Re: pv clock: kvm is incompatible with xen :-(

[Glauber Costa <gcosta@redhat.com>]

Gerd Hoffmann wrote:
> Jeremy Fitzhardinge wrote:
>> Xen could change the parameters in the instant after get_time_values(). 
>> That change could be as a result of suspend-resume, so the parameters
>> and the tsc could be wildly different.
> 
> Ah, ok, forgot the rdtsc in the picture.  With that in mind I fully
> agree that the loop is needed.  I think kvm guests can even hit that one
> with the vcpu migrating to a different physical cpu, so we better handle
> it correctly ;)

It's probably not needed for kvm, since we update everything everytime 
we get scheduled in the host side, which would cover the case for 
migration between physical cpus. But it's probably okay to do it to get 
a common denominator with xen, if needed.



-------------------------------------------------------------------------
This SF.net email is sponsored by the 2008 JavaOne(SM) Conference 
Don't miss this year's exciting event. There's still time to save $100. 
Use priority code J8TL2D2. 
http://ad.doubleclick.net/clk;198757673;13503038;p?http://java.sun.com/javaone