Hi Dmitry, > Subject: Re: [PATCH v2 2/5] drm/virtio: Add a helper to map and note the > dma addrs and lengths > > On 10/29/24 09:18, Kasireddy, Vivek wrote: > >>>> BTW, is any DG2 GPU suitable for testing of this patchset? Will I be > >>>> able to test it using a regular consumer A750 card? > >>> Yes, you can test with any DG2 dGPU as long as you can passthrough it to > >> the > >>> Guest VM. And, if there is an iGPU available on the Host, you can use > >> GTK/SDL UI > >>> for local display or Spice UI for remote display if there is no iGPU on the > >> Host. > >>> This is exactly how I started testing this patch series but I am now > >> predominantly > >>> testing this series with SRIOV enabled iGPUs and dGPUs. > >> Was hoping to try out SR-IOV on A750 if it's even possible at all. > > AFAIK, SRIOV is not supported on any versions of DG2 including A750. > > I'm having trouble with getting it to work. > > My testing setup: > > 1. Passthroughed A750 that uses XE driver I tested successfully with both i915 and Xe but DG2 is officially supported only with i915. Xe officially supports LNL and newer platforms. For older platforms, Mesa throws the following warning: MESA: warning: Support for this platform is experimental with Xe KMD, bug reports may be ignored. > 2. RaptorLake iGPU on host used for virtio-gpu, uses i915 driver I am testing with a similar setup: RPL-P iGPU + DG2 > 3. QEMU latest master branch + your QEMU vfio_dmabuf_2 patches applied > on top I just tried with latest Qemu master and it appears to be very sluggish in my environment (Fedora 39 Guest and Fedora 39 Host). But, few months old Qemu master + vfio_dmabuf_2 patches (actually, these patches are not needed to test this patch series with GTK/SDL) seems to work OK for me. And, here are the relevant Qemu launch options I am using: qemu-system-x86_64 -m 4096m -enable-kvm -cpu host,host-phys-bits=on,host-phys-bits-limit=39.... -device vfio-pci,host=0000:03:00.0 -device virtio-vga,max_outputs=1,xres=1920,yres=1080,blob=true -display gtk,gl=on -object memory-backend-memfd,id=mem1,size=4096M -machine memory-backend=mem1....... > 4. Latest linux-next kernel on host > 5. Latest linux-next kernel on guest + this v2 applied I just tested successfully with today's drm-tip (6.12) + v2 of this series. > > In guest I'm running this: > > seatd-launch -- weston --drm-device=card1 --additional-devices=card0 > > where card1 is A750 and card0 is virtio-gpu. > > I added printk's and see that virtio-gpu imports A750 dma-buf and gets > XE's SGT, but nothing shows on the QEMU display. Could you please try this test again with i915 instead of Xe? Also, are there any errors seen in Guest or Host logs? > I tried both GTK and SPICE displays. GTK should be simpler given that there are other components (Gstreamer, etc) needed for SPICE that have their own set of dependencies. > If I connect HDMI display to passthroughed A750 while > running weston command above, then I get weston working on the A750 > HDMI > display and still nothing is shown on virtio-gpu display. I tried this exact same test and it seems to work OK for me. Could you please also test Gnome + Wayland: XDG_SESSION_TYPE=wayland dbus-run-session -- /usr/bin/gnome-shell --wayland --no-x11 & Note that, for Weston, the primary device (drm-device=) needs to support KMS and have at-least one connector connected. For Gnome + Wayland, there is no such requirement as the primary device can work with dummy backend and be used only for rendering. Therefore, to test Gnome with DG2 in Guest, I typically do modprobe i915 enable_guc=3 disable_display=true > > I also had to force virtio-gpu driver to always probe before XE, > otherwise virtio-gpu gets PCI read errors and fails to probe because it > fails to detect virtio features. That is concerning. I guess we'll need to investigate how to fix this properly. As part of my tests, I typically blacklist Xe and i915 and load them later after booting to the cmd line and before launching the compositors. > > Am I doing anything wrong? Suggestions are welcome. Could you please share your Qemu launch parameters? I'll try to recreate the issue you are seeing. Thanks, Vivek > > -- > Best regards, > Dmitry
