Merge tag 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost

Pull virtio updates from Michael Tsirkin:

 - IRQ bypass support for vdpa and IFC

 - MLX5 vdpa driver

 - Endianness fixes for virtio drivers

 - Misc other fixes

* tag 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost: (71 commits)
  vdpa/mlx5: fix up endian-ness for mtu
  vdpa: Fix pointer math bug in vdpasim_get_config()
  vdpa/mlx5: Fix pointer math in mlx5_vdpa_get_config()
  vdpa/mlx5: fix memory allocation failure checks
  vdpa/mlx5: Fix uninitialised variable in core/mr.c
  vdpa_sim: init iommu lock
  virtio_config: fix up warnings on parisc
  vdpa/mlx5: Add VDPA driver for supported mlx5 devices
  vdpa/mlx5: Add shared memory registration code
  vdpa/mlx5: Add support library for mlx5 VDPA implementation
  vdpa/mlx5: Add hardware descriptive header file
  vdpa: Modify get_vq_state() to return error code
  net/vdpa: Use struct for set/get vq state
  vdpa: remove hard coded virtq num
  vdpasim: support batch updating
  vhost-vdpa: support IOTLB batching hints
  vhost-vdpa: support get/set backend features
  vhost: generialize backend features setting/getting
  vhost-vdpa: refine ioctl pre-processing
  vDPA: dont change vq irq after DRIVER_OK
  ...

5 files changed, 169 insertions, 87 deletions

diff --git a/drivers/vhost/Kconfig b/drivers/vhost/Kconfig
index d3688c6afb87..587fbae06182 100644
--- a/drivers/vhost/Kconfig
+++ b/drivers/vhost/Kconfig
@@ -65,6 +65,7 @@ config VHOST_VDPA
 	tristate "Vhost driver for vDPA-based backend"
 	depends on EVENTFD
 	select VHOST
+	select IRQ_BYPASS_MANAGER
 	depends on VDPA
 	help
 	  This kernel module can be loaded in host kernel to accelerate
diff --git a/drivers/vhost/net.c b/drivers/vhost/net.c
index eea902b83afe..531a00d703cd 100644
--- a/drivers/vhost/net.c
+++ b/drivers/vhost/net.c
@@ -73,7 +73,7 @@ enum {
 	VHOST_NET_FEATURES = VHOST_FEATURES |
 			 (1ULL << VHOST_NET_F_VIRTIO_NET_HDR) |
 			 (1ULL << VIRTIO_NET_F_MRG_RXBUF) |
-			 (1ULL << VIRTIO_F_IOMMU_PLATFORM)
+			 (1ULL << VIRTIO_F_ACCESS_PLATFORM)
 };
 
 enum {
@@ -1615,21 +1615,6 @@ done:
 	return err;
 }
 
-static int vhost_net_set_backend_features(struct vhost_net *n, u64 features)
-{
-	int i;
-
-	mutex_lock(&n->dev.mutex);
-	for (i = 0; i < VHOST_NET_VQ_MAX; ++i) {
-		mutex_lock(&n->vqs[i].vq.mutex);
-		n->vqs[i].vq.acked_backend_features = features;
-		mutex_unlock(&n->vqs[i].vq.mutex);
-	}
-	mutex_unlock(&n->dev.mutex);
-
-	return 0;
-}
-
 static int vhost_net_set_features(struct vhost_net *n, u64 features)
 {
 	size_t vhost_hlen, sock_hlen, hdr_len;
@@ -1653,7 +1638,7 @@ static int vhost_net_set_features(struct vhost_net *n, u64 features)
 	    !vhost_log_access_ok(&n->dev))
 		goto out_unlock;
 
