[Libvir] PATCH: Specify BIOS clock offset for HVM

Daniel P. Berrange berrange at redhat.com
Tue Jul 17 00:49:52 UTC 2007


On Mon, Jul 16, 2007 at 02:32:01PM +0100, Daniel P. Berrange wrote:
> On Mon, Jul 16, 2007 at 03:50:07AM -0400, Daniel Veillard wrote:
> > On Fri, Jul 13, 2007 at 05:07:03PM +0100, Daniel P. Berrange wrote:
> > > The attached patch introduces a new XML element for specifying information
> > > about the guest (BIOS) clock. For Xen HVM, and QEMU / KVM guests this is
> > > used to specifyc whether the guest clock should be in UTC, or localtime.
> > > The latter is useful for Windows which likes the BIOS to be localtime,
> > > while the former is useful for all other operating systems. The former is
> > > of course the default - so no change in existing semantics.
> > > 
> > > The <clock> element currently takes a single attribute 'offset'. This is
> > > either 'utc' or 'localtime', but if we port to VMWare, it will also allow
> > > an arbitrary numeric offset as well as these special constants.
> > > 
> > >    <clock offset='utc'/>
> > > 
> > > Or
> > > 
> > >    <clock offset='localtime'/>
> > > 
> > > 
> > > It may later also be desirable to add a 'sync=[yes|no]'  attribute to 
> > > specify whether the HV tries to keep the clock in sync with the HV while
> > > it is running. VMWare has this concept, and so does Xen paravirt - though
> > > Xen paravirt sets it via /proc/sys/xen/independant_wallclock inside the
> > > guest and AFAICT doesn't (yet) expose it to the guest config in Dom0.
> > > 
> > > Anyway, my patch implements use of utc/localtime offsets for Xen, and QEMU
> > > drivers. I've tested to verify that -localtime gets passed to the QEMU
> > > process as appropriate.
> > 
> >   Looks fine, the patch also includes a few cleanups. And this should
> > fix the clock annoyance when running Windows. I assume this will be
> > automatically added when installing a new Windows guest with virt-manager.
> 
> Yeah, ignore the unrelated cleanups - I didn't mean to include them - i'll
> commit them separately. Also ignore the stupid printf() debugging!

Ok, this is now committed, along with yet more test cases for XML parsing
and formatting.

Regards,
Dan.
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