[libvirt] [PATCH] qemu_cgroup: allow access to /dev/dri for virtio-vga

[Ján Tomko]

On Thu, May 19, 2016 at 10:05:38AM +0200, Peter Krempa wrote:
> On Thu, May 19, 2016 at 09:33:46 +0200, Ján Tomko wrote:
> > QEMU needs access to the /dev/dri/render* device for
> > virgl to work.
> > 
> > Allow access to all /dev/dri/* devices for domains with
> > <video>
> >   <model type='virtio' heads='1' primary='yes'>
> >     <acceleration accel3d='yes'/>
> >   </model>
> > </video>
> > 
> > https://bugzilla.redhat.com/show_bug.cgi?id=1337290
> > ---
> >  src/qemu/qemu_cgroup.c | 14 ++++++++++++++
> >  1 file changed, 14 insertions(+)
> > 
> > diff --git a/src/qemu/qemu_cgroup.c b/src/qemu/qemu_cgroup.c
> > index 1e04a68..d676d66 100644
> > --- a/src/qemu/qemu_cgroup.c
> > +++ b/src/qemu/qemu_cgroup.c
> > @@ -51,6 +51,7 @@ static const char *const defaultDeviceACL[] = {
> >  };
> >  #define DEVICE_PTY_MAJOR 136
> >  #define DEVICE_SND_MAJOR 116
> > +#define DEVICE_DRI_MAJOR 226
> >  
> >  
> >  static int
> > @@ -626,6 +627,19 @@ qemuSetupDevicesCgroup(virQEMUDriverPtr driver,
> >              goto cleanup;
> >      }
> >  
> > +    if (vm->def->nvideos) {
> > +        virDomainVideoDefPtr vid = vm->def->videos[0];
> 
> So only the primary video device can use accel? if yes please comment it
> here.
> 

Yes, currently libvirt only allows the primary video to be virtio.

> > +        if (vid->type == VIR_DOMAIN_VIDEO_TYPE_VIRTIO &&
> > +            vid->accel && vid->accel->accel3d) {
> 
> vid->accel->accel3d is a virTristateBool thus this check isn't enough.
> 
> > +            rv = virCgroupAllowDevice(priv->cgroup, 'c', DEVICE_DRI_MAJOR, -1,
> > +                                      VIR_CGROUP_DEVICE_RW);
> > +            virDomainAuditCgroupMajor(vm, priv->cgroup, "allow", DEVICE_DRI_MAJOR,
> > +                                      "sound", "rw", rv == 0);
> 
> I presume that "video" is a more appropriate reason.
> 
> > +            if (rv < 0)
> > +                goto cleanup;
> > +        }
> > +    }
> 
> ACK if only primary video can have accel. Otherwise please send a V2.
> 

Thanks, pushed with the issues fixed.

Jan



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