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.
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.