-	if ((features & (1ULL << VIRTIO_F_IOMMU_PLATFORM))) {
+	if ((features & (1ULL << VIRTIO_F_ACCESS_PLATFORM))) {
 		if (vhost_init_device_iotlb(&n->dev, true))
 			goto out_unlock;
 	}
@@ -1730,7 +1715,8 @@ static long vhost_net_ioctl(struct file *f, unsigned int ioctl,
 			return -EFAULT;
 		if (features & ~VHOST_NET_BACKEND_FEATURES)
 			return -EOPNOTSUPP;
-		return vhost_net_set_backend_features(n, features);
+		vhost_set_backend_features(&n->dev, features);
+		return 0;
 	case VHOST_RESET_OWNER:
 		return vhost_net_reset_owner(n);
 	case VHOST_SET_OWNER:
diff --git a/drivers/vhost/vdpa.c b/drivers/vhost/vdpa.c
index a54b60d6623f..3fab94f88894 100644
--- a/drivers/vhost/vdpa.c
+++ b/drivers/vhost/vdpa.c
@@ -27,37 +27,11 @@
 #include "vhost.h"
 
 enum {
-	VHOST_VDPA_FEATURES =
-		(1ULL << VIRTIO_F_NOTIFY_ON_EMPTY) |
-		(1ULL << VIRTIO_F_ANY_LAYOUT) |
-		(1ULL << VIRTIO_F_VERSION_1) |
-		(1ULL << VIRTIO_F_IOMMU_PLATFORM) |
-		(1ULL << VIRTIO_F_RING_PACKED) |
-		(1ULL << VIRTIO_F_ORDER_PLATFORM) |
-		(1ULL << VIRTIO_RING_F_INDIRECT_DESC) |
-		(1ULL << VIRTIO_RING_F_EVENT_IDX),
-
-	VHOST_VDPA_NET_FEATURES = VHOST_VDPA_FEATURES |
-		(1ULL << VIRTIO_NET_F_CSUM) |
-		(1ULL << VIRTIO_NET_F_GUEST_CSUM) |
-		(1ULL << VIRTIO_NET_F_MTU) |
-		(1ULL << VIRTIO_NET_F_MAC) |
-		(1ULL << VIRTIO_NET_F_GUEST_TSO4) |
-		(1ULL << VIRTIO_NET_F_GUEST_TSO6) |
-		(1ULL << VIRTIO_NET_F_GUEST_ECN) |
-		(1ULL << VIRTIO_NET_F_GUEST_UFO) |
-		(1ULL << VIRTIO_NET_F_HOST_TSO4) |
-		(1ULL << VIRTIO_NET_F_HOST_TSO6) |
-		(1ULL << VIRTIO_NET_F_HOST_ECN) |
-		(1ULL << VIRTIO_NET_F_HOST_UFO) |
-		(1ULL << VIRTIO_NET_F_MRG_RXBUF) |
-		(1ULL << VIRTIO_NET_F_STATUS) |
-		(1ULL << VIRTIO_NET_F_SPEED_DUPLEX),
+	VHOST_VDPA_BACKEND_FEATURES =
+	(1ULL << VHOST_BACKEND_F_IOTLB_MSG_V2) |
+	(1ULL << VHOST_BACKEND_F_IOTLB_BATCH),
 };
 
-/* Currently, only network backend w/o multiqueue is supported. */
-#define VHOST_VDPA_VQ_MAX	2
-
 #define VHOST_VDPA_DEV_MAX (1U << MINORBITS)
 
 struct vhost_vdpa {
@@ -73,16 +47,13 @@ struct vhost_vdpa {
 	int virtio_id;
 	int minor;
 	struct eventfd_ctx *config_ctx;
+	int in_batch;
 };
 
 static DEFINE_IDA(vhost_vdpa_ida);
 
 static dev_t vhost_vdpa_major;
 
-static const u64 vhost_vdpa_features[] = {
-	[VIRTIO_ID_NET] = VHOST_VDPA_NET_FEATURES,
-};
-
 static void handle_vq_kick(struct vhost_work *work)
 {
 	struct vhost_virtqueue *vq = container_of(work, struct vhost_virtqueue,
@@ -96,7 +67,7 @@ static void handle_vq_kick(struct vhost_work *work)
 static irqreturn_t vhost_vdpa_virtqueue_cb(void *private)
 {
 	struct vhost_virtqueue *vq = private;
-	struct eventfd_ctx *call_ctx = vq->call_ctx;
+	struct eventfd_ctx *call_ctx = vq->call_ctx.ctx;
 
 	if (call_ctx)
 		eventfd_signal(call_ctx, 1);
@@ -115,12 +86,45 @@ static irqreturn_t vhost_vdpa_config_cb(void *private)
 	return IRQ_HANDLED;
 }
 
