != (unsigned long)&__kvm_restore_fcsr + 4)
 			return NOTIFY_DONE;
 		break;
+	case DIE_MSAFP:
+		/* match 2nd/3rd instruction in __kvm_restore_msacsr */
+		if (!cpu_has_msa ||
+		    pc < (unsigned long)&__kvm_restore_msacsr + 4 ||
+		    pc > (unsigned long)&__kvm_restore_msacsr + 8)
+			return NOTIFY_DONE;
+		break;
 	}
 
 	/* Move PC forward a little and continue executing */
diff --git a/arch/mips/kvm/msa.S b/arch/mips/kvm/msa.S
new file mode 100644
index 000000000000..d02f0c6cc2cc
--- /dev/null
+++ b/arch/mips/kvm/msa.S
@@ -0,0 +1,161 @@
+/*
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License.  See the file "COPYING" in the main directory of this archive
+ * for more details.
+ *
+ * MIPS SIMD Architecture (MSA) context handling code for KVM.
+ *
+ * Copyright (C) 2015 Imagination Technologies Ltd.
+ */
+
+#include <asm/asm.h>
+#include <asm/asm-offsets.h>
+#include <asm/asmmacro.h>
+#include <asm/regdef.h>
+
+	.set	noreorder
+	.set	noat
+
+LEAF(__kvm_save_msa)
+	st_d	0,  VCPU_FPR0,  a0
+	st_d	1,  VCPU_FPR1,  a0
+	st_d	2,  VCPU_FPR2,  a0
+	st_d	3,  VCPU_FPR3,  a0
+	st_d	4,  VCPU_FPR4,  a0
+	st_d	5,  VCPU_FPR5,  a0
+	st_d	6,  VCPU_FPR6,  a0
+	st_d	7,  VCPU_FPR7,  a0
+	st_d	8,  VCPU_FPR8,  a0
+	st_d	9,  VCPU_FPR9,  a0
+	st_d	10, VCPU_FPR10, a0
+	st_d	11, VCPU_FPR11, a0
+	st_d	12, VCPU_FPR12, a0
+	st_d	13, VCPU_FPR13, a0
+	st_d	14, VCPU_FPR14, a0
+	st_d	15, VCPU_FPR15, a0
+	st_d	16, VCPU_FPR16, a0
+	st_d	17, VCPU_FPR17, a0
+	st_d	18, VCPU_FPR18, a0
+	st_d	19, VCPU_FPR19, a0
+	st_d	20, VCPU_FPR20, a0
+	st_d	21, VCPU_FPR21, a0
+	st_d	22, VCPU_FPR22, a0
+	st_d	23, VCPU_FPR23, a0
+	st_d	24, VCPU_FPR24, a0
+	st_d	25, VCPU_FPR25, a0
+	st_d	26, VCPU_FPR26, a0
+	st_d	27, VCPU_FPR27, a0
+	st_d	28, VCPU_FPR28, a0
+	st_d	29, VCPU_FPR29, a0
+	st_d	30, VCPU_FPR30, a0
+	st_d	31, VCPU_FPR31, a0
+	jr	ra
+	 nop
+	END(__kvm_save_msa)
+
+LEAF(__kvm_restore_msa)
+	ld_d	0,  VCPU_FPR0,  a0
+	ld_d	1,  VCPU_FPR1,  a0
+	ld_d	2,  VCPU_FPR2,  a0
+	ld_d	3,  VCPU_FPR3,  a0
+	ld_d	4,  VCPU_FPR4,  a0
+	ld_d	5,  VCPU_FPR5,  a0
+	ld_d	6,  VCPU_FPR6,  a0
+	ld_d	7,  VCPU_FPR7,  a0
+	ld_d	8,  VCPU_FPR8,  a0
+	ld_d	9,  VCPU_FPR9,  a0
+	ld_d	10, VCPU_FPR10, a0
+	ld_d	11, VCPU_FPR11, a0
+	ld_d	12, VCPU_FPR12, a0
+	ld_d	13, VCPU_FPR13, a0
+	ld_d	14, VCPU_FPR14, a0
+	ld_d	15, VCPU_FPR15, a0
+	ld_d	16, VCPU_FPR16, a0
+	ld_d	17, VCPU_FPR17, a0
+	ld_d	18, VCPU_FPR18, a0
+	ld_d	19, VCPU_FPR19, a0
+	ld_d	20, VCPU_FPR20, a0
+	ld_d	21, VCPU_FPR21, a0
+	ld_d	22, VCPU_FPR22, a0
+	ld_d	23, VCPU_FPR23, a0
+	ld_d	24, VCPU_FPR24, a0
+	ld_d	25, VCPU_FPR25, a0
+	ld_d	26, VCPU_FPR26, a0
+	ld_d	27, VCPU_FPR27, a0
+	ld_d	28, VCPU_FPR28, a0
+	ld_d	29, VCPU_FPR29, a0
+	ld_d	30, VCPU_FPR30, a0
+	ld_d	31, VCPU_FPR31, a0
+	jr	ra
+	 nop
+	END(__kvm_restore_msa)
+
+	.macro	kvm_restore_msa_upper	wr, off, base
+	.set	push
+	.set	noat
+#ifdef CONFIG_64BIT
+	ld	$1, \off(\base)
+	insert_d \wr, 1
+#elif defined(CONFIG_CPU_LITTLE_ENDIAN)
+	lw	$1, \off(\base)
+	insert_w \wr, 2
+	lw	$1, (\off+4)(\base)
+	insert_w \wr, 3
+#else /* CONFIG_CPU_BIG_ENDIAN */
+	lw	$1, (\off+4)(\base)
+	insert_w \wr, 2
+	lw	$1, \off(\base)
+	insert_w \wr, 3
+#endif
+	.set	pop
+	.endm
+
+LEAF(__kvm_restore_msa_upper)
+	kvm_restore_msa_upper	0,  VCPU_FPR0 +8, a0
+	kvm_restore_msa_upper	1,  VCPU_FPR1 +8, a0
+	kvm_restore_msa_upper	2,  VCPU_FPR2 +8, a0
+	kvm_restore_msa_upper	3,  VCPU_FPR3 +8, a0
+	kvm_restore_msa_upper	4,  VCPU_FPR4 +8, a0
+	kvm_restore_msa_upper	5,  VCPU_FPR5 +8, a0
+	kvm_restore_msa_upper	6,  VCPU_FPR6 +8, a0
+	kvm_restore_msa_upper	7,  VCPU_FPR7 +8, a0
+	kvm_restore_msa_upper	8,  VCPU_FPR8 +8, a0
+	kvm_restore_msa_upper	9,  VCPU_FPR9 +8, a0
+	kvm_restore_msa_upper	10, VCPU_FPR10+8, a0
+	kvm_restore_msa_upper	11, VCPU_FPR11+8, a0
+	kvm_restore_msa_upper	12, VCPU_FPR12+8, a0
+	kvm_restore_msa_upper	13, VCPU_FPR13+8, a0
+	kvm_restore_msa_upper	14, VCPU_FPR14+8, a0
+	kvm_restore_msa_upper	15, VCPU_FPR15+8, a0
+	kvm_restore_msa_upper	16, VCPU_FPR16+8, a0
+	kvm_restore_msa_upper	17, VCPU_FPR17+8, a0
+	kvm_restore_msa_upper	18, VCPU_FPR18+8, a0
+	kvm_restore_msa_upper	19, VCPU_FPR19+8, a0
+	kvm_restore_msa_upper	20, VCPU_FPR20+8, a0
+	kvm_restore_msa_upper	21, VCPU_FPR21+8, a0
+	kvm_restore_msa_upper	22, VCPU_FPR22+8, a0
+	kvm_restore_msa_upper	23, VCPU_FPR23+8, a0
+	kvm_restore_msa_upper	24, VCPU_FPR24+8, a0
+	kvm_restore_msa_upper	25, VCPU_FPR25+8, a0
+	kvm_restore_msa_upper	26, VCPU_FPR26+8, a0
+	kvm_restore_msa_upper	27, VCPU_FPR27+8, a0
+	kvm_restore_msa_upper	28, VCPU_FPR28+8, a0
+	kvm_restore_msa_upper	29, VCPU_FPR29+8, a0
+	kvm_restore_msa_upper	30, VCPU_FPR30+8, a0
+	kvm_restore_msa_upper	31, VCPU_FPR31+8, a0
+	jr	ra
+	 nop
+	END(__kvm_restore_msa_upper)
+
+LEAF(__kvm_restore_msacsr)
+	lw	t0, VCPU_MSA_CSR(a0)
+	/*
+	 * The ctcmsa must stay at this offset in __kvm_restore_msacsr.
+	 * See kvm_mips_csr_die_notify() which handles t0 containing a value
+	 * which triggers an MSA FP Exception, which must be stepped over and
+	 * ignored since the set cause bits must remain there for the guest.
+	 */
+	_ctcmsa	MSA_CSR, t0
+	jr	ra
+	 nop
+	END(__kvm_restore_msacsr)
-- 
cgit v1.2.3


