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vhost: do not verify ring mappings when IOMMU is enabled 

When IOMMU is enabled, we store virtqueue metadata as iova (though it
may has _phys suffix) and access them through dma helpers. Any
translation failures could be reported by IOMMU.

In this case, trying to validate iova against gpa won't work and will
cause a false error reporting. So this patch bypasses the ring
verification if IOMMU is enabled which is similar to the behavior
before 0ca1fd2d68 that calls vhost_memory_map() which is a nop when
IOMMU is enabled.

Fixes: 0ca1fd2d68 ("vhost: Simplify ring verification checks")
Cc: Dr. David Alan Gilbert <dgilbert@redhat.com>
Cc: Igor Mammedov <imammedo@redhat.com>
Cc: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>
Reviewed-by: Igor Mammedov <imammedo@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
This commit is contained in:
Jason Wang 2018-04-13 11:01:49 +08:00 committed by Michael S. Tsirkin
parent 38e83a71d0
commit aebbdbee55
1 changed files with 4 additions and 0 deletions
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4
hw/virtio/vhost.c
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@ -342,6 +342,10 @@ static int vhost_verify_ring_mappings(struct vhost_dev *dev,
"used ring"
};
if (vhost_dev_has_iommu(dev)) {
return 0;
}
for (i = 0; i < dev->nvqs; ++i) {
struct vhost_virtqueue *vq = dev->vqs + i;