Eugenio Pérez <eperezma@xxxxxxxxxx> wrote:
> 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 may not be the
> case, and the device may have a pair number of queues.
^^^^
even
I know, I know, I am Spanish myself O:-)
> To fix this, just resort to the lower even number of queues.
I don't understand what you try to achieve here.
> Fixes: 049eb15b5fc9 ("vhost: record the last virtqueue index for the
> virtio device")
> Signed-off-by: Eugenio Pérez <eperezma@xxxxxxxxxx>
> ---
> hw/net/vhost_net.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/hw/net/vhost_net.c b/hw/net/vhost_net.c
> index 0d888f29a6..edf56a597f 100644
> --- a/hw/net/vhost_net.c
> +++ b/hw/net/vhost_net.c
> @@ -330,7 +330,7 @@ int vhost_net_start(VirtIODevice *dev, NetClientState *ncs,
> NetClientState *peer;
>
> if (!cvq) {
> - last_index -= 1;
> + last_index &= ~1ULL;
> }
As far as I can see, that is a nop. last_index is defined as an int.
$ cat kk.c
#include <stdio.h>
int main(void)
{
int i = 7;
i &= -1ULL;
printf("%d\n", i);
i = 8;
i &= -1ULL;
printf("%d\n", i);
i = 0;
i &= -1ULL;
printf("%d\n", i);
i = -2;
i &= -1ULL;
printf("%d\n", i);
return 0;
}
$ ./kk
7
8
0
-2
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