From 2b6009d646887cac8888f1ce8694af0beefce88b Mon Sep 17 00:00:00 2001
From: James Hogan <james.hogan@imgtec.com>
Date: Fri, 6 Feb 2015 23:01:00 +0000
Subject: MIPS: KVM: Emulate MSA bits in COP0 interface

Emulate MSA related parts of COP0 interface so that the guest will be
able to enable/disable MSA (Config5.MSAEn) once the MSA capability has
been wired up.

As with the FPU (Status.CU1) setting Config5.MSAEn has no immediate
effect if the MSA state isn't live, as MSA state is restored lazily on
first use. Changes after the MSA state has been restored take immediate
effect, so that the guest can start getting MSA disabled exceptions
right away for guest MSA operations. The MSA state is saved lazily too,
as MSA may get re-enabled in the near future anyway.

A special case is also added for when Status.CU1 is set while FR=0 and
the MSA state is live. In this case we are at risk of getting reserved
instruction exceptions if we try and save the MSA state, so we lose the
MSA state sooner while MSA is still usable.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Paul Burton <paul.burton@imgtec.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Gleb Natapov <gleb@kernel.org>
Cc: linux-mips@linux-mips.org
Cc: kvm@vger.kernel.org
---
 arch/mips/kvm/emulate.c | 37 +++++++++++++++++++++++++++++++++++--
 1 file changed, 35 insertions(+), 2 deletions(-)

diff --git a/arch/mips/kvm/emulate.c b/arch/mips/kvm/emulate.c
index fbf169fb63df..07f554c72cb8 100644
--- a/arch/mips/kvm/emulate.c
+++ b/arch/mips/kvm/emulate.c
@@ -912,7 +912,13 @@ unsigned int kvm_mips_config1_wrmask(struct kvm_vcpu *vcpu)
 unsigned int kvm_mips_config3_wrmask(struct kvm_vcpu *vcpu)
 {
 	/* Config4 is optional */
-	return MIPS_CONF_M;
+	unsigned int mask = MIPS_CONF_M;
+
+	/* Permit MSA to be present if MSA is supported */
+	if (kvm_mips_guest_can_have_msa(&vcpu->arch))
+		mask |= MIPS_CONF3_MSA;
+
+	return mask;
 }
 
 /**
@@ -939,6 +945,10 @@ unsigned int kvm_mips_config5_wrmask(struct kvm_vcpu *vcpu)
 {
 	unsigned int mask = 0;
 
