[PATCH v1 1/3] virtio-net: Using single MSIX IRQ for TX/RX Q pair

@@ -72,6 +72,9 @@ struct send_queue {
 
 	/* Name of the send queue: output.$index */
 	char name[40];
+
+	/* Name of the channel, shared with irq. */
+	char channel_name[40];
 };
 
 /* Internal representation of a receive virtqueue */

@@ -1529,6 +1532,8 @@ static int virtnet_find_vqs(struct virtnet_info *vi)
 	int ret = -ENOMEM;
 	int i, total_vqs;
 	const char **names;
+	const char **channel_names;
+	unsigned *channels;
 
 	/* We expect 1 RX virtqueue followed by 1 TX virtqueue, followed by
 	 * possible N-1 RX/TX queue pairs used in multiqueue mode, followed by

@@ -1548,6 +1553,17 @@ static int virtnet_find_vqs(struct virtnet_info *vi)
 	if (!names)
 		goto err_names;
 
+	channel_names = kmalloc_array(vi->max_queue_pairs,
+				      sizeof(*channel_names),
+				      GFP_KERNEL);
+	if (!channel_names)
+		goto err_channel_names;
+
+	channels = kmalloc_array(total_vqs, sizeof(*channels),
+				 GFP_KERNEL);
+	if (!channels)
+		goto err_channels;
+
 	/* Parameters for control virtqueue, if any */
 	if (vi->has_cvq) {
 		callbacks[total_vqs - 1] = NULL;

@@ -1562,10 +1578,15 @@ static int virtnet_find_vqs(struct virtnet_info *vi)
 		sprintf(vi->sq[i].name, "output.%d", i);
 		names[rxq2vq(i)] = vi->rq[i].name;
 		names[txq2vq(i)] = vi->sq[i].name;
+		sprintf(vi->sq[i].channel_name, "txrx.%d", i);
+		channel_names[i] = vi->sq[i].channel_name;
+		channels[rxq2vq(i)] = i;
+		channels[txq2vq(i)] = i;
 	}
 
 	ret = vi->vdev->config->find_vqs(vi->vdev, total_vqs, vqs, callbacks,
-					 names);
+					 names, channels, channel_names,
+					 vi->max_queue_pairs);
 	if (ret)
 		goto err_find;
 

@@ -1580,6 +1601,8 @@ static int virtnet_find_vqs(struct virtnet_info *vi)
 		vi->sq[i].vq = vqs[txq2vq(i)];
 	}
 
+	kfree(channels);
+	kfree(channel_names);
 	kfree(names);
 	kfree(callbacks);
 	kfree(vqs);

@@ -1587,6 +1610,10 @@ static int virtnet_find_vqs(struct virtnet_info *vi)
 	return 0;
 
 err_find:
+	kfree(channels);
+err_channels:
+	kfree(channel_names);
+err_channel_names:
 	kfree(names);
 err_names:
 	kfree(callbacks);

@@ -418,7 +418,8 @@ static int init_vq(struct virtio_blk *vblk)
 	}
 
 	/* Discover virtqueues and write information to configuration.  */
-	err = vdev->config->find_vqs(vdev, num_vqs, vqs, callbacks, names);
+	err = vdev->config->find_vqs(vdev, num_vqs, vqs, callbacks, names,
+				     NULL, NULL, 0);
 	if (err)
 		goto err_find_vqs;
 

@@ -1923,7 +1923,8 @@ static int init_vqs(struct ports_device *portdev)
 	/* Find the queues. */
 	err = portdev->vdev->config->find_vqs(portdev->vdev, nr_queues, vqs,
 					      io_callbacks,
-					      (const char **)io_names);
+					      (const char **)io_names,
+					      NULL, NULL, 0);
 	if (err)
 		goto free;
 

