From 96935c61631fe2095246b5dce5c6fea960e34c87 Mon Sep 17 00:00:00 2001
From: Maxime Coquelin <maxime.coquelin@redhat.com>
Date: Thu, 16 Aug 2018 19:29:22 +0200
Subject: [PATCH] vhost: retranslate vring addr when memory table changes

[ backported from upstream commit d5022533c20aed365d513663806a999459037015 ]

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 07c848c7c..0eb5e0d65 100644
--- a/lib/librte_vhost/vhost_user.c
+++ b/lib/librte_vhost/vhost_user.c
@@ -622,8 +622,9 @@ dump_guest_pages(struct virtio_net *dev)
 #endif
 
 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;
@@ -732,6 +733,25 @@ vhost_user_set_mem_table(struct virtio_n
 			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;
@@ -1390,7 +1410,7 @@ 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:
-- 
2.17.1