vhost: allow backends to filter memory sections

This patch introduces a vhost op for vhost backends to allow
them to filter the memory sections that they can handle.

Signed-off-by: Tiwei Bie <tiwei.bie@intel.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

1 files changed, 11 insertions, 0 deletions

diff --git a/hw/virtio/vhost-user.c b/hw/virtio/vhost-user.c
index ca554d4ff1..da0756effe 100644
--- a/hw/virtio/vhost-user.c
+++ b/hw/virtio/vhost-user.c
@@ -1620,6 +1620,16 @@ vhost_user_crypto_close_session(struct vhost_dev *dev, uint64_t session_id)
     return 0;
 }
 
+static bool vhost_user_mem_section_filter(struct vhost_dev *dev,
+                                          MemoryRegionSection *section)
+{
+    bool result;
+
+    result = memory_region_get_fd(section->mr) >= 0;
+
+    return result;
+}
+
 const VhostOps user_ops = {
         .backend_type = VHOST_BACKEND_TYPE_USER,
         .vhost_backend_init = vhost_user_init,
@@ -1650,4 +1660,5 @@ const VhostOps user_ops = {
         .vhost_set_config = vhost_user_set_config,
         .vhost_crypto_create_session = vhost_user_crypto_create_session,
         .vhost_crypto_close_session = vhost_user_crypto_close_session,
+        .vhost_backend_mem_section_filter = vhost_user_mem_section_filter,
 };