@@ -100,7 +100,8 @@ int virtio_gpu_driver_load(struct drm_device *dev, unsigned long flags)
 		  virtio_gpu_config_changed_work_func);
 
 	ret = vgdev->vdev->config->find_vqs(vgdev->vdev, 2, vqs,
-					    callbacks, names);
+					    callbacks, names,
+					    NULL, NULL, 0);
 	if (ret) {
 		DRM_ERROR("failed to find virt queues\n");
 		goto err_vqs;

@@ -311,7 +311,10 @@ unmap:
 static int mic_find_vqs(struct virtio_device *vdev, unsigned nvqs,
 			struct virtqueue *vqs[],
 			vq_callback_t *callbacks[],
-			const char *names[])
+			const char *names[],
+			unsigned channels[],
+			const char *channel_names[],
+			unsigned nchannels)
 {
 	struct mic_vdev *mvdev = to_micvdev(vdev);
 	struct mic_device_ctrl __iomem *dc = mvdev->dc;

@@ -679,7 +679,8 @@ static int cfv_probe(struct virtio_device *vdev)
 		goto err;
 
 	/* Get the TX virtio ring. This is a "guest side vring". */
-	err = vdev->config->find_vqs(vdev, 1, &cfv->vq_tx, &vq_cbs, &names);
+	err = vdev->config->find_vqs(vdev, 1, &cfv->vq_tx, &vq_cbs, &names,
+				     NULL, NULL, 0);
 	if (err)
 		goto err;
 

@@ -145,9 +145,12 @@ static void rproc_virtio_del_vqs(struct virtio_device *vdev)
 }
 
 static int rproc_virtio_find_vqs(struct virtio_device *vdev, unsigned nvqs,
-		       struct virtqueue *vqs[],
-		       vq_callback_t *callbacks[],
-		       const char *names[])
+				 struct virtqueue *vqs[],
+				 vq_callback_t *callbacks[],
+				 const char *names[],
+				 unsigned channels[],
+				 const char *channel_names,
+				 unsigned nchannels)
 {
 	struct rproc *rproc = vdev_to_rproc(vdev);
 	int i, ret;

@@ -965,7 +965,8 @@ static int rpmsg_probe(struct virtio_device *vdev)
 	init_waitqueue_head(&vrp->sendq);
 
 	/* We expect two virtqueues, rx and tx (and in this order) */
-	err = vdev->config->find_vqs(vdev, 2, vqs, vq_cbs, names);
+	err = vdev->config->find_vqs(vdev, 2, vqs, vq_cbs, names,
+				     NULL, NULL, 0);
 	if (err)
 		goto free_vrp;
 

@@ -255,7 +255,10 @@ static void kvm_del_vqs(struct virtio_device *vdev)
 static int kvm_find_vqs(struct virtio_device *vdev, unsigned nvqs,
 			struct virtqueue *vqs[],
 			vq_callback_t *callbacks[],
-			const char *names[])
+			const char *names[],
+			unsigned channels[],
+			const char *channel_names[],
+			unsigned nchannels)
 {
 	struct kvm_device *kdev = to_kvmdev(vdev);
 	int i;

@@ -626,7 +626,10 @@ out:
 static int virtio_ccw_find_vqs(struct virtio_device *vdev, unsigned nvqs,
 			       struct virtqueue *vqs[],
 			       vq_callback_t *callbacks[],
-			       const char *names[])
+			       const char *names[],
+			       unsigned channels[],
+			       const char *channel_names[],
+			       unsigned nchannels)
 {
 	struct virtio_ccw_device *vcdev = to_vc_device(vdev);
 	unsigned long *indicatorp = NULL;

@@ -919,7 +919,8 @@ static int virtscsi_init(struct virtio_device *vdev,
 	}
 
 	/* Discover virtqueues and write information to configuration.  */
-	err = vdev->config->find_vqs(vdev, num_vqs, vqs, callbacks, names);
+	err = vdev->config->find_vqs(vdev, num_vqs, vqs, callbacks, names,
+				     NULL, NULL, 0);
 	if (err)
 		goto out;
 

