Hi
On Thu, Jun 8, 2023 at 6:26 AM Jiqian Chen <jiqian.c...@amd.com> wrote:
> After suspending and resuming guest VM, you will get
> a black screen, and the display can't come back.
>
> This is because when guest did suspending, it called
> into qemu to call virtio_gpu_gl_reset. In function
> virtio_gpu_gl_reset, it destroyed resources and reset
> renderer, which were used for display. As a result,
> guest's screen can't come back to the time when it was
> suspended and only showed black.
>
> So, this patch adds a new ctrl message
> VIRTIO_GPU_CMD_STATUS_FREEZING to get notification from
> guest. If guest is during suspending, it sets freezing
> status of virtgpu to true, this will prevent destroying
> resources and resetting renderer when guest calls into
> virtio_gpu_gl_reset. If guest is during resuming, it sets
> freezing to false, and then virtio_gpu_gl_reset will keep
> its origin actions and has no other impaction.
>
> Signed-off-by: Jiqian Chen <jiqian.c...@amd.com>
> ---
> 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(-)
>
> diff --git a/hw/display/virtio-gpu-gl.c b/hw/display/virtio-gpu-gl.c
> index e06be60dfb..e11ad233eb 100644
> --- a/hw/display/virtio-gpu-gl.c
> +++ b/hw/display/virtio-gpu-gl.c
> @@ -100,7 +100,14 @@ static void virtio_gpu_gl_reset(VirtIODevice *vdev)
> */
> if (gl->renderer_inited && !gl->renderer_reset) {
> virtio_gpu_virgl_reset_scanout(g);
> - gl->renderer_reset = true;
> + /*
> + * If guest is suspending, we shouldn't reset renderer,
> + * otherwise, the display can't come back to the time when
> + * it was suspended after guest resumed.
> + */
> + if (!g->freezing) {
> + gl->renderer_reset = true;
> + }
> }
> }
>
> diff --git a/hw/display/virtio-gpu-virgl.c b/hw/display/virtio-gpu-virgl.c
> index 73cb92c8d5..183ec92d53 100644
> --- a/hw/display/virtio-gpu-virgl.c
> +++ b/hw/display/virtio-gpu-virgl.c
> @@ -464,6 +464,9 @@ void virtio_gpu_virgl_process_cmd(VirtIOGPU *g,
> case VIRTIO_GPU_CMD_GET_EDID:
> virtio_gpu_get_edid(g, cmd);
> break;
> + case VIRTIO_GPU_CMD_STATUS_FREEZING:
> + virtio_gpu_cmd_status_freezing(g, cmd);
> + break;
> default:
> cmd->error = VIRTIO_GPU_RESP_ERR_UNSPEC;
> break;
> diff --git a/hw/display/virtio-gpu.c b/hw/display/virtio-gpu.c
> index 5e15c79b94..8f235d7848 100644
> --- a/hw/display/virtio-gpu.c
> +++ b/hw/display/virtio-gpu.c
> @@ -373,6 +373,16 @@ static void virtio_gpu_resource_create_blob(VirtIOGPU
> *g,
> QTAILQ_INSERT_HEAD(&g->reslist, res, next);
> }
>
> +void virtio_gpu_cmd_status_freezing(VirtIOGPU *g,
> + struct virtio_gpu_ctrl_command *cmd)
> +{
> + struct virtio_gpu_status_freezing sf;
> +
> + VIRTIO_GPU_FILL_CMD(sf);
> + virtio_gpu_bswap_32(&sf, sizeof(sf));
> + g->freezing = sf.freezing;
> +}
> +
> static void virtio_gpu_disable_scanout(VirtIOGPU *g, int scanout_id)
> {
> struct virtio_gpu_scanout *scanout =
> &g->parent_obj.scanout[scanout_id];
> @@ -986,6 +996,9 @@ void virtio_gpu_simple_process_cmd(VirtIOGPU *g,
> case VIRTIO_GPU_CMD_RESOURCE_DETACH_BACKING:
> virtio_gpu_resource_detach_backing(g, cmd);
> break;
> + case VIRTIO_GPU_CMD_STATUS_FREEZING:
> + virtio_gpu_cmd_status_freezing(g, cmd);
> + break;
> default:
> cmd->error = VIRTIO_GPU_RESP_ERR_UNSPEC;
> break;
> @@ -1344,6 +1357,8 @@ void virtio_gpu_device_realize(DeviceState *qdev,
> Error **errp)
> QTAILQ_INIT(&g->reslist);
> QTAILQ_INIT(&g->cmdq);
> QTAILQ_INIT(&g->fenceq);
> +
> + g->freezing = false;
> }
>
> void virtio_gpu_reset(VirtIODevice *vdev)
> @@ -1352,8 +1367,15 @@ void virtio_gpu_reset(VirtIODevice *vdev)
> struct virtio_gpu_simple_resource *res, *tmp;
> struct virtio_gpu_ctrl_command *cmd;
>
> - QTAILQ_FOREACH_SAFE(res, &g->reslist, next, tmp) {
> - virtio_gpu_resource_destroy(g, res);
> + /*
> + * If guest is suspending, we shouldn't destroy resources,
> + * otherwise, the display can't come back to the time when
> + * it was suspended after guest resumed.
