On 9/27/22 11:32, Gerd Hoffmann wrote: > On Mon, Sep 26, 2022 at 09:32:40PM +0300, Dmitry Osipenko wrote: >> On 9/23/22 15:32, Gerd Hoffmann wrote: >>> On Tue, Sep 13, 2022 at 12:50:22PM +0200, Antonio Caggiano wrote: >>>> From: Dmitry Osipenko <dmitry.osipe...@collabora.com> >>>> >>>> Host blobs don't need udmabuf, it's only needed by guest blobs. The host >>>> blobs are utilized by the Mesa virgl driver when persistent memory mapping >>>> is needed by a GL buffer, otherwise virgl driver doesn't use blobs. >>>> Persistent mapping support bumps GL version from 4.3 to 4.5 in guest. >>>> Relax the udmabuf requirement. >>> >>> What about blob=on,virgl=off? >>> >>> In that case qemu manages the resources and continued to require >>> udmabuf. >> >> The udmabuf is used only by the blob resource-creation command in Qemu. >> I couldn't find when we could hit that udmabuf code path in Qemu because >> BLOB_MEM_GUEST resource type is used only by crosvm+Venus when crosvm >> uses a dedicated render-server for virglrenderer. > > Recent enough linux guest driver will use BLOB_MEM_GUEST resources > with blob=on + virgl=off
I reproduced this case today using "-device virtio-gpu-device,blob=true". You're right, it doesn't work without udmabuf. [ 8.369306] virtio_gpu_dequeue_ctrl_func: 90 callbacks suppressed [ 8.369311] [drm:virtio_gpu_dequeue_ctrl_func] *ERROR* response 0x1200 (command 0x105) [ 8.371848] [drm:virtio_gpu_dequeue_ctrl_func] *ERROR* response 0x1205 (command 0x104) [ 8.373085] [drm:virtio_gpu_dequeue_ctrl_func] *ERROR* response 0x1200 (command 0x105) [ 8.376273] [drm:virtio_gpu_dequeue_ctrl_func] *ERROR* response 0x1205 (command 0x104) [ 8.416972] [drm:virtio_gpu_dequeue_ctrl_func] *ERROR* response 0x1200 (command 0x105) [ 8.418841] [drm:virtio_gpu_dequeue_ctrl_func] *ERROR* response 0x1205 (command 0x104) I see now why you're wanting to keep the udmabuf requirement for blob=on,virgl=off. >> - /dev/udmabuf isn't accessible by normal user >> - udmabuf driver isn't shipped by all of the popular Linux distros, >> for example Debian doesn't ship it > > That's why blob resources are off by default. > >> Because of all of the above, I don't think it makes sense to >> hard-require udmabuf at the start of Qemu. It's much better to fail >> resource creation dynamically. > > Disagree. When virgl/venus is enabled, then yes, qemu would let > virglrenderer manage resources and I'm ok with whatever requirements > virglrenderer has. When qemu manages resources by itself udmabuf is > a hard requirement for blob support though. Let's try to relax the udmabuf requirement only for blob=on,virgl=on. I'll update this patch. Thank you very much for the review! -- Best regards, Dmitry
