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(-) -- 2.34.1
