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

[Peter Krempa]

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.

> +        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.

Peter
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