Re: [PATCH v5 1/4] vhost: convert VHOST_VSOCK_SET_RUNNING to a generic ioctl

From: Guennadi Liakhovetski <guennadi.liakhovetski@linux.intel.com>
To: Mathieu Poirier <mathieu.poirier@linaro.org>
Cc: kvm@vger.kernel.org, linux-remoteproc@vger.kernel.org,
	virtualization@lists.linux-foundation.org,
	sound-open-firmware@alsa-project.org,
	Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>,
	Liam Girdwood <liam.r.girdwood@linux.intel.com>,
	"Michael S. Tsirkin" <mst@redhat.com>,
	Jason Wang <jasowang@redhat.com>,
	Ohad Ben-Cohen <ohad@wizery.com>,
	Bjorn Andersson <bjorn.andersson@linaro.org>,
	Vincent Whitchurch <vincent.whitchurch@axis.com>
Subject: Re: [PATCH v5 1/4] vhost: convert VHOST_VSOCK_SET_RUNNING to a generic ioctl
Date: Fri, 11 Sep 2020 09:59:12 +0200	[thread overview]
Message-ID: <20200911075912.GB26801@ubuntu> (raw)
In-Reply-To: <20200910164643.GA579940@xps15>

On Thu, Sep 10, 2020 at 10:46:43AM -0600, Mathieu Poirier wrote:
> On Thu, Sep 10, 2020 at 09:15:13AM +0200, Guennadi Liakhovetski wrote:
> > Hi Mathieu,
> > 
> > On Wed, Sep 09, 2020 at 04:42:14PM -0600, Mathieu Poirier wrote:
> > > On Wed, Aug 26, 2020 at 07:46:33PM +0200, Guennadi Liakhovetski wrote:
> > > > VHOST_VSOCK_SET_RUNNING is used by the vhost vsock driver to perform
> > > > crucial VirtQueue initialisation, like assigning .private fields and
> > > > calling vhost_vq_init_access(), and clean up. However, this ioctl is
> > > > actually extremely useful for any vhost driver, that doesn't have a
> > > > side channel to inform it of a status change, e.g. upon a guest
> > > > reboot. This patch makes that ioctl generic, while preserving its
> > > > numeric value and also keeping the original alias.
> > > > 
> > > > Signed-off-by: Guennadi Liakhovetski <guennadi.liakhovetski@linux.intel.com>
> > > > ---
> > > >  include/uapi/linux/vhost.h | 4 +++-
> > > >  1 file changed, 3 insertions(+), 1 deletion(-)
> > > > 
> > > > diff --git a/include/uapi/linux/vhost.h b/include/uapi/linux/vhost.h
> > > > index 75232185324a..11a4948b6216 100644
> > > > --- a/include/uapi/linux/vhost.h
> > > > +++ b/include/uapi/linux/vhost.h
> > > > @@ -97,6 +97,8 @@
> > > >  #define VHOST_SET_BACKEND_FEATURES _IOW(VHOST_VIRTIO, 0x25, __u64)
> > > >  #define VHOST_GET_BACKEND_FEATURES _IOR(VHOST_VIRTIO, 0x26, __u64)
> > > >  
> > > > +#define VHOST_SET_RUNNING _IOW(VHOST_VIRTIO, 0x61, int)
> > > > +
> > > 
> > > I don't see it used in the next patches and as such should be part of another
> > > series.
> > 
> > It isn't used in the next patches, it is used in this patch - see below.
> >
> 
> Right, but why is this part of this set?  What does it bring?  It should be part
> of a patchset where "VHOST_SET_RUNNING" is used.

Ok, I can remove this patch from this series and make it a part of the series, 
containing [1] "vhost: add an SOF Audio DSP driver"

Thanks
Guennadi

[1] https://www.spinics.net/lists/linux-virtualization/msg43309.html

> > > >  /* VHOST_NET specific defines */
> > > >  
> > > >  /* Attach virtio net ring to a raw socket, or tap device.
> > > > @@ -118,7 +120,7 @@
> > > >  /* VHOST_VSOCK specific defines */
> > > >  
> > > >  #define VHOST_VSOCK_SET_GUEST_CID	_IOW(VHOST_VIRTIO, 0x60, __u64)
> > > > -#define VHOST_VSOCK_SET_RUNNING		_IOW(VHOST_VIRTIO, 0x61, int)
> > > > +#define VHOST_VSOCK_SET_RUNNING		VHOST_SET_RUNNING
> > > >  
> > > >  /* VHOST_VDPA specific defines */
> > > >  
> > > > -- 
> > > > 2.28.0
> > > >