@@ -396,7 +396,8 @@ static int init_vqs(struct virtio_balloon *vb)
 	 * optionally stat.
 	 */
 	nvqs = virtio_has_feature(vb->vdev, VIRTIO_BALLOON_F_STATS_VQ) ? 3 : 2;
-	err = vb->vdev->config->find_vqs(vb->vdev, nvqs, vqs, callbacks, names);
+	err = vb->vdev->config->find_vqs(vb->vdev, nvqs, vqs, callbacks, names,
+					 NULL, NULL, 0);
 	if (err)
 		return err;
 

@@ -173,7 +173,8 @@ static int virtinput_init_vqs(struct virtio_input *vi)
 	static const char *names[] = { "events", "status" };
 	int err;
 
-	err = vi->vdev->config->find_vqs(vi->vdev, 2, vqs, cbs, names);
+	err = vi->vdev->config->find_vqs(vi->vdev, 2, vqs, cbs, names,
+					 NULL, NULL, 0);
 	if (err)
 		return err;
 	vi->evt = vqs[0];

@@ -480,9 +480,12 @@ error_available:
 }
 
 static int vm_find_vqs(struct virtio_device *vdev, unsigned nvqs,
-		       struct virtqueue *vqs[],
-		       vq_callback_t *callbacks[],
-		       const char *names[])
+			struct virtqueue *vqs[],
+			vq_callback_t *callbacks[],
+			const char *names[],
+			unsigned channels[],
+			const char *channel_names[],
+			unsigned nchannels)
 {
 	struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
 	unsigned int irq = platform_get_irq(vm_dev->pdev, 0);

@@ -418,11 +418,15 @@ err_new_queue:
 static int vp_modern_find_vqs(struct virtio_device *vdev, unsigned nvqs,
 			      struct virtqueue *vqs[],
 			      vq_callback_t *callbacks[],
-			      const char *names[])
+			      const char *names[],
+			      unsigned channels[],
+			      const char *channel_names[],
+			      unsigned nchannels)
 {
 	struct virtio_pci_device *vp_dev = to_vp_device(vdev);
 	struct virtqueue *vq;
-	int rc = vp_find_vqs(vdev, nvqs, vqs, callbacks, names);
+	int rc = vp_find_vqs(vdev, nvqs, vqs, callbacks, names,
+			     NULL, NULL, 0);
 
 	if (rc)
 		return rc;

@@ -41,6 +41,9 @@
  *		include a NULL entry for vqs that do not need a callback
  *	names: array of virtqueue names (mainly for debugging)
  *		include a NULL entry for vqs unused by driver
+ *	channels: array of channels each vq belong to
+ *	channel_names: names of channels
+ *	nchannels: number of channels
  *	Returns 0 on success or error status
  * @del_vqs: free virtqueues found by find_vqs().
  * @get_features: get the array of feature bits for this device.

@@ -70,7 +73,10 @@ struct virtio_config_ops {
 	int (*find_vqs)(struct virtio_device *, unsigned nvqs,
 			struct virtqueue *vqs[],
 			vq_callback_t *callbacks[],
-			const char *names[]);
+			const char *names[],
+			unsigned int channels[],
+			const char *channel_names,
+			unsigned nchannels);
 	void (*del_vqs)(struct virtio_device *);
 	u64 (*get_features)(struct virtio_device *vdev);
 	int (*finalize_features)(struct virtio_device *vdev);

@@ -156,7 +162,8 @@ struct virtqueue *virtio_find_single_vq(struct virtio_device *vdev,
 	vq_callback_t *callbacks[] = { c };
 	const char *names[] = { n };
 	struct virtqueue *vq;
-	int err = vdev->config->find_vqs(vdev, 1, &vq, callbacks, names);
+	int err = vdev->config->find_vqs(vdev, 1, &vq, callbacks, names,
+					 NULL, NULL, 0);
 	if (err < 0)
 		return ERR_PTR(err);
 	return vq;

@@ -76,6 +76,23 @@ static irqreturn_t vp_vring_interrupt(int irq, void *opaque)
 	return ret;
 }
 
