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>

diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index 631f9b720971d0b167d86d6b5a9db1f02971c0ac..577aa9551a979888e6f6efaa7ce2baf2ca8d0744 100644 (file)
--- 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;
        }
 }