Hello, I'm currently tracking a problem in libvirt regarding Xens handling of localtime and rtc_timeoffset. My current understanding (Xen-3.4.3 and Xen-4.1.2 under Linux) of Xend (the depcrecated Python one still used by libvirt) is as this: - for HV domains, the RTC gets setup to either UTC or localtime depending on "/domain/image/hvm/localtime" ± "/domain/image/hvm/rtc_offset". - if the OS of a domU changes its RTC, the rtc_offset gets adjusted and is saved in XenStore as "/vm/$UUID/rtc/timeoffset". - if the dom0 accesses its RTC, is accesses the real HW-RTC. - the Xen-Hypervisor initially read the HW-RTC to setup its Wallclock once, which is than used to simulate the domU RTCs. (The HW-RTC is otherwise only accessed on (ACPI-)Suspend and Resume, and with NTP-drift-correction from dom0). - on shut-down the rtc_offset is stored by Xend in the "/var/lib/xend/domains/$uuid/config.sxp" file in "/domain/image/hvm/rtc_timeoffset", from where it is loaded again on next start. - since PV domains don't have a RTC, they somehow(?) get either initialized to the localtime or UTC time depending on "/domain/image/linux/localtime".
@xen: Did I figure out that correct? @xen: Is there some documentation on the Xen-sxp domain configuration? For the Python based xen-xm format, I found (and updated) <http://wiki.xen.org/wiki/XenConfigurationFileOptions>, but for Xen-sxp I so far found no documentation, especially on what changed between xen-1, xen-2, xen-3.x, xen-4.x. @libvirt: Comparing Xend handling to <http://libvirt.org/formatdomain.html#elementsTime> the current translation done by libvirt looks wrong; I think is mandates back to the time when Xen supported only PV-domUs: libvirt translates the Xen configuration to "localtime" and "utc" ignoring the "rtc_offset", which exists for HV domains. For localtime=0 this translates to libvirts offset="variable"-case, but for localtime=1 there is no matching mapping in libvirt. Since for PV domains no rtc_timeoffset is tracked, there the mapping to "utc" and "localtime" looks right. For libvirt there was a patch <http://www.redhat.com/archives/libvir-list/2009-January/msg00757.html> which added some special handling for "localtime" to be either placed in "/domain/localtime" or "/domain/image/{hvm,linux}/localtime". Xend from 3.4.3 und 4.1.2 seems to accept either one, but /domain/image/hvm/localtime is preferred and overwrites the first one. When reading back the configuration the setting is always returned as /domain/image/{hvm,linux}/localtime. @John: Is there a case, where /domain/localtime is returned or is that key always translated to /domain/linux/{hvm,linux}/localtime? As you had a sun.com email address, was this some special case when using Xen with Solaris? @libvirt: The attached patch (for 0.8.7) would change the implementation to match the following: 1. For Xen-PV-domUs, use clock/@offset='utc' and clock/@offset='localtime'. 2. For Xen-HV-domUs, use clock/@offset='variable'. 3. For backward compatibility with old libvirt-XML-files convert clock/@offset='utc' → (localtime 0)(rtc_timeoffset 0) and clock/@offset='localtime' → (localtime 1)(rtc_timeosset 0). On readback that will be returned as clock/@offset='variable'! 4. For Xen-HV-domUs with (localtime=1)(rtc_timeoffset≠0) print a warning that there is no mapping to libvirts XML. 5. Always put the (localtime)(rtc_offset)-SEXPRs in "(image ({linux,hvm})", since this is where Xend-3.4 and Xend-4.1 return them. I also checked Xen-3.2, where this is okay, but the I don't have any older versions of Xen available (and running), the I can't verify that it still works there. Which leads me to a another question: Which versions of Xen are still supported by libvirt (and must be checked for regressions)? I don't want so actively remove the code for old Xen versions, but it gets harder and harder to maintain all those versions. So a statement like "Xen-3.x and Xen-4.y are actively supported by libvirt-0.a.b; older versions might still work (by accident ;-)" Before I forward-port that change to 0.9.10 I'd like to get some comments. Thanks in advance. Sincerely Philipp Hahn -- Philipp Hahn Open Source Software Engineer h...@univention.de Univention GmbH Linux for Your Business fon: +49 421 22 232- 0 Mary-Somerville-Str.1 D-28359 Bremen fax: +49 421 22 232-99 http://www.univention.de/
diff --git a/src/xen/xend_internal.c b/src/xen/xend_internal.c
index 835c230..e112aa3 100644
--- a/src/xen/xend_internal.c
+++ b/src/xen/xend_internal.c
@@ -903,7 +903,6 @@ xenDaemonListDomainsOld(virConnectPtr xend)
*
* Returns 0 for success, -1 (with errno) on error
*/
-
int
xenDaemonDomainCreateXML(virConnectPtr xend, const char *sexpr)
{
@@ -2148,7 +2147,6 @@ xenDaemonParseSxpr(virConnectPtr conn,
} else
def->onCrash = VIR_DOMAIN_LIFECYCLE_DESTROY;
- def->clock.offset = VIR_DOMAIN_CLOCK_OFFSET_UTC;
if (hvm) {
if (sexpr_int(root, "domain/image/hvm/acpi"))
def->features |= (1 << VIR_DOMAIN_FEATURE_ACPI);
@@ -2157,15 +2155,18 @@ xenDaemonParseSxpr(virConnectPtr conn,
if (sexpr_int(root, "domain/image/hvm/pae"))
def->features |= (1 << VIR_DOMAIN_FEATURE_PAE);
- /* Old XenD only allows localtime here for HVM */
- if (sexpr_int(root, "domain/image/hvm/localtime"))
+ def->clock.offset = VIR_DOMAIN_CLOCK_OFFSET_VARIABLE;
+ def->clock.data.adjustment = sexpr_int(root, "domain/image/hvm/rtc_timeoffset");
+ if (def->clock.data.adjustment && sexpr_int(root, "domain/image/hvm/localtime")) {
+ virXendError(VIR_ERR_INTERNAL_ERROR, _("Ignoring localtime=1 while rtc_timeoffset!=0"));
+ }
+ } else { /* !hvm */
+ if (sexpr_int(root, "domain/image/linux/localtime"))
def->clock.offset = VIR_DOMAIN_CLOCK_OFFSET_LOCALTIME;
+ else
+ def->clock.offset = VIR_DOMAIN_CLOCK_OFFSET_UTC;
}
- /* Current XenD allows localtime here, for PV and HVM */
- if (sexpr_int(root, "domain/localtime"))
- def->clock.offset = VIR_DOMAIN_CLOCK_OFFSET_LOCALTIME;
-
if (sexpr_node_copy(root, hvm ?
