Libvirt provides a portable, long term stable C API for managing the virtualization technologies provided by many operating systems. It includes support for QEMU, KVM, Xen, LXC, bhyve, Virtuozzo, VMware vCenter and ESX, VMware Desktop, Hyper-V, VirtualBox and the POWER Hypervisor.
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Osier Yang e31b5cf393 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 replying on the value from qemu,
this 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 "basetime" is introduced to not lose the
guest's basetime after libvirt restarting/reloading:

<clock offset='variable' adjustment='304' basis='utc' basetime='1370423588'/>
2013-06-07 14:45:08 +08:00
.gnulib@a363f4ed4a build: update to latest gnulib, for syntax-check 2013-05-10 20:52:57 -06:00
build-aux syntax-check: mandate space after mid-line semicolon 2013-05-28 08:26:05 -06:00
daemon maint: don't use config.h in .h files 2013-06-05 05:53:25 -06:00
docs docs: add spaces to formatstorage.html 2013-06-04 15:56:44 +02:00
examples syntax: prefer space after semicolon in for loop 2013-05-28 07:56:07 -06:00
gnulib maint: use LGPL correctly 2013-05-20 14:03:48 -06:00
include Change virConnectDomainEventGraphicsCallback signature 2013-05-22 18:53:59 +02:00
m4 FreeBSD: disable buggy -fstack-protector-all 2013-05-15 15:20:52 -06:00
po Release of libvirt 1.0.6 2013-06-03 12:09:56 +02:00
python syntax: prefer space after semicolon in for loop 2013-05-28 07:56:07 -06:00
src qemu: Report the offset from host UTC for RTC_CHANGE event 2013-06-07 14:45:08 +08:00
tests qemu: change two-state int parameters to bool 2013-06-06 17:22:53 +02:00
tools virsh: Allow attach-disk to specify disk wwn 2013-06-04 19:56:07 +08:00
.dir-locals.el build: avoid tabs that failed syntax-check 2012-09-06 09:43:46 -06:00
.gitignore maint: follow recommended practice for using LGPL 2013-05-20 14:15:21 -06:00
.gitmodules make .gnulib a submodule 2009-07-08 16:17:51 +02:00
.mailmap Autogenerate AUTHORS 2012-10-19 12:44:56 -04:00
AUTHORS.in Add John Ferlan to the committers list 2013-02-05 10:59:32 -05:00
autobuild.sh Set PKG_CONFIG_LIBDIR in autobuild.sh 2013-05-17 17:09:29 +01:00
autogen.sh build: fix incremental autogen.sh when no AUTHORS is present 2012-12-03 14:59:09 -07:00
bootstrap maint: update to latest gnulib 2013-05-08 14:54:04 -06:00
bootstrap.conf Include GNULIB mkdtemp module 2013-05-17 17:09:29 +01:00
cfg.mk maint: don't use config.h in .h files 2013-06-05 05:53:25 -06:00
ChangeLog-old virterror.c: Fix several spelling mistakes 2012-02-03 11:32:51 -07:00
configure.ac Release of libvirt 1.0.6 2013-06-03 12:09:56 +02:00
COPYING maint: follow recommended practice for using LGPL 2013-05-20 14:15:21 -06:00
COPYING.LESSER maint: follow recommended practice for using LGPL 2013-05-20 14:15:21 -06:00
HACKING syntax-check: mandate space after mid-line semicolon 2013-05-28 08:26:05 -06:00
libvirt.pc.in build: silence warning from autoconf 2012-05-30 09:22:02 -06:00
libvirt.spec.in spec: Explicitly require libgcrypt-devel 2013-06-03 15:15:44 +02:00
Makefile.am maint: use LGPL correctly 2013-05-20 14:03:48 -06:00
Makefile.nonreentrant maint: use LGPL correctly 2013-05-20 14:03:48 -06:00
mingw-libvirt.spec.in test: Return Libvirt logo as domain screenshot 2013-04-02 14:38:56 +02:00
README Correct typos in the documentation (Atsushi SAKAI) 2008-01-24 10:15:13 +00:00
README-hacking maint: relax git minimum version 2010-02-24 14:29:27 -05:00
run.in run: license as LGPL 2013-02-23 14:03:19 -07:00
TODO Update todo list file to point at bugzilla/website 2010-10-13 16:45:26 +01:00

         LibVirt : simple API for virtualization

  Libvirt is a C toolkit to interact with the virtualization capabilities
of recent versions of Linux (and other OSes). It is free software
available under the GNU Lesser General Public License. Virtualization of
the Linux Operating System means the ability to run multiple instances of
Operating Systems concurrently on a single hardware system where the basic
resources are driven by a Linux instance. The library aim at providing
long term stable C API initially for the Xen paravirtualization but
should be able to integrate other virtualization mechanisms if needed.

Daniel Veillard <veillard@redhat.com>