diff options
| author | Xiao Guangrong <xiaoguangrong@cn.fujitsu.com> | 2010-11-23 11:13:00 +0800 |
|---|---|---|
| committer | Avi Kivity <avi@redhat.com> | 2011-01-12 11:29:51 +0200 |
| commit | a4ee1ca4a36e7857d90ae8c2b85f1bde9a042c10 (patch) | |
| tree | 29707dd004ef14df318ac35321b95ac62570fc99 /arch | |
| parent | 407c61c6bd6a51b56d02f8bbad8aadf19db8c7b5 (diff) | |
KVM: MMU: delay flush all tlbs on sync_page path
Quote from Avi:
| 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.
Signed-off-by: Xiao Guangrong <xiaoguangrong@cn.fujitsu.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/x86/kvm/paging_tmpl.h | 12 |
1 files changed, 10 insertions, 2 deletions
diff --git a/arch/x86/kvm/paging_tmpl.h b/arch/x86/kvm/paging_tmpl.h index a43f4ccd30b..2b3d66c7b68 100644 --- a/arch/x86/kvm/paging_tmpl.h +++ b/arch/x86/kvm/paging_tmpl.h @@ -746,6 +746,14 @@ static void FNAME(prefetch_page)(struct kvm_vcpu *vcpu, * Using the cached information from sp->gfns is safe because: * - The spte has a reference to the struct page, so the pfn for a given gfn * can't change unless all sptes pointing to it are nuked first. + * + * Note: + * We should flush all tlbs if spte is dropped even though guest is + * responsible for it. Since if we don't, kvm_mmu_notifier_invalidate_page + * and kvm_mmu_notifier_invalidate_range_start detect the mapping page isn't + * used by guest then tlbs are not flushed, so guest is allowed to access the + * freed pages. + * And we increase kvm->tlbs_dirty to delay tlbs flush in this case. */ static int FNAME(sync_page)(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp) { @@ -781,14 +789,14 @@ static int FNAME(sync_page)(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp) gfn = gpte_to_gfn(gpte); if (FNAME(prefetch_invalid_gpte)(vcpu, sp, &sp->spt[i], gpte)) { - kvm_flush_remote_tlbs(vcpu->kvm); + vcpu->kvm->tlbs_dirty++; continue; } if (gfn != sp->gfns[i]) { drop_spte(vcpu->kvm, &sp->spt[i], shadow_trap_nonpresent_pte); - kvm_flush_remote_tlbs(vcpu->kvm); + vcpu->kvm->tlbs_dirty++; continue; } |