"domain/image/hvm/device_model" :
"domain/image/linux/device_model",
@@ -5759,31 +5760,15 @@ xenDaemonFormatSxpr(virConnectPtr conn,
}
virBufferVSprintf(&buf, "(on_crash '%s')", tmp);
- /* Set localtime here for current XenD (both PV & HVM) */
- if (def->clock.offset == VIR_DOMAIN_CLOCK_OFFSET_LOCALTIME) {
- if (def->clock.data.timezone) {
- virXendError(VIR_ERR_CONFIG_UNSUPPORTED,
- "%s", _("configurable timezones are not supported"));
- goto error;
- }
+ if (STREQ(def->os.type, "hvm"))
+ hvm = 1;
- virBufferAddLit(&buf, "(localtime 1)");
- } else if (def->clock.offset != VIR_DOMAIN_CLOCK_OFFSET_UTC) {
- virXendError(VIR_ERR_CONFIG_UNSUPPORTED,
- _("unsupported clock offset '%s'"),
- virDomainClockOffsetTypeToString(def->clock.offset));
- goto error;
- }
+ if (hvm)
+ virBufferAddLit(&buf, "(image (hvm ");
+ else
+ virBufferAddLit(&buf, "(image (linux ");
if (!def->os.bootloader) {
- if (STREQ(def->os.type, "hvm"))
- hvm = 1;
-
- if (hvm)
- virBufferAddLit(&buf, "(image (hvm ");
- else
- virBufferAddLit(&buf, "(image (linux ");
-
if (hvm &&
def->os.loader == NULL) {
virXendError(VIR_ERR_INTERNAL_ERROR,
@@ -5893,17 +5878,13 @@ xenDaemonFormatSxpr(virConnectPtr conn,
virBufferAddLit(&buf, "(serial none)");
}
- /* Set localtime here to keep old XenD happy for HVM */
- if (def->clock.offset == VIR_DOMAIN_CLOCK_OFFSET_LOCALTIME)
- virBufferAddLit(&buf, "(localtime 1)");
-
if (def->sounds) {
virBufferAddLit(&buf, "(soundhw '");
if (xenDaemonFormatSxprSound(def, &buf) < 0)
goto error;
virBufferAddLit(&buf, "')");
}
- }
+ } /* hvm */
/* get the device emulation model */
if (def->emulator && (hvm || xendConfigVersion >= 3))
@@ -5918,10 +5899,37 @@ xenDaemonFormatSxpr(virConnectPtr conn,
&buf, xendConfigVersion) < 0)
goto error;
}
+ } /* os.bootloader */
+
+ if (hvm) {
+ /* Set localtime here to keep old XenD happy for HVM */
+ if (def->clock.offset == VIR_DOMAIN_CLOCK_OFFSET_VARIABLE) {
+ virBufferVSprintf(&buf, "(localtime 0)(rtc_timeoffset %d)", def->clock.data.adjustment);
+ } else if (def->clock.offset == VIR_DOMAIN_CLOCK_OFFSET_LOCALTIME) {
+ if (def->clock.data.timezone) {
+ virXendError(VIR_ERR_CONFIG_UNSUPPORTED,
+ "%s", _("configurable timezones are not supported"));
+ goto error;
+ }
- virBufferAddLit(&buf, "))");
+ virBufferAddLit(&buf, "(localtime 1)(rtc_timeoffset 0)");
+ } else if (def->clock.offset == VIR_DOMAIN_CLOCK_OFFSET_UTC) {
+ virBufferAddLit(&buf, "(localtime 0)(rtc_timeoffset 0)");
+ } else {
+ virXendError(VIR_ERR_CONFIG_UNSUPPORTED,
+ _("unsupported clock offset '%s'"),
+ virDomainClockOffsetTypeToString(def->clock.offset));
+ goto error;
+ }
+ } else { /* !hvm */
+ if (def->clock.offset == VIR_DOMAIN_CLOCK_OFFSET_LOCALTIME)
+ virBufferAddLit(&buf, "(localtime 1)");
+ else if (def->clock.offset == VIR_DOMAIN_CLOCK_OFFSET_UTC)
+ virBufferAddLit(&buf, "(localtime 0)");
}
+ virBufferAddLit(&buf, "))"); /* image/{kvm,linux}/ */
+
for (i = 0 ; i < def->ndisks ; i++)
if (xenDaemonFormatSxprDisk(conn, def->disks[i],
&buf, hvm, xendConfigVersion, 0) < 0)
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