+static void vhost_vdpa_setup_vq_irq(struct vhost_vdpa *v, u16 qid)
+{
+	struct vhost_virtqueue *vq = &v->vqs[qid];
+	const struct vdpa_config_ops *ops = v->vdpa->config;
+	struct vdpa_device *vdpa = v->vdpa;
+	int ret, irq;
+
+	if (!ops->get_vq_irq)
+		return;
+
+	irq = ops->get_vq_irq(vdpa, qid);
+	spin_lock(&vq->call_ctx.ctx_lock);
+	irq_bypass_unregister_producer(&vq->call_ctx.producer);
+	if (!vq->call_ctx.ctx || irq < 0) {
+		spin_unlock(&vq->call_ctx.ctx_lock);
+		return;
+	}
+
+	vq->call_ctx.producer.token = vq->call_ctx.ctx;
+	vq->call_ctx.producer.irq = irq;
+	ret = irq_bypass_register_producer(&vq->call_ctx.producer);
+	spin_unlock(&vq->call_ctx.ctx_lock);
+}
+
+static void vhost_vdpa_unsetup_vq_irq(struct vhost_vdpa *v, u16 qid)
+{
+	struct vhost_virtqueue *vq = &v->vqs[qid];
+
+	spin_lock(&vq->call_ctx.ctx_lock);
+	irq_bypass_unregister_producer(&vq->call_ctx.producer);
+	spin_unlock(&vq->call_ctx.ctx_lock);
+}
+
 static void vhost_vdpa_reset(struct vhost_vdpa *v)
 {
 	struct vdpa_device *vdpa = v->vdpa;
-	const struct vdpa_config_ops *ops = vdpa->config;
 
-	ops->set_status(vdpa, 0);
+	vdpa_reset(vdpa);
+	v->in_batch = 0;
 }
 
 static long vhost_vdpa_get_device_id(struct vhost_vdpa *v, u8 __user *argp)
@@ -155,11 +159,15 @@ static long vhost_vdpa_set_status(struct vhost_vdpa *v, u8 __user *statusp)
 {
 	struct vdpa_device *vdpa = v->vdpa;
 	const struct vdpa_config_ops *ops = vdpa->config;
-	u8 status;
+	u8 status, status_old;
+	int nvqs = v->nvqs;
+	u16 i;
 
 	if (copy_from_user(&status, statusp, sizeof(status)))
 		return -EFAULT;
 
+	status_old = ops->get_status(vdpa);
+
 	/*
 	 * Userspace shouldn't remove status bits unless reset the
 	 * status to 0.
@@ -169,6 +177,14 @@ static long vhost_vdpa_set_status(struct vhost_vdpa *v, u8 __user *statusp)
 
 	ops->set_status(vdpa, status);
 
+	if ((status & VIRTIO_CONFIG_S_DRIVER_OK) && !(status_old & VIRTIO_CONFIG_S_DRIVER_OK))
+		for (i = 0; i < nvqs; i++)
+			vhost_vdpa_setup_vq_irq(v, i);
+
+	if ((status_old & VIRTIO_CONFIG_S_DRIVER_OK) && !(status & VIRTIO_CONFIG_S_DRIVER_OK))
+		for (i = 0; i < nvqs; i++)
+			vhost_vdpa_unsetup_vq_irq(v, i);
+
 	return 0;
 }
 
@@ -196,7 +212,6 @@ static long vhost_vdpa_get_config(struct vhost_vdpa *v,
 				  struct vhost_vdpa_config __user *c)
 {
 	struct vdpa_device *vdpa = v->vdpa;
-	const struct vdpa_config_ops *ops = vdpa->config;
 	struct vhost_vdpa_config config;
 	unsigned long size = offsetof(struct vhost_vdpa_config, buf);
 	u8 *buf;
@@ -209,7 +224,7 @@ static long vhost_vdpa_get_config(struct vhost_vdpa *v,
 	if (!buf)
 		return -ENOMEM;
 
