[dpdk-dev] [RFC 18/19] vhost: iommu: Invalidate vring in case of matching IOTLB invalidate

[Maxime Coquelin <maxime.coquelin@redhat.com>]

As soon as a page used by a ring is invalidated, the access_ok flag
is cleared, so that processing threads try to map them again.

Signed-off-by: Maxime Coquelin <maxime.coquelin@redhat.com>
---
 lib/librte_vhost/vhost.c      | 17 +++++++++++++++++
 lib/librte_vhost/vhost.h      |  1 +
 lib/librte_vhost/vhost_user.c | 38 +++++++++++++++++++++++++++++++++-----
 3 files changed, 51 insertions(+), 5 deletions(-)

diff --git a/lib/librte_vhost/vhost.c b/lib/librte_vhost/vhost.c
index 3f193bf..971ff51 100644
--- a/lib/librte_vhost/vhost.c
+++ b/lib/librte_vhost/vhost.c
@@ -274,6 +274,23 @@ vring_translate(struct virtio_net *dev, struct vhost_virtqueue *vq)
 	return 0;
 }
 
+void vring_invalidate(struct virtio_net *dev, struct vhost_virtqueue *vq)
+{
+	int vid = dev->vid;
+
+	/* Ensure no thread is using the vrings */
+	put_device(vid);
+	dev = get_device_wr(vid);
+
+	vq->access_ok = 0;
+	vq->desc = NULL;
+	vq->avail = NULL;
+	vq->used = NULL;
+
+	put_device_wr(vid);
+	get_device(vid);
+}
+
 static void
 init_vring_queue(struct virtio_net *dev, uint32_t vring_idx)
 {
diff --git a/lib/librte_vhost/vhost.h b/lib/librte_vhost/vhost.h
index 4b03977..9aef00e 100644
--- a/lib/librte_vhost/vhost.h
+++ b/lib/librte_vhost/vhost.h
@@ -358,5 +358,6 @@ void notify_iotlb_event(struct virtio_net *dev);
 uint64_t vhost_iova_to_vva(struct virtio_net *dev, struct vhost_virtqueue *vq,
 				uint64_t iova, uint64_t size, uint8_t perm);
 int vring_translate(struct virtio_net *dev, struct vhost_virtqueue *vq);
+void vring_invalidate(struct virtio_net *dev, struct vhost_virtqueue *vq);
 
 #endif /* _VHOST_NET_CDEV_H_ */
diff --git a/lib/librte_vhost/vhost_user.c b/lib/librte_vhost/vhost_user.c
index 0ebaac7..1ff83ca 100644
--- a/lib/librte_vhost/vhost_user.c
+++ b/lib/librte_vhost/vhost_user.c
@@ -356,11 +356,7 @@ vhost_user_set_vring_addr(struct virtio_net *dev, VhostUserMsg *msg)
 	 */
 	memcpy(&vq->ring_addrs, addr, sizeof(*addr));
 
-	vq->desc = NULL;
-	vq->avail = NULL;
-	vq->used = NULL;
-
-	vq->access_ok = 0;
+	vring_invalidate(dev, vq);
 
 	return 0;
 }
@@ -979,6 +975,35 @@ is_vring_iotlb_update(struct vhost_virtqueue *vq, struct vhost_iotlb_msg *imsg)
 }
 
 static int
+is_vring_iotlb_invalidate(struct vhost_virtqueue *vq,
+				struct vhost_iotlb_msg *imsg)
+{
+	uint64_t istart, iend, vstart, vend;
+
+	istart = imsg->iova;
+	iend = istart + imsg->size - 1;
+
+	vstart = (uint64_t)vq->desc;
+	vend = vstart + sizeof(struct vring_desc) * vq->size - 1;
+	if (vstart <= iend && istart <= vend)
+		return 1;
+
+	vstart = (uint64_t)vq->avail;
+	vend = vstart + sizeof(struct vring_avail);
+	vend += sizeof(uint16_t) * vq->size - 1;
+	if (vstart <= iend && istart <= vend)
+		return 1;
+
+	vstart = (uint64_t)vq->used;
+	vend = vstart + sizeof(struct vring_used);
+	vend += sizeof(struct vring_used_elem) * vq->size - 1;
+	if (vstart <= iend && istart <= vend)
+		return 1;
+
+	return 0;
+}
+
+static int
 vhost_user_iotlb_msg(struct virtio_net **pdev, struct VhostUserMsg *msg)
 {
 	struct virtio_net *dev = *pdev;
@@ -1009,6 +1034,9 @@ vhost_user_iotlb_msg(struct virtio_net **pdev, struct VhostUserMsg *msg)
 			struct vhost_virtqueue *vq = dev->virtqueue[i];
 
 			vhost_user_iotlb_remove(vq, imsg->iova, imsg->size);
+
+			if (is_vring_iotlb_invalidate(vq, imsg))
+				vring_invalidate(dev, vq);
 		}
 		break;
 	default:
-- 
2.9.4