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

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

Hi all,

Do you have any other comments on the modification of virtio-gpu S3?
Looking forward to your reply and comments.

On 2023/7/20 20:18, Jiqian Chen wrote:
> 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(+)
> 

-- 
Best regards,
Jiqian Chen.