[libvirt] [PATCH] virt-aa-helper: generate rules for gl enabled graphics devices

[Erik Skultety]

On Tue, Jan 15, 2019 at 06:34:41PM +0200, Christian Ehrhardt wrote:
> This adds the virt-aa-helper support for gl enabled graphics devices to
> generate rules for the needed rendernode paths.
>
> Example in domain xml:
> <graphics type='spice'>
>   <gl enable='yes' rendernode='/dev/dri/bar'/>
> </graphics>
>
> results in:
>   "/dev/dri" r,
>   "/dev/dri/bar" rw,
>
> Special cases are:
> - multiple devices with rendernodes -> all are added
> - non explicit rendernodes -> follow recently added virHostGetDRMRenderNode
> - rendernode without opengl (in egl-headless for example) -> still add
>   the node
>
> Fixes: https://bugs.launchpad.net/ubuntu/+source/libvirt/+bug/1757085
>
> Signed-off-by: Christian Ehrhardt <christian.ehrhardt at canonical.com>
> ---
>  src/security/virt-aa-helper.c | 20 +++++++++++++++++++-
>  1 file changed, 19 insertions(+), 1 deletion(-)
>
> diff --git a/src/security/virt-aa-helper.c b/src/security/virt-aa-helper.c
> index 64a425671d..327a8a0202 100644
> --- a/src/security/virt-aa-helper.c
> +++ b/src/security/virt-aa-helper.c
> @@ -938,7 +938,7 @@ get_files(vahControl * ctl)
>      size_t i;
>      char *uuid;
>      char uuidstr[VIR_UUID_STRING_BUFLEN];
> -    bool needsVfio = false, needsvhost = false;
> +    bool needsVfio = false, needsvhost = false, needDefaultRenderNode = false;
>
>      /* verify uuid is same as what we were given on the command line */
>      virUUIDFormat(ctl->def->uuid, uuidstr);
> @@ -1062,6 +1062,10 @@ get_files(vahControl * ctl)
>      for (i = 0; i < ctl->def->ngraphics; i++) {
>          virDomainGraphicsDefPtr graphics = ctl->def->graphics[i];
>          size_t n;
> +        const char *rendernode = virDomainGraphicsGetRenderNode(graphics);
> +
> +        if (rendernode)
> +            vah_add_file(&buf, rendernode, "rw");
>
>          for (n = 0; n < graphics->nListens; n++) {
>              virDomainGraphicsListenDef listenObj = graphics->listens[n];
> @@ -1071,6 +1075,20 @@ get_files(vahControl * ctl)
>                  vah_add_file(&buf, listenObj.socket, "rw"))
>                  goto cleanup;
>          }
> +
> +        if (graphics->data.spice.gl == VIR_TRISTATE_BOOL_YES) {
> +            if (!rendernode)
> +                needDefaultRenderNode = true;
> +        }

^This feels a bit detached from the hunk above. Also, what about EGL_HEADLESS,
you will want to add (potentially a default one) rendernode for egl_headless
too. You could also optimize this with
virDomainGraphicsNeedsAutoRenderNode and cover both graphics types.

> +    }
> +
> +    if (virDomainGraphicsDefHasOpenGL(ctl->def))
> +        vah_add_file(&buf, "/dev/dri", "r");

Why is ^this needed?

> +
> +    if (needDefaultRenderNode) {
> +        const char *rendernode = virHostGetDRMRenderNode();
> +        if (rendernode)
> +            vah_add_file(&buf, virHostGetDRMRenderNode(), "rw");

IUC the virDomainGraphicsNeedsAutoRenderNode part would come ^here.

I also agree with Michal's suggestion.

Erik