[ Upstream commit 315f02c60d9425b38eb8ad7f21b8a35e40db23f9 ]
Right now, if a call to kvm_tdp_mmu_zap_sp returns false, the caller will skip the TLB flush, which is wrong. There are two ways to fix it:
- since kvm_tdp_mmu_zap_sp will not yield and therefore will not flush the TLB itself, we could change the call to kvm_tdp_mmu_zap_sp to use "flush |= ..."
- or we can chain the flush argument through kvm_tdp_mmu_zap_sp down to __kvm_tdp_mmu_zap_gfn_range. Note that kvm_tdp_mmu_zap_sp will neither yield nor flush, so flush would never go from true to false.
This patch does the former to simplify application to stable kernels, and to make it further clearer that kvm_tdp_mmu_zap_sp will not flush.
Cc: seanjc@google.com Fixes: 048f49809c526 ("KVM: x86/mmu: Ensure TLBs are flushed for TDP MMU during NX zapping") Cc: stable@vger.kernel.org # 5.10.x: 048f49809c: KVM: x86/mmu: Ensure TLBs are flushed for TDP MMU during NX zapping Cc: stable@vger.kernel.org # 5.10.x: 33a3164161: KVM: x86/mmu: Don't allow TDP MMU to yield when recovering NX pages Cc: stable@vger.kernel.org Reviewed-by: Sean Christopherson seanjc@google.com Signed-off-by: Paolo Bonzini pbonzini@redhat.com --- arch/x86/kvm/mmu/mmu.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c index 387dca3f81cd..86cedf32526a 100644 --- a/arch/x86/kvm/mmu/mmu.c +++ b/arch/x86/kvm/mmu/mmu.c @@ -6007,7 +6007,7 @@ static void kvm_recover_nx_lpages(struct kvm *kvm) lpage_disallowed_link); WARN_ON_ONCE(!sp->lpage_disallowed); if (sp->tdp_mmu_page) { - flush = kvm_tdp_mmu_zap_sp(kvm, sp); + flush |= kvm_tdp_mmu_zap_sp(kvm, sp); } else { kvm_mmu_prepare_zap_page(kvm, sp, &invalid_list); WARN_ON_ONCE(sp->lpage_disallowed);