When we suspended guest VM, it called into Qemu to call
virtio_reset->__virtio_queue_reset, this cleared all virtqueue information
of virtgpu on Qemu end, but guest kernel still keep the virtqueus. As a
result, after guest resumed, if guest sent ctrl/cursor requests to Qemu
through virtqueue, but now Qemu can't get requests from the virtqueue.
(Failed in function virtio_queue_notify, vq->vring.desc is NULL)

So, this patch add freeze and restore function for virtgpu driver. In
freeze function, it flushes all virtqueue works and deletes virtqueues. In
restore function, it re-initializes virtqueues. And then, Qemu and guest
can communicate normally.

Signed-off-by: Jiqian Chen <jiqian.c...@amd.com>
---
 drivers/gpu/drm/virtio/virtgpu_drv.c | 23 +++++++++++++++++++++
 drivers/gpu/drm/virtio/virtgpu_drv.h |  1 +
 drivers/gpu/drm/virtio/virtgpu_kms.c | 30 +++++++++++++++++++---------
 3 files changed, 45 insertions(+), 9 deletions(-)

diff --git a/drivers/gpu/drm/virtio/virtgpu_drv.c 
b/drivers/gpu/drm/virtio/virtgpu_drv.c
index 644b8ee51009..8e751db129e4 100644
--- a/drivers/gpu/drm/virtio/virtgpu_drv.c
+++ b/drivers/gpu/drm/virtio/virtgpu_drv.c
@@ -130,6 +130,25 @@ static void virtio_gpu_config_changed(struct virtio_device 
*vdev)
        schedule_work(&vgdev->config_changed_work);
 }
 
+#ifdef CONFIG_PM
+static int virtio_gpu_freeze(struct virtio_device *dev)
+{
+       struct drm_device *ddev = dev->priv;
+       struct virtio_gpu_device *vgdev = ddev->dev_private;
+
+       flush_work(&vgdev->ctrlq.dequeue_work);
+       flush_work(&vgdev->cursorq.dequeue_work);
+       vgdev->vdev->config->del_vqs(vgdev->vdev);
+
+       return 0;
+}
+
+static int virtio_gpu_restore(struct virtio_device *dev)
+{
+       return virtio_gpu_init_vqs(dev);
+}
+#endif
+
 static struct virtio_device_id id_table[] = {
        { VIRTIO_ID_GPU, VIRTIO_DEV_ANY_ID },
        { 0 },
@@ -156,6 +175,10 @@ static struct virtio_driver virtio_gpu_driver = {
        .driver.owner = THIS_MODULE,
        .id_table = id_table,
        .probe = virtio_gpu_probe,
+#ifdef CONFIG_PM
+       .freeze = virtio_gpu_freeze,
+       .restore = virtio_gpu_restore,
+#endif
        .remove = virtio_gpu_remove,
        .config_changed = virtio_gpu_config_changed
 };
diff --git a/drivers/gpu/drm/virtio/virtgpu_drv.h 
b/drivers/gpu/drm/virtio/virtgpu_drv.h
index 4126c384286b..d93dd53a947d 100644
--- a/drivers/gpu/drm/virtio/virtgpu_drv.h
+++ b/drivers/gpu/drm/virtio/virtgpu_drv.h
@@ -282,6 +282,7 @@ extern struct drm_ioctl_desc 
virtio_gpu_ioctls[DRM_VIRTIO_NUM_IOCTLS];
 void virtio_gpu_create_context(struct drm_device *dev, struct drm_file *file);
 
 /* virtgpu_kms.c */
+int virtio_gpu_init_vqs(struct virtio_device *vdev);
 int virtio_gpu_init(struct virtio_device *vdev, struct drm_device *dev);
 void virtio_gpu_deinit(struct drm_device *dev);
 void virtio_gpu_release(struct drm_device *dev);
diff --git a/drivers/gpu/drm/virtio/virtgpu_kms.c 
b/drivers/gpu/drm/virtio/virtgpu_kms.c
index 5a3b5aaed1f3..871b7ba98257 100644
--- a/drivers/gpu/drm/virtio/virtgpu_kms.c
+++ b/drivers/gpu/drm/virtio/virtgpu_kms.c
@@ -114,16 +114,33 @@ static void virtio_gpu_get_capsets(struct 
virtio_gpu_device *vgdev,
        vgdev->num_capsets = num_capsets;
 }
 
-int virtio_gpu_init(struct virtio_device *vdev, struct drm_device *dev)
+int virtio_gpu_init_vqs(struct virtio_device *vdev)
 {
        static vq_callback_t *callbacks[] = {
                virtio_gpu_ctrl_ack, virtio_gpu_cursor_ack
        };
        static const char * const names[] = { "control", "cursor" };
+       struct drm_device *dev = vdev->priv;
+       struct virtio_gpu_device *vgdev = dev->dev_private;
+       struct virtqueue *vqs[2];
+       int ret;
+
+       virtio_gpu_init_vq(&vgdev->ctrlq, virtio_gpu_dequeue_ctrl_func);
+       virtio_gpu_init_vq(&vgdev->cursorq, virtio_gpu_dequeue_cursor_func);
+
+       ret = virtio_find_vqs(vgdev->vdev, 2, vqs, callbacks, names, NULL);
+       if (ret) {
+               DRM_ERROR("failed to find virt queues\n");
+               return ret;
+       }
+       vgdev->ctrlq.vq = vqs[0];
+       vgdev->cursorq.vq = vqs[1];
+       return 0;
+}
 
+int virtio_gpu_init(struct virtio_device *vdev, struct drm_device *dev)
+{
        struct virtio_gpu_device *vgdev;
-       /* this will expand later */
-       struct virtqueue *vqs[2];
        u32 num_scanouts, num_capsets;
        int ret = 0;
 
@@ -144,8 +161,6 @@ int virtio_gpu_init(struct virtio_device *vdev, struct 
drm_device *dev)
        ida_init(&vgdev->ctx_id_ida);
        ida_init(&vgdev->resource_ida);
        init_waitqueue_head(&vgdev->resp_wq);
-       virtio_gpu_init_vq(&vgdev->ctrlq, virtio_gpu_dequeue_ctrl_func);
-       virtio_gpu_init_vq(&vgdev->cursorq, virtio_gpu_dequeue_cursor_func);
 
        vgdev->fence_drv.context = dma_fence_context_alloc(1);
        spin_lock_init(&vgdev->fence_drv.lock);
@@ -207,13 +222,10 @@ int virtio_gpu_init(struct virtio_device *vdev, struct 
drm_device *dev)
        DRM_INFO("features: %ccontext_init\n",
                 vgdev->has_context_init ? '+' : '-');
 
-       ret = virtio_find_vqs(vgdev->vdev, 2, vqs, callbacks, names, NULL);
+       ret = virtio_gpu_init_vqs(vdev);
        if (ret) {
-               DRM_ERROR("failed to find virt queues\n");
                goto err_vqs;
        }
-       vgdev->ctrlq.vq = vqs[0];
-       vgdev->cursorq.vq = vqs[1];
        ret = virtio_gpu_alloc_vbufs(vgdev);
        if (ret) {
                DRM_ERROR("failed to alloc vbufs\n");
-- 
2.34.1


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