[dpdk-dev] [PATCH v5 3/5] vhost: handle memory hotplug for async vhost

[Cheng Jiang]

From: Jiayu Hu <jiayu.hu at intel.com>

When the guest memory is hotplugged, the vhost application which
enables DMA acceleration must stop DMA transfers before the vhost
re-maps the guest memory.

This patch is to notify the vhost application of stopping DMA
transfers.

Signed-off-by: Jiayu Hu <jiayu.hu at intel.com>
---
 lib/vhost/vhost_user.c | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/lib/vhost/vhost_user.c b/lib/vhost/vhost_user.c
index 031c578e54..39e8432d1c 100644
--- a/lib/vhost/vhost_user.c
+++ b/lib/vhost/vhost_user.c
@@ -1275,6 +1275,15 @@ vhost_user_set_mem_table(struct virtio_net **pdev, struct VhostUserMsg *msg,
 				vdpa_dev->ops->dev_close(dev->vid);
 			dev->flags &= ~VIRTIO_DEV_VDPA_CONFIGURED;
 		}
+
+		/* notify the backend application to stop DMA transfers */
+		if (dev->async_copy && dev->notify_ops->vring_state_changed) {
+			for (i = 0; i < dev->nr_vring; i++) {
+				dev->notify_ops->vring_state_changed(dev->vid,
+						i, 0);
+			}
+		}
+
 		free_mem_region(dev);
 		rte_free(dev->mem);
 		dev->mem = NULL;
-- 
2.29.2