+	/* Permit MSAEn changes if MSA supported and enabled */
+	if (kvm_mips_guest_has_msa(&vcpu->arch))
+		mask |= MIPS_CONF5_MSAEN;
+
 	/*
 	 * Permit guest FPU mode changes if FPU is enabled and the relevant
 	 * feature exists according to FIR register.
@@ -1125,6 +1135,18 @@ enum emulation_result kvm_mips_emulate_CP0(uint32_t inst, uint32_t *opc,
 				if (change & ST0_FR)
 					kvm_drop_fpu(vcpu);
 
+				/*
+				 * If MSA state is already live, it is undefined
+				 * how it interacts with FR=0 FPU state, and we
+				 * don't want to hit reserved instruction
+				 * exceptions trying to save the MSA state later
+				 * when CU=1 && FR=1, so play it safe and save
+				 * it first.
+				 */
+				if (change & ST0_CU1 && !(val & ST0_FR) &&
+				    vcpu->arch.fpu_inuse & KVM_MIPS_FPU_MSA)
+					kvm_lose_fpu(vcpu);
+
 				/*
 				 * Propagate CU1 (FPU enable) changes
 				 * immediately if the FPU context is already
@@ -1160,7 +1182,7 @@ enum emulation_result kvm_mips_emulate_CP0(uint32_t inst, uint32_t *opc,
 				val = old_val ^ change;
 
 
-				/* Handle changes in FPU modes */
+				/* Handle changes in FPU/MSA modes */
 				preempt_disable();
 
 				/*
@@ -1171,6 +1193,17 @@ enum emulation_result kvm_mips_emulate_CP0(uint32_t inst, uint32_t *opc,
 				    vcpu->arch.fpu_inuse & KVM_MIPS_FPU_FPU)
 					change_c0_config5(MIPS_CONF5_FRE, val);
 
+				/*
+				 * Propagate MSAEn changes immediately if the
+				 * MSA context is already loaded. When disabling
+				 * we leave the context loaded so it can be
+				 * quickly enabled again in the near future.
+				 */
+				if (change & MIPS_CONF5_MSAEN &&
+				    vcpu->arch.fpu_inuse & KVM_MIPS_FPU_MSA)
+					change_c0_config5(MIPS_CONF5_MSAEN,
+							  val);
+
 				preempt_enable();
 
 				kvm_write_c0_guest_config5(cop0, val);
-- 
cgit v1.2.3


From c2537ed9fb8e17d713e5e67fcede047699d25814 Mon Sep 17 00:00:00 2001
From: James Hogan <james.hogan@imgtec.com>
Date: Fri, 6 Feb 2015 10:56:27 +0000
Subject: MIPS: KVM: Add MSA exception handling

Add guest exception handling for MIPS SIMD Architecture (MSA) floating
point exceptions and MSA disabled exceptions.

MSA floating point exceptions from the guest need passing to the guest
kernel, so for these a guest MSAFPE is emulated.

MSA disabled exceptions are normally handled by passing a reserved
instruction exception to the guest (because no guest MSA was supported),
but the hypervisor can now handle them if the guest has MSA by passing
an MSA disabled exception to the guest, or if the guest has MSA enabled
by transparently restoring the guest MSA context and enabling MSA and
the FPU.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Paul Burton <paul.burton@imgtec.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Gleb Natapov <gleb@kernel.org>
Cc: linux-mips@linux-mips.org
Cc: kvm@vger.kernel.org
---
 arch/mips/include/asm/kvm_host.h | 16 +++++++++
 arch/mips/kvm/emulate.c          | 71 ++++++++++++++++++++++++++++++++++++++++
 arch/mips/kvm/mips.c             | 10 ++++++
 arch/mips/kvm/stats.c            |  2 ++
 arch/mips/kvm/trap_emul.c        | 43 ++++++++++++++++++++++--
 5 files changed, 140 insertions(+), 2 deletions(-)

diff --git a/arch/mips/include/asm/kvm_host.h b/arch/mips/include/asm/kvm_host.h
index 1dc0dca15cbd..4c25823563fe 100644
--- a/arch/mips/include/asm/kvm_host.h
+++ b/arch/mips/include/asm/kvm_host.h
@@ -123,7 +123,9 @@ struct kvm_vcpu_stat {
 	u32 resvd_inst_exits;
 	u32 break_inst_exits;
 	u32 trap_inst_exits;
+	u32 msa_fpe_exits;
 	u32 fpe_exits;
+	u32 msa_disabled_exits;
 	u32 flush_dcache_exits;
 	u32 halt_successful_poll;
 	u32 halt_wakeup;
@@ -144,7 +146,9 @@ enum kvm_mips_exit_types {
 	RESVD_INST_EXITS,
 	BREAK_INST_EXITS,
 	TRAP_INST_EXITS,
+	MSA_FPE_EXITS,
 	FPE_EXITS,
+	MSA_DISABLED_EXITS,
 	FLUSH_DCACHE_EXITS,
 	MAX_KVM_MIPS_EXIT_TYPES
 };
@@ -305,6 +309,7 @@ enum mips_mmu_types {
  */
 #define T_TRAP			13	/* Trap instruction */
 #define T_VCEI			14	/* Virtual coherency exception */
+#define T_MSAFPE		14	/* MSA floating point exception */
 #define T_FPE			15	/* Floating point exception */
 #define T_MSADIS		21	/* MSA disabled exception */
 #define T_WATCH			23	/* Watch address reference */
@@ -601,6 +606,7 @@ struct kvm_mips_callbacks {
 	int (*handle_res_inst)(struct kvm_vcpu *vcpu);
 	int (*handle_break)(struct kvm_vcpu *vcpu);
 	int (*handle_trap)(struct kvm_vcpu *vcpu);
+	int (*handle_msa_fpe)(struct kvm_vcpu *vcpu);
 	int (*handle_fpe)(struct kvm_vcpu *vcpu);
 	int (*handle_msa_disabled)(struct kvm_vcpu *vcpu);
 	int (*vm_init)(struct kvm *kvm);
@@ -756,11 +762,21 @@ extern enum emulation_result kvm_mips_emulate_trap_exc(unsigned long cause,
 						       struct kvm_run *run,
 						       struct kvm_vcpu *vcpu);
 
