On Wed, Aug 9, 2023 at 11:55 PM Akihiko Odaki <akihiko.od...@gmail.com> wrote:
> On 2023/08/10 10:11, Gurchetan Singh wrote: > > > > > > On Tue, Aug 8, 2023 at 10:18 PM Akihiko Odaki <akihiko.od...@gmail.com > > <mailto:akihiko.od...@gmail.com>> wrote: > > > > On 2023/08/09 11:11, Gurchetan Singh wrote: > > > This adds basic documentation for virtio-gpu. > > > > > > Suggested-by: Akihiko Odaki <akihiko.od...@daynix.com > > <mailto:akihiko.od...@daynix.com>> > > > Signed-off-by: Gurchetan Singh <gurchetansi...@chromium.org > > <mailto:gurchetansi...@chromium.org>> > > > --- > > > v2: - Incorporated suggestions by Akihiko Odaki > > > - Listed the currently supported capset_names (Bernard) > > > > > > v3: - Incorporated suggestions by Akihiko Odaki and Alyssa Ross > > > > > > v4: - Incorporated suggestions by Akihiko Odaki > > > > > > docs/system/device-emulation.rst | 1 + > > > docs/system/devices/virtio-gpu.rst | 115 > > +++++++++++++++++++++++++++++ > > > 2 files changed, 116 insertions(+) > > > create mode 100644 docs/system/devices/virtio-gpu.rst > > > > > > diff --git a/docs/system/device-emulation.rst > > b/docs/system/device-emulation.rst > > > index 4491c4cbf7..1167f3a9f2 100644 > > > --- a/docs/system/device-emulation.rst > > > +++ b/docs/system/device-emulation.rst > > > @@ -91,6 +91,7 @@ Emulated Devices > > > devices/nvme.rst > > > devices/usb.rst > > > devices/vhost-user.rst > > > + devices/virtio-gpu.rst > > > devices/virtio-pmem.rst > > > devices/vhost-user-rng.rst > > > devices/canokey.rst > > > diff --git a/docs/system/devices/virtio-gpu.rst > > b/docs/system/devices/virtio-gpu.rst > > > new file mode 100644 > > > index 0000000000..d56524270d > > > --- /dev/null > > > +++ b/docs/system/devices/virtio-gpu.rst > > > @@ -0,0 +1,115 @@ > > > +.. > > > + SPDX-License-Identifier: GPL-2.0 > > > + > > > +virtio-gpu > > > +========== > > > + > > > +This document explains the setup and usage of the virtio-gpu > device. > > > +The virtio-gpu device paravirtualizes the GPU and display > > controller. > > > + > > > +Linux kernel support > > > +-------------------- > > > + > > > +virtio-gpu requires a guest Linux kernel built with the > > > +``CONFIG_DRM_VIRTIO_GPU`` option. > > > + > > > +QEMU virtio-gpu variants > > > +------------------------ > > > + > > > +QEMU virtio-gpu device variants come in the following form: > > > + > > > + * ``virtio-vga[-BACKEND]`` > > > + * ``virtio-gpu[-BACKEND][-INTERFACE]`` > > > + * ``vhost-user-vga`` > > > + * ``vhost-user-pci`` > > > + > > > +**Backends:** QEMU provides a 2D virtio-gpu backend, and two > > accelerated > > > +backends: virglrenderer ('gl' device label) and rutabaga_gfx > > ('rutabaga' > > > +device label). There is a vhost-user backend that runs the > > graphics stack > > > +in a separate process for improved isolation. > > > + > > > +**Interfaces:** QEMU further categorizes virtio-gpu device > > variants based > > > +on the interface exposed to the guest. The interfaces can be > > classified > > > +into VGA and non-VGA variants. The VGA ones are prefixed with > > virtio-vga > > > +or vhost-user-vga while the non-VGA ones are prefixed with > > virtio-gpu or > > > +vhost-user-gpu. > > > + > > > +The VGA ones always use the PCI interface, but for the non-VGA > > ones, the > > > +user can further pick between MMIO or PCI. For MMIO, the user > > can suffix > > > +the device name with -device, though vhost-user-gpu does not > > support MMIO. > > > +For PCI, the user can suffix it with -pci. Without these > > suffixes, the > > > +platform default will be chosen. > > > + > > > +This document uses the PCI interface in examples. > > > > I think it's better to omit -pci. > > > > > > Are you suggesting to use "-device virtio-gpu-rutabaga" or "-device > > virtio-gpu-gl" in the examples? Or "-device virtio-gpu-rutabaga-device" > > or "-device virtio-gpu-gl-device"? The former I believe wouldn't > > launch, and the examples should ideally be directly applicable to a user. > > > > > > By the way you are not adding the aliases for Rutabaga so please do > so. > > You can find the table in: softmmu/qdev-monitor.c > > > > > > I don't follow this comment. Isn't "-device virtio-gpu-rutabaga-pci" > > (along with "-device virtio-gpu-rutabaga-device") an alias for the > > rutabaga device? Where would the alias be placed in the doc (we don't > > explicitly list aliases for other devices either), outside the > > "..parsed-literal::" launch command? > > virtio-gpu-gl should work, and you need add an alias definition to get > virtio-gpu-rutabaga work. > I see the problem: virtio-gpu-gl as a device works, but virtio-gpu-rutabaga doesn't. But the aliases for the gl device and rutabaga device are the same in softmmu/qdev-monitor.c? { "virtio-gpu-gl-device", "virtio-gpu-gl", QEMU_ARCH_VIRTIO_MMIO }, { "virtio-gpu-gl-pci", "virtio-gpu-gl", QEMU_ARCH_VIRTIO_PCI }, { "virtio-gpu-rutabaga-device", "virtio-gpu-rutabaga", QEMU_ARCH_VIRTIO_MMIO }, { "virtio-gpu-rutabaga-pci", "virtio-gpu-rutabaga", QEMU_ARCH_VIRTIO_PCI }, What else needs to be added? > Your documentation already says: > > Without these suffixes, the platform default will be chosen. > > You should confirm what you say in the documentation and fix the > documentation or code if something is wrong.
