[RFC] KVM: busy-spin detector

Commit Message

Marcelo Tosatti June 11, 2010, 2:25 a.m. UTC

None

Patch

Index: kvm/arch/x86/include/asm/kvm_host.h
===================================================================
--- kvm.orig/arch/x86/include/asm/kvm_host.h
+++ kvm/arch/x86/include/asm/kvm_host.h
@@ -301,6 +301,8 @@  struct kvm_vcpu_arch {
 		unsigned long mmu_seq;
 	} update_pte;
 
+	unsigned long last_rip;
+
 	struct fpu guest_fpu;
 
 	gva_t mmio_fault_cr2;
@@ -653,6 +655,8 @@  void kvm_disable_tdp(void);
 int complete_pio(struct kvm_vcpu *vcpu);
 bool kvm_check_iopl(struct kvm_vcpu *vcpu);
 
+void kvm_detect_spin(struct kvm_vcpu *vcpu);
+
 struct kvm_memory_slot *gfn_to_memslot_unaliased(struct kvm *kvm, gfn_t gfn);
 
 static inline struct kvm_mmu_page *page_header(hpa_t shadow_page)
Index: kvm/arch/x86/kvm/svm.c
===================================================================
--- kvm.orig/arch/x86/kvm/svm.c
+++ kvm/arch/x86/kvm/svm.c
@@ -1558,8 +1558,10 @@  static int nmi_interception(struct vcpu_
 
 static int intr_interception(struct vcpu_svm *svm)
 {
+	if (!svm_has(SVM_FEATURE_PAUSE_FILTER))
+		kvm_detect_spin(&svm->vcpu);
 	++svm->vcpu.stat.irq_exits;
-	return 1;
+	return 2;
 }
 
 static int nop_on_interception(struct vcpu_svm *svm)
Index: kvm/arch/x86/kvm/vmx.c
===================================================================
--- kvm.orig/arch/x86/kvm/vmx.c
+++ kvm/arch/x86/kvm/vmx.c
@@ -3116,7 +3116,9 @@  static int handle_exception(struct kvm_v
 static int handle_external_interrupt(struct kvm_vcpu *vcpu)
 {
 	++vcpu->stat.irq_exits;
-	return 1;
+	if (!cpu_has_vmx_ple())
+		kvm_detect_spin(vcpu);
+	return 2;
 }
 
 static int handle_triple_fault(struct kvm_vcpu *vcpu)
Index: kvm/arch/x86/kvm/x86.c
===================================================================
--- kvm.orig/arch/x86/kvm/x86.c
+++ kvm/arch/x86/kvm/x86.c
@@ -4523,6 +4523,17 @@  static void inject_pending_event(struct 
 	}
 }
 
+void kvm_detect_spin(struct kvm_vcpu *vcpu)
+{
+	unsigned long rip = kvm_rip_read(vcpu);
+
+	if (vcpu->arch.last_rip == rip)
+		kvm_vcpu_on_spin(vcpu);
+
+	vcpu->arch.last_rip = rip;
+}
+EXPORT_SYMBOL_GPL(kvm_detect_spin);
+
 static int vcpu_enter_guest(struct kvm_vcpu *vcpu)
 {
 	int r;
@@ -4654,6 +4665,8 @@  static int vcpu_enter_guest(struct kvm_v
 	kvm_lapic_sync_from_vapic(vcpu);
 
 	r = kvm_x86_ops->handle_exit(vcpu);
+	if (r == 1)
+		vcpu->arch.last_rip = ~(0UL);
 out:
 	return r;
 }