qemu: don't use chardev FD passing for vhostuser backend

QEMU chardevs have a bug which makes the vhostuser backend complain
about lack of support for FD passing when validating the chardev.
While this is ultimately QEMU's responsibility to fix, libvirt needs to
avoid tickling the bug.

Simply disabling chardev FD passing just for vhostuser's chardev is
the most prudent approach, avoiding need for a QEMU version number
check.
Signed-off-by: NDaniel P. Berrangé <berrange@redhat.com>

src/qemu/qemu_command.c

@@ -4939,6 +4939,7 @@ qemuOpenChrChardevUNIXSocket(const virDomainChrSourceDef *dev)
 enum {
     QEMU_BUILD_CHARDEV_TCP_NOWAIT = (1 << 0),
     QEMU_BUILD_CHARDEV_FILE_LOGD  = (1 << 1),
+    QEMU_BUILD_CHARDEV_UNIX_FD_PASS = (1 << 2),
 };
 
 /* This function outputs a -chardev command line option which describes only the
@@ -5082,7 +5083,8 @@ qemuBuildChrChardevStr(virLogManagerPtr logManager,
         break;
 
     case VIR_DOMAIN_CHR_TYPE_UNIX:
-        if (virQEMUCapsGet(qemuCaps, QEMU_CAPS_CHARDEV_FD_PASS)) {
+        if ((flags & QEMU_BUILD_CHARDEV_UNIX_FD_PASS) &&
+            virQEMUCapsGet(qemuCaps, QEMU_CAPS_CHARDEV_FD_PASS)) {
             if (qemuSecuritySetSocketLabel(secManager, (virDomainDefPtr)def) < 0)
                 goto cleanup;
             int fd = qemuOpenChrChardevUNIXSocket(dev);
@@ -5438,7 +5440,8 @@ qemuBuildMonitorCommandLine(virLogManagerPtr logManager,
                             qemuDomainObjPrivatePtr priv)
 {
     char *chrdev;
-    unsigned int cdevflags = QEMU_BUILD_CHARDEV_TCP_NOWAIT;
+    unsigned int cdevflags = QEMU_BUILD_CHARDEV_TCP_NOWAIT |
+        QEMU_BUILD_CHARDEV_UNIX_FD_PASS;
     if (priv->chardevStdioLogd)
         cdevflags |= QEMU_BUILD_CHARDEV_FILE_LOGD;
 
@@ -5573,7 +5576,8 @@ qemuBuildRNGBackendChrdevStr(virLogManagerPtr logManager,
                              char **chr,
                              bool chardevStdioLogd)
 {
-    unsigned int cdevflags = QEMU_BUILD_CHARDEV_TCP_NOWAIT;
+    unsigned int cdevflags = QEMU_BUILD_CHARDEV_TCP_NOWAIT |
+        QEMU_BUILD_CHARDEV_UNIX_FD_PASS;
     if (chardevStdioLogd)
         cdevflags |= QEMU_BUILD_CHARDEV_FILE_LOGD;
     *chr = NULL;
@@ -8712,7 +8716,8 @@ qemuBuildSmartcardCommandLine(virLogManagerPtr logManager,
     virBuffer opt = VIR_BUFFER_INITIALIZER;
     const char *database;
     const char *contAlias = NULL;
-    unsigned int cdevflags = QEMU_BUILD_CHARDEV_TCP_NOWAIT;
+    unsigned int cdevflags = QEMU_BUILD_CHARDEV_TCP_NOWAIT |
+        QEMU_BUILD_CHARDEV_UNIX_FD_PASS;
     if (chardevStdioLogd)
         cdevflags |= QEMU_BUILD_CHARDEV_FILE_LOGD;
 
@@ -8948,7 +8953,8 @@ qemuBuildShmemCommandLine(virLogManagerPtr logManager,
     virBuffer buf = VIR_BUFFER_INITIALIZER;
     char *devstr = NULL;
     int rc;
-    unsigned int cdevflags = QEMU_BUILD_CHARDEV_TCP_NOWAIT;
+    unsigned int cdevflags = QEMU_BUILD_CHARDEV_TCP_NOWAIT |
+        QEMU_BUILD_CHARDEV_UNIX_FD_PASS;
     if (chardevStdioLogd)
         cdevflags |= QEMU_BUILD_CHARDEV_FILE_LOGD;
 
