Re: [PATCH] vhost-user: Fix protocol feature bit conflict

[Alex Bennée]

Viresh Kumar <viresh.kumar@linaro.org> writes:

> On 16-10-23, 11:45, Manos Pitsidianakis wrote:
>> On Mon, 16 Oct 2023 11:32, Hanna Czenczek <hreitz@redhat.com> wrote:
>> > diff --git a/include/hw/virtio/vhost-user.h
>> > b/include/hw/virtio/vhost-user.h
>> > index 9f9ddf878d..1d4121431b 100644
>> > --- a/include/hw/virtio/vhost-user.h
>> > +++ b/include/hw/virtio/vhost-user.h
>> > @@ -29,7 +29,8 @@ enum VhostUserProtocolFeature {
>> >     VHOST_USER_PROTOCOL_F_INBAND_NOTIFICATIONS = 14,
>> >     VHOST_USER_PROTOCOL_F_CONFIGURE_MEM_SLOTS = 15,
>> >     VHOST_USER_PROTOCOL_F_STATUS = 16,
>> > -    VHOST_USER_PROTOCOL_F_SHARED_OBJECT = 17,
>> > +    /* Feature 17 reserved for VHOST_USER_PROTOCOL_F_XEN_MMAP. */
>> > +    VHOST_USER_PROTOCOL_F_SHARED_OBJECT = 18,
>> >     VHOST_USER_PROTOCOL_F_MAX
>> > };
>> 
>> May I ask, why not define VHOST_USER_PROTOCOL_F_XEN_MMAP as well instead of
>> a comment mention?
>
> Perhaps because we will never use it from Qemu code ?

Vikram's work on enabling xenpvh support will mean enabling grant
support and while I suspect most VirtIO backends will be within QEMU
itself if it ever want to off-load something to a vhost-user backend it
will need to ensure this flag is set.

>
> Anyway:
>
> Reviewed-by: Viresh Kumar <viresh.kumar@linaro.org>


-- 
Alex Bennée
Virtualisation Tech Lead @ Linaro