KVM: VMX: Move nmi injection failure processing to vm exit path

Instead of processing nmi injection failure in the vm entry path, move
it to the vm exit path (vm_complete_interrupts()).  This separates nmi
injection from nmi post-processing, and moves the nmi state from the VT
state into vcpu state (new variable nmi_injected specifying an injection
in progress).

Signed-off-by: Avi Kivity <avi@qumranet.com>

2 files changed, 33 insertions, 17 deletions

diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index 2adfacb00336..ce13b53d21c4 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -2151,7 +2151,6 @@ static void vmx_inject_nmi(struct kvm_vcpu *vcpu)
 {
         vmcs_write32(VM_ENTRY_INTR_INFO_FIELD,
                         INTR_TYPE_NMI_INTR | INTR_INFO_VALID_MASK | NMI_VECTOR);
-        vcpu->arch.nmi_pending = 0;
 }
 
 static void kvm_do_inject_irq(struct kvm_vcpu *vcpu)
@@ -2820,8 +2819,11 @@ static void enable_intr_window(struct kvm_vcpu *vcpu)
 static void vmx_complete_interrupts(struct vcpu_vmx *vmx)
 {
         u32 exit_intr_info;
+        u32 idt_vectoring_info;
         bool unblock_nmi;
         u8 vector;
+        int type;
+        bool idtv_info_valid;
 
         exit_intr_info = vmcs_read32(VM_EXIT_INTR_INFO);
         if (cpu_has_virtual_nmis()) {
@@ -2836,18 +2838,34 @@ static void vmx_complete_interrupts(struct vcpu_vmx *vmx)
                         vmcs_set_bits(GUEST_INTERRUPTIBILITY_INFO,
                                       GUEST_INTR_STATE_NMI);
         }
+
+        idt_vectoring_info = vmx->idt_vectoring_info;
+        idtv_info_valid = idt_vectoring_info & VECTORING_INFO_VALID_MASK;
+        vector = idt_vectoring_info & VECTORING_INFO_VECTOR_MASK;
+        type = idt_vectoring_info & VECTORING_INFO_TYPE_MASK;
+        if (vmx->vcpu.arch.nmi_injected) {
+                /*
+                 * SDM 3: 25.7.1.2
+                 * Clear bit "block by NMI" before VM entry if a NMI delivery
+                 * faulted.
+                 */
+                if (idtv_info_valid && type == INTR_TYPE_NMI_INTR)
+                        vmcs_clear_bits(GUEST_INTERRUPTIBILITY_INFO,
+                                        GUEST_INTR_STATE_NMI);
+                else
+                        vmx->vcpu.arch.nmi_injected = false;
+        }
 }
 
 static void vmx_intr_assist(struct kvm_vcpu *vcpu)
 {
         struct vcpu_vmx *vmx = to_vmx(vcpu);
-        u32 idtv_info_field, intr_info_field, exit_intr_info_field;
+        u32 idtv_info_field, intr_info_field;
         int vector;
 
         update_tpr_threshold(vcpu);
 
         intr_info_field = vmcs_read32(VM_ENTRY_INTR_INFO_FIELD);
-        exit_intr_info_field = vmcs_read32(VM_EXIT_INTR_INFO);
         idtv_info_field = vmx->idt_vectoring_info;
         if (intr_info_field & INTR_INFO_VALID_MASK) {
                 if (idtv_info_field & INTR_INFO_VALID_MASK) {
@@ -2871,17 +2889,6 @@ static void vmx_intr_assist(struct kvm_vcpu *vcpu)
 
                 KVMTRACE_1D(REDELIVER_EVT, vcpu, idtv_info_field, handler);
 
-                /*
-                 * SDM 3: 25.7.1.2
-                 * Clear bit "block by NMI" before VM entry if a NMI delivery
-                 * faulted.
-                 */
-                if ((idtv_info_field & VECTORING_INFO_TYPE_MASK)
-                    == INTR_TYPE_NMI_INTR && cpu_has_virtual_nmis())
-                        vmcs_write32(GUEST_INTERRUPTIBILITY_INFO,
-                                vmcs_read32(GUEST_INTERRUPTIBILITY_INFO) &
-                                ~GUEST_INTR_STATE_NMI);
-
                 vmcs_write32(VM_ENTRY_INTR_INFO_FIELD, idtv_info_field
                                 & ~INTR_INFO_RESVD_BITS_MASK);
                 vmcs_write32(VM_ENTRY_INSTRUCTION_LEN,
@@ -2894,9 +2901,17 @@ static void vmx_intr_assist(struct kvm_vcpu *vcpu)
                 return;
         }
         if (cpu_has_virtual_nmis()) {
-                if (vcpu->arch.nmi_pending) {
-                        if (vmx_nmi_enabled(vcpu))
-                                vmx_inject_nmi(vcpu);
+                if (vcpu->arch.nmi_pending && !vcpu->arch.nmi_injected) {
+                        if (vmx_nmi_enabled(vcpu)) {
+                                vcpu->arch.nmi_pending = false;
+                                vcpu->arch.nmi_injected = true;
+                        } else {
+                                enable_intr_window(vcpu);
+                                return;
+                        }
+                }
+                if (vcpu->arch.nmi_injected) {
+                        vmx_inject_nmi(vcpu);
                         enable_intr_window(vcpu);
                         return;
                 }
diff --git a/include/asm-x86/kvm_host.h b/include/asm-x86/kvm_host.h
index 4f2bd884fd3a..7cf69fd1dcfe 100644
--- a/include/asm-x86/kvm_host.h
+++ b/include/asm-x86/kvm_host.h
@@ -300,6 +300,7 @@ struct kvm_vcpu_arch {
         struct page *time_page;
 
         bool nmi_pending;
+        bool nmi_injected;
 
         u64 mtrr[0x100];
 };