-	ops->get_config(vdpa, config.off, buf, config.len);
+	vdpa_get_config(vdpa, config.off, buf, config.len);
 
 	if (copy_to_user(c->buf, buf, config.len)) {
 		kvfree(buf);
@@ -255,7 +270,6 @@ static long vhost_vdpa_get_features(struct vhost_vdpa *v, u64 __user *featurep)
 	u64 features;
 
 	features = ops->get_features(vdpa);
-	features &= vhost_vdpa_features[v->virtio_id];
 
 	if (copy_to_user(featurep, &features, sizeof(features)))
 		return -EFAULT;
@@ -279,10 +293,7 @@ static long vhost_vdpa_set_features(struct vhost_vdpa *v, u64 __user *featurep)
 	if (copy_from_user(&features, featurep, sizeof(features)))
 		return -EFAULT;
 
-	if (features & ~vhost_vdpa_features[v->virtio_id])
-		return -EINVAL;
-
-	if (ops->set_features(vdpa, features))
+	if (vdpa_set_features(vdpa, features))
 		return -EINVAL;
 
 	return 0;
@@ -332,14 +343,18 @@ static long vhost_vdpa_set_config_call(struct vhost_vdpa *v, u32 __user *argp)
 
 	return 0;
 }
+
 static long vhost_vdpa_vring_ioctl(struct vhost_vdpa *v, unsigned int cmd,
 				   void __user *argp)
 {
 	struct vdpa_device *vdpa = v->vdpa;
 	const struct vdpa_config_ops *ops = vdpa->config;
+	struct vdpa_vq_state vq_state;
 	struct vdpa_callback cb;
 	struct vhost_virtqueue *vq;
 	struct vhost_vring_state s;
+	u64 __user *featurep = argp;
+	u64 features;
 	u32 idx;
 	long r;
 
@@ -353,15 +368,32 @@ static long vhost_vdpa_vring_ioctl(struct vhost_vdpa *v, unsigned int cmd,
 	idx = array_index_nospec(idx, v->nvqs);
 	vq = &v->vqs[idx];
 
-	if (cmd == VHOST_VDPA_SET_VRING_ENABLE) {
+	switch (cmd) {
+	case VHOST_VDPA_SET_VRING_ENABLE:
 		if (copy_from_user(&s, argp, sizeof(s)))
 			return -EFAULT;
 		ops->set_vq_ready(vdpa, idx, s.num);
 		return 0;
-	}
+	case VHOST_GET_VRING_BASE:
+		r = ops->get_vq_state(v->vdpa, idx, &vq_state);
+		if (r)
+			return r;
 
-	if (cmd == VHOST_GET_VRING_BASE)
-		vq->last_avail_idx = ops->get_vq_state(v->vdpa, idx);
+		vq->last_avail_idx = vq_state.avail_index;
+		break;
+	case VHOST_GET_BACKEND_FEATURES:
+		features = VHOST_VDPA_BACKEND_FEATURES;
+		if (copy_to_user(featurep, &features, sizeof(features)))
+			return -EFAULT;
+		return 0;
+	case VHOST_SET_BACKEND_FEATURES:
+		if (copy_from_user(&features, featurep, sizeof(features)))
+			return -EFAULT;
+		if (features & ~VHOST_VDPA_BACKEND_FEATURES)
+			return -EOPNOTSUPP;
+		vhost_set_backend_features(&v->vdev, features);
+		return 0;
+	}
 
 	r = vhost_vring_ioctl(&v->vdev, cmd, argp);
 	if (r)
@@ -377,12 +409,13 @@ static long vhost_vdpa_vring_ioctl(struct vhost_vdpa *v, unsigned int cmd,
 		break;
 
 	case VHOST_SET_VRING_BASE:
-		if (ops->set_vq_state(vdpa, idx, vq->last_avail_idx))
+		vq_state.avail_index = vq->last_avail_idx;
+		if (ops->set_vq_state(vdpa, idx, &vq_state))
 			r = -EINVAL;
 		break;
 
