[vfio-users] Passing arbitrary IRQ to guest?

[Gerd Hoffmann]

On Mon, Aug 05, 2019 at 12:50:00PM -0700, Micah Morton wrote:
> On Thu, Aug 1, 2019 at 10:36 PM Gerd Hoffmann <kraxel at redhat.com> wrote:
> >
> >   Hi,
> >
> > > From my perspective, as a low-speed device where we don't really need
> > > the benefits of an IOMMU, I'd be more inclined to look at why it
> > > doesn't work with evdev.  We already have a tablet device in QEMU,
> > > what's it take to connect that to evdev?  Cc'ing Gerd as maybe he's
> > > already though about touchpad support.  Thanks,
> >
> > It's not clear why the touchpad doesn't work.  Possibly using libinput
> > helps, https://git.kraxel.org/cgit/qemu/log/?h=sirius/display-drm has
> > some code.  Wiring up to input-linux isn't done yet though, only the
> > drm ui uses libinput support so far.
> 
> To be clear are you saying that its a known issue that the touchpad
> doesn't work in VM guest with QEMU and evdev?

There are other reports of touchpad problems.  I don't know whenever
that is a general problem or specific to some devices.

libinput knows quirks for lots of input devices.  When passing through
the evdev to the guest as virtio device libinput can't see the device
identity and thus can't apply quirks.  Which might be the reason the
touchpad doesn't work.  Using libinput on the host side might fix this.

cheers,
  Gerd