vdpa: add trace events for vhost_vdpa_net_load_cmd

For better debuggability and observability.

Message-Id: <1707910082-10243-9-git-send-email-si-wei.liu@oracle.com>
Reviewed-by: Eugenio Pérez <eperezma@redhat.com>
Signed-off-by: Si-Wei Liu <si-wei.liu@oracle.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

net/trace-events

@@ -26,3 +26,5 @@ colo_filter_rewriter_conn_offset(uint32_t offset) ": offset=%u"
 
 # vhost-vdpa.c
 vhost_vdpa_set_address_space_id(void *v, unsigned vq_group, unsigned asid_num) "vhost_vdpa: %p vq_group: %u asid: %u"
+vhost_vdpa_net_load_cmd(void *s, uint8_t class, uint8_t cmd, int data_num, int data_size) "vdpa state: %p class: %u cmd: %u sg_num: %d size: %d"
+vhost_vdpa_net_load_cmd_retval(void *s, uint8_t class, uint8_t cmd, int r) "vdpa state: %p class: %u cmd: %u retval: %d"

net/vhost-vdpa.c

@@ -715,6 +715,7 @@ static ssize_t vhost_vdpa_net_load_cmd(VhostVDPAState *s,
 
     assert(data_size < vhost_vdpa_net_cvq_cmd_page_len() - sizeof(ctrl));
     cmd_size = sizeof(ctrl) + data_size;
+    trace_vhost_vdpa_net_load_cmd(s, class, cmd, data_num, data_size);
     if (vhost_svq_available_slots(svq) < 2 ||
         iov_size(out_cursor, 1) < cmd_size) {
         /*
@@ -746,6 +747,7 @@ static ssize_t vhost_vdpa_net_load_cmd(VhostVDPAState *s,
 
     r = vhost_vdpa_net_cvq_add(s, &out, 1, &in, 1);
     if (unlikely(r < 0)) {
+        trace_vhost_vdpa_net_load_cmd_retval(s, class, cmd, r);
         return r;
     }