[libvirt] [PATCH v2] qemu: Report the offset from host UTC for RTC_CHANGE event
https://bugzilla.redhat.com/show_bug.cgi?id=964177 Though both libvirt and QEMU's document say RTC_CHANGE returns the offset from the host UTC, qemu actually returns the offset from the specified date instead when specific date is provided (-rtc base=$date). It's not safe for qemu to fix it in code, it worked like that for 3 years, changing it now may break other QEMU use cases. What qemu tries to do is to fix the document: http://lists.gnu.org/archive/html/qemu-devel/2013-05/msg04782.html And in libvirt side, instead of reply on the qemu, this convert the offset returned from qemu to the offset from host UTC, by: /* * a: the offset from qemu RTC_CHANGE event * b: The specified date (-rtc base=$date) * c: the host date when libvirt gets the RTC_CHANGE event * offset: What libvirt will report */ offset = a + (b - c); The specified date (-rtc base=$date) is recorded in clock's def as an internal only member (may be useful to exposed outside?). Internal only XML tag "starttime" is introduced to not lose the domain process's starttime after libvirt restarting/reloading: <clock offset='variable' adjustment='304' basis='utc' starttime='1370423588'/> --- src/conf/domain_conf.c | 27 +++++++++++++++++++++++---- src/conf/domain_conf.h | 3 +++ src/qemu/qemu_command.c | 3 +++ src/qemu/qemu_process.c | 13 +++++++++++++ 4 files changed, 42 insertions(+), 4 deletions(-) diff --git a/src/conf/domain_conf.c b/src/conf/domain_conf.c index a16ebd1..7773abf 100644 --- a/src/conf/domain_conf.c +++ b/src/conf/domain_conf.c @@ -96,6 +96,7 @@ typedef enum { VIR_DOMAIN_XML_INTERNAL_PCI_ORIG_STATES = (1<<18), VIR_DOMAIN_XML_INTERNAL_ALLOW_ROM = (1<<19), VIR_DOMAIN_XML_INTERNAL_ALLOW_BOOT = (1<<20), + VIR_DOMAIN_XML_INTERNAL_STARTTIME = (1 << 21) } virDomainXMLInternalFlags; VIR_ENUM_IMPL(virDomainTaint, VIR_DOMAIN_TAINT_LAST, @@ -11193,6 +11194,16 @@ virDomainDefParseXML(xmlDocPtr xml, break; } + if (def->clock.offset == VIR_DOMAIN_CLOCK_OFFSET_VARIABLE && + flags & VIR_DOMAIN_XML_INTERNAL_STARTTIME) { + if (virXPathULongLong("number(./clock/@starttime)", ctxt, + &def->clock.data.variable.starttime) < 0) { + virReportError(VIR_ERR_XML_ERROR, "%s", + _("invalid starttime")); + goto error; + } + } + if ((n = virXPathNodeSet("./clock/timer", ctxt, &nodes)) < 0) goto error; @@ -15788,7 +15799,8 @@ virDomainResourceDefFormat(virBufferPtr buf, verify(((VIR_DOMAIN_XML_INTERNAL_STATUS | VIR_DOMAIN_XML_INTERNAL_ACTUAL_NET | - VIR_DOMAIN_XML_INTERNAL_PCI_ORIG_STATES) + VIR_DOMAIN_XML_INTERNAL_PCI_ORIG_STATES | + VIR_DOMAIN_XML_INTERNAL_STARTTIME) & DUMPXML_FLAGS) == 0); /* This internal version can accept VIR_DOMAIN_XML_INTERNAL_*, @@ -15810,7 +15822,8 @@ virDomainDefFormatInternal(virDomainDefPtr def, virCheckFlags(DUMPXML_FLAGS | VIR_DOMAIN_XML_INTERNAL_STATUS | VIR_DOMAIN_XML_INTERNAL_ACTUAL_NET | - VIR_DOMAIN_XML_INTERNAL_PCI_ORIG_STATES, + VIR_DOMAIN_XML_INTERNAL_PCI_ORIG_STATES | + VIR_DOMAIN_XML_INTERNAL_STARTTIME, -1); if (!(type = virDomainVirtTypeToString(def->virtType))) { @@ -16208,6 +16221,10 @@ virDomainDefFormatInternal(virDomainDefPtr def, virBufferAsprintf(buf, " adjustment='%lld' basis='%s'", def->clock.data.variable.adjustment, virDomainClockBasisTypeToString(def->clock.data.variable.basis)); + + if (flags & VIR_DOMAIN_XML_INTERNAL_STARTTIME) + virBufferAsprintf(buf, " starttime='%llu'", + def->clock.data.variable.starttime); break; case VIR_DOMAIN_CLOCK_OFFSET_TIMEZONE: virBufferEscapeString(buf, " timezone='%s'", def->clock.data.timezone); @@ -16586,7 +16603,8 @@ virDomainSaveStatus(virDomainXMLOptionPtr xmlopt, unsigned int flags = (VIR_DOMAIN_XML_SECURE | VIR_DOMAIN_XML_INTERNAL_STATUS | VIR_DOMAIN_XML_INTERNAL_ACTUAL_NET | - VIR_DOMAIN_XML_INTERNAL_PCI_ORIG_STATES); + VIR_DOMAIN_XML_INTERNAL_PCI_ORIG_STATES | + VIR_DOMAIN_XML_INTERNAL_STARTTIME); int ret = -1; char *xml; @@ -16674,7 +16692,8 @@ virDomainObjListLoadStatus(virDomainObjListPtr doms, if (!