In the virtio blk vDPA live migration use case, before the live
migration process, QEMU will set call fd to vDPA back-end. QEMU
and vDPA back-end stand by until live migration starts.
During live migration process, QEMU sets kick fd and a new call
fd. However, after the kick fd is set to the vDPA back-end, the
vDPA back-end configures device and data path starts. The new
call fd will cause some kind of "re-configuration", this kind
of "re-configuration" cause IO drop.
After this patch, vDPA back-end configures device after kick fd
and call fd are well set and make sure no IO drops.
This patch only impact virtio blk vDPA device and does not impact
net device.
Signed-off-by: Andy Pei <andy....@intel.com>
---
lib/vhost/vhost_user.c | 13 ++++++++++---
1 file changed, 10 insertions(+), 3 deletions(-)
diff --git a/lib/vhost/vhost_user.c b/lib/vhost/vhost_user.c
index b65fba3..568030a 100644
--- a/lib/vhost/vhost_user.c
+++ b/lib/vhost/vhost_user.c
@@ -2994,6 +2994,7 @@ static int is_vring_iotlb(struct virtio_net *dev,
uint32_t vdpa_type = 0;
uint32_t request;
uint32_t i;
+ uint16_t blk_call_fd;
dev = get_device(vid);
if (dev == NULL)
@@ -3227,9 +3228,15 @@ static int is_vring_iotlb(struct virtio_net *dev,
if (!vdpa_dev)
goto out;
- if (vdpa_type == RTE_VHOST_VDPA_DEVICE_TYPE_BLK
- && request != VHOST_USER_SET_VRING_CALL)
- goto out;
+ if (vdpa_type == RTE_VHOST_VDPA_DEVICE_TYPE_BLK) {
+ if (request == VHOST_USER_SET_VRING_CALL) {
+ blk_call_fd = ctx.msg.payload.u64 &
VHOST_USER_VRING_IDX_MASK;
+ if (blk_call_fd != dev->nr_vring - 1)
+ goto out;
+ } else {
+ goto out;
+ }
+ }
if (!(dev->flags & VIRTIO_DEV_VDPA_CONFIGURED)) {
if (vdpa_dev->ops->dev_conf(dev->vid))
--
1.8.3.1
