Re: [libvirt] [PATCH] RFC: qemu: add spice/virgl rendernode

Hi ----- Original Message ----- > On Mon, Feb 13, 2017 at 07:19:04AM -0500, Marc-André Lureau wrote: > > Hi > > > > ----- Original Message ----- > > > On Mon, Feb 13, 2017 at 03:51:48PM +0400, marcandre.lureau(a)redhat.com > > > wrote: > > > > From: Marc-André Lureau <marcandre.lureau(a)redhat.com&gt; > > > > > > > > I am working on a WIP series to add QEMU Spice/virgl rendernode option. > > > > Since rendernodes are not stable across reboots, I propose that QEMU > > > > accepts also a PCI address (other bus types may be added in the > > > > future). > > > > > > Hmm, can you elaborate on this aspect ? It feels like a parallel > > > to saying NIC device names are not stable, so we should configure > > > guests using PCI addresses instead of 'eth0', etc but we stuck with > > > using NIC names in libvirt on the basis that you can create udev > > > rules to ensure stable naming ? > > > > > > So is there not a case to be made that if you want stable render > > > device names when multiple NICs are present, then you should use > > > udev to ensure a given device always maps to the same PCI dev. > > > > I thought it was simpler to use a PCI address (do you expect users > > to create udev rules for the GPUs?) > > Well most users will only have 1 GPU so surely this won't be a problem > in the common case. Is it possible to get some stable naming rules into > udev upstream though, so all distros get stable names by default Optimus is getting more and more mainstream, see recent Fedora desktop effort (fwiw I have a t460p nouveau/i915). I don't think a random user of such hw/laptop should have to create udev rules. I suppose systemd-udev could learn to create stable path with help from src/udev/udev-builtin-path_id.c. I will work on it. However, I have virt-manager code to lookup GPU infos/path, using libdrm, and it is unlikely that it will work with the udev rules. So I'll have to patch libdrm to support that too.