4:54 a.m.
https://bugzilla.redhat.com/show_bug.cgi?id=1293351
Since we already have virtio channel events, we know when guest
agent within guest has (dis-)connected. Instead of us blindly
connecting to a socket that no one is listening to, we can just
follow what qemu-ga does. This has a nice benefit that we don't
need to 'guest-ping' the agent just to timeout and find out
nobody is listening.
The way that this commit is implemented:
- don't connect in qemuProcessStart directly, defer that to event
callback (which already follows the agent).
- after migration is settled, before we resume vCPUs, ask qemu
whether somebody is listening on the socket and if so, connect
to it.
Signed-off-by: Michal Privoznik <mprivozn(a)redhat.com>
---
diff to v3:
-Move cap detection into qemuConnectAgent
src/qemu/qemu_driver.c | 13 ++++++++++++-
src/qemu/qemu_migration.c | 12 ++++++++++++
src/qemu/qemu_process.c | 24 ++++++++++++++++++++++++
3 files changed, 48 insertions(+), 1 deletion(-)
diff --git a/src/qemu/qemu_driver.c b/src/qemu/qemu_driver.c
index 8ccf68b..3751ba6 100644
--- a/src/qemu/qemu_driver.c
+++ b/src/qemu/qemu_driver.c
@@ -6650,12 +6650,13 @@ qemuDomainSaveImageStartVM(virConnectPtr conn,
bool start_paused,
qemuDomainAsyncJob asyncJob)
{
- int ret = -1;
+ int rc, ret = -1;
virObjectEventPtr event;
int intermediatefd = -1;
virCommandPtr cmd = NULL;
char *errbuf = NULL;
virQEMUDriverConfigPtr cfg = virQEMUDriverGetConfig(driver);
+ qemuDomainObjPrivatePtr priv = vm->privateData;
if ((header->version == 2) &&
(header->compressed != QEMU_SAVE_FORMAT_RAW)) {
@@ -6710,6 +6711,16 @@ qemuDomainSaveImageStartVM(virConnectPtr conn,
goto cleanup;
}
+ if ((rc = qemuConnectAgent(driver, vm)) < 0) {
+ if (rc == -2)
+ goto cleanup;
+
+ VIR_WARN("Cannot connect to QEMU guest agent for %s",
+ vm->def->name);
+ virResetLastError();
+ priv->agentError = true;
+ }
+
event = virDomainEventLifecycleNewFromObj(vm,
VIR_DOMAIN_EVENT_STARTED,
VIR_DOMAIN_EVENT_STARTED_RESTORED);
diff --git a/src/qemu/qemu_migration.c b/src/qemu/qemu_migration.c
index 51e7125..9678adf 100644
--- a/src/qemu/qemu_migration.c
+++ b/src/qemu/qemu_migration.c
@@ -5795,6 +5795,7 @@ qemuMigrationFinish(virQEMUDriverPtr driver,
unsigned short port;
unsigned long long timeReceived = 0;
virObjectEventPtr event;
+ int rc;
VIR_DEBUG("driver=%p, dconn=%p, vm=%p, cookiein=%s, cookieinlen=%d, "
"cookieout=%p, cookieoutlen=%p, flags=%lx, retcode=%d",
@@ -5863,6 +5864,17 @@ qemuMigrationFinish(virQEMUDriverPtr driver,
if (qemuMigrationStopNBDServer(driver, vm, mig) < 0)
goto endjob;
+ if ((rc = qemuConnectAgent(driver, vm)) < 0) {
+ if (rc == -2)
+ goto endjob;
+
+ VIR_WARN("Cannot connect to QEMU guest agent for %s",
+ vm->def->name);
+ virResetLastError();
+ priv->agentError = true;
+ }
+
+
if (flags & VIR_MIGRATE_PERSIST_DEST) {
if (qemuMigrationPersist(driver, vm, mig, !v3proto) < 0) {
/* Hmpf. Migration was successful, but making it persistent
diff --git a/src/qemu/qemu_process.c b/src/qemu/qemu_process.c
index 05cbda2..e1a25dd 100644
--- a/src/qemu/qemu_process.c
+++ b/src/qemu/qemu_process.c
@@ -77,6 +77,10 @@
VIR_LOG_INIT("qemu.qemu_process");
+static int
+qemuProcessReconnectRefreshChannelVirtioState(virQEMUDriverPtr driver,
+ virDomainObjPtr vm);
+
/**
* qemuProcessRemoveDomainStatus
*
@@ -208,6 +212,26 @@ qemuConnectAgent(virQEMUDriverPtr driver, virDomainObjPtr vm)
if (!config)
return 0;
+ if (priv->agent)
+ return 0;
+
+ if (virQEMUCapsGet(priv->qemuCaps, QEMU_CAPS_VSERPORT_CHANGE) &&
+ config->state != VIR_DOMAIN_CHR_DEVICE_STATE_CONNECTED) {
+ /* So qemu is capable of sending us event whenever guest agent
+ * (dis-)connects. And we reflect its state in config->state. Well,
+ * nearly. It may happen that what we think about the guest agent state
+ * is not accurate, e.g. right after migration. Ask qemu to be sure. */
+
+ if (qemuProcessReconnectRefreshChannelVirtioState(driver, vm) < 0)
+ goto cleanup;
+
+ /* Now we are sure about the channel state. */
+ if (config->state != VIR_DOMAIN_CHR_DEVICE_STATE_CONNECTED) {
+ VIR_DEBUG("Deferring connecting to guest agent");
+ return 0;
+ }
+ }
+
if (virSecurityManagerSetDaemonSocketLabel(driver->securityManager,
vm->def) < 0) {
VIR_ERROR(_("Failed to set security context for agent for %s"),
--
2.4.10