drm/virtio: Implement VIRTIO_GPU_CMD_RESOURCE_DETACH_BACKING cmd

This cmd is useful to let the VMM (i.e, Qemu) know that the backing
store associated with a resource is no longer valid, so that the VMM
can perform any cleanup or unmap operations.

The fence related changes and virtio_gpu_object_detach()/
virtio_gpu_detach_object_fenced() routines are extracted from a
patch by Dmitry Osipenko <dmitry.osipenko@collabora.com>.

Cc: Gerd Hoffmann <kraxel@redhat.com>
Cc: Dmitry Osipenko <dmitry.osipenko@collabora.com>
Cc: Rob Clark <robdclark@gmail.com>
Cc: Gurchetan Singh <gurchetansingh@chromium.org>
Cc: Chia-I Wu <olvaffe@gmail.com>
Signed-off-by: Vivek Kasireddy <vivek.kasireddy@intel.com>
Tested-by: Dmitry Osipenko <dmitry.osipenko@collabora.com>
Reviewed-by: Dmitry Osipenko <dmitry.osipenko@collabora.com>
Signed-off-by: Dmitry Osipenko <dmitry.osipenko@collabora.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20241126031643.3490496-2-vivek.kasireddy@intel.com

diff --git a/drivers/gpu/drm/virtio/virtgpu_drv.h b/drivers/gpu/drm/virtio/virtgpu_drv.h
index 96eb576bc1b874ce3d7589931bdba6e4e8bb2b96..77892fa01ef0859998f3f83421f5bbd0e1b3aa76 100644 (file)
--- a/drivers/gpu/drm/virtio/virtgpu_drv.h
+++ b/drivers/gpu/drm/virtio/virtgpu_drv.h
@@ -92,6 +92,7 @@ struct virtio_gpu_object {
        uint32_t hw_res_handle;
        bool dumb;
        bool created;
+       bool attached;
        bool host3d_blob, guest_blob;
        uint32_t blob_mem, blob_flags;
 
@@ -353,6 +354,10 @@ void virtio_gpu_object_attach(struct virtio_gpu_device *vgdev,
                              struct virtio_gpu_object *obj,
                              struct virtio_gpu_mem_entry *ents,
                              unsigned int nents);
+void virtio_gpu_object_detach(struct virtio_gpu_device *vgdev,
+                             struct virtio_gpu_object *obj,
+                             struct virtio_gpu_fence *fence);
+int virtio_gpu_detach_object_fenced(struct virtio_gpu_object *bo);
 void virtio_gpu_cursor_ping(struct virtio_gpu_device *vgdev,
                            struct virtio_gpu_output *output);
 int virtio_gpu_cmd_get_display_info(struct virtio_gpu_device *vgdev);

diff --git a/drivers/gpu/drm/virtio/virtgpu_object.c b/drivers/gpu/drm/virtio/virtgpu_object.c
index c7e74cf130221bbed3aa447e416065b03bf3e2b4..d18263ddd972d7f0d00941faa7716d6653ec128b 100644 (file)
--- a/drivers/gpu/drm/virtio/virtgpu_object.c
+++ b/drivers/gpu/drm/virtio/virtgpu_object.c
@@ -97,6 +97,27 @@ static void virtio_gpu_free_object(struct drm_gem_object *obj)
        virtio_gpu_cleanup_object(bo);
 }
 
+int virtio_gpu_detach_object_fenced(struct virtio_gpu_object *bo)
+{
+       struct virtio_gpu_device *vgdev = bo->base.base.dev->dev_private;
+       struct virtio_gpu_fence *fence;
+
+       if (!bo->attached)
+               return 0;
+
+       fence = virtio_gpu_fence_alloc(vgdev, vgdev->fence_drv.context, 0);
+       if (!fence)
+               return -ENOMEM;
+
+       virtio_gpu_object_detach(vgdev, bo, fence);
+       virtio_gpu_notify(vgdev);
+
+       dma_fence_wait(&fence->f, false);
+       dma_fence_put(&fence->f);
+
+       return 0;
+}
+
 static const struct drm_gem_object_funcs virtio_gpu_shmem_funcs = {
        .free = virtio_gpu_free_object,
        .open = virtio_gpu_gem_object_open,

diff --git a/drivers/gpu/drm/virtio/virtgpu_vq.c b/drivers/gpu/drm/virtio/virtgpu_vq.c
index 0d3d0d09f39b9fa4994ce8c9c0c63e5d3e0be06b..ad91624df42dd9a7f1a74da9be5f0a444c3bdc73 100644 (file)
--- a/drivers/gpu/drm/virtio/virtgpu_vq.c
+++ b/drivers/gpu/drm/virtio/virtgpu_vq.c
@@ -645,6 +645,23 @@ virtio_gpu_cmd_resource_attach_backing(struct virtio_gpu_device *vgdev,
        virtio_gpu_queue_fenced_ctrl_buffer(vgdev, vbuf, fence);
 }
 
+static void
+virtio_gpu_cmd_resource_detach_backing(struct virtio_gpu_device *vgdev,
+                                      uint32_t resource_id,
+                                      struct virtio_gpu_fence *fence)
+{
+       struct virtio_gpu_resource_detach_backing *cmd_p;
+       struct virtio_gpu_vbuffer *vbuf;
+
+       cmd_p = virtio_gpu_alloc_cmd(vgdev, &vbuf, sizeof(*cmd_p));
+       memset(cmd_p, 0, sizeof(*cmd_p));
+
+       cmd_p->hdr.type = cpu_to_le32(VIRTIO_GPU_CMD_RESOURCE_DETACH_BACKING);
+       cmd_p->resource_id = cpu_to_le32(resource_id);
+
+       virtio_gpu_queue_fenced_ctrl_buffer(vgdev, vbuf, fence);
+}
+
 static void virtio_gpu_cmd_get_display_info_cb(struct virtio_gpu_device *vgdev,
                                               struct virtio_gpu_vbuffer *vbuf)
 {
@@ -1103,8 +1120,26 @@ void virtio_gpu_object_attach(struct virtio_gpu_device *vgdev,
                              struct virtio_gpu_mem_entry *ents,
                              unsigned int nents)
 {
+       if (obj->attached)
+               return;
+
        virtio_gpu_cmd_resource_attach_backing(vgdev, obj->hw_res_handle,
                                               ents, nents, NULL);
+
+       obj->attached = true;
+}
+
+void virtio_gpu_object_detach(struct virtio_gpu_device *vgdev,
+                             struct virtio_gpu_object *obj,
+                             struct virtio_gpu_fence *fence)
+{
+       if (!obj->attached)
+               return;
+
+       virtio_gpu_cmd_resource_detach_backing(vgdev, obj->hw_res_handle,
+                                              fence);
+
+       obj->attached = false;
 }
 
 void virtio_gpu_cursor_ping(struct virtio_gpu_device *vgdev,