[PATCH 1/2] virnetdevopenvswitch: Get names for dpdkvhostuserclient too

[Michal Privoznik]

There are two type of vhostuser ports:

  dpdkvhostuser - OVS creates the socket and QEMU connects to it
  dpdkvhostuserclient - QEMU creates the socket and OVS connects to it

But of course ovs-vsctl syntax for fetching ifname is different.
So far, we've implemented the former. The lack of implementation
for the latter means that we are not detecting the interface name
and thus not reporting it in domain XML, or failing to get
interface statistics.

Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=1767013

Signed-off-by: Michal Privoznik <mprivozn at redhat.com>
---
 src/qemu/qemu_command.c         |  1 +
 src/qemu/qemu_hotplug.c         |  1 +
 src/util/virnetdevopenvswitch.c | 60 +++++++++++++++++++++++----------
 src/util/virnetdevopenvswitch.h |  1 +
 tests/qemuxml2argvmock.c        |  1 +
 5 files changed, 46 insertions(+), 18 deletions(-)

diff --git a/src/qemu/qemu_command.c b/src/qemu/qemu_command.c
index b0c2a5efb5..0e803145d1 100644
--- a/src/qemu/qemu_command.c
+++ b/src/qemu/qemu_command.c
@@ -8004,6 +8004,7 @@ qemuBuildInterfaceCommandLine(virQEMUDriverPtr driver,
             goto cleanup;
 
         if (virNetDevOpenvswitchGetVhostuserIfname(net->data.vhostuser->data.nix.path,
+                                                   net->data.vhostuser->data.nix.listen,
                                                    &net->ifname) < 0)
             goto cleanup;
 
diff --git a/src/qemu/qemu_hotplug.c b/src/qemu/qemu_hotplug.c
index 81bbe178a9..8c22075be1 100644
--- a/src/qemu/qemu_hotplug.c
+++ b/src/qemu/qemu_hotplug.c
@@ -1305,6 +1305,7 @@ qemuDomainAttachNetDevice(virQEMUDriverPtr driver,
             goto cleanup;
 
         if (virNetDevOpenvswitchGetVhostuserIfname(net->data.vhostuser->data.nix.path,
+                                                   net->data.vhostuser->data.nix.listen,
                                                    &net->ifname) < 0)
             goto cleanup;
 
diff --git a/src/util/virnetdevopenvswitch.c b/src/util/virnetdevopenvswitch.c
index a7b6af594d..d809152f33 100644
--- a/src/util/virnetdevopenvswitch.c
+++ b/src/util/virnetdevopenvswitch.c
@@ -471,9 +471,20 @@ virNetDevOpenvswitchInterfaceGetMaster(const char *ifname, char **master)
 /**
  * virNetDevOpenvswitchVhostuserGetIfname:
  * @path: the path of the unix socket
+ * @server: true if OVS creates the @path
  * @ifname: the retrieved name of the interface
  *
- * Retrieves the ovs ifname from vhostuser unix socket path.
+ * Retrieves the OVS ifname from vhostuser UNIX socket path.
+ * There are two types of vhostuser ports which differ in client/server
+ * role:
+ *
+ * dpdkvhostuser - OVS creates the socket and QEMU connects to it
+ *                 (@server = true)
+ * dpdkvhostuserclient - QEMU creates the socket and OVS connects to it
+ *                       (@server = false)
+ *
+ * Since the way of retrieving ifname is different in these two cases,
+ * caller must set @server according to the interface definition.
  *
  * Returns: 1 if interface is an openvswitch interface,
  *          0 if it is not, but no other error occurred,
@@ -481,33 +492,46 @@ virNetDevOpenvswitchInterfaceGetMaster(const char *ifname, char **master)
  */
 int
 virNetDevOpenvswitchGetVhostuserIfname(const char *path,
+                                       bool server,
                                        char **ifname)
 {
-    const char *tmpIfname = NULL;
+    g_autoptr(virCommand) cmd = NULL;
     int status;
-    g_autoptr(virCommand) cmd = NULL;
 
-    /* Openvswitch vhostuser path are hardcoded to
-     * /<runstatedir>/openvswitch/<ifname>
-     * for example: /var/run/openvswitch/dpdkvhostuser0
-     *
-     * so we pick the filename and check it's a openvswitch interface
-     */
-    if (!path ||
-        !(tmpIfname = strrchr(path, '/')))
-        return 0;
-
-    tmpIfname++;
     cmd = virCommandNew(OVS_VSCTL);
     virNetDevOpenvswitchAddTimeout(cmd);
-    virCommandAddArgList(cmd, "get", "Interface", tmpIfname, "name", NULL);
-    if (virCommandRun(cmd, &status) < 0 ||
-        status) {
+
+    if (server) {
+        virCommandAddArgList(cmd, "--no-headings", "--columns=name", "find",
+                             "Interface", NULL);
+        virCommandAddArgPair(cmd, "options:vhost-server-path", "path");
+    } else {
+        const char *tmpIfname = NULL;
+
+        /* Openvswitch vhostuser path are hardcoded to
+         * /<runstatedir>/openvswitch/<ifname>
+         * for example: /var/run/openvswitch/dpdkvhostuser0
+         *
+         * so we pick the filename and check it's a openvswitch interface
+         */
+        if (!path ||
+            !(tmpIfname = strrchr(path, '/'))) {
+            return 0;
+        }
+
+        tmpIfname++;
+        virCommandAddArgList(cmd, "get", "Interface", tmpIfname, "name", NULL);
+    }
+
+    virCommandSetOutputBuffer(cmd, ifname);
+    if (virCommandRun(cmd, &status) < 0)
+        return -1;
+
+    if (status != 0) {
         /* it's not a openvswitch vhostuser interface. */
         return 0;
     }
 
-    *ifname = g_strdup(tmpIfname);
     return 1;
 }
 
diff --git a/src/util/virnetdevopenvswitch.h b/src/util/virnetdevopenvswitch.h
index c9ea592058..5cd1d22ae3 100644
--- a/src/util/virnetdevopenvswitch.h
+++ b/src/util/virnetdevopenvswitch.h
@@ -61,6 +61,7 @@ int virNetDevOpenvswitchInterfaceGetMaster(const char *ifname, char **master)
     ATTRIBUTE_NONNULL(1) G_GNUC_WARN_UNUSED_RESULT;
 
 int virNetDevOpenvswitchGetVhostuserIfname(const char *path,
+                                           bool server,
                                            char **ifname)
     ATTRIBUTE_NONNULL(2) G_GNUC_WARN_UNUSED_RESULT G_GNUC_NO_INLINE;
 
diff --git a/tests/qemuxml2argvmock.c b/tests/qemuxml2argvmock.c
index 2cdbe7e356..6900232b33 100644
--- a/tests/qemuxml2argvmock.c
+++ b/tests/qemuxml2argvmock.c
@@ -217,6 +217,7 @@ virCommandPassFD(virCommandPtr cmd,
 
 int
 virNetDevOpenvswitchGetVhostuserIfname(const char *path G_GNUC_UNUSED,
+                                       bool server G_GNUC_UNUSED,
                                        char **ifname)
 {
     *ifname = g_strdup("vhost-user0");
-- 
2.26.2