KVM: Do not re-execute INTn instruction.

Re-inject event instead. This is what Intel suggest. Also use correct
instruction length when re-injecting soft fault/interrupt.

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

1 files changed, 25 insertions, 7 deletions

diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index 8981654ad061..29b49f09a019 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -801,8 +801,9 @@ static void vmx_queue_exception(struct kvm_vcpu *vcpu, unsigned nr,
                 return;
         }
 
-        if (nr == BP_VECTOR || nr == OF_VECTOR) {
-                vmcs_write32(VM_ENTRY_INSTRUCTION_LEN, 1);
+        if (kvm_exception_is_soft(nr)) {
+                vmcs_write32(VM_ENTRY_INSTRUCTION_LEN,
+                             vmx->vcpu.arch.event_exit_inst_len);
                 intr_info |= INTR_TYPE_SOFT_EXCEPTION;
         } else
                 intr_info |= INTR_TYPE_HARD_EXCEPTION;
@@ -2445,9 +2446,11 @@ static void enable_nmi_window(struct kvm_vcpu *vcpu)
         vmcs_write32(CPU_BASED_VM_EXEC_CONTROL, cpu_based_vm_exec_control);
 }
 
-static void vmx_inject_irq(struct kvm_vcpu *vcpu, int irq)
+static void vmx_inject_irq(struct kvm_vcpu *vcpu)
 {
         struct vcpu_vmx *vmx = to_vmx(vcpu);
+        uint32_t intr;
+        int irq = vcpu->arch.interrupt.nr;
 
         KVMTRACE_1D(INJ_VIRQ, vcpu, (u32)irq, handler);
 
@@ -2462,8 +2465,14 @@ static void vmx_inject_irq(struct kvm_vcpu *vcpu, int irq)
                 kvm_rip_write(vcpu, vmx->rmode.irq.rip - 1);
                 return;
         }
-        vmcs_write32(VM_ENTRY_INTR_INFO_FIELD,
-                        irq | INTR_TYPE_EXT_INTR | INTR_INFO_VALID_MASK);
+        intr = irq | INTR_INFO_VALID_MASK;
+        if (vcpu->arch.interrupt.soft) {
+                intr |= INTR_TYPE_SOFT_INTR;
+                vmcs_write32(VM_ENTRY_INSTRUCTION_LEN,
+                             vmx->vcpu.arch.event_exit_inst_len);
+        } else
+                intr |= INTR_TYPE_EXT_INTR;
+        vmcs_write32(VM_ENTRY_INTR_INFO_FIELD, intr);
 }
 
 static void vmx_inject_nmi(struct kvm_vcpu *vcpu)
@@ -3024,6 +3033,7 @@ static int handle_task_switch(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run)
                                               GUEST_INTR_STATE_NMI);
                         break;
                 case INTR_TYPE_EXT_INTR:
+                case INTR_TYPE_SOFT_INTR:
                         kvm_clear_interrupt_queue(vcpu);
                         break;
                 case INTR_TYPE_HARD_EXCEPTION:
@@ -3295,16 +3305,24 @@ static void vmx_complete_interrupts(struct vcpu_vmx *vmx)
                 vmcs_clear_bits(GUEST_INTERRUPTIBILITY_INFO,
                                 GUEST_INTR_STATE_NMI);
                 break;
-        case INTR_TYPE_HARD_EXCEPTION:
         case INTR_TYPE_SOFT_EXCEPTION:
+                vmx->vcpu.arch.event_exit_inst_len =
+                        vmcs_read32(VM_EXIT_INSTRUCTION_LEN);
+                /* fall through */
+        case INTR_TYPE_HARD_EXCEPTION:
                 if (idt_vectoring_info & VECTORING_INFO_DELIVER_CODE_MASK) {
                         u32 err = vmcs_read32(IDT_VECTORING_ERROR_CODE);
                         kvm_queue_exception_e(&vmx->vcpu, vector, err);
                 } else
                         kvm_queue_exception(&vmx->vcpu, vector);
                 break;
+        case INTR_TYPE_SOFT_INTR:
+                vmx->vcpu.arch.event_exit_inst_len =
+                        vmcs_read32(VM_EXIT_INSTRUCTION_LEN);
+                /* fall through */
         case INTR_TYPE_EXT_INTR:
-                kvm_queue_interrupt(&vmx->vcpu, vector);
+                kvm_queue_interrupt(&vmx->vcpu, vector,
+                        type == INTR_TYPE_SOFT_INTR);
                 break;
         default:
                 break;