+static irqreturn_t vp_channel_interrupt(int irq, void *opaque)
+{
+	struct virtio_pci_channel *vp_channel = opaque;
+	struct virtio_pci_vq_info *info;
+	irqreturn_t ret = IRQ_NONE;
+	unsigned long flags;
+
+	spin_lock_irqsave(&vp_channel->lock, flags);
+	list_for_each_entry(info, &vp_channel->virtqueues, node) {
+		if (vring_interrupt(irq, info->vq) == IRQ_HANDLED)
+			ret = IRQ_HANDLED;
+	}
+	spin_unlock_irqrestore(&vp_channel->lock, flags);
+
+	return ret;
+}
+
 /* A small wrapper to also acknowledge the interrupt when it's handled.
  * I really need an EIO hook for the vring so I can ack the interrupt once we
  * know that we'll be handling the IRQ but before we invoke the callback since

@@ -112,8 +129,12 @@ static void vp_free_vectors(struct virtio_device *vdev)
 		vp_dev->intx_enabled = 0;
 	}
 
-	for (i = 0; i < vp_dev->msix_used_vectors; ++i)
-		free_irq(vp_dev->msix_entries[i].vector, vp_dev);
+	if (vp_dev->msix_used_vectors)
+		free_irq(vp_dev->msix_entries[0].vector, vp_dev);
+
+	for (i = 1; i < vp_dev->msix_used_vectors; ++i)
+		free_irq(vp_dev->msix_entries[i].vector,
+			 &vp_dev->channels[i - 1]);
 
 	for (i = 0; i < vp_dev->msix_vectors; i++)
 		if (vp_dev->msix_affinity_masks[i])

@@ -137,8 +158,7 @@ static void vp_free_vectors(struct virtio_device *vdev)
 	vp_dev->msix_affinity_masks = NULL;
 }
 
-static int vp_request_msix_vectors(struct virtio_device *vdev, int nvectors,
-				   bool per_vq_vectors)
+static int vp_request_msix_vectors(struct virtio_device *vdev, int nvectors)
 {
 	struct virtio_pci_device *vp_dev = to_vp_device(vdev);
 	const char *name = dev_name(&vp_dev->vdev.dev);

@@ -175,8 +195,8 @@ static int vp_request_msix_vectors(struct virtio_device *vdev, int nvectors,
 	vp_dev->msix_enabled = 1;
 
 	/* Set the vector used for configuration */
-	v = vp_dev->msix_used_vectors;
-	snprintf(vp_dev->msix_names[v], sizeof *vp_dev->msix_names,
+	v = 0;
+	snprintf(vp_dev->msix_names[0], sizeof(*vp_dev->msix_names),
 		 "%s-config", name);
 	err = request_irq(vp_dev->msix_entries[v].vector,
 			  vp_config_changed, 0, vp_dev->msix_names[v],

@@ -192,18 +212,6 @@ static int vp_request_msix_vectors(struct virtio_device *vdev, int nvectors,
 		goto error;
 	}
 
-	if (!per_vq_vectors) {
-		/* Shared vector for all VQs */
-		v = vp_dev->msix_used_vectors;
-		snprintf(vp_dev->msix_names[v], sizeof *vp_dev->msix_names,
-			 "%s-virtqueues", name);
-		err = request_irq(vp_dev->msix_entries[v].vector,
-				  vp_vring_interrupt, 0, vp_dev->msix_names[v],
-				  vp_dev);
-		if (err)
-			goto error;
-		++vp_dev->msix_used_vectors;
-	}
 	return 0;
 error:
 	vp_free_vectors(vdev);

@@ -228,6 +236,7 @@ static struct virtqueue *vp_setup_vq(struct virtio_device *vdev, unsigned index,
 				     u16 msix_vec)
 {
 	struct virtio_pci_device *vp_dev = to_vp_device(vdev);
+	struct virtio_pci_channel *vp_channel;
 	struct virtio_pci_vq_info *info = kmalloc(sizeof *info, GFP_KERNEL);
 	struct virtqueue *vq;
 	unsigned long flags;

