virtio-devices: vhost-user: Send set_vring_num before setup inflight …

…I/O tracking

backend like SPDK required to know how many virt queues to be handled
before gets VHOST_USER_SET_INFLIGHT_FD message.

fix dpdk core dump while processing vhost_user_set_inflight_fd:
    #0 0x00007fffef47c347 in vhost_user_set_inflight_fd (pdev=0x7fffe2895998, msg=0x7fffe28956f0, main_fd=545) at ../lib/librte_vhost/vhost_user.c:1570
    #1 0x00007fffef47e7b9 in vhost_user_msg_handler (vid=0, fd=545) at ../lib/librte_vhost/vhost_user.c:2735
    #2 0x00007fffef46bac0 in vhost_user_read_cb (connfd=545, dat=0x7fffdc0008c0, remove=0x7fffe2895a64) at ../lib/librte_vhost/socket.c:309
    #3 0x00007fffef45b3f6 in fdset_event_dispatch (arg=0x7fffef6dc2e0 <vhost_user+8192>) at ../lib/librte_vhost/fd_man.c:286
    #4 0x00007ffff09926f3 in rte_thread_init (arg=0x15ee180) at ../lib/librte_eal/common/eal_common_thread.c:175

Signed-off-by: Arafatms <arafatms@outlook.com>

virtio-devices/src/vhost_user/blk.rs

@@ -24,7 +24,6 @@ use vhost::vhost_user::message::VhostUserConfigFlags;
 use vhost::vhost_user::message::VHOST_USER_CONFIG_OFFSET;
 use vhost::vhost_user::message::{VhostUserProtocolFeatures, VhostUserVirtioFeatures};
 use vhost::vhost_user::{MasterReqHandler, VhostUserMaster, VhostUserMasterReqHandler};
-use vhost::VhostBackend;
 use virtio_bindings::bindings::virtio_blk::{
     VIRTIO_BLK_F_BLK_SIZE, VIRTIO_BLK_F_CONFIG_WCE, VIRTIO_BLK_F_DISCARD, VIRTIO_BLK_F_FLUSH,
     VIRTIO_BLK_F_GEOMETRY, VIRTIO_BLK_F_MQ, VIRTIO_BLK_F_RO, VIRTIO_BLK_F_SEG_MAX,
@@ -128,15 +127,6 @@ impl Blk {
             config.num_queues = num_queues as u16;
         }
 
-        // Send set_vring_base here, since it could tell backends, like SPDK,
-        // how many virt queues to be handled, which backend required to know
-        // at early stage.
-        for i in 0..num_queues {
-            vu.socket_handle()
-                .set_vring_base(i, 0)
-                .map_err(Error::VhostUserSetVringBase)?;
-        }
-
         Ok(Blk {
             common: VirtioCommon {
                 device_type: VirtioDeviceType::Block as u32,

virtio-devices/src/vhost_user/vu_common_ctrl.rs

@@ -141,6 +141,15 @@ impl VhostUserHandle {
         // Let's first provide the memory table to the backend.
         self.update_mem_table(mem)?;
 
+        // Send set_vring_num here, since it could tell backends, like SPDK,
+        // how many virt queues to be handled, which backend required to know
+        // at early stage.
+        for (queue_index, queue) in queues.iter().enumerate() {
+            self.vu
+                .set_vring_num(queue_index, queue.actual_size())
+                .map_err(Error::VhostUserSetVringNum)?;
+        }
+
         // Setup for inflight I/O tracking shared memory.
         if let Some(inflight) = inflight {
             if inflight.fd.is_none() {
@@ -168,10 +177,6 @@ impl VhostUserHandle {
         for (queue_index, queue) in queues.into_iter().enumerate() {
             let actual_size: usize = queue.actual_size().try_into().unwrap();
 
-            self.vu
-                .set_vring_num(queue_index, queue.actual_size())
-                .map_err(Error::VhostUserSetVringNum)?;
-
             let config_data = VringConfigData {
                 queue_max_size: queue.get_max_size(),
                 queue_size: queue.actual_size(),