Re: [RFC PATCH for 8.1 5/6] vdpa: move CVQ isolation check to net_init_vhost_vdpa

[Stefano Garzarella]

On Fri, Mar 17, 2023 at 03:55:41PM +0100, Eugenio Pérez wrote:
> Evaluating it at start time instead of initialization time may make the
> guest capable of dynamically adding or removing migration blockers.
>
> Also, moving to initialization reduces the number of ioctls in the
> migration, reducing failure possibilities.
>
> Signed-off-by: Eugenio Pérez <eperezma@redhat.com>
> ---
> net/vhost-vdpa.c | 200 +++++++++++++++++++++++++++++++++++++----------
> 1 file changed, 157 insertions(+), 43 deletions(-)
>
> diff --git a/net/vhost-vdpa.c b/net/vhost-vdpa.c
> index 4397c0d4b3..818a24fb0e 100644
> --- a/net/vhost-vdpa.c
> +++ b/net/vhost-vdpa.c
> @@ -43,6 +43,13 @@ typedef struct VhostVDPAState {
>
>     /* The device always have SVQ enabled */
>     bool always_svq;
> +
> +    /* The device can isolate CVQ in its own ASID if MQ is negotiated */
> +    bool cvq_isolated_mq;
> +
> +    /* The device can isolate CVQ in its own ASID if MQ is not negotiated */
> +    bool cvq_isolated;
> +

I am not familiar with how CVQ works, so my question might be trivial
;-) but why do we need to have 2 variables depending on F_MQ?

Thanks,
Stefano