The -1 assumes that cvq device model is accounted in data_queue_pairs,
if cvq does not exists, but it's actually the opposite: Devices with
!cvq are ok but devices with cvq does not add the last queue to
data_queue_pairs.
This is not a problem to vhost-net, but it is to vhost-vdpa:
* Devices with cvq gets initialized at last data vq device model, not
at cvq one.
* Devices with !cvq never gets initialized, since last_index is the
first queue of the last device model.
Because of that, the right change in last_index is to actually add the
cvq, not to remove the missing one.
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.
Also, as the previous commit, rename it to index_end.
Tested with vp_vdpa with host's vhost=on and vhost=off, with ctrl_vq=on
and ctrl_vq=off.
Fixes: 049eb15b5fc9 ("vhost: record the last virtqueue index for the virtio
device")
Reviewed-by: Juan Quintela <quint...@redhat.com>
Signed-off-by: Eugenio Pérez <epere...@redhat.com>
---
hw/net/vhost_net.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)
diff --git a/hw/net/vhost_net.c b/hw/net/vhost_net.c
index 29f2c4212f..30379d2ca4 100644
--- a/hw/net/vhost_net.c
+++ b/hw/net/vhost_net.c
@@ -326,11 +326,11 @@ int vhost_net_start(VirtIODevice *dev, NetClientState
*ncs,
VirtIONet *n = VIRTIO_NET(dev);
int nvhosts = data_queue_pairs + cvq;
struct vhost_net *net;
- int r, e, i, last_index = data_queue_pairs * 2;
+ int r, e, i, index_end = data_queue_pairs * 2;
NetClientState *peer;
- if (!cvq) {
- last_index -= 1;
+ if (cvq) {
+ index_end += 1;
}
if (!k->set_guest_notifiers) {
@@ -347,7 +347,7 @@ int vhost_net_start(VirtIODevice *dev, NetClientState *ncs,
}
net = get_vhost_net(peer);
- vhost_net_set_vq_index(net, i * 2, last_index);
+ vhost_net_set_vq_index(net, i * 2, index_end);
/* Suppress the masking guest notifiers on vhost user
* because vhost user doesn't interrupt masking/unmasking
--
2.27.0
