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 <pbonzini@redhat.com>
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
(cherry picked from commit 4c4a6f790ee862ee9f0dc8b35c71f55bcf792b71)
OraBug: 27031246 nested virt: L2 windows guest reboot hangs with L1 KVM hypervisor
Signed-off-by: Liran Alon <liran.alon@oracle.com>
Signed-off-by: Krish Sadhukhan <krish.sadhukhan@oracle.com>
Tested-by: Xuan Bai <xuan.bai@oracle.com>
Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index cf3323f4ac2dce70ac38d7a1553b4c4f45e4839a..e5967412a1a35ffedbc0ad90cbdc5e1531306fcc 100644 (file)
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -177,7 +177,8 @@ struct vmcs {
 struct loaded_vmcs {
        struct vmcs *vmcs;
        int cpu;
-       int launched;
+       bool launched;
+       bool nmi_known_unmasked;
        struct list_head loaded_vmcss_on_cpu_link;
 };
 
@@ -4906,10 +4907,8 @@ 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)
@@ -4923,16 +4922,21 @@ 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);
@@ -8007,7 +8011,7 @@ 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
@@ -8031,7 +8035,7 @@ 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);
 }