+extern enum emulation_result kvm_mips_emulate_msafpe_exc(unsigned long cause,
+							 uint32_t *opc,
+							 struct kvm_run *run,
+							 struct kvm_vcpu *vcpu);
+
 extern enum emulation_result kvm_mips_emulate_fpe_exc(unsigned long cause,
 						      uint32_t *opc,
 						      struct kvm_run *run,
 						      struct kvm_vcpu *vcpu);
 
+extern enum emulation_result kvm_mips_emulate_msadis_exc(unsigned long cause,
+							 uint32_t *opc,
+							 struct kvm_run *run,
+							 struct kvm_vcpu *vcpu);
+
 extern enum emulation_result kvm_mips_complete_mmio_load(struct kvm_vcpu *vcpu,
 							 struct kvm_run *run);
 
diff --git a/arch/mips/kvm/emulate.c b/arch/mips/kvm/emulate.c
index 07f554c72cb8..6230f376a44e 100644
--- a/arch/mips/kvm/emulate.c
+++ b/arch/mips/kvm/emulate.c
@@ -2179,6 +2179,41 @@ enum emulation_result kvm_mips_emulate_trap_exc(unsigned long cause,
 	return er;
 }
 
+enum emulation_result kvm_mips_emulate_msafpe_exc(unsigned long cause,
+						  uint32_t *opc,
+						  struct kvm_run *run,
+						  struct kvm_vcpu *vcpu)
+{
+	struct mips_coproc *cop0 = vcpu->arch.cop0;
+	struct kvm_vcpu_arch *arch = &vcpu->arch;
+	enum emulation_result er = EMULATE_DONE;
+
+	if ((kvm_read_c0_guest_status(cop0) & ST0_EXL) == 0) {
+		/* save old pc */
+		kvm_write_c0_guest_epc(cop0, arch->pc);
+		kvm_set_c0_guest_status(cop0, ST0_EXL);
+
+		if (cause & CAUSEF_BD)
+			kvm_set_c0_guest_cause(cop0, CAUSEF_BD);
+		else
+			kvm_clear_c0_guest_cause(cop0, CAUSEF_BD);
+
+		kvm_debug("Delivering MSAFPE @ pc %#lx\n", arch->pc);
+
+		kvm_change_c0_guest_cause(cop0, (0xff),
+					  (T_MSAFPE << CAUSEB_EXCCODE));
+
+		/* Set PC to the exception entry point */
+		arch->pc = KVM_GUEST_KSEG0 + 0x180;
+
+	} else {
+		kvm_err("Trying to deliver MSAFPE when EXL is already set\n");
+		er = EMULATE_FAIL;
+	}
+
+	return er;
+}
+
 enum emulation_result kvm_mips_emulate_fpe_exc(unsigned long cause,
 					       uint32_t *opc,
 					       struct kvm_run *run,
@@ -2214,6 +2249,41 @@ enum emulation_result kvm_mips_emulate_fpe_exc(unsigned long cause,
 	return er;
 }
 
+enum emulation_result kvm_mips_emulate_msadis_exc(unsigned long cause,
+						  uint32_t *opc,
+						  struct kvm_run *run,
+						  struct kvm_vcpu *vcpu)
+{
+	struct mips_coproc *cop0 = vcpu->arch.cop0;
+	struct kvm_vcpu_arch *arch = &vcpu->arch;
+	enum emulation_result er = EMULATE_DONE;
+
+	if ((kvm_read_c0_guest_status(cop0) & ST0_EXL) == 0) {
+		/* save old pc */
+		kvm_write_c0_guest_epc(cop0, arch->pc);
+		kvm_set_c0_guest_status(cop0, ST0_EXL);
+
+		if (cause & CAUSEF_BD)
+			kvm_set_c0_guest_cause(cop0, CAUSEF_BD);
+		else
+			kvm_clear_c0_guest_cause(cop0, CAUSEF_BD);
+
+		kvm_debug("Delivering MSADIS @ pc %#lx\n", arch->pc);
+
+		kvm_change_c0_guest_cause(cop0, (0xff),
+					  (T_MSADIS << CAUSEB_EXCCODE));
+
+		/* Set PC to the exception entry point */
+		arch->pc = KVM_GUEST_KSEG0 + 0x180;
+
+	} else {
+		kvm_err("Trying to deliver MSADIS when EXL is already set\n");
+		er = EMULATE_FAIL;
+	}
+
+	return er;
+}
+
 /* ll/sc, rdhwr, sync emulation */
 
