virtio: create admin queues alongside other virtqueues

Admin virtqueue is just another virtqueue nothing that special about it.
The current implementation treats it somehow separate though in terms
of creation and deletion. Unify the admin virtqueue creation and
deletion flows to be aligned with the rest of virtqueues, creating
it from vp_find_vqs_*() helpers. Let the admin virtqueue to be deleted
by vp_del_vqs() as the rest.

Call vp_find_one_vq_msix() with slow_path argument being "true" to make
sure that in case of limited interrupt vectors the config vector is used
for admin queue.

Signed-off-by: Jiri Pirko <jiri@nvidia.com>
Message-Id: <20240716113552.80599-10-jiri@resnulli.us>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

drivers/virtio/virtio.c

@@ -305,15 +305,9 @@ static int virtio_dev_probe(struct device *_d)
 	if (err)
 		goto err;
 
-	if (dev->config->create_avq) {
-		err = dev->config->create_avq(dev);
-		if (err)
-			goto err;
-	}
-
 	err = drv->probe(dev);
 	if (err)
-		goto err_probe;
+		goto err;
 
 	/* If probe didn't do it, mark device DRIVER_OK ourselves. */
 	if (!(dev->config->get_status(dev) & VIRTIO_CONFIG_S_DRIVER_OK))
@@ -326,9 +320,6 @@ static int virtio_dev_probe(struct device *_d)
 
 	return 0;
 
-err_probe:
-	if (dev->config->destroy_avq)
-		dev->config->destroy_avq(dev);
 err:
 	virtio_add_status(dev, VIRTIO_CONFIG_S_FAILED);
 	return err;
@@ -344,9 +335,6 @@ static void virtio_dev_remove(struct device *_d)
 
 	drv->remove(dev);
 
-	if (dev->config->destroy_avq)
-		dev->config->destroy_avq(dev);
-
 	/* Driver should have reset device. */
 	WARN_ON_ONCE(dev->config->get_status(dev));
 
@@ -524,9 +512,6 @@ int virtio_device_freeze(struct virtio_device *dev)
 		}
 	}
 
-	if (dev->config->destroy_avq)
-		dev->config->destroy_avq(dev);
-
 	return 0;
 }
 EXPORT_SYMBOL_GPL(virtio_device_freeze);
@@ -562,16 +547,10 @@ int virtio_device_restore(struct virtio_device *dev)
 	if (ret)
 		goto err;
 
-	if (dev->config->create_avq) {
-		ret = dev->config->create_avq(dev);
-		if (ret)
-			goto err;
-	}
-
 	if (drv->restore) {
 		ret = drv->restore(dev);
 		if (ret)
-			goto err_restore;
+			goto err;
 	}
 
 	/* If restore didn't do it, mark device DRIVER_OK ourselves. */
@@ -582,9 +561,6 @@ int virtio_device_restore(struct virtio_device *dev)
 
 	return 0;
 
-err_restore:
-	if (dev->config->destroy_avq)
-		dev->config->destroy_avq(dev);
 err:
 	virtio_add_status(dev, VIRTIO_CONFIG_S_FAILED);
 	return ret;

drivers/virtio/virtio_pci_common.c

@@ -262,9 +262,6 @@ void vp_del_vqs(struct virtio_device *vdev)
 	int i;
 
 	list_for_each_entry_safe(vq, n, &vdev->vqs, list) {
-		if (vp_dev->is_avq && vp_dev->is_avq(vdev, vq->index))
-			continue;
-
 		if (vp_dev->per_vq_vectors) {
 			int v = vp_dev->vqs[vq->index]->msix_vector;
 
@@ -371,14 +368,23 @@ static int vp_find_vqs_msix(struct virtio_device *vdev, unsigned int nvqs,
 			    struct irq_affinity *desc)
 {
 	struct virtio_pci_device *vp_dev = to_vp_device(vdev);
+	struct virtio_pci_admin_vq *avq = &vp_dev->admin_vq;
 	struct virtqueue_info *vqi;
 	int i, err, nvectors, allocated_vectors, queue_idx = 0;
+	struct virtqueue *vq;
 	bool per_vq_vectors;
+	u16 avq_num = 0;
 
 	vp_dev->vqs = kcalloc(nvqs, sizeof(*vp_dev->vqs), GFP_KERNEL);
 	if (!vp_dev->vqs)
 		return -ENOMEM;
 
