[ovs-dev] [PATCH] ovsdb: Expose vhost-user socket directory in ovsdb

[Robert Wojciechowicz]

In order to correctly interoperate with Openstack and ODL,
the vhost-user socket directory must be exposed from OVS via OVSDB.
Different distros may package OVS in different ways,
so the locations of these sockets may vary depending on how
ovs-vswitchd has been started. Some clients need information where
the sockets are located when instantiating Qemu virtual machines.
The full vhost-user socket directory is constructed from current
OVS working directory and optionally from specified subdirectory.
This patch exposes vhost-user socket directory in Open_vSwitch
table in other_config column in two following keys:
1. ovs-run-dir    - OVS working directory
2. vhost-sock-dir - subdirectory of ovs-run-dir (might be empty)

Signed-off-by: Robert Wojciechowicz <robertx.wojciechowicz at intel.com>
---
 lib/netdev-dpdk.c    | 38 ++++++++++++++++++++++++++++++++++----
 lib/netdev-dpdk.h    |  9 +++++++++
 vswitchd/bridge.c    |  2 ++
 vswitchd/vswitch.xml | 11 +++++++++++
 4 files changed, 56 insertions(+), 4 deletions(-)

diff --git a/lib/netdev-dpdk.c b/lib/netdev-dpdk.c
index 9ffa7ff..4e68bd6 100644
--- a/lib/netdev-dpdk.c
+++ b/lib/netdev-dpdk.c
@@ -138,9 +138,13 @@ BUILD_ASSERT_DECL((MAX_NB_MBUF / ROUND_DOWN_POW2(MAX_NB_MBUF/MIN_NB_MBUF))
 
 #ifdef VHOST_CUSE
 static char *cuse_dev_name = NULL;    /* Character device cuse_dev_name. */
+#else
+static char *sock_dir_subcomponent = NULL;   /* Subdir of OVS run dir
+                                                for vhost-user sockets */
 #endif
 static char *vhost_sock_dir = NULL;   /* Location of vhost-user sockets */
 
+
 /*
  * Maximum amount of time in micro seconds to try and enqueue to vhost.
  */
@@ -3086,9 +3090,6 @@ dpdk_init__(const struct smap *ovs_other_config)
     bool auto_determine = true;
     int err = 0;
     cpu_set_t cpuset;
-#ifndef VHOST_CUSE
-    char *sock_dir_subcomponent;
-#endif
 
     if (!smap_get_bool(ovs_other_config, "dpdk-init", false)) {
         VLOG_INFO("DPDK Disabled - to change this requires a restart.\n");
@@ -3119,10 +3120,11 @@ dpdk_init__(const struct smap *ovs_other_config)
             VLOG_ERR("vhost-user sock directory request '%s/%s' has invalid"
                      "characters '..' - using %s instead.",
                      ovs_rundir(), sock_dir_subcomponent, ovs_rundir());
+            sock_dir_subcomponent = "";
         }
-        free(sock_dir_subcomponent);
     } else {
         vhost_sock_dir = sock_dir_subcomponent;
+        sock_dir_subcomponent = "";
 #endif
     }
 
@@ -3244,6 +3246,34 @@ dpdk_init(const struct smap *ovs_other_config)
     }
 }
 
+void
+dpdk_set_config(const struct ovsrec_open_vswitch *cfg)
+{
+    struct smap dpdk_args;
+    const struct ovsdb_datum *datum;
+    size_t i;
+
+    ovs_mutex_lock(&dpdk_mutex);
+
+    smap_init(&dpdk_args);
+    /* read current values from database */
+    datum = ovsrec_open_vswitch_get_other_config(cfg, OVSDB_TYPE_STRING,
+                                                 OVSDB_TYPE_STRING);
+    for (i = 0; i < datum->n; i++) {
+      smap_add(&dpdk_args, datum->keys[i].string, datum->values[i].string);
+    }
+    /* add default paths to the database */
+    smap_add_format(&dpdk_args, "ovs-run-dir", "%s", ovs_rundir());
+    if (sock_dir_subcomponent) {
+      smap_add_format(&dpdk_args, "vhost-sock-dir", "%s",
+                      sock_dir_subcomponent);
+    }
+    ovsrec_open_vswitch_set_other_config(cfg, &dpdk_args);
+    smap_destroy(&dpdk_args);
+
+    ovs_mutex_unlock(&dpdk_mutex);
+}
+
 static const struct netdev_class dpdk_class =
     NETDEV_DPDK_CLASS(
         "dpdk",
diff --git a/lib/netdev-dpdk.h b/lib/netdev-dpdk.h
index ee748e0..08abcac 100644
--- a/lib/netdev-dpdk.h
+++ b/lib/netdev-dpdk.h
@@ -3,6 +3,8 @@
 
 #include <config.h>
 
+#include "lib/vswitch-idl.h"
+
 struct dp_packet;
 struct smap;
 
@@ -25,6 +27,7 @@ struct smap;
 
 void netdev_dpdk_register(void);
 void free_dpdk_buf(struct dp_packet *);
+void dpdk_set_config(const struct ovsrec_open_vswitch *cfg);
 int pmd_thread_setaffinity_cpu(unsigned cpu);
 
 #else
@@ -45,6 +48,12 @@ free_dpdk_buf(struct dp_packet *buf OVS_UNUSED)
     /* Nothing */
 }
 
+static inline void
+dpdk_set_config(const struct ovsrec_open_vswitch *cfg)
+{
+    /* Nothing */
+}
+
 static inline int
 pmd_thread_setaffinity_cpu(unsigned cpu OVS_UNUSED)
 {
diff --git a/vswitchd/bridge.c b/vswitchd/bridge.c
index 41ec4ba..d248721 100644
--- a/vswitchd/bridge.c
+++ b/vswitchd/bridge.c
@@ -393,6 +393,7 @@ bridge_init(const char *remote)
     ovsdb_idl_omit(idl, &ovsrec_open_vswitch_col_db_version);
     ovsdb_idl_omit(idl, &ovsrec_open_vswitch_col_system_type);
     ovsdb_idl_omit(idl, &ovsrec_open_vswitch_col_system_version);
+    ovsdb_idl_omit_alert(idl, &ovsrec_open_vswitch_col_other_config);
 
     ovsdb_idl_omit_alert(idl, &ovsrec_bridge_col_datapath_id);
     ovsdb_idl_omit_alert(idl, &ovsrec_bridge_col_datapath_version);
@@ -2957,6 +2958,7 @@ bridge_run(void)
 
         if (cfg) {
             ovsrec_open_vswitch_set_cur_cfg(cfg, cfg->next_cfg);
+            dpdk_set_config(cfg);
             discover_types(cfg);
         }
 
diff --git a/vswitchd/vswitch.xml b/vswitchd/vswitch.xml
index 944d8ec..8d06d29 100644
--- a/vswitchd/vswitch.xml
+++ b/vswitchd/vswitch.xml
@@ -311,6 +311,17 @@
         </p>
       </column>
 
+      <column name="other_config" key="ovs-run-dir"
+              type='{"type": "string"}'>
+        <p>
+          Specifies the Open vSwitch run directory.
+        </p>
+        <p>
+          Defaults to the working directory of the application. Changing this
+          value requires restarting the daemon.
+        </p>
+      </column>
+
       <column name="other_config" key="n-handler-threads"
               type='{"type": "integer", "minInteger": 1}'>
         <p>
-- 
1.8.3.1