@@ -242,9 +251,16 @@ static struct virtqueue *vp_setup_vq(struct virtio_device *vdev, unsigned index,
 
 	info->vq = vq;
 	if (callback) {
-		spin_lock_irqsave(&vp_dev->lock, flags);
-		list_add(&info->node, &vp_dev->virtqueues);
-		spin_unlock_irqrestore(&vp_dev->lock, flags);
+		if (msix_vec != VIRTIO_MSI_NO_VECTOR) {
+			vp_channel = &vp_dev->channels[msix_vec - 1];
+			spin_lock_irqsave(&vp_channel->lock, flags);
+			list_add(&info->node, &vp_channel->virtqueues);
+			spin_unlock_irqrestore(&vp_channel->lock, flags);
+		} else {
+			spin_lock_irqsave(&vp_dev->lock, flags);
+			list_add(&info->node, &vp_dev->virtqueues);
+			spin_unlock_irqrestore(&vp_dev->lock, flags);
+		}
 	} else {
 		INIT_LIST_HEAD(&info->node);
 	}

@@ -257,15 +273,17 @@ out_info:
 	return vq;
 }
 
-static void vp_del_vq(struct virtqueue *vq)
+static void vp_del_vq(struct virtqueue *vq,
+		      struct virtio_pci_channel *channel)
 {
 	struct virtio_pci_device *vp_dev = to_vp_device(vq->vdev);
 	struct virtio_pci_vq_info *info = vp_dev->vqs[vq->index];
+	spinlock_t *lock = channel ? &channel->lock : &vp_dev->lock;
 	unsigned long flags;
 
-	spin_lock_irqsave(&vp_dev->lock, flags);
+	spin_lock_irqsave(lock, flags);
 	list_del(&info->node);
-	spin_unlock_irqrestore(&vp_dev->lock, flags);
+	spin_unlock_irqrestore(lock, flags);
 
 	vp_dev->del_vq(info);
 	kfree(info);

@@ -275,95 +293,103 @@ static void vp_del_vq(struct virtqueue *vq)
 void vp_del_vqs(struct virtio_device *vdev)
 {
 	struct virtio_pci_device *vp_dev = to_vp_device(vdev);
+	struct virtio_pci_vq_info *info, *ninfo;
+	struct virtio_pci_channel *channel;
 	struct virtqueue *vq, *n;
-	struct virtio_pci_vq_info *info;
+	int i;
 
-	list_for_each_entry_safe(vq, n, &vdev->vqs, list) {
-		info = vp_dev->vqs[vq->index];
-		if (vp_dev->per_vq_vectors &&
-			info->msix_vector != VIRTIO_MSI_NO_VECTOR)
-			free_irq(vp_dev->msix_entries[info->msix_vector].vector,
-				 vq);
-		vp_del_vq(vq);
+	if (vp_dev->nchannels) {
+		for (i = 0; i < vp_dev->nchannels; i++) {
+			channel = &vp_dev->channels[i];
+			list_for_each_entry_safe(info, ninfo,
+						&channel->virtqueues, node) {
+				vp_del_vq(info->vq, channel);
+			}
+		}
+	} else {
+		list_for_each_entry_safe(vq, n, &vdev->vqs, list) {
+			vp_del_vq(vq, NULL);
+		}
 	}
-	vp_dev->per_vq_vectors = false;
+
+	vp_dev->nchannels = 0;
 
 	vp_free_vectors(vdev);
 	kfree(vp_dev->vqs);
 	vp_dev->vqs = NULL;
+	kfree(vp_dev->channels);
 }
 
 static int vp_try_to_find_vqs(struct virtio_device *vdev, unsigned nvqs,
 			      struct virtqueue *vqs[],
 			      vq_callback_t *callbacks[],
 			      const char *names[],
-			      bool use_msix,
-			      bool per_vq_vectors)
+			      unsigned *channels,
+			      const char *channel_names[],
+			      unsigned nchannels)
 {
 	struct virtio_pci_device *vp_dev = to_vp_device(vdev);
 	u16 msix_vec;
-	int i, err, nvectors, allocated_vectors;
+	int i, err = 0;
 
 	vp_dev->vqs = kmalloc(nvqs * sizeof *vp_dev->vqs, GFP_KERNEL);
 	if (!vp_dev->vqs)
 		return -ENOMEM;
 
