[virglrenderer-devel] coherent memory access for virgl

[Gerd Hoffmann]

On Fri, Mar 08, 2019 at 02:10:54PM +0100, Tomeu Vizoso wrote:
> On 3/8/19 2:08 PM, Gerd Hoffmann wrote:
> > On Fri, Mar 08, 2019 at 10:43:04AM +0100, Tomeu Vizoso wrote:
> > > On 10/11/18 1:04 PM, Gerd Hoffmann wrote:
> > > > 
> > > > > * virtio-gpu resource IDs are placed by the guest proxy in the wl_dmabuf
> > > > > protocol stream instead of (guest) dmabuf FDs. The proxy in the host
> > > > > replaces those to the corresponding (host) dmabuf FD.
> > > > 
> > > > Yes.
> > > 
> > > Hi Gerd,
> > > 
> > > how were you thinking that we would prevent a malicious guest from
> > > connecting to the host proxy via VSOCK and guessing virtio-gpu resource IDs?
> > 
> > Each virtio-gpu device (and therefore each guest) has its own resource
> > id namespace, so you can't guess IDs of other guests.  Guessing IDs of
> > other processes in the same guest is probably possible.  I think that
> > doesn't allow actually accessing these resources, you can only ask the
> > host to do something with them.
> > 
> > Maybe that is a good reason do make wayland proxying a virtio-gpu
> > extension.  That way guest userspace would not deal with virtio-gpu
> > resource IDs but with gbm handles, and the virtio-gpu drm driver would
> > translate gbm handles to resource ids before proxying buffer control
> > messages to the host side.
> 
> By virtio-gpu extension you mean adding ioctls to send and receive protocol
> data along with references to buffers?

That'll probably work best.  Also a virtio protocol extension.

cheers,
  Gerd