(obj = virDomainObjParseFile(statusFile, caps, xmlopt, expectedVirtTypes, VIR_DOMAIN_XML_INTERNAL_STATUS | VIR_DOMAIN_XML_INTERNAL_ACTUAL_NET | - VIR_DOMAIN_XML_INTERNAL_PCI_ORIG_STATES))) + VIR_DOMAIN_XML_INTERNAL_PCI_ORIG_STATES | + VIR_DOMAIN_XML_INTERNAL_STARTTIME))) goto error; virUUIDFormat(obj->def->uuid, uuidstr); diff --git a/src/conf/domain_conf.h b/src/conf/domain_conf.h index 3a71d6c..cca92b4 100644 --- a/src/conf/domain_conf.h +++ b/src/conf/domain_conf.h @@ -1767,6 +1767,9 @@ struct _virDomainClockDef { struct { long long adjustment; int basis; + + /* Store the start time of guest process, internal only */ + unsigned long long starttime; } variable; /* Timezone name, when diff --git a/src/qemu/qemu_command.c b/src/qemu/qemu_command.c index c4a162a..9254525 100644 --- a/src/qemu/qemu_command.c +++ b/src/qemu/qemu_command.c @@ -5518,6 +5518,9 @@ qemuBuildClockArgStr(virDomainClockDefPtr def) now += def->data.variable.adjustment; gmtime_r(&now, &nowbits); + /* Store the starttime of qemu process */ + def->data.variable.starttime = now; + virBufferAsprintf(&buf, "base=%d-%02d-%02dT%02d:%02d:%02d", nowbits.tm_year + 1900, nowbits.tm_mon + 1, diff --git a/src/qemu/qemu_process.c b/src/qemu/qemu_process.c index d4fd4fb..39c62b3 100644 --- a/src/qemu/qemu_process.c +++ b/src/qemu/qemu_process.c @@ -796,6 +796,19 @@ qemuProcessHandleRTCChange(qemuMonitorPtr mon ATTRIBUTE_UNUSED, virQEMUDriverConfigPtr cfg = virQEMUDriverGetConfig(driver); virObjectLock(vm); + + /* QEMU's RTC_CHANGE event returns the offset from the specified + * date instead of the host UTC if a specific date is provided + * (-rtc base=$date). We need to convert it to be offset from + * host UTC. + */ + if (vm->def->clock.offset == VIR_DOMAIN_CLOCK_OFFSET_VARIABLE) { + time_t now = time(NULL); + + offset += vm->def->clock.data.variable.starttime - + (unsigned long long)now; + } + event = virDomainEventRTCChangeNewFromObj(vm, offset); if (vm->def->clock.offset == VIR_DOMAIN_CLOCK_OFFSET_VARIABLE) -- 1.8.1.4
On 06/05/2013 04:32 AM, Osier Yang wrote:
https://bugzilla.redhat.com/show_bug.cgi?id=964177
Though both libvirt and QEMU's document say RTC_CHANGE returns the offset from the host UTC, qemu actually returns the offset from the specified date instead when specific date is provided (-rtc base=$date).
It's not safe for qemu to fix it in code, it worked like that for 3 years, changing it now may break other QEMU use cases. What qemu tries to do is to fix the document:
http://lists.gnu.org/archive/html/qemu-devel/2013-05/msg04782.html
And in libvirt side, instead of reply on the qemu, this convert
Unclear grammar. Not sure if you meant: instead of replaying the value from qemu or: instead of relying on the value from qemu but either alternative makes more sense. s/convert/converts/
the offset returned from qemu to the offset from host UTC, by:
/* * a: the offset from qemu RTC_CHANGE event * b: The specified date (-rtc base=$date) * c: the host date when libvirt gets the RTC_CHANGE event * offset: What libvirt will report */
offset = a + (b - c);
The specified date (-rtc base=$date) is recorded in clock's def as an internal only member (may be useful to exposed outside?).