 	case VHOST_SET_VRING_CALL:
-		if (vq->call_ctx) {
+		if (vq->call_ctx.ctx) {
 			cb.callback = vhost_vdpa_virtqueue_cb;
 			cb.private = vq;
 		} else {
@@ -390,6 +423,7 @@ static long vhost_vdpa_vring_ioctl(struct vhost_vdpa *v, unsigned int cmd,
 			cb.private = NULL;
 		}
 		ops->set_vq_cb(vdpa, idx, &cb);
+		vhost_vdpa_setup_vq_irq(v, idx);
 		break;
 
 	case VHOST_SET_VRING_NUM:
@@ -519,13 +553,15 @@ static int vhost_vdpa_map(struct vhost_vdpa *v,
 	if (r)
 		return r;
 
-	if (ops->dma_map)
+	if (ops->dma_map) {
 		r = ops->dma_map(vdpa, iova, size, pa, perm);
-	else if (ops->set_map)
-		r = ops->set_map(vdpa, dev->iotlb);
-	else
+	} else if (ops->set_map) {
+		if (!v->in_batch)
+			r = ops->set_map(vdpa, dev->iotlb);
+	} else {
 		r = iommu_map(v->domain, iova, pa, size,
 			      perm_to_iommu_flags(perm));
+	}
 
 	return r;
 }
@@ -538,12 +574,14 @@ static void vhost_vdpa_unmap(struct vhost_vdpa *v, u64 iova, u64 size)
 
 	vhost_vdpa_iotlb_unmap(v, iova, iova + size - 1);
 
-	if (ops->dma_map)
+	if (ops->dma_map) {
 		ops->dma_unmap(vdpa, iova, size);
-	else if (ops->set_map)
-		ops->set_map(vdpa, dev->iotlb);
-	else
+	} else if (ops->set_map) {
+		if (!v->in_batch)
+			ops->set_map(vdpa, dev->iotlb);
+	} else {
 		iommu_unmap(v->domain, iova, size);
+	}
 }
 
 static int vhost_vdpa_process_iotlb_update(struct vhost_vdpa *v,
@@ -636,6 +674,8 @@ static int vhost_vdpa_process_iotlb_msg(struct vhost_dev *dev,
 					struct vhost_iotlb_msg *msg)
 {
 	struct vhost_vdpa *v = container_of(dev, struct vhost_vdpa, vdev);
+	struct vdpa_device *vdpa = v->vdpa;
+	const struct vdpa_config_ops *ops = vdpa->config;
 	int r = 0;
 
 	r = vhost_dev_check_owner(dev);
@@ -649,6 +689,14 @@ static int vhost_vdpa_process_iotlb_msg(struct vhost_dev *dev,
 	case VHOST_IOTLB_INVALIDATE:
 		vhost_vdpa_unmap(v, msg->iova, msg->size);
 		break;
+	case VHOST_IOTLB_BATCH_BEGIN:
+		v->in_batch = true;
+		break;
+	case VHOST_IOTLB_BATCH_END:
+		if (v->in_batch && ops->set_map)
+			ops->set_map(vdpa, dev->iotlb);
+		v->in_batch = false;
+		break;
 	default:
 		r = -EINVAL;
 		break;
@@ -765,6 +813,18 @@ err:
 	return r;
 }
 
+static void vhost_vdpa_clean_irq(struct vhost_vdpa *v)
+{
+	struct vhost_virtqueue *vq;
+	int i;
+
+	for (i = 0; i < v->nvqs; i++) {
+		vq = &v->vqs[i];
+		if (vq->call_ctx.producer.irq)
+			irq_bypass_unregister_producer(&vq->call_ctx.producer);
+	}
+}
+
 static int vhost_vdpa_release(struct inode *inode, struct file *filep)
 {
 	struct vhost_vdpa *v = filep->private_data;
@@ -777,6 +837,7 @@ static int vhost_vdpa_release(struct inode *inode, struct file *filep)
 	vhost_vdpa_iotlb_free(v);
 	vhost_vdpa_free_domain(v);
 	vhost_vdpa_config_put(v);
+	vhost_vdpa_clean_irq(v);
 	vhost_dev_cleanup(&v->vdev);
 	kfree(v->vdev.vqs);
 	mutex_unlock(&d->mutex);
@@ -872,7 +933,7 @@ static int vhost_vdpa_probe(struct vdpa_device *vdpa)
 {
 	const struct vdpa_config_ops *ops = vdpa->config;
 	struct vhost_vdpa *v;
-	int minor, nvqs = VHOST_VDPA_VQ_MAX;
+	int minor;
 	int r;
 
