Re: [PATCH] vhost-user: add NEED_REPLY flag

[Stefano Garzarella]

On Mon, Aug 12, 2024 at 12:53:19PM GMT, 陆知行 wrote:
> Hi, can someone review this patch?
> I find requests which call  vhost_user_get_u64 does not set NEED_REPLY flag

Can you provide an example to trigger this issue?

Also, with this change all calls to vhost_user_get_u64() will set that 
flag, is that following the vhost-user user specification?

Please use `scripts/checkpatch.pl` before sending patches, this one for 
example is missing SoB.

Thanks,
Stefano

> luzhixing12345 <luzhixing12345@gmail.com> 于2024年8月4日周日 23:50写道：
>
> > Front-end message requests which need reply should set NEED_REPLY_MASK
> > in flag, and response from slave need clear NEED_REPLY_MASK flag.
> >
> > ---
> >  hw/virtio/vhost-user.c                    | 2 +-
> >  subprojects/libvhost-user/libvhost-user.c | 1 +
> >  2 files changed, 2 insertions(+), 1 deletion(-)
> >
> > diff --git a/hw/virtio/vhost-user.c b/hw/virtio/vhost-user.c
> > index 00561daa06..edf2271e0a 100644
> > --- a/hw/virtio/vhost-user.c
> > +++ b/hw/virtio/vhost-user.c
> > @@ -1082,7 +1082,7 @@ static int vhost_user_get_u64(struct vhost_dev *dev,
> > int request, uint64_t *u64)
> >      int ret;
> >      VhostUserMsg msg = {
> >          .hdr.request = request,
> > -        .hdr.flags = VHOST_USER_VERSION,
> > +        .hdr.flags = VHOST_USER_VERSION | VHOST_USER_NEED_REPLY_MASK,
> >      };
> >
> >      if (vhost_user_per_device_request(request) && dev->vq_index != 0) {
> > diff --git a/subprojects/libvhost-user/libvhost-user.c
> > b/subprojects/libvhost-user/libvhost-user.c
> > index 9c630c2170..40f665bd7f 100644
> > --- a/subprojects/libvhost-user/libvhost-user.c
> > +++ b/subprojects/libvhost-user/libvhost-user.c
> > @@ -667,6 +667,7 @@ vu_send_reply(VuDev *dev, int conn_fd, VhostUserMsg
> > *vmsg)
> >  {
> >      /* Set the version in the flags when sending the reply */
> >      vmsg->flags &= ~VHOST_USER_VERSION_MASK;
> > +    vmsg->flags &= ~VHOST_USER_NEED_REPLY_MASK;
> >      vmsg->flags |= VHOST_USER_VERSION;
> >      vmsg->flags |= VHOST_USER_REPLY_MASK;
> >
> > --
> > 2.34.1