The vhost_vdpa_one_time_request() branch in vhost_vdpa_set_backend_cap() incorrectly sends down iotls 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 would do the trick. Signed-off-by: Si-Wei Liu <si-wei....@oracle.com> --- hw/virtio/vhost-vdpa.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/hw/virtio/vhost-vdpa.c b/hw/virtio/vhost-vdpa.c index c5ed7a3..27ea706 100644 --- a/hw/virtio/vhost-vdpa.c +++ b/hw/virtio/vhost-vdpa.c @@ -665,7 +665,7 @@ 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; -- 1.8.3.1