Internal only XML tag "starttime" is introduced to not lose the domain process's starttime after libvirt restarting/reloading:
<clock offset='variable' adjustment='304' basis='utc' starttime='1370423588'/> --- src/conf/domain_conf.c | 27 +++++++++++++++++++++++---- src/conf/domain_conf.h | 3 +++ src/qemu/qemu_command.c | 3 +++ src/qemu/qemu_process.c | 13 +++++++++++++ 4 files changed, 42 insertions(+), 4 deletions(-)
diff --git a/src/conf/domain_conf.c b/src/conf/domain_conf.c index a16ebd1..7773abf 100644 --- a/src/conf/domain_conf.c +++ b/src/conf/domain_conf.c @@ -96,6 +96,7 @@ typedef enum { VIR_DOMAIN_XML_INTERNAL_PCI_ORIG_STATES = (1<<18), VIR_DOMAIN_XML_INTERNAL_ALLOW_ROM = (1<<19), VIR_DOMAIN_XML_INTERNAL_ALLOW_BOOT = (1<<20), + VIR_DOMAIN_XML_INTERNAL_STARTTIME = (1 << 21)
Please add the trailing comma, so that the next edit to this code can also be a one-liner.
+++ b/src/conf/domain_conf.h @@ -1767,6 +1767,9 @@ struct _virDomainClockDef { struct { long long adjustment; int basis; + + /* Store the start time of guest process, internal only */ + unsigned long long starttime;
Might be worth mentioning how to interpret the value - is it seconds since Epoch?
+++ b/src/qemu/qemu_process.c @@ -796,6 +796,19 @@ qemuProcessHandleRTCChange(qemuMonitorPtr mon ATTRIBUTE_UNUSED, virQEMUDriverConfigPtr cfg = virQEMUDriverGetConfig(driver);
virObjectLock(vm); + + /* QEMU's RTC_CHANGE event returns the offset from the specified + * date instead of the host UTC if a specific date is provided + * (-rtc base=$date). We need to convert it to be offset from + * host UTC. + */ + if (vm->def->clock.offset == VIR_DOMAIN_CLOCK_OFFSET_VARIABLE) { + time_t now = time(NULL); + + offset += vm->def->clock.data.variable.starttime - + (unsigned long long)now; + } +
Looks correct. ACK with the nits fixed up. -- Eric Blake eblake redhat com +1-919-301-3266 Libvirt virtualization library http://libvirt.org
On 06/06/13 05:28, Eric Blake wrote:
On 06/05/2013 04:32 AM, Osier Yang wrote:
https://bugzilla.redhat.com/show_bug.cgi?id=964177
Though both libvirt and QEMU's document say RTC_CHANGE returns the offset from the host UTC, qemu actually returns the offset from the specified date instead when specific date is provided (-rtc base=$date).
It's not safe for qemu to fix it in code, it worked like that for 3 years, changing it now may break other QEMU use cases. What qemu tries to do is to fix the document:
http://lists.gnu.org/archive/html/qemu-devel/2013-05/msg04782.html
And in libvirt side, instead of reply on the qemu, this convert Unclear grammar. Not sure if you meant:
instead of replaying the value from qemu
or:
instead of relying on the value from qemu
Will use this.
but either alternative makes more sense.
s/convert/converts/
the offset returned from qemu to the offset from host UTC, by:
/* * a: the offset from qemu RTC_CHANGE event * b: The specified date (-rtc base=$date) * c: the host date when libvirt gets the RTC_CHANGE event * offset: What libvirt will report */
offset = a + (b - c);
The specified date (-rtc base=$date) is recorded in clock's def as an internal only member (may be useful to exposed outside?).
Internal only XML tag "starttime" is introduced to not lose the domain process's starttime after libvirt restarting/reloading:
<clock offset='variable' adjustment='304' basis='utc' starttime='1370423588'/> --- src/conf/domain_conf.c | 27 +++++++++++++++++++++++---- src/conf/domain_conf.h | 3 +++ src/qemu/qemu_command.c | 3 +++ src/qemu/qemu_process.c | 13 +++++++++++++ 4 files changed, 42 insertions(+), 4 deletions(-)
diff --git a/src/conf/domain_conf.c b/src/conf/domain_conf.c index a16ebd1..7773abf 100644 --- a/src/conf/domain_conf.c +++ b/src/conf/domain_conf.c @@ -96,6 +96,7 @@ typedef enum { VIR_DOMAIN_XML_INTERNAL_PCI_ORIG_STATES = (1<<18), VIR_DOMAIN_XML_INTERNAL_ALLOW_ROM = (1<<19), VIR_DOMAIN_XML_INTERNAL_ALLOW_BOOT = (1<<20), + VIR_DOMAIN_XML_INTERNAL_STARTTIME = (1 << 21) Please add the trailing comma, so that the next edit to this code can also be a one-liner.
+++ b/src/conf/domain_conf.h @@ -1767,6 +1767,9 @@ struct _virDomainClockDef { struct { long long adjustment; int basis; + + /* Store the start time of guest process, internal only */ + unsigned long long starttime; Might be worth mentioning how to interpret the value - is it seconds since Epoch?
Hm, just realized that "starttime" may be confused with the start time of guest process, what we want actually is the date of "-rtc base=$date". And only valid for clock.offset == VARIABLE. So I change it to "basedate", with the nits fixed:
participants (2)
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Eric Blake -
Osier Yang