Re: [Qemu-devel] [PATCH v2] net:Enable vhost with vhostforce, vhost options for guests without MSI-X support

[Jason Wang <jasowang@redhat.com>]

On 06/05/2015 10:32 PM, Pankaj Gupta wrote:
>     We use vhostforce to enable vhost even if Guests don't have MSI-X support
> and we fall back to QEMU virtio-net. This patch will enable vhost unconditionally 
> whenever we have vhostforce='ON' or vhost='ON'. 
>
> Initially, I wanted to remove vhostforce completely as an additional argument. 
> But after discussing this in mailing list found that some programs are using vhostforce
> and some vhost. So, we want to keep semantics of both the options.
>
> Signed-off-by: Pankaj Gupta <pagupta@redhat.com>
> ---
>  net/tap.c | 6 +++---
>  1 file changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/net/tap.c b/net/tap.c
> index d1ca314..4618359 100644
> --- a/net/tap.c
> +++ b/net/tap.c
> @@ -649,13 +649,13 @@ static void net_init_tap_one(const NetdevTapOptions *tap, NetClientState *peer,
>          }
>      }
>  
> -    if (tap->has_vhost ? tap->vhost :
> -        vhostfdname || (tap->has_vhostforce && tap->vhostforce)) {
> +    if ((tap->has_vhost ? tap->vhost :
> +        vhostfdname) || tap->vhostforce) {
>          VhostNetOptions options;
>  
>          options.backend_type = VHOST_BACKEND_TYPE_KERNEL;
>          options.net_backend = &s->nc;
> -        options.force = tap->has_vhostforce && tap->vhostforce;
> +        options.force = true;
>  
>          if (tap->has_vhostfd || tap->has_vhostfds) {
>              vhostfd = monitor_fd_param(cur_mon, vhostfdname, &err);

In this case, I believe there's no need to have vhost_net_query() and
query_guest_notifiers() callbacks (and maybe more others).