Il 19/08/2014 10:50, Xiao Guangrong ha scritto: > Okay, what confused me it that it seems that the single line patch > is ok to you. :)
No, it was late and I was confused. :) > Now, do we really need to care the case 2? like David said: > "Sorry I didn't explain myself very well: Since we can get a single wrong > mmio exit no matter what, it has to be handled in userspace. So my point > was, it doesn't really help to fix that one very specific way that it can > happen, because it can just happen in other ways. (E.g. update memslots > occurs after is_noslot_pfn() and before mmio exit)." > > What's your idea? > > > I think if you always treat the low bit as zero in mmio sptes, you can > > do that without losing a bit of the generation. > > What's you did is avoiding cache a invalid generation number into spte, but > actually if we can figure it out when we check mmio access, it's ok. Like the > updated patch i posted should fix it, that way avoids doubly increase the > number. Yes. > Okay, if you're interested increasing the number doubly, there is the simpler > one: This wastes a bit in the mmio spte though. My idea is to increase the memslots generation twice, but drop the low bit in the mmio spte. Paolo -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