-	if (!use_msix) {
+	if (nchannels) {
+		vp_dev->channels = kmalloc(nchannels *
+					   sizeof(*vp_dev->channels),
+					   GFP_KERNEL);
+		if (!vp_dev->channels)
+			goto error_find;
+	}
+	vp_dev->nchannels = nchannels;
+
+	for (i = 0; i < nchannels; i++) {
+		spin_lock_init(&vp_dev->channels[i].lock);
+		INIT_LIST_HEAD(&vp_dev->channels[i].virtqueues);
+	}
+
+	if (!nchannels) {
 		/* Old style: one normal interrupt for change and all vqs. */
 		err = vp_request_intx(vdev);
 		if (err)
 			goto error_find;
 	} else {
-		if (per_vq_vectors) {
-			/* Best option: one for change interrupt, one per vq. */
-			nvectors = 1;
-			for (i = 0; i < nvqs; ++i)
-				if (callbacks[i])
-					++nvectors;
-		} else {
-			/* Second best: one for change, shared for all vqs. */
-			nvectors = 2;
-		}
+		err = vp_request_msix_vectors(vdev, nchannels + 1);
+		if (err)
+			goto error_find;
+	}
+
+	for (i = 0; i < nchannels; i++) {
+		snprintf(vp_dev->msix_names[i + 1],
+			sizeof(*vp_dev->msix_names),
+			"%s-%s",
+			dev_name(&vp_dev->vdev.dev), channel_names[i]);
+		err = request_irq(vp_dev->msix_entries[i + 1].vector,
+				vp_channel_interrupt, 0,
+				vp_dev->msix_names[i + 1],
+				&vp_dev->channels[i]);
 
-		err = vp_request_msix_vectors(vdev, nvectors, per_vq_vectors);
 		if (err)
 			goto error_find;
+		++vp_dev->msix_used_vectors;
 	}
 
-	vp_dev->per_vq_vectors = per_vq_vectors;
-	allocated_vectors = vp_dev->msix_used_vectors;
 	for (i = 0; i < nvqs; ++i) {
 		if (!names[i]) {
 			vqs[i] = NULL;
 			continue;
 		} else if (!callbacks[i] || !vp_dev->msix_enabled)
 			msix_vec = VIRTIO_MSI_NO_VECTOR;
-		else if (vp_dev->per_vq_vectors)
-			msix_vec = allocated_vectors++;
 		else
-			msix_vec = VP_MSIX_VQ_VECTOR;
+			msix_vec = channels[i] + 1;
 		vqs[i] = vp_setup_vq(vdev, i, callbacks[i], names[i], msix_vec);
 		if (IS_ERR(vqs[i])) {
 			err = PTR_ERR(vqs[i]);
 			goto error_find;
 		}
 
-		if (!vp_dev->per_vq_vectors || msix_vec == VIRTIO_MSI_NO_VECTOR)
-			continue;
-
-		/* allocate per-vq irq if available and necessary */
-		snprintf(vp_dev->msix_names[msix_vec],
-			 sizeof *vp_dev->msix_names,
-			 "%s-%s",
-			 dev_name(&vp_dev->vdev.dev), names[i]);
-		err = request_irq(vp_dev->msix_entries[msix_vec].vector,
-				  vring_interrupt, 0,
-				  vp_dev->msix_names[msix_vec],
-				  vqs[i]);
-		if (err) {
-			vp_del_vq(vqs[i]);
-			goto error_find;
-		}
 	}
 	return 0;
 

