KVM: Add statistics for guest irq injections

These can help show whether a guest is making progress or not.
Signed-off-by: Avi Kivity <avi@qumranet.com>

arch/x86/kvm/svm.c

@@ -1519,6 +1519,7 @@ static inline void svm_inject_irq(struct vcpu_svm *svm, int irq)
 
 	KVMTRACE_1D(INJ_VIRQ, &svm->vcpu, (u32)irq, handler);
 
+	++svm->vcpu.stat.irq_injections;
 	control = &svm->vmcb->control;
 	control->int_vector = irq;
 	control->int_ctl &= ~V_INTR_PRIO_MASK;

arch/x86/kvm/vmx.c

@@ -2341,6 +2341,7 @@ static void vmx_inject_irq(struct kvm_vcpu *vcpu, int irq)
 
 	KVMTRACE_1D(INJ_VIRQ, vcpu, (u32)irq, handler);
 
+	++vcpu->stat.irq_injections;
 	if (vcpu->arch.rmode.active) {
 		vmx->rmode.irq.pending = true;
 		vmx->rmode.irq.vector = irq;

arch/x86/kvm/x86.c

@@ -92,6 +92,7 @@ struct kvm_stats_debugfs_item debugfs_entries[] = {
 	{ "fpu_reload", VCPU_STAT(fpu_reload) },
 	{ "insn_emulation", VCPU_STAT(insn_emulation) },
 	{ "insn_emulation_fail", VCPU_STAT(insn_emulation_fail) },
+	{ "irq_injections", VCPU_STAT(irq_injections) },
 	{ "mmu_shadow_zapped", VM_STAT(mmu_shadow_zapped) },
 	{ "mmu_pte_write", VM_STAT(mmu_pte_write) },
 	{ "mmu_pte_updated", VM_STAT(mmu_pte_updated) },

include/asm-x86/kvm_host.h

@@ -413,6 +413,7 @@ struct kvm_vcpu_stat {
 	u32 insn_emulation;
 	u32 insn_emulation_fail;
 	u32 hypercalls;
+	u32 irq_injections;
 };
 
 struct descriptor_table {