[PATCH] kvm: Fix perf timer mode IP reporting

[Andi Kleen <andi@xxxxxxxxxxxxxx>]

From: Andi Kleen <ak@xxxxxxxxxxxxxxx>

KVM and perf have a special backdoor mechanism to report the IP for interrupts
re-executed after vm exit. This works for the NMIs that perf normally uses.

However when perf is in timer mode it doesn't work because the timer interrupt
doesn't get this special treatment. This is common when KVM is running
nested in another hypervisor which may not implement the PMU, so only
timer mode is available.

Call the functions to set up the backdoor IP also for non NMI interrupts.

I renamed the functions to set up the backdoor IP reporting to be more
appropiate for their new use.  The SVM change is only compile tested.

Signed-off-by: Andi Kleen <ak@xxxxxxxxxxxxxxx>
---
 arch/x86/kvm/svm.c | 6 ++++--
 arch/x86/kvm/vmx.c | 6 ++++--
 arch/x86/kvm/x86.c | 8 ++++----
 arch/x86/kvm/x86.h | 4 ++--
 4 files changed, 14 insertions(+), 10 deletions(-)

diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
index ba9891ac5c56..41bf6a9de853 100644
--- a/arch/x86/kvm/svm.c
+++ b/arch/x86/kvm/svm.c
@@ -4872,14 +4872,14 @@ static void svm_vcpu_run(struct kvm_vcpu *vcpu)
 	vcpu->arch.regs[VCPU_REGS_RIP] = svm->vmcb->save.rip;
 
 	if (unlikely(svm->vmcb->control.exit_code == SVM_EXIT_NMI))
-		kvm_before_handle_nmi(&svm->vcpu);
+		kvm_before_interrupt(&svm->vcpu);
 
 	stgi();
 
 	/* Any pending NMI will happen here */
 
 	if (unlikely(svm->vmcb->control.exit_code == SVM_EXIT_NMI))
-		kvm_after_handle_nmi(&svm->vcpu);
+		kvm_after_interrupt(&svm->vcpu);
 
 	sync_cr8_to_lapic(vcpu);
 
@@ -5234,6 +5234,7 @@ static int svm_check_intercept(struct kvm_vcpu *vcpu,
 
 static void svm_handle_external_intr(struct kvm_vcpu *vcpu)
 {
+	kvm_before_interrupt(vcpu);
 	local_irq_enable();
 	/*
 	 * We must have an instruction with interrupts enabled, so
@@ -5241,6 +5242,7 @@ static void svm_handle_external_intr(struct kvm_vcpu *vcpu)
 	 */
 	asm("nop");
 	local_irq_disable();
+	kvm_after_interrupt(vcpu);
 }
 
 static void svm_sched_in(struct kvm_vcpu *vcpu, int cpu)
diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index ca5d2b93385c..a02178914f6c 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -8606,9 +8606,9 @@ static void vmx_complete_atomic_exit(struct vcpu_vmx *vmx)
 
 	/* We need to handle NMIs before interrupts are enabled */
 	if (is_nmi(exit_intr_info)) {
-		kvm_before_handle_nmi(&vmx->vcpu);
+		kvm_before_interrupt(&vmx->vcpu);
 		asm("int $2");
-		kvm_after_handle_nmi(&vmx->vcpu);
+		kvm_after_interrupt(&vmx->vcpu);
 	}
 }
 
@@ -8627,6 +8627,7 @@ static void vmx_handle_external_intr(struct kvm_vcpu *vcpu)
 		unsigned long tmp;
 #endif
 
+		kvm_before_interrupt(vcpu);
 		vector =  exit_intr_info & INTR_INFO_VECTOR_MASK;
 		desc = (gate_desc *)vmx->host_idt_base + vector;
 		entry = gate_offset(*desc);
@@ -8650,6 +8651,7 @@ static void vmx_handle_external_intr(struct kvm_vcpu *vcpu)
 			[ss]"i"(__KERNEL_DS),
 			[cs]"i"(__KERNEL_CS)
 			);
+		kvm_after_interrupt(vcpu);
 	}
 }
 
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 0e846f0cb83b..96dae9ca7641 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -5975,17 +5975,17 @@ static struct perf_guest_info_callbacks kvm_guest_cbs = {
 	.get_guest_ip		= kvm_get_guest_ip,
 };
 
-void kvm_before_handle_nmi(struct kvm_vcpu *vcpu)
+void kvm_before_interrupt(struct kvm_vcpu *vcpu)
 {
 	__this_cpu_write(current_vcpu, vcpu);
 }
-EXPORT_SYMBOL_GPL(kvm_before_handle_nmi);
+EXPORT_SYMBOL_GPL(kvm_before_interrupt);
 
-void kvm_after_handle_nmi(struct kvm_vcpu *vcpu)
+void kvm_after_interrupt(struct kvm_vcpu *vcpu)
 {
 	__this_cpu_write(current_vcpu, NULL);
 }
-EXPORT_SYMBOL_GPL(kvm_after_handle_nmi);
+EXPORT_SYMBOL_GPL(kvm_after_interrupt);
 
 static void kvm_set_mmio_spte_mask(void)
 {
diff --git a/arch/x86/kvm/x86.h b/arch/x86/kvm/x86.h
index 612067074905..adb269538e7c 100644
--- a/arch/x86/kvm/x86.h
+++ b/arch/x86/kvm/x86.h
@@ -155,8 +155,8 @@ static inline bool kvm_check_has_quirk(struct kvm *kvm, u64 quirk)
 	return !(kvm->arch.disabled_quirks & quirk);
 }
 
-void kvm_before_handle_nmi(struct kvm_vcpu *vcpu);
-void kvm_after_handle_nmi(struct kvm_vcpu *vcpu);
+void kvm_before_interrupt(struct kvm_vcpu *vcpu);
+void kvm_after_interrupt(struct kvm_vcpu *vcpu);
 void kvm_set_pending_timer(struct kvm_vcpu *vcpu);
 int kvm_inject_realmode_interrupt(struct kvm_vcpu *vcpu, int irq, int inc_eip);
 
-- 
2.9.4