Thread (82 messages) 82 messages, 3 authors, 2022-07-18

Re: [PATCH v11 02/40] virtio: struct virtio_config_ops add callbacks for queue_reset

From: Jason Wang <jasowang@redhat.com>
Date: 2022-06-30 06:39:30
Also in: bpf, kvm, linux-remoteproc, linux-s390, linux-um, platform-driver-x86, virtualization

On Wed, Jun 29, 2022 at 2:57 PM Xuan Zhuo [off-list ref] wrote:
quoted hunk ↗ jump to hunk
reset can be divided into the following four steps (example):
 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

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@linux.alibaba.com>
---
 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 b47c2e7ed0ee..ded51b0d4823 100644
--- a/include/linux/virtio_config.h
+++ b/include/linux/virtio_config.h
@@ -78,6 +78,16 @@ 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
+ *     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 {
@@ -104,6 +114,8 @@ 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);
I wonder if a single op with a boolean parameter is sufficient here.

Thanks
 };

 /* If driver didn't advertise the feature, it will never appear. */
--
2.31.0
  
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