Re: [Xen-devel] Re: [PATCH 3/5] x86/pvclock: add vsyscall implementation

Avi Kivity
2009-11-01T09:29:35Z

On 10/29/2009 06:15 PM, Dan Magenheimer wrote:
> On a related note, though some topic drift, many of
> the problems that occur in virtualization due to migration
> could be better addressed if Linux had an architected
> interface to allow it to be signaled if a migration
> occurred, and if Linux could signal applications of
> the same. I don't have any cycles (pun intended) to
> think about this right now, but if anyone else starts
> looking at it, I'd love to be cc'ed.
>

IMO that's not a good direction. The hypervisor should not depend on
the guest for migration (the guest may be broken, or malicious, or being
debugged, or slow). So the notification must be asynchronous, which
means that it will only be delivered to applications after migration has
completed.

Instead of a "migration has occured, run for the hills" signal we're
better of finding out why applications want to know about this event and
addressing specific needs.

--
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