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

Pull virtio updates from Michael Tsirkin:
 "Several new features here:

   - Virtio find vqs API has been reworked (required to fix the
     scalability issue we have with adminq, which I hope to merge later
     in the cycle)

   - vDPA driver for Marvell OCTEON

   - virtio fs performance improvement

   - mlx5 migration speedups

  Fixes, cleanups all over the place"

* tag 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost: (56 commits)
  virtio: rename virtio_find_vqs_info() to virtio_find_vqs()
  virtio: remove unused virtio_find_vqs() and virtio_find_vqs_ctx() helpers
  virtio: convert the rest virtio_find_vqs() users to virtio_find_vqs_info()
  virtio_balloon: convert to use virtio_find_vqs_info()
  virtiofs: convert to use virtio_find_vqs_info()
  scsi: virtio_scsi: convert to use virtio_find_vqs_info()
  virtio_net: convert to use virtio_find_vqs_info()
  virtio_crypto: convert to use virtio_find_vqs_info()
  virtio_console: convert to use virtio_find_vqs_info()
  virtio_blk: convert to use virtio_find_vqs_info()
  virtio: rename find_vqs_info() op to find_vqs()
  virtio: remove the original find_vqs() op
  virtio: call virtio_find_vqs_info() from virtio_find_single_vq() directly
  virtio: convert find_vqs() op implementations to find_vqs_info()
  virtio_pci: convert vp_*find_vqs() ops to find_vqs_info()
  virtio: introduce virtio_queue_info struct and find_vqs_info() config op
  virtio: make virtio_find_single_vq() call virtio_find_vqs()
  virtio: make virtio_find_vqs() call virtio_find_vqs_ctx()
  caif_virtio: use virtio_find_single_vq() for single virtqueue finding
  vdpa/mlx5: Don't enable non-active VQs in .set_vq_ready()
  ...

3 files changed, 45 insertions, 65 deletions

diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c
index b60955682474..9ac25d08f473 100644
--- a/drivers/vhost/vhost.c
+++ b/drivers/vhost/vhost.c
@@ -1346,10 +1346,36 @@ static void vhost_dev_unlock_vqs(struct vhost_dev *d)
 		mutex_unlock(&d->vqs[i]->mutex);
 }
 
-static inline int vhost_get_avail_idx(struct vhost_virtqueue *vq,
-				      __virtio16 *idx)
+static inline int vhost_get_avail_idx(struct vhost_virtqueue *vq)
 {
-	return vhost_get_avail(vq, *idx, &vq->avail->idx);
+	__virtio16 idx;
+	int r;
+
+	r = vhost_get_avail(vq, idx, &vq->avail->idx);
+	if (unlikely(r < 0)) {
+		vq_err(vq, "Failed to access available index at %p (%d)\n",
+		       &vq->avail->idx, r);
+		return r;
+	}
+
+	/* Check it isn't doing very strange thing with available indexes */
+	vq->avail_idx = vhost16_to_cpu(vq, idx);
+	if (unlikely((u16)(vq->avail_idx - vq->last_avail_idx) > vq->num)) {
+		vq_err(vq, "Invalid available index change from %u to %u",
+		       vq->last_avail_idx, vq->avail_idx);
+		return -EINVAL;
+	}
+
+	/* We're done if there is nothing new */
+	if (vq->avail_idx == vq->last_avail_idx)
+		return 0;
+
+	/*
+	 * We updated vq->avail_idx so we need a memory barrier between
+	 * the index read above and the caller reading avail ring entries.
+	 */
+	smp_rmb();
+	return 1;
 }
 
 static inline int vhost_get_avail_head(struct vhost_virtqueue *vq,
@@ -2554,38 +2580,17 @@ int vhost_get_vq_desc(struct vhost_virtqueue *vq,
 {
 	struct vring_desc desc;
 	unsigned int i, head, found = 0;
-	u16 last_avail_idx;
-	__virtio16 avail_idx;
+	u16 last_avail_idx = vq->last_avail_idx;
 	__virtio16 ring_head;
 	int ret, access;
 
-	/* Check it isn't doing very strange things with descriptor numbers. */
-	last_avail_idx = vq->last_avail_idx;
-
 	if (vq->avail_idx == vq->last_avail_idx) {
-		if (unlikely(vhost_get_avail_idx(vq, &avail_idx))) {
-			vq_err(vq, "Failed to access avail idx at %p\n",
-				&vq->avail->idx);
-			return -EFAULT;
-		}
-		vq->avail_idx = vhost16_to_cpu(vq, avail_idx);
-
-		if (unlikely((u16)(vq->avail_idx - last_avail_idx) > vq->num)) {
-			vq_err(vq, "Guest moved avail index from %u to %u",
-				last_avail_idx, vq->avail_idx);
-			return -EFAULT;
-		}
+		ret = vhost_get_avail_idx(vq);
+		if (unlikely(ret < 0))
+			return ret;
 
