This patchset adds DRM native context support to VirtIO-GPU on Qemu. Contarary to Virgl and Venus contexts that mediates high level GFX APIs, DRM native context [1] mediates lower level kernel driver UAPI, which reflects in a less CPU overhead and less/simpler code needed to support it. DRM context consists of a host and guest parts that have to be implemented for each GPU driver. On a guest side, DRM context presents a virtual GPU as a real/native host GPU device for GL/VK applications.
[1] https://www.youtube.com/watch?v=9sFP_yddLLQ Today there are four DRM native context drivers existing in a wild: - Freedreno (Qualcomm SoC GPUs), completely upstreamed - AMDGPU, completely upstreamed - Intel (i915), merge requests are opened - Asahi (Apple SoC GPUs), partially merged upstream # How to try out DRM context: 1. DRM context uses host blobs and on host requires latest 6.13 version of Linux kernel that contains necessary KVM fixes. 2. Use latest Mesa (both guest and host) and libvirglrenderer versions. Use build flags documented in tha patch #10 of this series. 3. On guest, use latest Linux kernel v6.14-rc or newer. Example Qemu cmdline that enables DRM context: qemu-system-x86_64 -device virtio-vga-gl,hostmem=4G,blob=on,drm_native_context=on \ -machine q35,accel=kvm,memory-backend=mem1 \ -object memory-backend-memfd,id=mem1,size=8G -m 8G # Note about known performance problem in Qemu: DRM contexts are mapping host blobs extensively and these mapping operations work slowly in Qemu. Exact reason is unknown. Mappings work fast on Crosvm For DRM contexts this problem is more visible than for Venus/Virgl. Changelog: v8: - Addressed review comments from Akihiko Odaki on the doc patch. - Added r-bs from Akihiko Odaki on the doc patches. - Extended vrend doc with info about hostmem requirement for GL 4.6 v7: - Added r-b from Alex Bennée to the async fencing patch. - Updated virtio-gpu doc patch with addressed review comments from Akihiko Odaki. v6: - Fixed compilation warning using older version of virglrenderer, which wasn't fixed properly in v5. - Added t-bs from Alex Bennée. - Added patches to improve virgl/venus doc by adding links to the Mesa doc as was suggested by Akihiko Odaki. - Updated patch that documents guest/host requirements. Added links to Asahi nctx and reworked the doc structure by adding requirements to each context-type section instead of having one big blob or requirements, which was objected by Akihiko Odaki. v5: - Added r-bs from Akihiko Odaki. - Added acks from Michael Tsirkin. - Fixed compilation warning using older version of virglrenderer that was reported by Alex Bennée. Noticed that I need to keep old virgl_write_fence() code around for the older virglrenderer in "Support asynchronous fencing" patch, so added it back and verified that old virglrenderer works properly. - Added new patch from Alex Bennée that adds more virtio-gpu documentation with a couple corrections and additions to it from me. - Rebased patches on top of latest staging tree. v4: - Improved SDL2/dmabuf patch by reusing existing Meson X11 config option, better handling EGL error and extending comment telling that it's safe to enable SDL2 EGL preference hint. As was suggested by Akihiko Odaki. - Replaced another QSLIST_FOREACH_SAFE with QSLIST_EMPTY+FIRST in the async-fencing patch for more consistency of the code. As was suggested by Akihiko Odaki. - Added missing braces around if-statement that was spotted by Alex Bennée. - Renamed 'drm=on' option of virtio-gpu-gl device to 'drm_native_context=on' for more clarity as was suggested by Alex Bennée. Haven't added added new context-type option that was also proposed by Alex, might do it with a separate patch. This context-type option will duplicate and depecate existing options, but in a longer run likely will be worthwhile adding it. - Dropped Linux headers-update patch as headers has been updated in the staging tree. v3: - Improved EGL presence-check code on X11 systems for the SDL2 hint that prefers EGL over GLX by using better ifdefs and checking Xlib presence at a build time to avoid build failure if lib SDL2 and system are configured with a disabled X11 support. Also added clarifying comment telling that X11 hint doesn't affect Wayland systems. Suggested by Akihiko Odaki. - Corrected strerror(err) that used negative error where it should be positive and vice versa that was caught by Akihiko Odaki. Added clarifying comment for the case where we get positive error code from virglrenderer that differs from other virglrenderer API functions. - Improved QSLIST usage by dropping mutex protecting the async fence list and using atomic variant of QSLIST helpers instead. Switched away from using FOREACH helper to improve readability of the code, showing that we don't precess list in unoptimal way. Like was suggested by Akihiko Odaki. - Updated patchset base to Venus v18. v2: - Updated SDL2-dmabuf patch by making use of error_report() and checking presense of X11+EGL in the system before making SDL2 to prefer EGL backend over GLX, suggested by Akihiko Odaki. - Improved SDL2's dmabuf-presence check that wasn't done properly in v1, where EGL was set up only after first console was fully inited, and thus, SDL's display .has_dmabuf callback didn't work for the first console. Now dmabuf support status is pre-checked before console is registered. - Updated commit description of the patch that fixes SDL2's context switching logic with a more detailed explanation of the problem. Suggested by Akihiko Odaki. - Corrected rebase typo in the async-fencing patch and switched async-fencing to use a sigle-linked list instead of the double, as was suggested by Akihiko Odaki. - Replaced "=true" with "=on" in the DRM native context documentation example and made virtio_gpu_virgl_init() to fail with a error message if DRM context can't be initialized instead of giving a warning message, as was suggested by Akihiko Odaki. - Added patchew's dependecy tag to the cover letter as was suggested by Akihiko Odaki. Alex Bennée (1): docs/system: virtio-gpu: Document host/guest requirements Dmitry Osipenko (8): ui/sdl2: Restore original context after new context creation virtio-gpu: Handle virgl fence creation errors virtio-gpu: Support asynchronous fencing virtio-gpu: Support DRM native context ui/sdl2: Don't disable scanout when display is refreshed ui/gtk: Don't disable scanout when display is refreshed docs/system: virtio-gpu: Add link to Mesa VirGL doc docs/system: virtio-gpu: Update Venus link Pierre-Eric Pelloux-Prayer (1): ui/sdl2: Implement dpy dmabuf functions docs/system/devices/virtio-gpu.rst | 122 ++++++++++++++++++++- hw/display/virtio-gpu-gl.c | 5 + hw/display/virtio-gpu-virgl.c | 164 ++++++++++++++++++++++++++++- hw/display/virtio-gpu.c | 15 +++ include/hw/virtio/virtio-gpu.h | 16 +++ include/ui/sdl2.h | 7 ++ meson.build | 6 +- ui/gtk-egl.c | 1 - ui/gtk-gl-area.c | 1 - ui/sdl2-gl.c | 68 +++++++++++- ui/sdl2.c | 42 ++++++++ 11 files changed, 435 insertions(+), 12 deletions(-) -- 2.47.1
