On Wed, 2013-08-07 at 10:24 +1000, Paul Mackerras wrote: > On Tue, Aug 06, 2013 at 07:02:48AM +0000, Bhushan Bharat-R65777 wrote: > > > > I am trying to me the Linux pte search and update generic so that this can be used for powerpc as well. > > > > I am not sure which of the below two should be ok, please help > > Given that the BookE code uses gfn_to_pfn_memslot() to get the host > pfn, and then kvm_set_pfn_dirty(pfn) on pages that you're going to let > the guest write to, I don't think you need to set the dirty and/or > accessed bits in the Linux PTE explicitly. If you care about the > WIMGE bits you can do find_linux_pte_or_hugepte() and just look at the > PTE, but you really should be using mmu_notifier_retry() to guard > against concurrent changes to the Linux PTE. See the HV KVM code or > patch 21 of my recent series to see how it's used. Hmm... we only get a callback on invalidate_range_start(), not invalidate_range_end() (and even if we did get a callback for the latter, it'd probably be racy). So we may have a problem here regardless of getting WIMG from the PTE, unless it's guaranteed that hva_to_pfn() will fail after invalidate_range_start(). > You probably should be calling kvm_set_pfn_accessed() as well. Yeah... I think it'll only affect the quality of page-out decisions (as opposed to corruption and such), but still it should be fixed. -Scott -- 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
