KVM: VMX: Rewrite vmx_complete_interrupt()'s twisted maze of if() statements

...with a more straightforward switch().

Also fix a bug when NMI could be dropped on exit. Although this should
never happen in practice, since NMIs can only be injected, never triggered
internally by the guest like exceptions.

Signed-off-by: Gleb Natapov <gleb@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>

1 files changed, 25 insertions, 18 deletions

diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index 631f9b720971..577aa9551a97 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -3277,7 +3277,6 @@ static void vmx_complete_interrupts(struct vcpu_vmx *vmx)
         u8 vector;
         int type;
         bool idtv_info_valid;
-        u32 error;
 
         idtv_info_valid = idt_vectoring_info & VECTORING_INFO_VALID_MASK;
         exit_intr_info = vmcs_read32(VM_EXIT_INTR_INFO);
@@ -3302,34 +3301,42 @@ static void vmx_complete_interrupts(struct vcpu_vmx *vmx)
                 vmx->vnmi_blocked_time +=
                         ktime_to_ns(ktime_sub(ktime_get(), vmx->entry_time));
 
+        vmx->vcpu.arch.nmi_injected = false;
+        kvm_clear_exception_queue(&vmx->vcpu);
+        kvm_clear_interrupt_queue(&vmx->vcpu);
+
+        if (!idtv_info_valid)
+                return;
+
         vector = idt_vectoring_info & VECTORING_INFO_VECTOR_MASK;
         type = idt_vectoring_info & VECTORING_INFO_TYPE_MASK;
-        if (vmx->vcpu.arch.nmi_injected) {
+
+        switch(type) {
+        case INTR_TYPE_NMI_INTR:
+                vmx->vcpu.arch.nmi_injected = true;
                 /*
                  * SDM 3: 27.7.1.2 (September 2008)
-                 * Clear bit "block by NMI" before VM entry if a NMI delivery
-                 * faulted.
+                 * 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;
-        }
-        kvm_clear_exception_queue(&vmx->vcpu);
-        if (idtv_info_valid && (type == INTR_TYPE_HARD_EXCEPTION ||
-                                type == INTR_TYPE_SOFT_EXCEPTION)) {
+                vmcs_clear_bits(GUEST_INTERRUPTIBILITY_INFO,
+                                GUEST_INTR_STATE_NMI);
+                break;
+        case INTR_TYPE_HARD_EXCEPTION:
+        case INTR_TYPE_SOFT_EXCEPTION:
                 if (idt_vectoring_info & VECTORING_INFO_DELIVER_CODE_MASK) {
-                        error = vmcs_read32(IDT_VECTORING_ERROR_CODE);
-                        kvm_queue_exception_e(&vmx->vcpu, vector, error);
+                        u32 err = vmcs_read32(IDT_VECTORING_ERROR_CODE);
+                        kvm_queue_exception_e(&vmx->vcpu, vector, err);
                 } else
                         kvm_queue_exception(&vmx->vcpu, vector);
                 vmx->idt_vectoring_info = 0;
-        }
-        kvm_clear_interrupt_queue(&vmx->vcpu);
-        if (idtv_info_valid && type == INTR_TYPE_EXT_INTR) {
+                break;
+        case INTR_TYPE_EXT_INTR:
                 kvm_queue_interrupt(&vmx->vcpu, vector);
                 vmx->idt_vectoring_info = 0;
+                break;
+        default:
+                break;
         }
 }