[VIRTIO GPU PATCH v3 0/1] Add new feature flag VIRTIO_GPU_F_FREEZE_S3

[Jiqian Chen <Jiqian.Chen@amd.com>]

v3:

Hi all,
Thanks for Gerd Hoffmann's advice. V3 makes below changes:
* Use enum for freeze mode, so this can be extended with more
  modes in the future.
* Rename functions and paratemers with "_S3" postfix.
* Explain in more detail

And latest version on QEMU and Linux kernel side:
	QEMU: https://lore.kernel.org/qemu-devel/20230720120816.8751-1-Jiqian.Chen@amd.com
	Kernel: https://lore.kernel.org/lkml/20230720115805.8206-1-Jiqian.Chen@amd.com/T/#t

Best regards,
Jiqian Chen.


v2:
link,
https://lists.oasis-open.org/archives/virtio-comment/202307/msg00160.html

Hi all,
Thanks to Gerd Hoffmann for his suggestions. V2 makes below changes:
* Elaborate on the types of resources.
* Add some descriptions for S3 and S4.


v1:
link,
https://lists.oasis-open.org/archives/virtio-comment/202306/msg00595.html

Hi all,
I am working to implement virtgpu S3 function on Xen.

Currently on Xen, if we start a guest through Qemu with enabling virtgpu,
and then suspend and s3resume guest. We can find that the guest kernel
comes back, but the display doesn't. It just shown a black screen.

That is because when guest was during suspending, it called into Qemu and
Qemu destroyed all resources and reset renderer. This made the display
gone after guest resumed.

So, I add a mechanism that when guest is suspending, it will notify Qemu,
and then Qemu will not destroy resources. That can help guest's display
come back.

As discussed and suggested by Robert Beckett and Gerd Hoffmann on v1
qemu's mailing list. Due to that mechanism needs cooperation between
guest and host. What's more, as virtio drivers by design paravirt
drivers, it is reasonable for guest to accept some cooperation with host
to manage suspend/resume. So I request to add a new feature flag, so that
guest and host can negotiate whenever freezing is supported or not.

Jiqian Chen (1):
  virtio-gpu: Add new feature flag VIRTIO_GPU_F_FREEZE_S3

 device-types/gpu/description.tex | 42 ++++++++++++++++++++++++++++++++
 1 file changed, 42 insertions(+)

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2.34.1