vhost-vdpa: backend feature should set only once

The vhost_vdpa_one_time_request() branch in
vhost_vdpa_set_backend_cap() incorrectly sends down
ioctls on vhost_dev with non-zero index. This may
end up with multiple VHOST_SET_BACKEND_FEATURES
ioctl calls sent down on the vhost-vdpa fd that is
shared between all these vhost_dev's.

To fix it, send down ioctl only once via the first
vhost_dev with index 0. Toggle the polarity of the
vhost_vdpa_one_time_request() test should do the
trick.

Fixes: 4d191cfdc7 ("vhost-vdpa: classify one time request")
Signed-off-by: Si-Wei Liu <si-wei.liu@oracle.com>
Reviewed-by: Stefano Garzarella <sgarzare@redhat.com>
Acked-by: Jason Wang <jasowang@redhat.com>
Acked-by: Eugenio Pérez <eperezma@redhat.com>
Message-Id: <1651890498-24478-6-git-send-email-si-wei.liu@oracle.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
This commit is contained in:
Si-Wei Liu 2022-05-06 19:28:16 -07:00 committed by Michael S. Tsirkin
parent 6f3910b5ee
commit 6aee7e4233
1 changed files with 1 additions and 1 deletions

View File

@ -667,7 +667,7 @@ static int vhost_vdpa_set_backend_cap(struct vhost_dev *dev)
features &= f;
if (vhost_vdpa_one_time_request(dev)) {
if (!vhost_vdpa_one_time_request(dev)) {
r = vhost_vdpa_call(dev, VHOST_SET_BACKEND_FEATURES, &features);
if (r) {
return -EFAULT;