Gerd Hoffmann wrote: > Glauber Costa wrote: >> 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. > > No, it wouldn't. The corner case we must catch is: guest reads time > info, kvm reschedules the guest to another pcpu, guest reads the tsc. > The time info used by the guest for the tsc delta is stale then, it > belongs to the previous pcpu. > > cheers, > Gerd > Agreed.
------------------------------------------------------------------------- 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 _______________________________________________ kvm-devel mailing list kvm-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/kvm-devel
