[RFC V1 5/7] vdpa/cpr: use VHOST_NEW_OWNER

[Steve Sistare <steven.sistare@oracle.com>]

Block CPR if the kernel does not support VHOST_NEW_OWNER.
After CPR, call VHOST_NEW_OWNER in new QEMU.

Signed-off-by: Steve Sistare <steven.sistare@oracle.com>
---
 hw/virtio/trace-events    |  1 +
 hw/virtio/vhost-vdpa.c    | 24 ++++++++++++++++++++++--
 include/hw/virtio/vhost.h |  1 +
 3 files changed, 24 insertions(+), 2 deletions(-)

diff --git a/hw/virtio/trace-events b/hw/virtio/trace-events
index 3cf84e04a7..990c61be79 100644
--- a/hw/virtio/trace-events
+++ b/hw/virtio/trace-events
@@ -64,6 +64,7 @@ vhost_vdpa_set_vring_kick(void *dev, unsigned int index, int fd) "dev: %p index:
 vhost_vdpa_set_vring_call(void *dev, unsigned int index, int fd) "dev: %p index: %u fd: %d"
 vhost_vdpa_get_features(void *dev, uint64_t features) "dev: %p features: 0x%"PRIx64
 vhost_vdpa_set_owner(void *dev) "dev: %p"
+vhost_vdpa_new_owner(void *dev) "dev: %p"
 vhost_vdpa_vq_get_addr(void *dev, void *vq, uint64_t desc_user_addr, uint64_t avail_user_addr, uint64_t used_user_addr) "dev: %p vq: %p desc_user_addr: 0x%"PRIx64" avail_user_addr: 0x%"PRIx64" used_user_addr: 0x%"PRIx64
 vhost_vdpa_get_iova_range(void *dev, uint64_t first, uint64_t last) "dev: %p first: 0x%"PRIx64" last: 0x%"PRIx64
 vhost_vdpa_set_config_call(void *dev, int fd)"dev: %p fd: %d"
diff --git a/hw/virtio/vhost-vdpa.c b/hw/virtio/vhost-vdpa.c
index 3cdaa12ed5..9e3f414ac2 100644
--- a/hw/virtio/vhost-vdpa.c
+++ b/hw/virtio/vhost-vdpa.c
@@ -769,6 +769,7 @@ static int vhost_vdpa_cleanup(struct vhost_dev *dev)
     vhost_vdpa_svq_cleanup(dev);
 
     dev->opaque = NULL;
+    migrate_del_blocker(&dev->cpr_blocker);
 
     return 0;
 }
@@ -848,13 +849,13 @@ static int vhost_vdpa_set_backend_cap(struct vhost_dev *dev)
     uint64_t f = 0x1ULL << VHOST_BACKEND_F_IOTLB_MSG_V2 |
         0x1ULL << VHOST_BACKEND_F_IOTLB_BATCH |
         0x1ULL << VHOST_BACKEND_F_IOTLB_ASID |
-        0x1ULL << VHOST_BACKEND_F_SUSPEND;
+        0x1ULL << VHOST_BACKEND_F_SUSPEND |
+        0x1ULL << VHOST_BACKEND_F_NEW_OWNER;
     int r;
 
     if (vhost_vdpa_call(dev, VHOST_GET_BACKEND_FEATURES, &features)) {
         return -EFAULT;
     }
-
     features &= f;
 
     if (vhost_vdpa_first_dev(dev)) {
@@ -1360,6 +1361,18 @@ static int vhost_vdpa_dev_start(struct vhost_dev *dev, bool started)
     }
 
     if (started) {
+        /*
+         * Register a blocker the first time device is started (when we know
+         * its capabilities).
+         */
+        if (!dev->cpr_blocker &&
+            !(dev->backend_cap & BIT_ULL(VHOST_BACKEND_F_NEW_OWNER))) {
+            error_setg(&dev->cpr_blocker, "vhost-vdpa: device does not support "
+                                          "VHOST_BACKEND_F_NEW_OWNER");
+            migrate_add_blocker_modes(&dev->cpr_blocker, &error_abort,
+                                      MIG_MODE_CPR_EXEC, -1);
+        }
+
         if (vhost_dev_has_iommu(dev) && (v->shadow_vqs_enabled)) {
             error_report("SVQ can not work while IOMMU enable, please disable"
                          "IOMMU and try again");
@@ -1518,10 +1531,17 @@ static int vhost_vdpa_get_features(struct vhost_dev *dev,
 
 static int vhost_vdpa_set_owner(struct vhost_dev *dev)
 {
+    struct vhost_vdpa *v = dev->opaque;
+
     if (!vhost_vdpa_first_dev(dev)) {
         return 0;
     }
 
+    if (v->shared->reused) {
+        trace_vhost_vdpa_new_owner(dev);
+        return vhost_vdpa_call(dev, VHOST_NEW_OWNER, NULL);
+    }
+
     trace_vhost_vdpa_set_owner(dev);
     return vhost_vdpa_call(dev, VHOST_SET_OWNER, NULL);
 }
diff --git a/include/hw/virtio/vhost.h b/include/hw/virtio/vhost.h
index d75faf46e9..3f1b802f85 100644
--- a/include/hw/virtio/vhost.h
+++ b/include/hw/virtio/vhost.h
@@ -133,6 +133,7 @@ struct vhost_dev {
     QLIST_HEAD(, vhost_iommu) iommu_list;
     IOMMUNotifier n;
     const VhostDevConfigOps *config_ops;
+    Error *cpr_blocker;
 };
 
 extern const VhostOps kernel_ops;
-- 
2.39.3