@@ -376,22 +402,48 @@ error_find:
 int vp_find_vqs(struct virtio_device *vdev, unsigned nvqs,
 		struct virtqueue *vqs[],
 		vq_callback_t *callbacks[],
-		const char *names[])
+		const char *names[],
+		unsigned channels[],
+		const char *channel_names[],
+		unsigned nchannels)
 {
-	int err;
+	int err, i;
+	const char *cnames[] = {"virtqueues"};
+
+	if (nchannels) {
+		/* Try channel settings */
+		err = vp_try_to_find_vqs(vdev, nvqs, vqs, callbacks, names,
+					 channels, channel_names, nchannels);
+		if (!err)
+			return 0;
+	}
+
+	channels = kmalloc_array(nvqs, sizeof(unsigned), GFP_KERNEL);
+	if (!channels)
+		return -ENOMEM;
 
 	/* Try MSI-X with one vector per queue. */
-	err = vp_try_to_find_vqs(vdev, nvqs, vqs, callbacks, names, true, true);
+	for (i = 0; i < nvqs; i++)
+		channels[i] = i;
+	err = vp_try_to_find_vqs(vdev, nvqs, vqs, callbacks, names, channels,
+				 names, nvqs);
 	if (!err)
-		return 0;
+		goto out;
+
 	/* Fallback: MSI-X with one vector for config, one shared for queues. */
-	err = vp_try_to_find_vqs(vdev, nvqs, vqs, callbacks, names,
-				 true, false);
+	for (i = 0; i < nvqs; i++)
+		channels[i] = 0;
+	err = vp_try_to_find_vqs(vdev, nvqs, vqs, callbacks, names, channels,
+				 cnames, 1);
 	if (!err)
-		return 0;
+		goto out;
+
 	/* Finally fall back to regular interrupts. */
-	return vp_try_to_find_vqs(vdev, nvqs, vqs, callbacks, names,
-				  false, false);
+	err = vp_try_to_find_vqs(vdev, nvqs, vqs, callbacks, names,
+				NULL, NULL, 0);
+out:
+	kfree(channels);
+	return err;
 }
 
 const char *vp_bus_name(struct virtio_device *vdev)

@@ -48,6 +48,11 @@ struct virtio_pci_vq_info {
 	unsigned msix_vector;
 };
 
+struct virtio_pci_channel {
+	spinlock_t lock;
+	struct list_head virtqueues;
+};
+
 /* Our device structure */
 struct virtio_pci_device {
 	struct virtio_device vdev;

@@ -88,6 +93,10 @@ struct virtio_pci_device {
 	/* array of all queues for house-keeping */
 	struct virtio_pci_vq_info **vqs;
 
+	/* array of channels */
+	struct virtio_pci_channel *channels;
+	unsigned nchannels;
+
 	/* MSI-X support */
 	int msix_enabled;
 	int intx_enabled;

@@ -98,12 +107,9 @@ struct virtio_pci_device {
 	char (*msix_names)[256];
 	/* Number of available vectors */
 	unsigned msix_vectors;
-	/* Vectors allocated, excluding per-vq vectors if any */
+	/* Vectors allocated */
 	unsigned msix_used_vectors;
 
-	/* Whether we have vector per vq */
-	bool per_vq_vectors;
-
 	struct virtqueue *(*setup_vq)(struct virtio_pci_device *vp_dev,
 				      struct virtio_pci_vq_info *info,
 				      unsigned idx,

@@ -137,9 +143,12 @@ bool vp_notify(struct virtqueue *vq);
 void vp_del_vqs(struct virtio_device *vdev);
 /* the config->find_vqs() implementation */
 int vp_find_vqs(struct virtio_device *vdev, unsigned nvqs,
-		       struct virtqueue *vqs[],
-		       vq_callback_t *callbacks[],
-		       const char *names[]);
+		struct virtqueue *vqs[],
+		vq_callback_t *callbacks[],
+		const char *names[],
+		unsigned channels[],
+		const char *channel_names[],
+		unsigned nchannels);
 const char *vp_bus_name(struct virtio_device *vdev);
 
 /* Setup the affinity for a virtqueue: