On 14/07/2017 11:39, Wanpeng Li wrote: > However, commit 0be9c7a89f750 (KVM: VMX: set "blocked by NMI" flag if EPT > violation happens during IRET from NMI) just fixes the fault due to EPT > violation. > This patch tries to fix the fault due to the page fault of shadow page table. > > Cc: Paolo Bonzini <[email protected]> > Cc: Radim Krčmář <[email protected]> > Signed-off-by: Wanpeng Li <[email protected]> > --- > arch/x86/kvm/vmx.c | 5 +++++ > 1 file changed, 5 insertions(+) > > diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c > index 84e62ac..32ca063 100644 > --- a/arch/x86/kvm/vmx.c > +++ b/arch/x86/kvm/vmx.c > @@ -5709,6 +5709,11 @@ static int handle_exception(struct kvm_vcpu *vcpu) > } > > if (is_page_fault(intr_info)) { > + > + if (!(to_vmx(vcpu)->idt_vectoring_info & > VECTORING_INFO_VALID_MASK) && > + (intr_info & INTR_INFO_UNBLOCK_NMI)) > + vmcs_set_bits(GUEST_INTERRUPTIBILITY_INFO, > GUEST_INTR_STATE_NMI); > + > cr2 = vmcs_readl(EXIT_QUALIFICATION); > /* EPT won't cause page fault directly */ > WARN_ON_ONCE(!vcpu->arch.apf.host_apf_reason && enable_ept);
vmx_recover_nmi_blocking is supposed to do the same. EPT and PML-full exits need separate code because they store bit 12 in the exit qualification rather than the VM-exit interruption info. I think the bug is in the handling of vmx->nmi_known_unmasked. The following patch fixes it for me, can you test it too? Thanks, Paolo --------- 8< ------------------- From: Paolo Bonzini <[email protected] Subject: [PATCH] KVM: nVMX: track NMI blocking state separately for each VMCS vmx_recover_nmi_blocking is using a cached value of the guest interruptibility info, which is stored in vmx->nmi_known_unmasked. vmx_recover_nmi_blocking is run for both normal and nested guests, so the cached value must be per-VMCS. This fixes eventinj.flat in a nested non-EPT environment. With EPT it works, because the EPT violation handler doesn't have the vmx->nmi_known_unmasked optimization (it is unnecessary because, unlike vmx_recover_nmi_blocking, it can just look at the exit qualification). Thanks to Wanpeng Li for debugging the testcase and providing an initial patch. Signed-off-by: Paolo Bonzini <[email protected]> diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c index 32db3f5dce7f..504df356a10c 100644 --- a/arch/x86/kvm/vmx.c +++ b/arch/x86/kvm/vmx.c @@ -198,7 +198,8 @@ struct loaded_vmcs { struct vmcs *vmcs; struct vmcs *shadow_vmcs; int cpu; - int launched; + bool launched; + bool nmi_known_unmasked; struct list_head loaded_vmcss_on_cpu_link; }; @@ -5497,10 +5498,8 @@ static void vmx_inject_nmi(struct kvm_vcpu *vcpu) { struct vcpu_vmx *vmx = to_vmx(vcpu); - if (!is_guest_mode(vcpu)) { - ++vcpu->stat.nmi_injections; - vmx->nmi_known_unmasked = false; - } + ++vcpu->stat.nmi_injections; + vmx->loaded_vmcs->nmi_known_unmasked = false; if (vmx->rmode.vm86_active) { if (kvm_inject_realmode_interrupt(vcpu, NMI_VECTOR, 0) != EMULATE_DONE) @@ -5514,16 +5513,21 @@ static void vmx_inject_nmi(struct kvm_vcpu *vcpu) static bool vmx_get_nmi_mask(struct kvm_vcpu *vcpu) { - if (to_vmx(vcpu)->nmi_known_unmasked) + struct vcpu_vmx *vmx = to_vmx(vcpu); + bool masked; + + if (vmx->loaded_vmcs->nmi_known_unmasked) return false; - return vmcs_read32(GUEST_INTERRUPTIBILITY_INFO) & GUEST_INTR_STATE_NMI; + masked = vmcs_read32(GUEST_INTERRUPTIBILITY_INFO) & GUEST_INTR_STATE_NMI; + vmx->loaded_vmcs->nmi_known_unmasked = !masked; + return masked; } static void vmx_set_nmi_mask(struct kvm_vcpu *vcpu, bool masked) { struct vcpu_vmx *vmx = to_vmx(vcpu); - vmx->nmi_known_unmasked = !masked; + vmx->loaded_vmcs->nmi_known_unmasked = !masked; if (masked) vmcs_set_bits(GUEST_INTERRUPTIBILITY_INFO, GUEST_INTR_STATE_NMI); @@ -8719,7 +8723,7 @@ static void vmx_recover_nmi_blocking(struct vcpu_vmx *vmx) idtv_info_valid = vmx->idt_vectoring_info & VECTORING_INFO_VALID_MASK; - if (vmx->nmi_known_unmasked) + if (vmx->loaded_vmcs->nmi_known_unmasked) return; /* * Can't use vmx->exit_intr_info since we're not sure what @@ -8743,7 +8747,7 @@ static void vmx_recover_nmi_blocking(struct vcpu_vmx *vmx) vmcs_set_bits(GUEST_INTERRUPTIBILITY_INFO, GUEST_INTR_STATE_NMI); else - vmx->nmi_known_unmasked = + vmx->loaded_vmcs->nmi_known_unmasked = !(vmcs_read32(GUEST_INTERRUPTIBILITY_INFO) & GUEST_INTR_STATE_NMI); }
