[dpdk-dev] [PATCH 18.05-RC3 1/2] vhost: retranslate vring addr when memory table changes

[Xiao Wang <xiao.w.wang@intel.com>]

From: Maxime Coquelin <maxime.coquelin@redhat.com>

When the vhost-user master sends memory updates using
VHOST_USER_SET_MEM request, the user backends unmap and then
mmap again the memory regions in its address space.

If the ring addresses have already been translated, it needs to
be translated again as they point to unmapped memory.

Signed-off-by: Maxime Coquelin <maxime.coquelin@redhat.com>
---
 lib/librte_vhost/vhost_user.c | 24 ++++++++++++++++++++++--
 1 file changed, 22 insertions(+), 2 deletions(-)

diff --git a/lib/librte_vhost/vhost_user.c b/lib/librte_vhost/vhost_user.c
index 7244e1c06..947290fc3 100644
--- a/lib/librte_vhost/vhost_user.c
+++ b/lib/librte_vhost/vhost_user.c
@@ -716,8 +716,9 @@ vhost_memory_changed(struct VhostUserMemory *new,
 }
 
 static int
-vhost_user_set_mem_table(struct virtio_net *dev, struct VhostUserMsg *pmsg)
+vhost_user_set_mem_table(struct virtio_net **pdev, struct VhostUserMsg *pmsg)
 {
+	struct virtio_net *dev = *pdev;
 	struct VhostUserMemory memory = pmsg->payload.memory;
 	struct rte_vhost_mem_region *reg;
 	void *mmap_addr;
@@ -854,6 +855,25 @@ vhost_user_set_mem_table(struct virtio_net *dev, struct VhostUserMsg *pmsg)
 			mmap_offset);
 	}
 
+	for (i = 0; i < dev->nr_vring; i++) {
+		struct vhost_virtqueue *vq = dev->virtqueue[i];
+
+		if (vq->desc || vq->avail || vq->used) {
+			/*
+			 * If the memory table got updated, the ring addresses
+			 * need to be translated again as virtual addresses have
+			 * changed.
+			 */
+			vring_invalidate(dev, vq);
+
+			dev = translate_ring_addresses(dev, i);
+			if (!dev)
+				return -1;
+
+			*pdev = dev;
+		}
+	}
+
 	dump_guest_pages(dev);
 
 	return 0;
@@ -1566,7 +1586,7 @@ vhost_user_msg_handler(int vid, int fd)
 		break;
 
 	case VHOST_USER_SET_MEM_TABLE:
-		ret = vhost_user_set_mem_table(dev, &msg);
+		ret = vhost_user_set_mem_table(&dev, &msg);
 		break;
 
 	case VHOST_USER_SET_LOG_BASE:
-- 
2.15.1