 #define OPCODE 0xfc000000
@@ -2421,6 +2491,7 @@ enum emulation_result kvm_mips_check_privilege(unsigned long cause,
 		case T_BREAK:
 		case T_RES_INST:
 		case T_TRAP:
+		case T_MSAFPE:
 		case T_FPE:
 		case T_MSADIS:
 			break;
diff --git a/arch/mips/kvm/mips.c b/arch/mips/kvm/mips.c
index a17f21015a0b..e02c7e5a12ff 100644
--- a/arch/mips/kvm/mips.c
+++ b/arch/mips/kvm/mips.c
@@ -50,7 +50,9 @@ struct kvm_stats_debugfs_item debugfs_entries[] = {
 	{ "resvd_inst",	  VCPU_STAT(resvd_inst_exits),	 KVM_STAT_VCPU },
 	{ "break_inst",	  VCPU_STAT(break_inst_exits),	 KVM_STAT_VCPU },
 	{ "trap_inst",	  VCPU_STAT(trap_inst_exits),	 KVM_STAT_VCPU },
+	{ "msa_fpe",	  VCPU_STAT(msa_fpe_exits),	 KVM_STAT_VCPU },
 	{ "fpe",	  VCPU_STAT(fpe_exits),		 KVM_STAT_VCPU },
+	{ "msa_disabled", VCPU_STAT(msa_disabled_exits), KVM_STAT_VCPU },
 	{ "flush_dcache", VCPU_STAT(flush_dcache_exits), KVM_STAT_VCPU },
 	{ "halt_successful_poll", VCPU_STAT(halt_successful_poll), KVM_STAT_VCPU },
 	{ "halt_wakeup",  VCPU_STAT(halt_wakeup),	 KVM_STAT_VCPU },
@@ -1256,6 +1258,12 @@ int kvm_mips_handle_exit(struct kvm_run *run, struct kvm_vcpu *vcpu)
 		ret = kvm_mips_callbacks->handle_trap(vcpu);
 		break;
 
+	case T_MSAFPE:
+		++vcpu->stat.msa_fpe_exits;
+		trace_kvm_exit(vcpu, MSA_FPE_EXITS);
+		ret = kvm_mips_callbacks->handle_msa_fpe(vcpu);
+		break;
+
 	case T_FPE:
 		++vcpu->stat.fpe_exits;
 		trace_kvm_exit(vcpu, FPE_EXITS);
@@ -1263,6 +1271,8 @@ int kvm_mips_handle_exit(struct kvm_run *run, struct kvm_vcpu *vcpu)
 		break;
 
 	case T_MSADIS:
+		++vcpu->stat.msa_disabled_exits;
+		trace_kvm_exit(vcpu, MSA_DISABLED_EXITS);
 		ret = kvm_mips_callbacks->handle_msa_disabled(vcpu);
 		break;
 
diff --git a/arch/mips/kvm/stats.c b/arch/mips/kvm/stats.c
index 3843828f3b91..888bb67070ac 100644
--- a/arch/mips/kvm/stats.c
+++ b/arch/mips/kvm/stats.c
@@ -26,7 +26,9 @@ char *kvm_mips_exit_types_str[MAX_KVM_MIPS_EXIT_TYPES] = {
 	"Reserved Inst",
 	"Break Inst",
 	"Trap Inst",
+	"MSA FPE",
 	"FPE",
+	"MSA Disabled",
 	"D-Cache Flushes",
 };
 
diff --git a/arch/mips/kvm/trap_emul.c b/arch/mips/kvm/trap_emul.c
index 421d5b815f24..d836ed5b0bc7 100644
--- a/arch/mips/kvm/trap_emul.c
+++ b/arch/mips/kvm/trap_emul.c
@@ -362,6 +362,24 @@ static int kvm_trap_emul_handle_trap(struct kvm_vcpu *vcpu)
 	return ret;
 }
 
+static int kvm_trap_emul_handle_msa_fpe(struct kvm_vcpu *vcpu)
+{
+	struct kvm_run *run = vcpu->run;
+	uint32_t __user *opc = (uint32_t __user *)vcpu->arch.pc;
+	unsigned long cause = vcpu->arch.host_cp0_cause;
+	enum emulation_result er = EMULATE_DONE;
+	int ret = RESUME_GUEST;
+
+	er = kvm_mips_emulate_msafpe_exc(cause, opc, run, vcpu);
+	if (er == EMULATE_DONE) {
+		ret = RESUME_GUEST;
+	} else {
+		run->exit_reason = KVM_EXIT_INTERNAL_ERROR;
+		ret = RESUME_HOST;
+	}
+	return ret;
+}
+
 static int kvm_trap_emul_handle_fpe(struct kvm_vcpu *vcpu)
 {
 	struct kvm_run *run = vcpu->run;
@@ -380,16 +398,36 @@ static int kvm_trap_emul_handle_fpe(struct kvm_vcpu *vcpu)
 	return ret;
 }
 
+/**
+ * kvm_trap_emul_handle_msa_disabled() - Guest used MSA while disabled in root.
+ * @vcpu:	Virtual CPU context.
+ *
+ * Handle when the guest attempts to use MSA when it is disabled.
+ */
 static int kvm_trap_emul_handle_msa_disabled(struct kvm_vcpu *vcpu)
 {
+	struct mips_coproc *cop0 = vcpu->arch.cop0;
 	struct kvm_run *run = vcpu->run;
 	uint32_t __user *opc = (uint32_t __user *) vcpu->arch.pc;
 	unsigned long cause = vcpu->arch.host_cp0_cause;
 	enum emulation_result er = EMULATE_DONE;
 	int ret = RESUME_GUEST;
 
-	/* No MSA supported in guest, guest reserved instruction exception */
-	er = kvm_mips_emulate_ri_exc(cause, opc, run, vcpu);
+	if (!kvm_mips_guest_has_msa(&vcpu->arch) ||
+	    (kvm_read_c0_guest_status(cop0) & (ST0_CU1 | ST0_FR)) == ST0_CU1) {
+		/*
+		 * No MSA in guest, or FPU enabled and not in FR=1 mode,
+		 * guest reserved instruction exception
+		 */
+		er = kvm_mips_emulate_ri_exc(cause, opc, run, vcpu);
+	} else if (!(kvm_read_c0_guest_config5(cop0) & MIPS_CONF5_MSAEN)) {
+		/* MSA disabled by guest, guest MSA disabled exception */
+		er = kvm_mips_emulate_msadis_exc(cause, opc, run, vcpu);
+	} else {
+		/* Restore MSA/FPU state */
+		kvm_own_msa(vcpu);
+		er = EMULATE_DONE;
+	}
 
 	switch (er) {
 	case EMULATE_DONE:
@@ -608,6 +646,7 @@ static struct kvm_mips_callbacks kvm_trap_emul_callbacks = {
 	.handle_res_inst = kvm_trap_emul_handle_res_inst,
 	.handle_break = kvm_trap_emul_handle_break,
 	.handle_trap = kvm_trap_emul_handle_trap,
+	.handle_msa_fpe = kvm_trap_emul_handle_msa_fpe,
 	.handle_fpe = kvm_trap_emul_handle_fpe,
 	.handle_msa_disabled = kvm_trap_emul_handle_msa_disabled,
 