@@ -9108,7 +9114,8 @@ qemuBuildSerialCommandLine(virLogManagerPtr logManager,
 {
     size_t i;
     bool havespice = false;
-    unsigned int cdevflags = QEMU_BUILD_CHARDEV_TCP_NOWAIT;
+    unsigned int cdevflags = QEMU_BUILD_CHARDEV_TCP_NOWAIT |
+        QEMU_BUILD_CHARDEV_UNIX_FD_PASS;
     if (chardevStdioLogd)
         cdevflags |= QEMU_BUILD_CHARDEV_FILE_LOGD;
 
@@ -9171,7 +9178,8 @@ qemuBuildParallelsCommandLine(virLogManagerPtr logManager,
                               bool chardevStdioLogd)
 {
     size_t i;
-    unsigned int cdevflags = QEMU_BUILD_CHARDEV_TCP_NOWAIT;
+    unsigned int cdevflags = QEMU_BUILD_CHARDEV_TCP_NOWAIT |
+        QEMU_BUILD_CHARDEV_UNIX_FD_PASS;
     if (chardevStdioLogd)
         cdevflags |= QEMU_BUILD_CHARDEV_FILE_LOGD;
 
@@ -9208,7 +9216,8 @@ qemuBuildChannelsCommandLine(virLogManagerPtr logManager,
                              bool chardevStdioLogd)
 {
     size_t i;
-    unsigned int cdevflags = QEMU_BUILD_CHARDEV_TCP_NOWAIT;
+    unsigned int cdevflags = QEMU_BUILD_CHARDEV_TCP_NOWAIT |
+        QEMU_BUILD_CHARDEV_UNIX_FD_PASS;
     if (chardevStdioLogd)
         cdevflags |= QEMU_BUILD_CHARDEV_FILE_LOGD;
 
@@ -9265,7 +9274,8 @@ qemuBuildConsoleCommandLine(virLogManagerPtr logManager,
                             bool chardevStdioLogd)
 {
     size_t i;
-    unsigned int cdevflags = QEMU_BUILD_CHARDEV_TCP_NOWAIT;
+    unsigned int cdevflags = QEMU_BUILD_CHARDEV_TCP_NOWAIT |
+        QEMU_BUILD_CHARDEV_UNIX_FD_PASS;
     if (chardevStdioLogd)
         cdevflags |= QEMU_BUILD_CHARDEV_FILE_LOGD;
 
@@ -9445,7 +9455,8 @@ qemuBuildRedirdevCommandLine(virLogManagerPtr logManager,
                              bool chardevStdioLogd)
 {
     size_t i;
-    unsigned int cdevflags = QEMU_BUILD_CHARDEV_TCP_NOWAIT;
+    unsigned int cdevflags = QEMU_BUILD_CHARDEV_TCP_NOWAIT |
+        QEMU_BUILD_CHARDEV_UNIX_FD_PASS;
     if (chardevStdioLogd)
         cdevflags |= QEMU_BUILD_CHARDEV_FILE_LOGD;
 

tests/qemuxml2argvdata/net-vhostuser.args

@@ -14,8 +14,7 @@ QEMU_AUDIO_DRV=none \
 -display none \
 -no-user-config \
 -nodefaults \
--chardev socket,id=charmonitor,path=/tmp/lib/domain--1-QEMUGuest1/monitor.sock,\
-server,nowait \
+-chardev socket,id=charmonitor,fd=1729,server,nowait \
 -mon chardev=charmonitor,id=monitor,mode=control \
 -rtc base=utc \
 -no-shutdown \

tests/qemuxml2argvtest.c

@@ -1266,7 +1266,7 @@ mymain(void)
     DO_TEST("misc-no-reboot", NONE);
     DO_TEST("misc-uuid", NONE);
     DO_TEST_PARSE_ERROR("vhost_queues-invalid", NONE);
-    DO_TEST("net-vhostuser", NONE);
+    DO_TEST("net-vhostuser", QEMU_CAPS_CHARDEV_FD_PASS);
     DO_TEST("net-vhostuser-multiq",
             QEMU_CAPS_VHOSTUSER_MULTIQUEUE);
     DO_TEST_FAILURE("net-vhostuser-multiq", NONE);