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Re: [Xen-devel] how to keep time of windows pvhvm synchronized with host

At 14:53 +0100 on 24 Sep (1285340029), ANNIE LI wrote:
> > I had expected arch_set_info_guest() to be called for every vcpu in the
> > HVM guest on restore, because boot_vcpu() is called from 
> > hvm_load_cpu_ctxt().
> arch_set_info_guest is called when vm is booting, but it is not called 
> on HVM guest restore.
> I will check boot_vcpu() and hvm_load_cpu_ctxt() further.
> > Yes, do_settime() updates the master copy of wc_sec and wc_nsec from its
> > inputs, and then copies them to all domains' private copies.  So the
> > question is:
> >   - is the _master_ copy of wc_sec always zero; or
>  From my recent logs, wc_sec is not zero, but it always keeps as certain 
> unchanged value. In do_settime(...),
> Input parameters secs, nsecs and system_time_base change every time when 
> calling this function. But wc_secs
> keep unchanged although it is calculated from those 3 parameters by: 
> (secs * 1000000000ULL) + (u64)nsecs - system_time_base;
> Anything wrong here?

No, that's fine.  wc_secs is what you add to NOW() to get wallclock to
it shouldn't change, or at least very rarely.  I thought from your
earlier email that it was always zero, which would be odd.

> >   - is the master copy right and the HVM domain's copy wrong; or
> Is update_domain_wallclock_time doing HVM domain's copy? From my log, 
> wc_secs of HVM domain's copy is
> same as that of master copy.

That's reassuring.

> >   - is the HVM domain's copy right as seen from Xen but
> >     wrong as seen from the tools inside the guest?
> wc_secs value from tools inside the guest is same as HVM domain's copy.

And is that equal to zero?  If not, what exactly is the problem?  I
think I've got confused about what's going wrong.



Tim Deegan <Tim.Deegan@xxxxxxxxxx>
Principal Software Engineer, XenServer Engineering
Citrix Systems UK Ltd.  (Company #02937203, SL9 0BG)

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