On Wed, Nov 17, 2010 at 06:26:51PM +0200, Avi Kivity wrote: > On 11/17/2010 05:29 PM, Marcelo Tosatti wrote: > >> diff --git a/arch/x86/kvm/paging_tmpl.h b/arch/x86/kvm/paging_tmpl.h > >> index ba00eef..58b4d9a 100644 > >> --- a/arch/x86/kvm/paging_tmpl.h > >> +++ b/arch/x86/kvm/paging_tmpl.h > >> @@ -781,6 +781,7 @@ static int FNAME(sync_page)(struct kvm_vcpu *vcpu, > >> struct kvm_mmu_page *sp, > >> else > >> nonpresent = shadow_notrap_nonpresent_pte; > >> drop_spte(vcpu->kvm,&sp->spt[i], nonpresent); > >> + kvm_flush_remote_tlbs(vcpu->kvm); > >> continue; > >> } > > > >This is not needed. Guest is responsible for flushing on > >present->nonpresent change. > > sync_page > drop_spte > kvm_mmu_notifier_invalidate_page > kvm_unmap_rmapp > spte doesn't exist -> no flush > page is freed > guest can write into freed page?
Ugh right. > I don't think we need to flush immediately; set a "tlb dirty" bit > somewhere that is cleareded when we flush the tlb. > kvm_mmu_notifier_invalidate_page() can consult the bit and force a > flush if set. Yep. -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
