[PATCH 07/24] qemu: Store chardev 'wait' flag in chardev source private data

[Peter Krempa]

We have just one case when we wish to wait for incomming connections for
a listening socket and that is for vhost-user network devices.

Passing this via a flag to qemuBuildChrChardevStr is unwieldy. Add a
field to qemuDomainChrSourcePrivate and populate it for our special
case inside of qemuDomainPrepareChardevSourceOne.

Since we wait for incomming connections only on startup of a new VM we
also need to pass in a flag whether qemuDomainPrepareChardevSourceOne
is called on a new start or on hotplug.

Signed-off-by: Peter Krempa <pkrempa at redhat.com>
---
 src/qemu/qemu_command.c | 6 +++---
 src/qemu/qemu_domain.c  | 8 +++++++-
 src/qemu/qemu_domain.h  | 2 ++
 src/qemu/qemu_driver.c  | 3 ++-
 4 files changed, 14 insertions(+), 5 deletions(-)

diff --git a/src/qemu/qemu_command.c b/src/qemu/qemu_command.c
index b637cd2bf5..0baf3acde6 100644
--- a/src/qemu/qemu_command.c
+++ b/src/qemu/qemu_command.c
@@ -5051,7 +5051,7 @@ qemuBuildChrChardevStr(virLogManager *logManager G_GNUC_UNUSED,
                        const virDomainChrSourceDef *dev,
                        const char *alias,
                        virQEMUCaps *qemuCaps,
-                       unsigned int cdevflags)
+                       unsigned int cdevflags G_GNUC_UNUSED)
 {
     qemuDomainChrSourcePrivate *chrSourcePriv = QEMU_DOMAIN_CHR_SOURCE_PRIVATE(dev);
     g_auto(virBuffer) buf = VIR_BUFFER_INITIALIZER;
@@ -5148,7 +5148,7 @@ qemuBuildChrChardevStr(virLogManager *logManager G_GNUC_UNUSED,

         if (dev->data.tcp.listen) {
             virBufferAddLit(&buf, ",server=on");
-            if (cdevflags & QEMU_BUILD_CHARDEV_TCP_NOWAIT)
+            if (!chrSourcePriv->wait)
                 virBufferAddLit(&buf, ",wait=off");
         }

@@ -5199,7 +5199,7 @@ qemuBuildChrChardevStr(virLogManager *logManager G_GNUC_UNUSED,
         }
         if (dev->data.nix.listen) {
             virBufferAddLit(&buf, ",server=on");
-            if (cdevflags & QEMU_BUILD_CHARDEV_TCP_NOWAIT)
+            if (!chrSourcePriv->wait)
                 virBufferAddLit(&buf, ",wait=off");
         }

diff --git a/src/qemu/qemu_domain.c b/src/qemu/qemu_domain.c
index 550afca36e..e6d6bf10f1 100644
--- a/src/qemu/qemu_domain.c
+++ b/src/qemu/qemu_domain.c
@@ -9735,6 +9735,7 @@ qemuDomainPrepareChardevSourceOne(virDomainDeviceDef *dev,
                                   void *opaque)
 {
     struct qemuDomainPrepareChardevSourceData *data = opaque;
+    qemuDomainChrSourcePrivate *charpriv = QEMU_DOMAIN_CHR_SOURCE_PRIVATE(charsrc);

     switch ((virDomainDeviceType) dev->type) {

@@ -9750,8 +9751,13 @@ qemuDomainPrepareChardevSourceOne(virDomainDeviceDef *dev,
         }
         break;

-    case VIR_DOMAIN_DEVICE_DISK:
     case VIR_DOMAIN_DEVICE_NET:
+        /* when starting a fresh VM, vhost-user network sockets wait for connection */
+        if (!data->hotplug)
+            charpriv->wait = true;
+        break;
+
+    case VIR_DOMAIN_DEVICE_DISK:
     case VIR_DOMAIN_DEVICE_SHMEM:
     case VIR_DOMAIN_DEVICE_LEASE:
     case VIR_DOMAIN_DEVICE_FS:
diff --git a/src/qemu/qemu_domain.h b/src/qemu/qemu_domain.h
index f84acf408b..2d93cf2253 100644
--- a/src/qemu/qemu_domain.h
+++ b/src/qemu/qemu_domain.h
@@ -344,6 +344,7 @@ struct _qemuDomainChrSourcePrivate {

     int fd; /* file descriptor of the chardev source */
     int logfd; /* file descriptor of the logging source */
+    bool wait; /* wait for incomming connections on chardev */
 };


@@ -866,6 +867,7 @@ int qemuDomainPrepareChannel(virDomainChrDef *chr,

 struct qemuDomainPrepareChardevSourceData {
     virQEMUDriverConfig *cfg;
+    bool hotplug;
 };

 int
diff --git a/src/qemu/qemu_driver.c b/src/qemu/qemu_driver.c
index 10feb606ad..4301f3f89e 100644
--- a/src/qemu/qemu_driver.c
+++ b/src/qemu/qemu_driver.c
@@ -6794,7 +6794,8 @@ qemuDomainAttachDeviceLive(virDomainObj *vm,
     int ret = -1;
     const char *alias = NULL;
     g_autoptr(virQEMUDriverConfig) cfg = virQEMUDriverGetConfig(driver);
-    struct qemuDomainPrepareChardevSourceData chardevBackendData = { .cfg = cfg };
+    struct qemuDomainPrepareChardevSourceData chardevBackendData = { .cfg = cfg,
+                                                                     .hotplug = true };

     if (qemuDomainDeviceBackendChardevForeachOne(dev,
                                                  qemuDomainPrepareChardevSourceOne,
-- 
2.31.1