Il 03/07/2013 10:18, Takuya Yoshikawa ha scritto: > Since kvm_arch_prepare_memory_region() is called right after installing > the slot marked invalid, wraparound checking should be there to avoid > zapping mmio sptes when mmio generation is still MMIO_MAX_GEN - 1. > > Signed-off-by: Takuya Yoshikawa <[email protected]> > --- > This seems to be the simplest solution for fixing the off-by-one issue > we discussed before. > > arch/x86/kvm/mmu.c | 5 +---- > arch/x86/kvm/x86.c | 7 +++++++ > 2 files changed, 8 insertions(+), 4 deletions(-) > > diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c > index 0d094da..bf7af1e 100644 > --- a/arch/x86/kvm/mmu.c > +++ b/arch/x86/kvm/mmu.c > @@ -4383,11 +4383,8 @@ void kvm_mmu_invalidate_mmio_sptes(struct kvm *kvm) > /* > * The very rare case: if the generation-number is round, > * zap all shadow pages. > - * > - * The max value is MMIO_MAX_GEN - 1 since it is not called > - * when mark memslot invalid. > */ > - if (unlikely(kvm_current_mmio_generation(kvm) >= (MMIO_MAX_GEN - 1))) { > + if (unlikely(kvm_current_mmio_generation(kvm) >= MMIO_MAX_GEN)) { > printk_ratelimited(KERN_INFO "kvm: zapping shadow pages for > mmio generation wraparound\n"); > kvm_mmu_invalidate_zap_all_pages(kvm); > } > diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c > index 7d71c0f..9ddd4ff 100644 > --- a/arch/x86/kvm/x86.c > +++ b/arch/x86/kvm/x86.c > @@ -7046,6 +7046,13 @@ int kvm_arch_prepare_memory_region(struct kvm *kvm, > memslot->userspace_addr = userspace_addr; > } > > + /* > + * In these cases, slots->generation has been increased for marking the > + * slot invalid, so we need wraparound checking here. > + */ > + if ((change == KVM_MR_DELETE) || (change == KVM_MR_MOVE)) > + kvm_mmu_invalidate_mmio_sptes(kvm); > + > return 0; > } > >
Applied, thanks. Paolo -- 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