+	if (vp_dev->avq_index) {
+		err = vp_dev->avq_index(vdev, &avq->vq_index, &avq_num);
+		if (err)
+			goto error_find;
+	}
+
 	per_vq_vectors = vector_policy != VP_VQ_VECTOR_POLICY_SHARED;
 
 	if (per_vq_vectors) {
@@ -415,6 +421,18 @@ static int vp_find_vqs_msix(struct virtio_device *vdev, unsigned int nvqs,
 			goto error_find;
 		}
 	}
+
+	if (!avq_num)
+		return 0;
+	sprintf(avq->name, "avq.%u", avq->vq_index);
+	vq = vp_find_one_vq_msix(vdev, avq->vq_index, NULL, avq->name, false,
+				 true, &allocated_vectors, vector_policy,
+				 &vp_dev->admin_vq.info);
+	if (IS_ERR(vq)) {
+		err = PTR_ERR(vq);
+		goto error_find;
+	}
+
 	return 0;
 
 error_find:
@@ -427,12 +445,21 @@ static int vp_find_vqs_intx(struct virtio_device *vdev, unsigned int nvqs,
 			    struct virtqueue_info vqs_info[])
 {
 	struct virtio_pci_device *vp_dev = to_vp_device(vdev);
+	struct virtio_pci_admin_vq *avq = &vp_dev->admin_vq;
 	int i, err, queue_idx = 0;
+	struct virtqueue *vq;
+	u16 avq_num = 0;
 
 	vp_dev->vqs = kcalloc(nvqs, sizeof(*vp_dev->vqs), GFP_KERNEL);
 	if (!vp_dev->vqs)
 		return -ENOMEM;
 
+	if (vp_dev->avq_index) {
+		err = vp_dev->avq_index(vdev, &avq->vq_index, &avq_num);
+		if (err)
+			goto out_del_vqs;
+	}
+
 	err = request_irq(vp_dev->pci_dev->irq, vp_interrupt, IRQF_SHARED,
 			dev_name(&vdev->dev), vp_dev);
 	if (err)
@@ -456,6 +483,16 @@ static int vp_find_vqs_intx(struct virtio_device *vdev, unsigned int nvqs,
 		}
 	}
 
+	if (!avq_num)
+		return 0;
+	sprintf(avq->name, "avq.%u", avq->vq_index);
+	vq = vp_setup_vq(vdev, queue_idx++, NULL, avq->name, false,
+			 VIRTIO_MSI_NO_VECTOR, &vp_dev->admin_vq.info);
+	if (IS_ERR(vq)) {
+		err = PTR_ERR(vq);
+		goto out_del_vqs;
+	}
+
 	return 0;
 out_del_vqs:
 	vp_del_vqs(vdev);

drivers/virtio/virtio_pci_common.h

@@ -44,7 +44,7 @@ struct virtio_pci_vq_info {
 
 struct virtio_pci_admin_vq {
 	/* Virtqueue info associated with this admin queue. */
-	struct virtio_pci_vq_info info;
+	struct virtio_pci_vq_info *info;
 	/* serializing admin commands execution. */
 	struct mutex cmd_lock;
 	u64 supported_cmds;
@@ -105,7 +105,7 @@ struct virtio_pci_device {
 	void (*del_vq)(struct virtio_pci_vq_info *info);
 
 	u16 (*config_vector)(struct virtio_pci_device *vp_dev, u16 vector);
-	bool (*is_avq)(struct virtio_device *vdev, unsigned int index);
+	int (*avq_index)(struct virtio_device *vdev, u16 *index, u16 *num);
 };
 
 /* Constants for MSI-X */

drivers/virtio/virtio_pci_modern.c

@@ -63,7 +63,7 @@ static int virtqueue_exec_admin_cmd(struct virtio_pci_admin_vq *admin_vq,
 	struct virtqueue *vq;
 	int ret, len;
 
-	vq = admin_vq->info.vq;
+	vq = admin_vq->info->vq;
 	if (!vq)
 		return -EIO;
 
@@ -203,27 +203,12 @@ static void virtio_pci_admin_cmd_list_init(struct virtio_device *virtio_dev)
 
 static void vp_modern_avq_activate(struct virtio_device *vdev)
 {
-	struct virtio_pci_device *vp_dev = to_vp_device(vdev);
-	struct virtio_pci_admin_vq *admin_vq = &vp_dev->admin_vq;
-
 	if (!virtio_has_feature(vdev, VIRTIO_F_ADMIN_VQ))
 		return;
 
-	__virtqueue_unbreak(admin_vq->info.vq);
 	virtio_pci_admin_cmd_list_init(vdev);
 }
 
-static void vp_modern_avq_deactivate(struct virtio_device *vdev)
-{
-	struct virtio_pci_device *vp_dev = to_vp_device(vdev);
-	struct virtio_pci_admin_vq *admin_vq = &vp_dev->admin_vq;
-
-	if (!virtio_has_feature(vdev, VIRTIO_F_ADMIN_VQ))
-		return;
-
-	__virtqueue_break(admin_vq->info.vq);
-}
-
 static void vp_transport_features(struct virtio_device *vdev, u64 features)
 {
 	struct virtio_pci_device *vp_dev = to_vp_device(vdev);
@@ -418,8 +403,6 @@ static void vp_reset(struct virtio_device *vdev)
 	while (vp_modern_get_status(mdev))
 		msleep(1);
 
