KVM: x86: Fix perf timer mode IP reporting

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.

v2: Moved the functions inline.
For the normal interrupt case the before/after functions are now
called from x86.c, not arch specific code.
For the NMI case we still need to call it in the architecture
specific code, because it's already needed in the low level *_run
functions.
Signed-off-by: NAndi Kleen <ak@linux.intel.com>
[Removed unnecessary calls from arch handle_external_intr. - Radim]
Signed-off-by: NRadim Krčmář <rkrcmar@redhat.com>

arch/x86/kvm/svm.c

@@ -5599,14 +5599,14 @@ 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);
 

arch/x86/kvm/vmx.c

@@ -9292,9 +9292,9 @@ 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);
 	}
 }
 

arch/x86/kvm/x86.c

@@ -6370,7 +6370,8 @@ static void kvm_timer_init(void)
 			  kvmclock_cpu_online, kvmclock_cpu_down_prep);
 }
 
-static DEFINE_PER_CPU(struct kvm_vcpu *, current_vcpu);
+DEFINE_PER_CPU(struct kvm_vcpu *, current_vcpu);
+EXPORT_PER_CPU_SYMBOL_GPL(current_vcpu);
 
 int kvm_is_in_guest(void)
 {
@@ -6403,18 +6404,6 @@ 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)
-{
-	__this_cpu_write(current_vcpu, vcpu);
-}
-EXPORT_SYMBOL_GPL(kvm_before_handle_nmi);
-
-void kvm_after_handle_nmi(struct kvm_vcpu *vcpu)
-{
-	__this_cpu_write(current_vcpu, NULL);
-}
-EXPORT_SYMBOL_GPL(kvm_after_handle_nmi);
-
 static void kvm_set_mmio_spte_mask(void)
 {
 	u64 mask;
@@ -7429,7 +7418,9 @@ static int vcpu_enter_guest(struct kvm_vcpu *vcpu)
 
 	kvm_put_guest_xcr0(vcpu);
 
+	kvm_before_interrupt(vcpu);
 	kvm_x86_ops->handle_external_intr(vcpu);
+	kvm_after_interrupt(vcpu);
 
 	++vcpu->stat.exits;
 

arch/x86/kvm/x86.h

@@ -203,8 +203,6 @@ 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_set_pending_timer(struct kvm_vcpu *vcpu);
 int kvm_inject_realmode_interrupt(struct kvm_vcpu *vcpu, int irq, int inc_eip);
 
@@ -286,4 +284,16 @@ static inline bool kvm_pause_in_guest(struct kvm *kvm)
 	return kvm->arch.pause_in_guest;
 }
 
+DECLARE_PER_CPU(struct kvm_vcpu *, current_vcpu);
+
+static inline void kvm_before_interrupt(struct kvm_vcpu *vcpu)
+{
+	__this_cpu_write(current_vcpu, vcpu);
+}
+
+static inline void kvm_after_interrupt(struct kvm_vcpu *vcpu)
+{
+	__this_cpu_write(current_vcpu, NULL);
+}
+
 #endif