在 2022/4/6 上午11:43, Xuan Zhuo 写道:
Performing reset on a queue is divided into four steps:
1. transport: notify the device to reset the queue
2. vring: recycle the buffer submitted
3. vring: reset/resize the vring (may re-alloc)
4. transport: mmap vring to device, and enable the queue
Nit: it looks to me we'd better say it's an example (since step 3 or
even 2 is not a must).
In order to support queue reset, add two callbacks(reset_vq,
enable_reset_vq) in struct virtio_config_ops to implement steps 1 and 4.
Signed-off-by: Xuan Zhuo <xuanzhuo@xxxxxxxxxxxxxxxxx>
---
include/linux/virtio_config.h | 12 ++++++++++++
1 file changed, 12 insertions(+)
diff --git a/include/linux/virtio_config.h b/include/linux/virtio_config.h
index 4d107ad31149..d4adcd0e1c57 100644
--- a/include/linux/virtio_config.h
+++ b/include/linux/virtio_config.h
@@ -74,6 +74,16 @@ struct virtio_shm_region {
* @set_vq_affinity: set the affinity for a virtqueue (optional).
* @get_vq_affinity: get the affinity for a virtqueue (optional).
* @get_shm_region: get a shared memory region based on the index.
+ * @reset_vq: reset a queue individually (optional).
+ * vq: the virtqueue
+ * Returns 0 on success or error status
+ * reset_vq will guarantee that the callbacks are disabled and synchronized.
+ * Except for the callback, the caller should guarantee that the vring is
I wonder what's the implications for virtio hardening[1]. In that
series, we agree to have a synchronize_vqs() config ops to make sure
callbacks are synchronized.
It uses a global flag and a device wise synchronization mechanism. It
looks to me we need to switch to
1) per virtqueue flag
2) per virtqueue synchronization
Thanks
+ * not accessed by any functions of virtqueue.
+ * @enable_reset_vq: enable a reset queue
+ * vq: the virtqueue
+ * Returns 0 on success or error status
+ * If reset_vq is set, then enable_reset_vq must also be set.
*/
typedef void vq_callback_t(struct virtqueue *);
struct virtio_config_ops {
@@ -100,6 +110,8 @@ struct virtio_config_ops {
int index);
bool (*get_shm_region)(struct virtio_device *vdev,
struct virtio_shm_region *region, u8 id);
+ int (*reset_vq)(struct virtqueue *vq);
+ int (*enable_reset_vq)(struct virtqueue *vq);
};
/* If driver didn't advertise the feature, it will never appear. */
