KVM: x86: Differentiate Soft vs. Hard IRQs vs. reinjected in tracepoint

In the IRQ injection tracepoint, differentiate between Hard IRQs and Soft
"IRQs", i.e. interrupts that are reinjected after incomplete delivery of
a software interrupt from an INTn instruction.  Tag reinjected interrupts
as such, even though the information is usually redundant since soft
interrupts are only ever reinjected by KVM.  Though rare in practice, a
hard IRQ can be reinjected.

Signed-off-by: Sean Christopherson <seanjc@google.com>
[MSS: change "kvm_inj_virq" event "reinjected" field type to bool]
Signed-off-by: Maciej S. Szmigiero <maciej.szmigiero@oracle.com>
Message-Id: <9664d49b3bd21e227caa501cff77b0569bebffe2.1651440202.git.maciej.szmigiero@oracle.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

arch/x86/include/asm/kvm_host.h

@@ -1405,7 +1405,7 @@ struct kvm_x86_ops {
 	u32 (*get_interrupt_shadow)(struct kvm_vcpu *vcpu);
 	void (*patch_hypercall)(struct kvm_vcpu *vcpu,
 				unsigned char *hypercall_addr);
-	void (*inject_irq)(struct kvm_vcpu *vcpu);
+	void (*inject_irq)(struct kvm_vcpu *vcpu, bool reinjected);
 	void (*inject_nmi)(struct kvm_vcpu *vcpu);
 	void (*queue_exception)(struct kvm_vcpu *vcpu);
 	void (*cancel_injection)(struct kvm_vcpu *vcpu);

arch/x86/kvm/svm/svm.c

@@ -3435,7 +3435,7 @@ static void svm_inject_nmi(struct kvm_vcpu *vcpu)
 	++vcpu->stat.nmi_injections;
 }
 
-static void svm_inject_irq(struct kvm_vcpu *vcpu)
+static void svm_inject_irq(struct kvm_vcpu *vcpu, bool reinjected)
 {
 	struct vcpu_svm *svm = to_svm(vcpu);
 	u32 type;
@@ -3449,7 +3449,8 @@ static void svm_inject_irq(struct kvm_vcpu *vcpu)
 		type = SVM_EVTINJ_TYPE_INTR;
 	}
 
-	trace_kvm_inj_virq(vcpu->arch.interrupt.nr);
+	trace_kvm_inj_virq(vcpu->arch.interrupt.nr,
+			   vcpu->arch.interrupt.soft, reinjected);
 	++vcpu->stat.irq_injections;
 
 	svm->vmcb->control.event_inj = vcpu->arch.interrupt.nr |

arch/x86/kvm/trace.h

@@ -333,18 +333,24 @@ TRACE_EVENT_KVM_EXIT(kvm_exit);
  * Tracepoint for kvm interrupt injection:
  */
 TRACE_EVENT(kvm_inj_virq,
-	TP_PROTO(unsigned int irq),
-	TP_ARGS(irq),
+	TP_PROTO(unsigned int vector, bool soft, bool reinjected),
+	TP_ARGS(vector, soft, reinjected),
 
 	TP_STRUCT__entry(
-		__field(	unsigned int,	irq		)
+		__field(	unsigned int,	vector		)
+		__field(	bool,		soft		)
+		__field(	bool,		reinjected	)
 	),
 
 	TP_fast_assign(
-		__entry->irq		= irq;
+		__entry->vector		= vector;
+		__entry->soft		= soft;
+		__entry->reinjected	= reinjected;
 	),
 
-	TP_printk("irq %u", __entry->irq)
+	TP_printk("%s 0x%x%s",
+		  __entry->soft ? "Soft/INTn" : "IRQ", __entry->vector,
+		  __entry->reinjected ? " [reinjected]" : "")
 );
 
 #define EXS(x) { x##_VECTOR, "#" #x }

arch/x86/kvm/vmx/vmx.c

@@ -4573,13 +4573,13 @@ static void vmx_enable_nmi_window(struct kvm_vcpu *vcpu)
 	exec_controls_setbit(to_vmx(vcpu), CPU_BASED_NMI_WINDOW_EXITING);
 }
 
-static void vmx_inject_irq(struct kvm_vcpu *vcpu)
+static void vmx_inject_irq(struct kvm_vcpu *vcpu, bool reinjected)
 {
 	struct vcpu_vmx *vmx = to_vmx(vcpu);
 	uint32_t intr;
 	int irq = vcpu->arch.interrupt.nr;
 
-	trace_kvm_inj_virq(irq);
+	trace_kvm_inj_virq(irq, vcpu->arch.interrupt.soft, reinjected);
 
 	++vcpu->stat.irq_injections;
 	if (vmx->rmode.vm86_active) {

arch/x86/kvm/x86.c

@@ -9448,7 +9448,7 @@ static int inject_pending_event(struct kvm_vcpu *vcpu, bool *req_immediate_exit)
 			static_call(kvm_x86_inject_nmi)(vcpu);
 			can_inject = false;
 		} else if (vcpu->arch.interrupt.injected) {
-			static_call(kvm_x86_inject_irq)(vcpu);
+			static_call(kvm_x86_inject_irq)(vcpu, true);
 			can_inject = false;
 		}
 	}
@@ -9539,7 +9539,7 @@ static int inject_pending_event(struct kvm_vcpu *vcpu, bool *req_immediate_exit)
 			goto out;
 		if (r) {
 			kvm_queue_interrupt(vcpu, kvm_cpu_get_interrupt(vcpu), false);
-			static_call(kvm_x86_inject_irq)(vcpu);
+			static_call(kvm_x86_inject_irq)(vcpu, false);
 			WARN_ON(static_call(kvm_x86_interrupt_allowed)(vcpu, true) < 0);
 		}
 		if (kvm_cpu_has_injectable_intr(vcpu))