> + */
> + if (!g->freezing) {
> + QTAILQ_FOREACH_SAFE(res, &g->reslist, next, tmp) {
> + virtio_gpu_resource_destroy(g, res);
> + }
> }
>
> while (!QTAILQ_EMPTY(&g->cmdq)) {
> diff --git a/include/hw/virtio/virtio-gpu.h
> b/include/hw/virtio/virtio-gpu.h
> index 2e28507efe..c21c2990fb 100644
> --- a/include/hw/virtio/virtio-gpu.h
> +++ b/include/hw/virtio/virtio-gpu.h
> @@ -173,6 +173,7 @@ struct VirtIOGPU {
>
> uint64_t hostmem;
>
> + bool freezing;
> bool processing_cmdq;
> QEMUTimer *fence_poll;
> QEMUTimer *print_stats;
> @@ -284,5 +285,7 @@ void virtio_gpu_virgl_reset_scanout(VirtIOGPU *g);
> void virtio_gpu_virgl_reset(VirtIOGPU *g);
> int virtio_gpu_virgl_init(VirtIOGPU *g);
> int virtio_gpu_virgl_get_num_capsets(VirtIOGPU *g);
> +void virtio_gpu_cmd_status_freezing(VirtIOGPU *g,
> + struct virtio_gpu_ctrl_command *cmd);
>
> #endif
> diff --git a/include/standard-headers/linux/virtio_gpu.h
> b/include/standard-headers/linux/virtio_gpu.h
> index 2da48d3d4c..aefffbd751 100644
> --- a/include/standard-headers/linux/virtio_gpu.h
> +++ b/include/standard-headers/linux/virtio_gpu.h
> @@ -116,6 +116,9 @@ enum virtio_gpu_ctrl_type {
> VIRTIO_GPU_RESP_ERR_INVALID_RESOURCE_ID,
> VIRTIO_GPU_RESP_ERR_INVALID_CONTEXT_ID,
> VIRTIO_GPU_RESP_ERR_INVALID_PARAMETER,
> +
> + /* status */
> + VIRTIO_GPU_CMD_STATUS_FREEZING = 0x1300,
> };
>
Adding a new command requires new feature flag (and maybe it should be in
the <0x1000 range instead)
But I am not sure we need a new message at the virtio-gpu level. Gerd, wdyt?
Maybe it's not a good place to reset all GPU resources during QEMU reset()
after all, if it's called during s3 and there is no mechanism to restore
it. Damien?
thanks
...
> enum virtio_gpu_shm_id {
> @@ -453,4 +456,10 @@ struct virtio_gpu_resource_unmap_blob {
> uint32_t padding;
> };
>
> +/* VIRTIO_GPU_CMD_STATUS_FREEZING */
> +struct virtio_gpu_status_freezing {
> + struct virtio_gpu_ctrl_hdr hdr;
> + __u32 freezing;
> +};
> +
> #endif
> --
> 2.34.1
>
>
>
--
Marc-André Lureau
