On Wed, Mar 10, 2010 at 07:08:31PM +0900, Takuya Yoshikawa wrote: > Gleb Natapov wrote: > >>>> > >>>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. > > > > Oh, I maight fail to tell what I worried about. > Opposite, I mean, I worried about NOT reentering the guest case. > Are you thinking about something specific here? If we inject exceptions when they occur and we inject interrupt when they arrive what problem do you see? I guess this is how real CPU actually works. I doubt it re-reads string instruction on each iteration. > I know that current implementation with reentrance is OK. Current implementation does not reenter guest on each iteration for pio string, so currently we have both variants. > > To inject a page fault without reentering the guest, we need to add > some more hacks to the emulator IIUC. > No, we just need to enter guest if exception happens. I see that this in handled incorrectly in my current patch series. -- 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