-- 
cgit v1.2.3


From ab86bd600400357ffa0dfdb1797f587476d01352 Mon Sep 17 00:00:00 2001
From: James Hogan <james.hogan@imgtec.com>
Date: Tue, 2 Dec 2014 15:48:24 +0000
Subject: MIPS: KVM: Expose MSA registers

Add KVM register numbers for the MIPS SIMD Architecture (MSA) registers,
and implement access to them with the KVM_GET_ONE_REG / KVM_SET_ONE_REG
ioctls when the MSA capability is enabled (exposed in a later patch) and
present in the guest according to its Config3.MSAP bit.

The MSA vector registers use the same register numbers as the FPU
registers except with a different size (128bits). Since MSA depends on
Status.FR=1, these registers are inaccessible when Status.FR=0. These
registers are returned as a single native endian 128bit value, rather
than least significant half first with each 64-bit half native endian as
the kernel uses internally.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Paul Burton <paul.burton@imgtec.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Gleb Natapov <gleb@kernel.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: linux-mips@linux-mips.org
Cc: kvm@vger.kernel.org
Cc: linux-api@vger.kernel.org
Cc: linux-doc@vger.kernel.org
---
 Documentation/virtual/kvm/api.txt | 12 +++++++-
 arch/mips/include/uapi/asm/kvm.h  | 12 ++++++--
 arch/mips/kvm/mips.c              | 65 +++++++++++++++++++++++++++++++++++++++
 3 files changed, 86 insertions(+), 3 deletions(-)

diff --git a/Documentation/virtual/kvm/api.txt b/Documentation/virtual/kvm/api.txt
index a1e9bfa5fe9e..62809871814b 100644
--- a/Documentation/virtual/kvm/api.txt
+++ b/Documentation/virtual/kvm/api.txt
@@ -1981,8 +1981,11 @@ registers, find a list below:
   MIPS  | KVM_REG_MIPS_COUNT_HZ         | 64
   MIPS  | KVM_REG_MIPS_FPR_32(0..31)    | 32
   MIPS  | KVM_REG_MIPS_FPR_64(0..31)    | 64
+  MIPS  | KVM_REG_MIPS_VEC_128(0..31)   | 128
   MIPS  | KVM_REG_MIPS_FCR_IR           | 32
   MIPS  | KVM_REG_MIPS_FCR_CSR          | 32
+  MIPS  | KVM_REG_MIPS_MSA_IR           | 32
+  MIPS  | KVM_REG_MIPS_MSA_CSR          | 32
 
 ARM registers are mapped using the lower 32 bits.  The upper 16 of that
 is the register group type, or coprocessor number:
@@ -2040,14 +2043,21 @@ MIPS FPU registers (see KVM_REG_MIPS_FPR_{32,64}() above) have the following
 id bit patterns depending on the size of the register being accessed. They are
 always accessed according to the current guest FPU mode (Status.FR and
 Config5.FRE), i.e. as the guest would see them, and they become unpredictable
-if the guest FPU mode is changed:
+if the guest FPU mode is changed. MIPS SIMD Architecture (MSA) vector
+registers (see KVM_REG_MIPS_VEC_128() above) have similar patterns as they
+overlap the FPU registers:
   0x7020 0000 0003 00 <0:3> <reg:5> (32-bit FPU registers)
   0x7030 0000 0003 00 <0:3> <reg:5> (64-bit FPU registers)
+  0x7040 0000 0003 00 <0:3> <reg:5> (128-bit MSA vector registers)
 
 MIPS FPU control registers (see KVM_REG_MIPS_FCR_{IR,CSR} above) have the
 following id bit patterns:
   0x7020 0000 0003 01 <0:3> <reg:5>
 
+MIPS MSA control registers (see KVM_REG_MIPS_MSA_{IR,CSR} above) have the
+following id bit patterns:
+  0x7020 0000 0003 02 <0:3> <reg:5>
+
 
 4.69 KVM_GET_ONE_REG
 
diff --git a/arch/mips/include/uapi/asm/kvm.h b/arch/mips/include/uapi/asm/kvm.h
index 401e6a6f8bb8..6985eb59b085 100644
--- a/arch/mips/include/uapi/asm/kvm.h
+++ b/arch/mips/include/uapi/asm/kvm.h
@@ -58,7 +58,7 @@ struct kvm_fpu {
  *
  * Register set = 2: KVM specific registers (see definitions below).
  *
- * Register set = 3: FPU registers (see definitions below).
+ * Register set = 3: FPU / MSA registers (see definitions below).
  *
  * Other sets registers may be added in the future.  Each set would
  * have its own identifier in bits[31..16].
@@ -148,7 +148,7 @@ struct kvm_fpu {
 
 
 /*
- * KVM_REG_MIPS_FPU - Floating Point registers.
+ * KVM_REG_MIPS_FPU - Floating Point and MIPS SIMD Architecture (MSA) registers.
  *
  *  bits[15..8]  - Register subset (see definitions below).
  *  bits[7..5]   - Must be zero.
@@ -157,12 +157,14 @@ struct kvm_fpu {
 
 #define KVM_REG_MIPS_FPR	(KVM_REG_MIPS_FPU | 0x0000000000000000ULL)
 #define KVM_REG_MIPS_FCR	(KVM_REG_MIPS_FPU | 0x0000000000000100ULL)
+#define KVM_REG_MIPS_MSACR	(KVM_REG_MIPS_FPU | 0x0000000000000200ULL)
 
