[PATCH v2 1/1] vhost: Fix last queue index of devices with no cvq

[Eugenio Pérez]

The -1 assumes that all devices with no cvq have an spare vq allocated
for them, but with no offer of VIRTIO_NET_F_CTRL_VQ. This is an invalid
device by the standard, so just stick to the right number of device
models.

This is not a problem to vhost-net, but it is to vhost-vdpa, which
device model trust to reach the last index to finish starting the
device.

Tested with vp_vdpa with host's vhost=on and vhost=off.

Fixes: 049eb15b5fc9 ("vhost: record the last virtqueue index for the virtio 
device")
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Eugenio Pérez <eperezma@redhat.com>
---
 hw/net/vhost_net.c | 4 ----
 1 file changed, 4 deletions(-)

diff --git a/hw/net/vhost_net.c b/hw/net/vhost_net.c
index 0d888f29a6..a859cc943d 100644
--- a/hw/net/vhost_net.c
+++ b/hw/net/vhost_net.c
@@ -329,10 +329,6 @@ int vhost_net_start(VirtIODevice *dev, NetClientState *ncs,
     int r, e, i, last_index = data_queue_pairs * 2;
     NetClientState *peer;
 
-    if (!cvq) {
-        last_index -= 1;
-    }
-
     if (!k->set_guest_notifiers) {
         error_report("binding does not support guest notifiers");
         return -ENOSYS;
-- 
2.27.0