 	/* Currently, we only accept the network devices. */
@@ -893,14 +954,14 @@ static int vhost_vdpa_probe(struct vdpa_device *vdpa)
 	atomic_set(&v->opened, 0);
 	v->minor = minor;
 	v->vdpa = vdpa;
-	v->nvqs = nvqs;
+	v->nvqs = vdpa->nvqs;
 	v->virtio_id = ops->get_device_id(vdpa);
 
 	device_initialize(&v->dev);
 	v->dev.release = vhost_vdpa_release_dev;
 	v->dev.parent = &vdpa->dev;
 	v->dev.devt = MKDEV(MAJOR(vhost_vdpa_major), minor);
-	v->vqs = kmalloc_array(nvqs, sizeof(struct vhost_virtqueue),
+	v->vqs = kmalloc_array(v->nvqs, sizeof(struct vhost_virtqueue),
 			       GFP_KERNEL);
 	if (!v->vqs) {
 		r = -ENOMEM;
diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c
index 74d135ee7e26..5857d4eec9d7 100644
--- a/drivers/vhost/vhost.c
+++ b/drivers/vhost/vhost.c
@@ -298,6 +298,13 @@ static void vhost_vq_meta_reset(struct vhost_dev *d)
 		__vhost_vq_meta_reset(d->vqs[i]);
 }
 
+static void vhost_vring_call_reset(struct vhost_vring_call *call_ctx)
+{
+	call_ctx->ctx = NULL;
+	memset(&call_ctx->producer, 0x0, sizeof(struct irq_bypass_producer));
+	spin_lock_init(&call_ctx->ctx_lock);
+}
+
 static void vhost_vq_reset(struct vhost_dev *dev,
 			   struct vhost_virtqueue *vq)
 {
@@ -319,13 +326,13 @@ static void vhost_vq_reset(struct vhost_dev *dev,
 	vq->log_base = NULL;
 	vq->error_ctx = NULL;
 	vq->kick = NULL;
-	vq->call_ctx = NULL;
 	vq->log_ctx = NULL;
 	vhost_reset_is_le(vq);
 	vhost_disable_cross_endian(vq);
 	vq->busyloop_timeout = 0;
 	vq->umem = NULL;
 	vq->iotlb = NULL;
+	vhost_vring_call_reset(&vq->call_ctx);
 	__vhost_vq_meta_reset(vq);
 }
 
@@ -685,8 +692,8 @@ void vhost_dev_cleanup(struct vhost_dev *dev)
 			eventfd_ctx_put(dev->vqs[i]->error_ctx);
 		if (dev->vqs[i]->kick)
 			fput(dev->vqs[i]->kick);
-		if (dev->vqs[i]->call_ctx)
-			eventfd_ctx_put(dev->vqs[i]->call_ctx);
+		if (dev->vqs[i]->call_ctx.ctx)
+			eventfd_ctx_put(dev->vqs[i]->call_ctx.ctx);
 		vhost_vq_reset(dev, dev->vqs[i]);
 	}
 	vhost_dev_free_iovecs(dev);
@@ -1405,7 +1412,7 @@ static long vhost_set_memory(struct vhost_dev *d, struct vhost_memory __user *m)
 
