vhost-user: don't merge regions with different fds

vhost currently merges regions with contiguious virtual and physical
addresses.  This breaks for vhost-user since that also needs fds to
match.

Add a vhost_ops entry to compare the fds for vhost-user only.

Cc: qemu-stable@nongnu.org
Cc: Victor Kaplansky <victork@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

1 files changed, 4 insertions, 0 deletions

diff --git a/include/hw/virtio/vhost-backend.h b/include/hw/virtio/vhost-backend.h
index c59cc81915..a6e5c97e3a 100644
--- a/include/hw/virtio/vhost-backend.h
+++ b/include/hw/virtio/vhost-backend.h
@@ -70,6 +70,9 @@ typedef int (*vhost_set_vring_enable_op)(struct vhost_dev *dev,
 typedef bool (*vhost_requires_shm_log_op)(struct vhost_dev *dev);
 typedef int (*vhost_migration_done_op)(struct vhost_dev *dev,
                                        char *mac_addr);
+typedef bool (*vhost_backend_can_merge_op)(struct vhost_dev *dev,
+                                           uint64_t start1, uint64_t size1,
+                                           uint64_t start2, uint64_t size2);
 
 typedef struct VhostOps {
     VhostBackendType backend_type;
@@ -97,6 +100,7 @@ typedef struct VhostOps {
     vhost_set_vring_enable_op vhost_set_vring_enable;
     vhost_requires_shm_log_op vhost_requires_shm_log;
     vhost_migration_done_op vhost_migration_done;
+    vhost_backend_can_merge_op vhost_backend_can_merge;
 } VhostOps;
 
 extern const VhostOps user_ops;