 /*
  * KVM_REG_MIPS_FPR - Floating point / Vector registers.
  */
 #define KVM_REG_MIPS_FPR_32(n)	(KVM_REG_MIPS_FPR | KVM_REG_SIZE_U32  | (n))
 #define KVM_REG_MIPS_FPR_64(n)	(KVM_REG_MIPS_FPR | KVM_REG_SIZE_U64  | (n))
+#define KVM_REG_MIPS_VEC_128(n)	(KVM_REG_MIPS_FPR | KVM_REG_SIZE_U128 | (n))
 
 /*
  * KVM_REG_MIPS_FCR - Floating point control registers.
@@ -170,6 +172,12 @@ struct kvm_fpu {
 #define KVM_REG_MIPS_FCR_IR	(KVM_REG_MIPS_FCR | KVM_REG_SIZE_U32 |  0)
 #define KVM_REG_MIPS_FCR_CSR	(KVM_REG_MIPS_FCR | KVM_REG_SIZE_U32 | 31)
 
+/*
+ * KVM_REG_MIPS_MSACR - MIPS SIMD Architecture (MSA) control registers.
+ */
+#define KVM_REG_MIPS_MSA_IR	 (KVM_REG_MIPS_MSACR | KVM_REG_SIZE_U32 |  0)
+#define KVM_REG_MIPS_MSA_CSR	 (KVM_REG_MIPS_MSACR | KVM_REG_SIZE_U32 |  1)
+
 
 /*
  * KVM MIPS specific structures and definitions
diff --git a/arch/mips/kvm/mips.c b/arch/mips/kvm/mips.c
index e02c7e5a12ff..35d3146895f1 100644
--- a/arch/mips/kvm/mips.c
+++ b/arch/mips/kvm/mips.c
@@ -531,6 +531,7 @@ static int kvm_mips_get_reg(struct kvm_vcpu *vcpu,
 	struct mips_fpu_struct *fpu = &vcpu->arch.fpu;
 	int ret;
 	s64 v;
+	s64 vs[2];
 	unsigned int idx;
 
 	switch (reg->id) {
@@ -579,6 +580,35 @@ static int kvm_mips_get_reg(struct kvm_vcpu *vcpu,
 		v = fpu->fcr31;
 		break;
 
+	/* MIPS SIMD Architecture (MSA) registers */
+	case KVM_REG_MIPS_VEC_128(0) ... KVM_REG_MIPS_VEC_128(31):
+		if (!kvm_mips_guest_has_msa(&vcpu->arch))
+			return -EINVAL;
+		/* Can't access MSA registers in FR=0 mode */
+		if (!(kvm_read_c0_guest_status(cop0) & ST0_FR))
+			return -EINVAL;
+		idx = reg->id - KVM_REG_MIPS_VEC_128(0);
+#ifdef CONFIG_CPU_LITTLE_ENDIAN
+		/* least significant byte first */
+		vs[0] = get_fpr64(&fpu->fpr[idx], 0);
+		vs[1] = get_fpr64(&fpu->fpr[idx], 1);
+#else
+		/* most significant byte first */
+		vs[0] = get_fpr64(&fpu->fpr[idx], 1);
+		vs[1] = get_fpr64(&fpu->fpr[idx], 0);
+#endif
+		break;
+	case KVM_REG_MIPS_MSA_IR:
+		if (!kvm_mips_guest_has_msa(&vcpu->arch))
+			return -EINVAL;
+		v = boot_cpu_data.msa_id;
+		break;
+	case KVM_REG_MIPS_MSA_CSR:
+		if (!kvm_mips_guest_has_msa(&vcpu->arch))
+			return -EINVAL;
+		v = fpu->msacsr;
+		break;
+
 	/* Co-processor 0 registers */
 	case KVM_REG_MIPS_CP0_INDEX:
 		v = (long)kvm_read_c0_guest_index(cop0);
@@ -664,6 +694,10 @@ static int kvm_mips_get_reg(struct kvm_vcpu *vcpu,
 		u32 v32 = (u32)v;
 
 		return put_user(v32, uaddr32);
+	} else if ((reg->id & KVM_REG_SIZE_MASK) == KVM_REG_SIZE_U128) {
+		void __user *uaddr = (void __user *)(long)reg->addr;
+
+		return copy_to_user(uaddr, vs, 16);
 	} else {
 		return -EINVAL;
 	}
@@ -675,6 +709,7 @@ static int kvm_mips_set_reg(struct kvm_vcpu *vcpu,
 	struct mips_coproc *cop0 = vcpu->arch.cop0;
 	struct mips_fpu_struct *fpu = &vcpu->arch.fpu;
 	s64 v;
+	s64 vs[2];
 	unsigned int idx;
 
 	if ((reg->id & KVM_REG_SIZE_MASK) == KVM_REG_SIZE_U64) {
@@ -689,6 +724,10 @@ static int kvm_mips_set_reg(struct kvm_vcpu *vcpu,
 		if (get_user(v32, uaddr32) != 0)
 			return -EFAULT;
 		v = (s64)v32;
+	} else if ((reg->id & KVM_REG_SIZE_MASK) == KVM_REG_SIZE_U128) {
+		void __user *uaddr = (void __user *)(long)reg->addr;
+
+		return copy_from_user(vs, uaddr, 16);
 	} else {
 		return -EINVAL;
 	}
@@ -742,6 +781,32 @@ static int kvm_mips_set_reg(struct kvm_vcpu *vcpu,
 		fpu->fcr31 = v;
 		break;
 
