diff options
| -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 e46d08107a50..5c802d47892c 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. */ @@ -136,6 +137,17 @@ 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; } |