On Wed, May 27, 2015 at 10:39:23AM +0530, Aneesh Kumar K.V wrote: > [email protected] writes: > > > From: Jérôme Glisse <[email protected]> > > > > The mmu_notifier_invalidate_range_start() and > > mmu_notifier_invalidate_range_end() > > can be considered as forming an "atomic" section for the cpu page table > > update > > point of view. Between this two function the cpu page table content is > > unreliable > > for the address range being invalidated. > > > > Current user such as kvm need to know when they can trust the content of > > the cpu > > page table. This becomes even more important to new users of the > > mmu_notifier > > api (such as HMM or ODP). > > I don't see kvm using the new APIs in this patch. Also what is that HMM use > this > for, to protect walking of mirror page table ?. I am sure you are > covering that in the later patches. May be you may want to mention > the details here too.
KVM side is not done, i looked at KVM code long time ago and thought oh it could take advantage of this but now i do not remember exactly. I would need to check back. For HMM this is simple, no device fault can populate or walk the mirror page table on a range that is being invalidated. But concurrent fault/walk can happen outside the invalidated range. All handled in hmm_device_fault_start(). Cheers, Jérôme -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
