migration/rdma: Replace flawed device detail dump by tracing

qemu_rdma_dump_id() dumps RDMA device details to stdout.

rdma_start_outgoing_migration() calls it via qemu_rdma_source_init()
and qemu_rdma_resolve_host() to show source device details.
rdma_start_incoming_migration() arranges its call via
rdma_accept_incoming_migration() and qemu_rdma_accept() to show
destination device details.

Two issues:

1. rdma_start_outgoing_migration() can run in HMP context.  The
   information should arguably go the monitor, not stdout.

2. ibv_query_port() failure is reported as error.  Its callers remain
   unaware of this failure (qemu_rdma_dump_id() can't fail), so
   reporting this to the user as an error is problematic.

Fixable, but the device detail dump is noise, except when
troubleshooting.  Tracing is a better fit.  Similar function
qemu_rdma_dump_id() was converted to tracing in commit
733252deb8b (Tracify migration/rdma.c).

Convert qemu_rdma_dump_id(), too.

While there, touch up qemu_rdma_dump_gid()'s outdated comment.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Fabiano Rosas <farosas@suse.de>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20230928132019.2544702-54-armbru@redhat.com>

2 files changed, 10 insertions, 15 deletions

diff --git a/migration/rdma.c b/migration/rdma.c
index ab2ea85..f6fc226 100644
--- a/migration/rdma.c
+++ b/migration/rdma.c
@@ -734,38 +734,31 @@ static void rdma_delete_block(RDMAContext *rdma, RDMALocalBlock *block)
 }
 
 /*
- * Put in the log file which RDMA device was opened and the details
- * associated with that device.
+ * Trace RDMA device open, with device details.
  */
 static void qemu_rdma_dump_id(const char *who, struct ibv_context *verbs)
 {
     struct ibv_port_attr port;
 
     if (ibv_query_port(verbs, 1, &port)) {
-        error_report("Failed to query port information");
+        trace_qemu_rdma_dump_id_failed(who);
         return;
     }
 
-    printf("%s RDMA Device opened: kernel name %s "
-           "uverbs device name %s, "
-           "infiniband_verbs class device path %s, "
-           "infiniband class device path %s, "
-           "transport: (%d) %s\n",
-                who,
+    trace_qemu_rdma_dump_id(who,
                 verbs->device->name,
                 verbs->device->dev_name,
                 verbs->device->dev_path,
                 verbs->device->ibdev_path,
                 port.link_layer,
-                (port.link_layer == IBV_LINK_LAYER_INFINIBAND) ? "Infiniband" :
-                 ((port.link_layer == IBV_LINK_LAYER_ETHERNET)
-                    ? "Ethernet" : "Unknown"));
+                port.link_layer == IBV_LINK_LAYER_INFINIBAND ? "Infiniband"
+                : port.link_layer == IBV_LINK_LAYER_ETHERNET ? "Ethernet"
+                : "Unknown");
 }
 
 /*
- * Put in the log file the RDMA gid addressing information,
- * useful for folks who have trouble understanding the
- * RDMA device hierarchy in the kernel.
+ * Trace RDMA gid addressing information.
+ * Useful for understanding the RDMA device hierarchy in the kernel.
  */
 static void qemu_rdma_dump_gid(const char *who, struct rdma_cm_id *id)
 {
diff --git a/migration/trace-events b/migration/trace-events
index 6a50994..ee9c8f4 100644
--- a/migration/trace-events
+++ b/migration/trace-events
@@ -214,6 +214,8 @@ qemu_rdma_close(void) ""
 qemu_rdma_connect_pin_all_requested(void) ""
 qemu_rdma_connect_pin_all_outcome(bool pin) "%d"
 qemu_rdma_dest_init_trying(const char *host, const char *ip) "%s => %s"
+qemu_rdma_dump_id_failed(const char *who) "%s RDMA Device opened, but can't query port information"
+qemu_rdma_dump_id(const char *who, const char *name, const char *dev_name, const char *dev_path, const char *ibdev_path, int transport, const char *transport_name) "%s RDMA Device opened: kernel name %s uverbs device name %s, infiniband_verbs class device path %s, infiniband class device path %s, transport: (%d) %s"
 qemu_rdma_dump_gid(const char *who, const char *src, const char *dst) "%s Source GID: %s, Dest GID: %s"
 qemu_rdma_exchange_get_response_start(const char *desc) "CONTROL: %s receiving..."
 qemu_rdma_exchange_get_response_none(const char *desc, int type) "Surprise: got %s (%d)"