Re: [libvirt] [PATCH v2] Support reboots with the QEMU driver

For controlled shutdown we issue a 'system_powerdown' command to the QEMU monitor. This triggers an ACPI event which (most) guest OS wire up to a controlled shutdown. There is no equiv ACPI event to trigger a controlled reboot. This patch attempts to fake a reboot. - In qemuDomainObjPrivatePtr we have a bool fakeReboot flag. - The virDomainReboot method sets this flag and then triggers a normal 'system_powerdown'. - The QEMU process is started with '-no-shutdown' so that the guest CPUs pause when it powers off the guest - When we receive the 'POWEROFF' event from QEMU JSON monitor if fakeReboot is not set we invoke the qemuProcessKill command and shutdown continues normally - If fakeReboot was set, we spawn a background thread which issues 'system_reset' to perform a warm reboot of the guest hardware. Then it issues 'cont' to start the CPUs again

+++ b/src/qemu/qemu_command.c @@ -3222,6 +3222,13 @@ qemuBuildCommandLine(virConnectPtr conn, def->onReboot != VIR_DOMAIN_LIFECYCLE_RESTART) virCommandAddArg(cmd, "-no-reboot"); + /* If JSON monitor is enabled, we can receive an event + * when QEMU stops. If we use no-shutdown, then we can + * watch for this event and do a soft/warm reboot. + */ + if (monitor_json) + virCommandAddArg(cmd, "-no-shutdown"); +

+static int qemuDomainReboot(virDomainPtr dom, unsigned int flags ATTRIBUTE_UNUSED) { + struct qemud_driver *driver = dom->conn->privateData; + virDomainObjPtr vm; + int ret = -1; + qemuDomainObjPrivatePtr priv;