-	vp_modern_avq_deactivate(vdev);
-
 	/* Flush pending VQ/configuration callbacks. */
 	vp_synchronize_vectors(vdev);
 }
@@ -595,9 +578,6 @@ static struct virtqueue *setup_vq(struct virtio_pci_device *vp_dev,
 		goto err;
 	}
 
-	if (is_avq)
-		vp_dev->admin_vq.info.vq = vq;
-
 	return vq;
 
 err:
@@ -741,41 +721,6 @@ static bool vp_get_shm_region(struct virtio_device *vdev,
 	return true;
 }
 
-static int vp_modern_create_avq(struct virtio_device *vdev)
-{
-	struct virtio_pci_device *vp_dev = to_vp_device(vdev);
-	struct virtio_pci_admin_vq *avq = &vp_dev->admin_vq;
-	struct virtqueue *vq;
-	u16 num;
-	int err;
-
-	err = vp_avq_index(vdev, &avq->vq_index, &num);
-	if (err || !num)
-		return err;
-
-	sprintf(avq->name, "avq.%u", avq->vq_index);
-	vq = vp_dev->setup_vq(vp_dev, &vp_dev->admin_vq.info, avq->vq_index, NULL,
-			      avq->name, NULL, VIRTIO_MSI_NO_VECTOR);
-	if (IS_ERR(vq)) {
-		dev_err(&vdev->dev, "failed to setup admin virtqueue, err=%ld",
-			PTR_ERR(vq));
-		return PTR_ERR(vq);
-	}
-
-	vp_modern_set_queue_enable(&vp_dev->mdev, avq->info.vq->index, true);
-	return 0;
-}
-
-static void vp_modern_destroy_avq(struct virtio_device *vdev)
-{
-	struct virtio_pci_device *vp_dev = to_vp_device(vdev);
-
-	if (!virtio_has_feature(vdev, VIRTIO_F_ADMIN_VQ))
-		return;
-
-	vp_dev->del_vq(&vp_dev->admin_vq.info);
-}
-
 static const struct virtio_config_ops virtio_pci_config_nodev_ops = {
 	.get		= NULL,
 	.set		= NULL,
@@ -794,8 +739,6 @@ static const struct virtio_config_ops virtio_pci_config_nodev_ops = {
 	.get_shm_region  = vp_get_shm_region,
 	.disable_vq_and_reset = vp_modern_disable_vq_and_reset,
 	.enable_vq_after_reset = vp_modern_enable_vq_after_reset,
-	.create_avq = vp_modern_create_avq,
-	.destroy_avq = vp_modern_destroy_avq,
 };
 
 static const struct virtio_config_ops virtio_pci_config_ops = {
@@ -816,8 +759,6 @@ static const struct virtio_config_ops virtio_pci_config_ops = {
 	.get_shm_region  = vp_get_shm_region,
 	.disable_vq_and_reset = vp_modern_disable_vq_and_reset,
 	.enable_vq_after_reset = vp_modern_enable_vq_after_reset,
-	.create_avq = vp_modern_create_avq,
-	.destroy_avq = vp_modern_destroy_avq,
 };
 
 /* the PCI probing function */
@@ -841,7 +782,7 @@ int virtio_pci_modern_probe(struct virtio_pci_device *vp_dev)
 	vp_dev->config_vector = vp_config_vector;
 	vp_dev->setup_vq = setup_vq;
 	vp_dev->del_vq = del_vq;
-	vp_dev->is_avq = vp_is_avq;
+	vp_dev->avq_index = vp_avq_index;
 	vp_dev->isr = mdev->isr;
 	vp_dev->vdev.id = mdev->id;
 

include/linux/virtio_config.h

@@ -104,8 +104,6 @@ struct virtqueue_info {
  *	Returns 0 on success or error status
  *	If disable_vq_and_reset is set, then enable_vq_after_reset must also be
  *	set.
- * @create_avq: create admin virtqueue resource.
- * @destroy_avq: destroy admin virtqueue resource.
  */
 struct virtio_config_ops {
 	void (*get)(struct virtio_device *vdev, unsigned offset,
@@ -133,8 +131,6 @@ struct virtio_config_ops {
 			       struct virtio_shm_region *region, u8 id);
 	int (*disable_vq_and_reset)(struct virtqueue *vq);
 	int (*enable_vq_after_reset)(struct virtqueue *vq);
-	int (*create_avq)(struct virtio_device *vdev);
-	void (*destroy_avq)(struct virtio_device *vdev);
 };
 
 /* If driver didn't advertise the feature, it will never appear. */