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

Pull virtio fixes from Michael Tsirkin:
 "Last minute bugfixes.

  A couple of security things.

  And an error handling bugfix that is never encountered by most people,
  but that also makes it kind of safe to push at the last minute, and it
  helps push the fix to stable a bit sooner"

* tag 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost:
  vhost: make sure log_num < in_num
  vhost: block speculation of translated descriptors
  virtio_ring: fix unmap of indirect descriptors

Author: torvalds

drivers/vhost/vhost.c

@@ -2071,8 +2071,10 @@ static int translate_desc(struct vhost_virtqueue *vq, u64 addr, u32 len,
 		_iov = iov + ret;
 		size = node->size - addr + node->start;
 		_iov->iov_len = min((u64)len - s, size);
-		_iov->iov_base = (void __user *)(unsigned long)
-			(node->userspace_addr + addr - node->start);
+		_iov->iov_base = (void __user *)
+			((unsigned long)node->userspace_addr +
+			 array_index_nospec((unsigned long)(addr - node->start),
+					    node->size));
 		s += size;
 		addr += size;
 		++ret;
@@ -2178,7 +2180,7 @@ static int get_indirect(struct vhost_virtqueue *vq,
 		/* If this is an input descriptor, increment that count. */
 		if (access == VHOST_ACCESS_WO) {
 			*in_num += ret;
-			if (unlikely(log)) {
+			if (unlikely(log && ret)) {
 				log[*log_num].addr = vhost64_to_cpu(vq, desc.addr);
 				log[*log_num].len = vhost32_to_cpu(vq, desc.len);
 				++*log_num;
@@ -2319,7 +2321,7 @@ int vhost_get_vq_desc(struct vhost_virtqueue *vq,
 			/* If this is an input descriptor,
 			 * increment that count. */
 			*in_num += ret;
-			if (unlikely(log)) {
+			if (unlikely(log && ret)) {
 				log[*log_num].addr = vhost64_to_cpu(vq, desc.addr);
 				log[*log_num].len = vhost32_to_cpu(vq, desc.len);
 				++*log_num;

drivers/virtio/virtio_ring.c

@@ -566,13 +566,17 @@ static inline int virtqueue_add_split(struct virtqueue *_vq,
 
 unmap_release:
 	err_idx = i;
-	i = head;
+
+	if (indirect)
+		i = 0;
+	else
+		i = head;
 
 	for (n = 0; n < total_sg; n++) {
 		if (i == err_idx)
 			break;
 		vring_unmap_one_split(vq, &desc[i]);
-		i = virtio16_to_cpu(_vq->vdev, vq->split.vring.desc[i].next);
+		i = virtio16_to_cpu(_vq->vdev, desc[i].next);
 	}
 
 	if (indirect)