KVM: Move page fault processing to common code

The code that dispatches the page fault and emulates if we failed to map
is duplicated across vmx and svm.  Merge it to simplify further bugfixing.
Signed-off-by: NAvi Kivity <avi@qumranet.com>

drivers/kvm/mmu.c

@@ -1347,6 +1347,42 @@ void __kvm_mmu_free_some_pages(struct kvm_vcpu *vcpu)
 	}
 }
 
+int kvm_mmu_page_fault(struct kvm_vcpu *vcpu, gva_t cr2, u32 error_code)
+{
+	int r;
+	enum emulation_result er;
+
+	mutex_lock(&vcpu->kvm->lock);
+	r = vcpu->mmu.page_fault(vcpu, cr2, error_code);
+	if (r < 0)
+		goto out;
+
+	if (!r) {
+		r = 1;
+		goto out;
+	}
+
+	er = emulate_instruction(vcpu, vcpu->run, cr2, error_code, 0);
+	mutex_unlock(&vcpu->kvm->lock);
+
+	switch (er) {
+	case EMULATE_DONE:
+		return 1;
+	case EMULATE_DO_MMIO:
+		++vcpu->stat.mmio_exits;
+		return 0;
+	case EMULATE_FAIL:
+		kvm_report_emulation_failure(vcpu, "pagetable");
+		return 1;
+	default:
+		BUG();
+	}
+out:
+	mutex_unlock(&vcpu->kvm->lock);
+	return r;
+}
+EXPORT_SYMBOL_GPL(kvm_mmu_page_fault);
+
 static void free_mmu_pages(struct kvm_vcpu *vcpu)
 {
 	struct kvm_mmu_page *page;

drivers/kvm/svm.c

@@ -933,45 +933,14 @@ static int pf_interception(struct vcpu_svm *svm, struct kvm_run *kvm_run)
 	struct kvm *kvm = svm->vcpu.kvm;
 	u64 fault_address;
 	u32 error_code;
-	enum emulation_result er;
-	int r;
 
 	if (!irqchip_in_kernel(kvm) &&
 		is_external_interrupt(exit_int_info))
 		push_irq(&svm->vcpu, exit_int_info & SVM_EVTINJ_VEC_MASK);
 
-	mutex_lock(&kvm->lock);
-
 	fault_address  = svm->vmcb->control.exit_info_2;
 	error_code = svm->vmcb->control.exit_info_1;
-	r = kvm_mmu_page_fault(&svm->vcpu, fault_address, error_code);
-	if (r < 0) {
-		mutex_unlock(&kvm->lock);
-		return r;
-	}
-	if (!r) {
-		mutex_unlock(&kvm->lock);
-		return 1;
-	}
-	er = emulate_instruction(&svm->vcpu, kvm_run, fault_address,
-				 error_code, 0);
-	mutex_unlock(&kvm->lock);
-
-	switch (er) {
-	case EMULATE_DONE:
-		return 1;
-	case EMULATE_DO_MMIO:
-		++svm->vcpu.stat.mmio_exits;
-		return 0;
-	case EMULATE_FAIL:
-		kvm_report_emulation_failure(&svm->vcpu, "pagetable");
-		break;
-	default:
-		BUG();
-	}
-
-	kvm_run->exit_reason = KVM_EXIT_UNKNOWN;
-	return 0;
+	return kvm_mmu_page_fault(&svm->vcpu, fault_address, error_code);
 }
 
 static int ud_interception(struct vcpu_svm *svm, struct kvm_run *kvm_run)

drivers/kvm/vmx.c

@@ -1796,7 +1796,6 @@ static int handle_exception(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run)
 	unsigned long cr2, rip;
 	u32 vect_info;
 	enum emulation_result er;
-	int r;
 
 	vect_info = vmcs_read32(IDT_VECTORING_INFO_FIELD);
 	intr_info = vmcs_read32(VM_EXIT_INTR_INFO);
@@ -1834,33 +1833,7 @@ static int handle_exception(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run)
 		error_code = vmcs_read32(VM_EXIT_INTR_ERROR_CODE);
 	if (is_page_fault(intr_info)) {
 		cr2 = vmcs_readl(EXIT_QUALIFICATION);
-
-		mutex_lock(&vcpu->kvm->lock);
-		r = kvm_mmu_page_fault(vcpu, cr2, error_code);
-		if (r < 0) {
-			mutex_unlock(&vcpu->kvm->lock);
-			return r;
-		}
-		if (!r) {
-			mutex_unlock(&vcpu->kvm->lock);
-			return 1;
-		}
-
-		er = emulate_instruction(vcpu, kvm_run, cr2, error_code, 0);
-		mutex_unlock(&vcpu->kvm->lock);
-
-		switch (er) {
-		case EMULATE_DONE:
-			return 1;
-		case EMULATE_DO_MMIO:
-			++vcpu->stat.mmio_exits;
-			return 0;
-		case EMULATE_FAIL:
-			kvm_report_emulation_failure(vcpu, "pagetable");
-			break;
-		default:
-			BUG();
-		}
+		return kvm_mmu_page_fault(vcpu, cr2, error_code);
 	}
 
 	if (vcpu->rmode.active &&

drivers/kvm/x86.h

@@ -85,11 +85,7 @@ struct kvm_vcpu {
 	struct x86_emulate_ctxt emulate_ctxt;
 };
 
-static inline int kvm_mmu_page_fault(struct kvm_vcpu *vcpu, gva_t gva,
-				     u32 error_code)
-{
-	return vcpu->mmu.page_fault(vcpu, gva, error_code);
-}
+int kvm_mmu_page_fault(struct kvm_vcpu *vcpu, gva_t gva, u32 error_code);
 
 static inline void kvm_mmu_free_some_pages(struct kvm_vcpu *vcpu)
 {