[QEMU PATCH 0/1]

[Jiqian Chen]

Hi all,

I am working to implement virtgpu S3 function on Xen.

Currently on Xen, if we start a guest who enables virtgpu, and then
run "echo mem > /sys/power/state" to suspend guest. And run
"sudo xl trigger <guest id> s3resume" to resume guest. We can find that
the guest kernel comes back, but the display doesn't. It just shown a
black screen.

Through reading codes, I founded that when guest was during suspending,
it called into Qemu to call virtio_gpu_gl_reset. In virtio_gpu_gl_reset,
it destroyed all resources and reset renderer. This made the display
gone after guest resumed.

I think we should keep resources or prevent they being destroyed when
guest is suspending. So, I add a new status named freezing to virtgpu,
and add a new ctrl message VIRTIO_GPU_CMD_STATUS_FREEZING to get
notification from guest. If freezing is set to true, and then Qemu will
realize that guest is suspending, it will not destroy resources and will
not reset renderer. If freezing is set to false, Qemu will do its origin
actions, and has no other impaction.

And now, display can come back and applications can continue their
status after guest resumes.

Jiqian Chen (1):
  virtgpu: do not destroy resources when guest suspend

 hw/display/virtio-gpu-gl.c                  |  9 ++++++-
 hw/display/virtio-gpu-virgl.c               |  3 +++
 hw/display/virtio-gpu.c                     | 26 +++++++++++++++++++--
 include/hw/virtio/virtio-gpu.h              |  3 +++
 include/standard-headers/linux/virtio_gpu.h |  9 +++++++
 5 files changed, 47 insertions(+), 3 deletions(-)

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2.34.1