4 files changed, 93 insertions, 8 deletions

diff --git a/drivers/xen/Makefile b/drivers/xen/Makefile
index 0e8637035457..74354708c6c4 100644
--- a/drivers/xen/Makefile
+++ b/drivers/xen/Makefile
@@ -2,6 +2,7 @@ ifneq ($(CONFIG_ARM),y)
 obj-y	+= manage.o balloon.o
 obj-$(CONFIG_HOTPLUG_CPU)		+= cpu_hotplug.o
 endif
+obj-$(CONFIG_X86)			+= fallback.o
 obj-y	+= grant-table.o features.o events.o
 obj-y	+= xenbus/
 
diff --git a/drivers/xen/events.c b/drivers/xen/events.c
index 912ac81b6dbf..0be4df39e953 100644
--- a/drivers/xen/events.c
+++ b/drivers/xen/events.c
@@ -1395,10 +1395,10 @@ void xen_evtchn_do_upcall(struct pt_regs *regs)
 {
 	struct pt_regs *old_regs = set_irq_regs(regs);
 
+	irq_enter();
 #ifdef CONFIG_X86
 	exit_idle();
 #endif
-	irq_enter();
 
 	__xen_evtchn_do_upcall();
 
diff --git a/drivers/xen/fallback.c b/drivers/xen/fallback.c
new file mode 100644
index 000000000000..0ef7c4d40f86
--- /dev/null
+++ b/drivers/xen/fallback.c
@@ -0,0 +1,80 @@
+#include <linux/kernel.h>
+#include <linux/string.h>
+#include <linux/bug.h>
+#include <linux/export.h>
+#include <asm/hypervisor.h>
+#include <asm/xen/hypercall.h>
+
+int xen_event_channel_op_compat(int cmd, void *arg)
+{
+	struct evtchn_op op;
+	int rc;
+
+	op.cmd = cmd;
+	memcpy(&op.u, arg, sizeof(op.u));
+	rc = _hypercall1(int, event_channel_op_compat, &op);
+
+	switch (cmd) {
+	case EVTCHNOP_close:
+	case EVTCHNOP_send:
+	case EVTCHNOP_bind_vcpu:
+	case EVTCHNOP_unmask:
+		/* no output */
+		break;
+
+#define COPY_BACK(eop) \
+	case EVTCHNOP_##eop: \
+		memcpy(arg, &op.u.eop, sizeof(op.u.eop)); \
+		break
+
+	COPY_BACK(bind_interdomain);
+	COPY_BACK(bind_virq);
+	COPY_BACK(bind_pirq);
+	COPY_BACK(status);
+	COPY_BACK(alloc_unbound);
+	COPY_BACK(bind_ipi);
+#undef COPY_BACK
+
+	default:
+		WARN_ON(rc != -ENOSYS);
+		break;
+	}
+
+	return rc;
+}
+EXPORT_SYMBOL_GPL(xen_event_channel_op_compat);
+
+int HYPERVISOR_physdev_op_compat(int cmd, void *arg)
+{
+	struct physdev_op op;
+	int rc;
+
+	op.cmd = cmd;
+	memcpy(&op.u, arg, sizeof(op.u));
+	rc = _hypercall1(int, physdev_op_compat, &op);
+
+	switch (cmd) {
+	case PHYSDEVOP_IRQ_UNMASK_NOTIFY:
+	case PHYSDEVOP_set_iopl:
+	case PHYSDEVOP_set_iobitmap:
+	case PHYSDEVOP_apic_write:
+		/* no output */
+		break;
+
+#define COPY_BACK(pop, fld) \
+	case PHYSDEVOP_##pop: \
+		memcpy(arg, &op.u.fld, sizeof(op.u.fld)); \
+		break
+
+	COPY_BACK(irq_status_query, irq_status_query);
+	COPY_BACK(apic_read, apic_op);
+	COPY_BACK(ASSIGN_VECTOR, irq_op);
+#undef COPY_BACK
+
+	default:
+		WARN_ON(rc != -ENOSYS);
+		break;
+	}
+
+	return rc;
+}
diff --git a/drivers/xen/privcmd.c b/drivers/xen/privcmd.c
index 8adb9cc267f9..71f5c459b088 100644
--- a/drivers/xen/privcmd.c
+++ b/drivers/xen/privcmd.c
@@ -361,13 +361,13 @@ static long privcmd_ioctl_mmap_batch(void __user *udata, int version)
 	down_write(&mm->mmap_sem);
 
 	vma = find_vma(mm, m.addr);
-	ret = -EINVAL;
 	if (!vma ||
 	    vma->vm_ops != &privcmd_vm_ops ||
 	    (m.addr != vma->vm_start) ||
 	    ((m.addr + (nr_pages << PAGE_SHIFT)) != vma->vm_end) ||
 	    !privcmd_enforce_singleshot_mapping(vma)) {
 		up_write(&mm->mmap_sem);
+		ret = -EINVAL;
 		goto out;
 	}
 
@@ -383,12 +383,16 @@ static long privcmd_ioctl_mmap_batch(void __user *udata, int version)
 
 	up_write(&mm->mmap_sem);
 
-	if (state.global_error && (version == 1)) {
-		/* Write back errors in second pass. */
-		state.user_mfn = (xen_pfn_t *)m.arr;
-		state.err      = err_array;
-		ret = traverse_pages(m.num, sizeof(xen_pfn_t),
-				     &pagelist, mmap_return_errors_v1, &state);
+	if (version == 1) {
+		if (state.global_error) {
+			/* Write back errors in second pass. */
+			state.user_mfn = (xen_pfn_t *)m.arr;
+			state.err      = err_array;
+			ret = traverse_pages(m.num, sizeof(xen_pfn_t),
+					     &pagelist, mmap_return_errors_v1, &state);
+		} else
+			ret = 0;
+
 	} else if (version == 2) {
 		ret = __copy_to_user(m.err, err_array, m.num * sizeof(int));
 		if (ret)