+	/* MIPS SIMD Architecture (MSA) registers */
+	case KVM_REG_MIPS_VEC_128(0) ... KVM_REG_MIPS_VEC_128(31):
+		if (!kvm_mips_guest_has_msa(&vcpu->arch))
+			return -EINVAL;
+		idx = reg->id - KVM_REG_MIPS_VEC_128(0);
+#ifdef CONFIG_CPU_LITTLE_ENDIAN
+		/* least significant byte first */
+		set_fpr64(&fpu->fpr[idx], 0, vs[0]);
+		set_fpr64(&fpu->fpr[idx], 1, vs[1]);
+#else
+		/* most significant byte first */
+		set_fpr64(&fpu->fpr[idx], 1, vs[0]);
+		set_fpr64(&fpu->fpr[idx], 0, vs[1]);
+#endif
+		break;
+	case KVM_REG_MIPS_MSA_IR:
+		if (!kvm_mips_guest_has_msa(&vcpu->arch))
+			return -EINVAL;
+		/* Read-only */
+		break;
+	case KVM_REG_MIPS_MSA_CSR:
+		if (!kvm_mips_guest_has_msa(&vcpu->arch))
+			return -EINVAL;
+		fpu->msacsr = v;
+		break;
+
 	/* Co-processor 0 registers */
 	case KVM_REG_MIPS_CP0_INDEX:
 		kvm_write_c0_guest_index(cop0, v);
-- 
cgit v1.2.3


From d952bd070f79b6dcbad52c03dbc41cbc8ba086c8 Mon Sep 17 00:00:00 2001
From: James Hogan <james.hogan@imgtec.com>
Date: Mon, 8 Dec 2014 23:07:56 +0000
Subject: MIPS: KVM: Wire up MSA capability

Now that the code is in place for KVM to support MIPS SIMD Architecutre
(MSA) in MIPS guests, wire up the new KVM_CAP_MIPS_MSA capability.

For backwards compatibility, the capability must be explicitly enabled
in order to detect or make use of MSA from the guest.

The capability is not supported if the hardware supports MSA vector
partitioning, since the extra support cannot be tested yet and it
extends the state that the userland program would have to save.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Gleb Natapov <gleb@kernel.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: linux-mips@linux-mips.org
Cc: kvm@vger.kernel.org
Cc: linux-api@vger.kernel.org
Cc: linux-doc@vger.kernel.org
---
 Documentation/virtual/kvm/api.txt | 12 ++++++++++++
 arch/mips/kvm/mips.c              | 18 ++++++++++++++++++
 include/uapi/linux/kvm.h          |  1 +
 3 files changed, 31 insertions(+)

diff --git a/Documentation/virtual/kvm/api.txt b/Documentation/virtual/kvm/api.txt
index 62809871814b..1490eb0ef798 100644
--- a/Documentation/virtual/kvm/api.txt
+++ b/Documentation/virtual/kvm/api.txt
@@ -3335,6 +3335,18 @@ done the KVM_REG_MIPS_FPR_* and KVM_REG_MIPS_FCR_* registers can be accessed
 Config5.FRE bits are accessible via the KVM API and also from the guest,
 depending on them being supported by the FPU.
 
+6.10 KVM_CAP_MIPS_MSA
+
+Architectures: mips
+Target: vcpu
+Parameters: args[0] is reserved for future use (should be 0).
+
+This capability allows the use of the MIPS SIMD Architecture (MSA) by the guest.
+It allows the Config3.MSAP bit to be set to enable the use of MSA by the guest.
+Once this is done the KVM_REG_MIPS_VEC_* and KVM_REG_MIPS_MSA_* registers can be
+accessed, and the Config5.MSAEn bit is accessible via the KVM API and also from
+the guest.
+
 7. Capabilities that can be enabled on VMs
 ------------------------------------------
 
diff --git a/arch/mips/kvm/mips.c b/arch/mips/kvm/mips.c
index 35d3146895f1..bb68e8d520e8 100644
--- a/arch/mips/kvm/mips.c
+++ b/arch/mips/kvm/mips.c
@@ -880,6 +880,9 @@ static int kvm_vcpu_ioctl_enable_cap(struct kvm_vcpu *vcpu,
 	case KVM_CAP_MIPS_FPU:
 		vcpu->arch.fpu_enabled = true;
 		break;
+	case KVM_CAP_MIPS_MSA:
+		vcpu->arch.msa_enabled = true;
+		break;
 	default:
 		r = -EINVAL;
 		break;
@@ -1071,6 +1074,21 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext)
 	case KVM_CAP_MIPS_FPU:
 		r = !!cpu_has_fpu;
 		break;
+	case KVM_CAP_MIPS_MSA:
+		/*
+		 * We don't support MSA vector partitioning yet:
+		 * 1) It would require explicit support which can't be tested
+		 *    yet due to lack of support in current hardware.
+		 * 2) It extends the state that would need to be saved/restored
+		 *    by e.g. QEMU for migration.
+		 *
+		 * When vector partitioning hardware becomes available, support
+		 * could be added by requiring a flag when enabling
+		 * KVM_CAP_MIPS_MSA capability to indicate that userland knows
+		 * to save/restore the appropriate extra state.
+		 */
+		r = cpu_has_msa && !(boot_cpu_data.msa_id & MSA_IR_WRPF);
+		break;
 	default:
 		r = 0;
 		break;
diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h
index ce49688976d2..05a2083f7a28 100644
--- a/include/uapi/linux/kvm.h
+++ b/include/uapi/linux/kvm.h
@@ -803,6 +803,7 @@ struct kvm_ppc_smmu_info {
 #define KVM_CAP_S390_USER_STSI 109
 #define KVM_CAP_S390_SKEYS 110
 #define KVM_CAP_MIPS_FPU 111
+#define KVM_CAP_MIPS_MSA 112
 
 #ifdef KVM_CAP_IRQ_ROUTING
 
-- 
cgit v1.2.3