KVM: nVMX: Ack and write vector info to intr_info if L1 asks us to

This feature emulates the "Acknowledge interrupt on exit" behavior.
We can safely emulate it for L1 to run L2 even if L0 itself has it
disabled (to run L1).

Signed-off-by: Bandan Das <bsd@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>

diff --git a/arch/x86/kvm/irq.c b/arch/x86/kvm/irq.c
index 484bc874688b4ba2bfb8199702671779ffd69d2f..bd0da433e6d72471b259616980cfeac8748bd5cf 100644 (file)
--- a/arch/x86/kvm/irq.c
+++ b/arch/x86/kvm/irq.c
@@ -113,6 +113,7 @@ int kvm_cpu_get_interrupt(struct kvm_vcpu *v)
 
        return kvm_get_apic_interrupt(v);       /* APIC */
 }
+EXPORT_SYMBOL_GPL(kvm_cpu_get_interrupt);
 
 void kvm_inject_pending_timer_irqs(struct kvm_vcpu *vcpu)
 {

diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index f00a6e9021b0f9a0d9fbf535546f98ef5040f582..4378014a41a93a0354c8fabf60bac7aeef3a1ce7 100644 (file)
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -4526,6 +4526,16 @@ static bool nested_exit_on_intr(struct kvm_vcpu *vcpu)
                PIN_BASED_EXT_INTR_MASK;
 }
 
+/*
+ * In nested virtualization, check if L1 has set
+ * VM_EXIT_ACK_INTR_ON_EXIT
+ */
+static bool nested_exit_intr_ack_set(struct kvm_vcpu *vcpu)
+{
+       return get_vmcs12(vcpu)->vm_exit_controls &
+               VM_EXIT_ACK_INTR_ON_EXIT;
+}
+
 static bool nested_exit_on_nmi(struct kvm_vcpu *vcpu)
 {
        return get_vmcs12(vcpu)->pin_based_vm_exec_control &
@@ -8563,6 +8573,14 @@ static void nested_vmx_vmexit(struct kvm_vcpu *vcpu, u32 exit_reason,
        prepare_vmcs12(vcpu, vmcs12, exit_reason, exit_intr_info,
                       exit_qualification);
 
+       if ((exit_reason == EXIT_REASON_EXTERNAL_INTERRUPT)
+           && nested_exit_intr_ack_set(vcpu)) {
+               int irq = kvm_cpu_get_interrupt(vcpu);
+               WARN_ON(irq < 0);
+               vmcs12->vm_exit_intr_info = irq |
+                       INTR_INFO_VALID_MASK | INTR_TYPE_EXT_INTR;
+       }
+
        trace_kvm_nested_vmexit_inject(vmcs12->vm_exit_reason,
                                       vmcs12->exit_qualification,
                                       vmcs12->idt_vectoring_info_field,