-		/* If there's nothing new since last we looked, return
-		 * invalid.
-		 */
-		if (vq->avail_idx == last_avail_idx)
+		if (!ret)
 			return vq->num;
-
-		/* Only get avail ring entries after they have been
-		 * exposed by guest.
-		 */
-		smp_rmb();
 	}
 
 	/* Grab the next descriptor number they're advertising, and increment
@@ -2846,35 +2851,21 @@ EXPORT_SYMBOL_GPL(vhost_add_used_and_signal_n);
 /* return true if we're sure that avaiable ring is empty */
 bool vhost_vq_avail_empty(struct vhost_dev *dev, struct vhost_virtqueue *vq)
 {
-	__virtio16 avail_idx;
 	int r;
 
 	if (vq->avail_idx != vq->last_avail_idx)
 		return false;
 
-	r = vhost_get_avail_idx(vq, &avail_idx);
-	if (unlikely(r))
-		return false;
-
-	vq->avail_idx = vhost16_to_cpu(vq, avail_idx);
-	if (vq->avail_idx != vq->last_avail_idx) {
-		/* Since we have updated avail_idx, the following
-		 * call to vhost_get_vq_desc() will read available
-		 * ring entries. Make sure that read happens after
-		 * the avail_idx read.
-		 */
-		smp_rmb();
-		return false;
-	}
+	r = vhost_get_avail_idx(vq);
 
-	return true;
+	/* Note: we treat error as non-empty here */
+	return r == 0;
 }
 EXPORT_SYMBOL_GPL(vhost_vq_avail_empty);
 
 /* OK, now we need to know about added descriptors. */
 bool vhost_enable_notify(struct vhost_dev *dev, struct vhost_virtqueue *vq)
 {
-	__virtio16 avail_idx;
 	int r;
 
 	if (!(vq->used_flags & VRING_USED_F_NO_NOTIFY))
@@ -2898,25 +2889,13 @@ bool vhost_enable_notify(struct vhost_dev *dev, struct vhost_virtqueue *vq)
 	/* They could have slipped one in as we were doing that: make
 	 * sure it's written, then check again. */
 	smp_mb();
-	r = vhost_get_avail_idx(vq, &avail_idx);
-	if (r) {
-		vq_err(vq, "Failed to check avail idx at %p: %d\n",
-		       &vq->avail->idx, r);
-		return false;
-	}
 
-	vq->avail_idx = vhost16_to_cpu(vq, avail_idx);
-	if (vq->avail_idx != vq->last_avail_idx) {
-		/* Since we have updated avail_idx, the following
-		 * call to vhost_get_vq_desc() will read available
-		 * ring entries. Make sure that read happens after
-		 * the avail_idx read.
-		 */
-		smp_rmb();
-		return true;
-	}
+	r = vhost_get_avail_idx(vq);
+	/* Note: we treat error as empty here */
+	if (unlikely(r < 0))
+		return false;
 
-	return false;
+	return r;
 }
 EXPORT_SYMBOL_GPL(vhost_enable_notify);
 
diff --git a/drivers/vhost/vringh.c b/drivers/vhost/vringh.c
index 7b8fd977f71c..73e153f9b449 100644
--- a/drivers/vhost/vringh.c
+++ b/drivers/vhost/vringh.c
@@ -1614,4 +1614,5 @@ EXPORT_SYMBOL(vringh_need_notify_iotlb);
 
 #endif
 
+MODULE_DESCRIPTION("host side of a virtio ring");
 MODULE_LICENSE("GPL");
diff --git a/drivers/vhost/vsock.c b/drivers/vhost/vsock.c
index ec20ecff85c7..bf664ec9341b 100644
--- a/drivers/vhost/vsock.c
+++ b/drivers/vhost/vsock.c
@@ -667,6 +667,7 @@ static int vhost_vsock_dev_open(struct inode *inode, struct file *file)
 	}
 
 	vsock->guest_cid = 0; /* no CID assigned yet */
+	vsock->seqpacket_allow = false;
 
 	atomic_set(&vsock->queued_replies, 0);
 
@@ -810,8 +811,7 @@ static int vhost_vsock_set_features(struct vhost_vsock *vsock, u64 features)
 			goto err;
 	}
 
-	if (features & (1ULL << VIRTIO_VSOCK_F_SEQPACKET))
-		vsock->seqpacket_allow = true;
+	vsock->seqpacket_allow = features & (1ULL << VIRTIO_VSOCK_F_SEQPACKET);
 
 	for (i = 0; i < ARRAY_SIZE(vsock->vqs); i++) {
 		vq = &vsock->vqs[i];