virtio: introduce virtio_queue_info struct and find_vqs_info() config op

Introduce a structure virtio_queue_info to carry name, callback and ctx
together. In order to allow config implementations to accept config op
with array of virtio_queue_info structures, introduce a new
find_vqs_info() op. Do the needed conversion in virtio_find_vqs_ctx().
Note that whole virtio_find_vqs_ctx() is going to be eventually removed
at the and of this patchset.

Suggested-by: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
Signed-off-by: Jiri Pirko <jiri@nvidia.com>
Message-Id: <20240708074814.1739223-5-jiri@resnulli.us>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

diff --git a/include/linux/virtio_config.h b/include/linux/virtio_config.h
index 82a1d798b2f10929ff718e7881ffb39aea35bc15..fb7a1fd00ee5442f907880948a36d74e4c014181 100644 (file)
--- a/include/linux/virtio_config.h
+++ b/include/linux/virtio_config.h
@@ -18,6 +18,20 @@ struct virtio_shm_region {
 
 typedef void vq_callback_t(struct virtqueue *);
 
+/**
+ * struct virtqueue_info - Info for a virtqueue passed to find_vqs().
+ * @name: virtqueue description. Used mainly for debugging, NULL for
+ *        a virtqueue unused by the driver.
+ * @callback: A callback to invoke on a used buffer notification.
+ *            NULL for a virtqueue that does not need a callback.
+ * @ctx: A flag to indicate to maintain an extra context per virtqueue.
+ */
+struct virtqueue_info {
+       const char *name;
+       vq_callback_t *callback;
+       bool ctx;
+};
+
 /**
  * struct virtio_config_ops - operations for configuring a virtio device
  * Note: Do not assume that a transport implements all of the operations
@@ -58,6 +72,12 @@ typedef void vq_callback_t(struct virtqueue *);
  *     names: array of virtqueue names (mainly for debugging)
  *             include a NULL entry for vqs unused by driver
  *     Returns 0 on success or error status
+ * @find_vqs_info: find virtqueues and instantiate them.
+ *     vdev: the virtio_device
+ *     nvqs: the number of virtqueues to find
+ *     vqs: on success, includes new virtqueues
+ *     vqs_info: array of virtqueue info structures
+ *     Returns 0 on success or error status
  * @del_vqs: free virtqueues found by find_vqs().
  * @synchronize_cbs: synchronize with the virtqueue callbacks (optional)
  *      The function guarantees that all memory operations on the
@@ -109,6 +129,10 @@ struct virtio_config_ops {
                        struct virtqueue *vqs[], vq_callback_t *callbacks[],
                        const char * const names[], const bool *ctx,
                        struct irq_affinity *desc);
+       int (*find_vqs_info)(struct virtio_device *vdev, unsigned int nvqs,
+                            struct virtqueue *vqs[],
+                            struct virtqueue_info vqs_info[],
+                            struct irq_affinity *desc);
        void (*del_vqs)(struct virtio_device *);
        void (*synchronize_cbs)(struct virtio_device *);
        u64 (*get_features)(struct virtio_device *vdev);
@@ -117,7 +141,7 @@ struct virtio_config_ops {
        int (*set_vq_affinity)(struct virtqueue *vq,
                               const struct cpumask *cpu_mask);
        const struct cpumask *(*get_vq_affinity)(struct virtio_device *vdev,
-                       int index);
+                                                int index);
        bool (*get_shm_region)(struct virtio_device *vdev,
                               struct virtio_shm_region *region, u8 id);
        int (*disable_vq_and_reset)(struct virtqueue *vq);
@@ -210,14 +234,39 @@ static inline bool virtio_has_dma_quirk(const struct virtio_device *vdev)
        return !virtio_has_feature(vdev, VIRTIO_F_ACCESS_PLATFORM);
 }
 
+static inline
+int virtio_find_vqs_info(struct virtio_device *vdev, unsigned int nvqs,
+                        struct virtqueue *vqs[],
+                        struct virtqueue_info vqs_info[],
+                        struct irq_affinity *desc)
+{
+       return vdev->config->find_vqs_info(vdev, nvqs, vqs, vqs_info, desc);
+}
+
 static inline
 int virtio_find_vqs_ctx(struct virtio_device *vdev, unsigned nvqs,
                        struct virtqueue *vqs[], vq_callback_t *callbacks[],
                        const char * const names[], const bool *ctx,
                        struct irq_affinity *desc)
 {
-       return vdev->config->find_vqs(vdev, nvqs, vqs, callbacks, names, ctx,
-                                     desc);
+       struct virtqueue_info *vqs_info;
+       int err, i;
+
+       if (!vdev->config->find_vqs_info)
+               return vdev->config->find_vqs(vdev, nvqs, vqs, callbacks,
+                                             names, ctx, desc);
+
+       vqs_info = kmalloc_array(nvqs, sizeof(*vqs_info), GFP_KERNEL);
+       if (!vqs_info)
+               return -ENOMEM;
+       for (i = 0; i < nvqs; i++) {
+               vqs_info[i].name = names[i];
+               vqs_info[i].callback = callbacks[i];
+               vqs_info[i].ctx = ctx ? ctx[i] : false;
+       }
+       err = virtio_find_vqs_info(vdev, nvqs, vqs, vqs_info, desc);
+       kfree(vqs_info);
+       return err;
 }
 
 static inline