Re: [libvirt] [PATCH] qemu: Issue rtc_reset_reinjection command after guest-set-time

On 08/13/2014 06:51 AM, Michal Privoznik wrote: s/_/-/2 in the subject line > An advice appeared there on the qemu-devel list [1]. When a domain is > suspended and then resumed guest kernel is not aware of this. So we've > introduced virDomainSetTime API that resets the time within guest > using qemu-ga. On the other hand, qemu itself is trying to make RTC > beat faster to catch the difference. But if we don't tell qemu that > guest's time was reset via the other method, both mechanisms are > applied resulting in again wrong guest time. In order to avoid summing > both corrections we need to tell qemu that it should not use the RTC > injection if the guest time is set via guest agent. > > 1: http://www.mail-archive.com/qemu-devel@nongnu.org/msg236435.html > > Signed-off-by: Michal Privoznik <mprivozn(a)redhat.com&gt; > --- > +++ b/src/qemu/qemu_driver.c > @@ -16879,6 +16879,16 @@ qemuDomainSetTime(virDomainPtr dom, > rv = qemuAgentSetTime(priv->agent, seconds, nseconds, rtcSync); > qemuDomainObjExitAgent(vm); > > + if (!virDomainObjIsActive(vm)) { > + virReportError(VIR_ERR_OPERATION_INVALID, > + "%s", _("domain is not running")); > + goto endjob; > + } > + > + qemuDomainObjEnterMonitor(driver, vm); > + rv = qemuMonitorRTCResetReinjection(priv->mon); > + qemuDomainObjExitMonitor(driver, vm); This forces the command to fail if qemu is too old to have rtc-reset-reinjection but the agent is new enough to set time. Should you make this code conditional on whether qemu supports the QMP command?

> } > + > +int > +qemuMonitorJSONRTCResetReinjection(qemuMonitorPtr mon) > +{ > + int ret = -1; > + virJSONValuePtr cmd; > + virJSONValuePtr reply = NULL; > + > + if (!(cmd = qemuMonitorJSONMakeCommand("rtc-reset-reinjection", > + NULL))) > + return ret; > + > + ret = qemuMonitorJSONCommand(mon, cmd, &reply); > + > + if (ret == 0) > + ret = qemuMonitorJSONCheckError(cmd, reply); > + > + virJSONValueFree(cmd); > + virJSONValueFree(reply); > + return ret; > +} Is it worth enhancing the testsuite to add coverage for this command and expected response?