Hi all, V2 patch of kernel is https://lore.kernel.org/lkml/20230630073448.842767-1-Jiqian.Chen@xxxxxxx/T/#t. On 2023/6/30 15:34, Jiqian Chen wrote: > v2: > > Hi all, > > Thanks to Marc-André Lureau, Robert Beckett and Gerd Hoffmann for > their advice and guidance. V2 makes below changes: > > * Change VIRTIO_CPU_CMD_STATUS_FREEZING to 0x0400 (<0x1000) > * Add a new feature flag VIRTIO_GPU_F_FREEZING, so that guest and > host can negotiate whenever freezing is supported or not. > > V2 of Qemu patch https://lore.kernel.org/qemu-devel/20230630070016.841459-1-Jiqian.Chen@xxxxxxx/T/#t > > Best regards, > Jiqian Chen. > > v1: > > link: https://lore.kernel.org/lkml/20230608063857.1677973-1-Jiqian.Chen@xxxxxxx/ > > 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 shows a > black screen. > > In response to the above phenomenon, I have found two problems. > > First, if we move mouse on the black screen, guest kernel still sends a > cursor request to Qemu, but Qemu doesn't response. Because when guest > is suspending, it calls device_suspend, and then call into Qemu to call > virtio_reset->__virtio_queue_reset. In __virtio_queue_reset, it clears > all virtqueue information on Qemu end. So, after guest resumes, Qemu > can't get message from virtqueue. > > Second, the reason why display can't come back is that when guest is > suspending, it calls into Qemu to call virtio_reset->virtio_gpu_gl_reset. > In virtio_gpu_gl_reset, it destroys all resources and resets renderer, > which are used for display. So after guest resumes, the display can't > come back to the status when guest is suspended. > > This patch initializes virtqueue when guest is resuming to solve first > problem. And it notifies Qemu that guest is suspending to prevent Qemu > destroying resources, this is to solve second problem. And then, I can > bring the display back, and everything continues their actions after > guest resumes. > > Modifications on Qemu end is: > https://lore.kernel.org/qemu-devel/20230608025655.1674357-2-Jiqian.Chen@xxxxxxx/ > > Jiqian Chen (1): > virtgpu: init vq during resume and notify qemu guest status > > drivers/gpu/drm/virtio/virtgpu_debugfs.c | 1 + > drivers/gpu/drm/virtio/virtgpu_drv.c | 37 ++++++++++++++++++++++++ > drivers/gpu/drm/virtio/virtgpu_drv.h | 4 +++ > drivers/gpu/drm/virtio/virtgpu_kms.c | 36 +++++++++++++++++------ > drivers/gpu/drm/virtio/virtgpu_vq.c | 15 ++++++++++ > include/uapi/linux/virtio_gpu.h | 15 ++++++++++ > 6 files changed, 99 insertions(+), 9 deletions(-) > -- Best regards, Jiqian Chen.