 	memcpy(newmem, &mem, size);
 	if (copy_from_user(newmem->regions, m->regions,
-			   mem.nregions * sizeof *m->regions)) {
+			   flex_array_size(newmem, regions, mem.nregions))) {
 		kvfree(newmem);
 		return -EFAULT;
 	}
@@ -1629,7 +1636,10 @@ long vhost_vring_ioctl(struct vhost_dev *d, unsigned int ioctl, void __user *arg
 			r = PTR_ERR(ctx);
 			break;
 		}
-		swap(ctx, vq->call_ctx);
+
+		spin_lock(&vq->call_ctx.ctx_lock);
+		swap(ctx, vq->call_ctx.ctx);
+		spin_unlock(&vq->call_ctx.ctx_lock);
 		break;
 	case VHOST_SET_VRING_ERR:
 		if (copy_from_user(&f, argp, sizeof f)) {
@@ -2435,8 +2445,8 @@ static bool vhost_notify(struct vhost_dev *dev, struct vhost_virtqueue *vq)
 void vhost_signal(struct vhost_dev *dev, struct vhost_virtqueue *vq)
 {
 	/* Signal the Guest tell them we used something up. */
-	if (vq->call_ctx && vhost_notify(dev, vq))
-		eventfd_signal(vq->call_ctx, 1);
+	if (vq->call_ctx.ctx && vhost_notify(dev, vq))
+		eventfd_signal(vq->call_ctx.ctx, 1);
 }
 EXPORT_SYMBOL_GPL(vhost_signal);
 
@@ -2576,6 +2586,21 @@ struct vhost_msg_node *vhost_dequeue_msg(struct vhost_dev *dev,
 }
 EXPORT_SYMBOL_GPL(vhost_dequeue_msg);
 
+void vhost_set_backend_features(struct vhost_dev *dev, u64 features)
+{
+	struct vhost_virtqueue *vq;
+	int i;
+
+	mutex_lock(&dev->mutex);
+	for (i = 0; i < dev->nvqs; ++i) {
+		vq = dev->vqs[i];
+		mutex_lock(&vq->mutex);
+		vq->acked_backend_features = features;
+		mutex_unlock(&vq->mutex);
+	}
+	mutex_unlock(&dev->mutex);
+}
+EXPORT_SYMBOL_GPL(vhost_set_backend_features);
 
 static int __init vhost_init(void)
 {
diff --git a/drivers/vhost/vhost.h b/drivers/vhost/vhost.h
index c8e96a095d3b..9032d3c2a9f4 100644
--- a/drivers/vhost/vhost.h
+++ b/drivers/vhost/vhost.h
@@ -13,6 +13,7 @@
 #include <linux/virtio_ring.h>
 #include <linux/atomic.h>
 #include <linux/vhost_iotlb.h>
+#include <linux/irqbypass.h>
 
 struct vhost_work;
 typedef void (*vhost_work_fn_t)(struct vhost_work *work);
@@ -60,6 +61,12 @@ enum vhost_uaddr_type {
 	VHOST_NUM_ADDRS = 3,
 };
 
+struct vhost_vring_call {
+	struct eventfd_ctx *ctx;
+	struct irq_bypass_producer producer;
+	spinlock_t ctx_lock;
+};
+
 /* The virtqueue structure describes a queue attached to a device. */
 struct vhost_virtqueue {
 	struct vhost_dev *dev;
@@ -72,7 +79,7 @@ struct vhost_virtqueue {
 	vring_used_t __user *used;
 	const struct vhost_iotlb_map *meta_iotlb[VHOST_NUM_ADDRS];
 	struct file *kick;
-	struct eventfd_ctx *call_ctx;
+	struct vhost_vring_call call_ctx;
 	struct eventfd_ctx *error_ctx;
 	struct eventfd_ctx *log_ctx;
 
@@ -207,6 +214,8 @@ void vhost_enqueue_msg(struct vhost_dev *dev,
 		       struct vhost_msg_node *node);
 struct vhost_msg_node *vhost_dequeue_msg(struct vhost_dev *dev,
 					 struct list_head *head);
+void vhost_set_backend_features(struct vhost_dev *dev, u64 features);
+
 __poll_t vhost_chr_poll(struct file *file, struct vhost_dev *dev,
 			    poll_table *wait);
 ssize_t vhost_chr_read_iter(struct vhost_dev *dev, struct iov_iter *to,