On Wed, Mar 10, 2010 at 06:12:34PM +0900, Takuya Yoshikawa wrote: > Gleb Natapov wrote: > >On Wed, Mar 10, 2010 at 11:30:20AM +0900, Takuya Yoshikawa wrote: > >>Gleb Natapov wrote: > >>>On Tue, Mar 09, 2010 at 04:50:29PM +0200, Avi Kivity wrote: > >>>>On 03/09/2010 04:09 PM, Gleb Natapov wrote: > >>>>>Currently when string instruction is only partially complete we go back > >>>>>to a guest mode, guest tries to reexecute instruction and exits again > >>>>>and at this point emulation continues. Avoid all of this by restarting > >>>>>instruction without going back to a guest mode. > >>>>What happens if rcx is really big? Going back into the guest gave > >>>>us a preemption point. > >>>> > >>>Two solutions. We can check if reschedule is required and yield cpu if > >>>needed. Or we can enter guest from time to time. > >>One generic question: from the viewpoint of KVM's policy, is it OK to make > >>the semantics different from real CPUs? > >> > >>Semantics, may be better to use other words, but I'm little bit worried that > >>the second solution may change something, not mentioning about bugs but some > >>behavior patterns depending on the "time to time". > >> > >Entering guest from time to time will not change semantics of the > >processor (if code is not modified under processor's feet at least). > >Currently we reenter guest mode after each iteration of string > >instruction for all instruction but ins/outs. > > > > E.g., is there no chance that during the repetitions, in the middle of the > repetitions, page faults occur? If it can, without entering the guest, can > we handle it? > -- I lack some basic assumptions? > If page fault occurs we inject it to the guest. -- Gleb. -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
