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b62d67da3e
commite31b5cf393attempted to fix libvirt's VIR_DOMAIN_EVENT_ID_RTC_CHANGE, which is documentated to always provide the new offset of the domain's real time clock from UTC. The problem was that, in the case that qemu is provided with an "-rtc base=x" where x is an absolute time (rather than "utc" or "localtime"), the offset sent by qemu's RTC_CHANGE event is *not* the new offset from UTC, but rather is the sum of all changes to the domain's RTC since it was started with base=x. So, despite what was said in commite31b5cf393, if we assume that the original value stored in "adjustment" was the offset from UTC at the time the domain was started, we can always determine the current offset from UTC by simply adding the most recent (i.e. current) offset from qemu to that original adjustment. This patch accomplishes that by storing the initial adjustment in the domain's status as "adjustment0". Each time a new RTC_CHANGE event is received from qemu, we simply add adjustment0 to the value sent by qemu, store that as the new adjustment, and forward that value on to any event handler. This patch (*not*e31b5cf393, which should be reverted prior to applying this patch) fixes: https://bugzilla.redhat.com/show_bug.cgi?id=964177 (for the case where basis='utc'. It does not fix basis='localtime')
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>