diff options
| author | Andy Lutomirski <luto@kernel.org> | 2016-02-02 21:46:40 -0800 |
|---|---|---|
| committer | Alistair Strachan <astrachan@google.com> | 2019-01-16 12:43:27 -0800 |
| commit | 7389e826abae820e1149cfb8a39f2a877bb2a478 (patch) | |
| tree | c7bcbe936bb74d6c15693adf48827e6e837a79ae | |
| parent | 6bb68f96a00a13a71c3fa8c77aa0609a6b31dc2e (diff) | |
UPSTREAM: vring: Use the DMA API on Xen
Signed-off-by: Andy Lutomirski <luto@kernel.org>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: David Vrabel <david.vrabel@citrix.com>
Reviewed-by: Wei Liu <wei.liu2@citrix.com>
(cherry picked from commit 78fe39872378b0bef00a91181f1947acb8a08500)
Bug: 121166534
Test: Ran cuttlefish with android-4.4 + VSOCKETS, VMWARE_VMCI_VSOCKETS
Signed-off-by: Alistair Strachan <astrachan@google.com>
Change-Id: Ibf85aad139f319354cd2ee8833ca9434c15640d8
| -rw-r--r-- | drivers/virtio/virtio_ring.c | 12 |
1 files changed, 12 insertions, 0 deletions
diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c index 7e74a5386ef3..9a31cb74b4cd 100644 --- a/drivers/virtio/virtio_ring.c +++ b/drivers/virtio/virtio_ring.c @@ -25,6 +25,7 @@ #include <linux/hrtimer.h> #include <linux/kmemleak.h> #include <linux/dma-mapping.h> +#include <xen/xen.h> #ifdef DEBUG /* For development, we want to crash whenever the ring is screwed. */ @@ -131,6 +132,17 @@ struct vring_virtqueue { static bool vring_use_dma_api(struct virtio_device *vdev) { + /* + * In theory, it's possible to have a buggy QEMU-supposed + * emulated Q35 IOMMU and Xen enabled at the same time. On + * such a configuration, virtio has never worked and will + * not work without an even larger kludge. Instead, enable + * the DMA API if we're a Xen guest, which at least allows + * all of the sensible Xen configurations to work correctly. + */ + if (xen_domain()) + return true; + return false; } |