Re: swapping with MMU Notifiers V2

Carsten Otte
2008-01-29T17:17:06Z

Andrea Arcangeli wrote:
> Didn't realize s390 doesn't need those at all. Do you think
> mmu_notifier.h should also go in asm/mmu_notifier? We can always move
> them there later after merging with some compat code if needed.
No I think mmu_notifier.h is fine in include/linux. I just think kvm
should only _use_ it on archs that do require assistence.

On s390, we use the same page table to translate host.user ->
host.phys and guest.phys -> host.phys. Using storage keys, the host
memory management takes into account dirty and reference operations
done by the guest when doing it's swapping descitions. The host does
invalidate a page table entry by using a magic "invalidate page table
entry" instruction. Running virtual cpus are guaranteed not to rely on
tlb data once the page table entry was invalidated by that
instruction. Maybe we should just fix other hardware ;-).