KVM: SVM: move special nested exit handling to separate function

This patch moves the handling for special nested vmexits like #pf to a
separate function. This makes the kvm_override parameter obsolete and
makes the code more readable.
Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
Signed-off-by: Avi Kivity <avi@redhat.com>

arch/x86/kvm/svm.c

@@ -47,6 +47,10 @@ MODULE_LICENSE("GPL");
 #define SVM_FEATURE_LBRV (1 << 1)
 #define SVM_FEATURE_SVML (1 << 2)
 
+#define NESTED_EXIT_HOST	0	/* Exit handled on host level */
+#define NESTED_EXIT_DONE	1	/* Exit caused nested vmexit  */
+#define NESTED_EXIT_CONTINUE	2	/* Further checks needed      */
+
 #define DEBUGCTL_RESERVED_BITS (~(0x3fULL))
 
 /* Turn on to get debugging output*/
@@ -126,7 +130,7 @@ module_param(nested, int, S_IRUGO);
 static void svm_flush_tlb(struct kvm_vcpu *vcpu);
 static void svm_complete_interrupts(struct vcpu_svm *svm);
 
-static int nested_svm_exit_handled(struct vcpu_svm *svm, bool kvm_override);
+static int nested_svm_exit_handled(struct vcpu_svm *svm);
 static int nested_svm_vmexit(struct vcpu_svm *svm);
 static int nested_svm_check_exception(struct vcpu_svm *svm, unsigned nr,
 				      bool has_error_code, u32 error_code);
@@ -1365,7 +1369,7 @@ static int nested_svm_check_exception(struct vcpu_svm *svm, unsigned nr,
 	svm->vmcb->control.exit_info_1 = error_code;
 	svm->vmcb->control.exit_info_2 = svm->vcpu.arch.cr2;
 
-	return nested_svm_exit_handled(svm, false);
+	return nested_svm_exit_handled(svm);
 }
 
 static inline int nested_svm_intr(struct vcpu_svm *svm)
@@ -1379,7 +1383,7 @@ static inline int nested_svm_intr(struct vcpu_svm *svm)
 
 		svm->vmcb->control.exit_code = SVM_EXIT_INTR;
 
-		if (nested_svm_exit_handled(svm, false)) {
+		if (nested_svm_exit_handled(svm)) {
 			nsvm_printk("VMexit -> INTR\n");
 			return 1;
 		}
@@ -1465,31 +1469,39 @@ static bool nested_svm_exit_handled_msr(struct vcpu_svm *svm)
 	return ret;
 }
 
-static int nested_svm_exit_handled(struct vcpu_svm *svm, bool kvm_override)
+static int nested_svm_exit_special(struct vcpu_svm *svm)
 {
 	u32 exit_code = svm->vmcb->control.exit_code;
-	bool vmexit = false;
 
-	if (kvm_override) {
-		switch (exit_code) {
-		case SVM_EXIT_INTR:
-		case SVM_EXIT_NMI:
-			return 0;
+	switch (exit_code) {
+	case SVM_EXIT_INTR:
+	case SVM_EXIT_NMI:
+		return NESTED_EXIT_HOST;
 		/* For now we are always handling NPFs when using them */
-		case SVM_EXIT_NPF:
-			if (npt_enabled)
-				return 0;
-			break;
-		/* When we're shadowing, trap PFs */
-		case SVM_EXIT_EXCP_BASE + PF_VECTOR:
-			if (!npt_enabled)
-				return 0;
-			break;
-		default:
-			break;
-		}
+	case SVM_EXIT_NPF:
+		if (npt_enabled)
+			return NESTED_EXIT_HOST;
+		break;
+	/* When we're shadowing, trap PFs */
+	case SVM_EXIT_EXCP_BASE + PF_VECTOR:
+		if (!npt_enabled)
+			return NESTED_EXIT_HOST;
+		break;
+	default:
+		break;
 	}
 
+	return NESTED_EXIT_CONTINUE;
+}
+
+/*
+ * If this function returns true, this #vmexit was already handled
+ */
+static int nested_svm_exit_handled(struct vcpu_svm *svm)
+{
+	u32 exit_code = svm->vmcb->control.exit_code;
+	int vmexit = NESTED_EXIT_HOST;
+
 	switch (exit_code) {
 	case SVM_EXIT_MSR:
 		vmexit = nested_svm_exit_handled_msr(svm);
@@ -1497,42 +1509,42 @@ static int nested_svm_exit_handled(struct vcpu_svm *svm, bool kvm_override)
 	case SVM_EXIT_READ_CR0 ... SVM_EXIT_READ_CR8: {
 		u32 cr_bits = 1 << (exit_code - SVM_EXIT_READ_CR0);
 		if (svm->nested.intercept_cr_read & cr_bits)
-			vmexit = true;
+			vmexit = NESTED_EXIT_DONE;
 		break;
 	}
 	case SVM_EXIT_WRITE_CR0 ... SVM_EXIT_WRITE_CR8: {
 		u32 cr_bits = 1 << (exit_code - SVM_EXIT_WRITE_CR0);
 		if (svm->nested.intercept_cr_write & cr_bits)
-			vmexit = true;
+			vmexit = NESTED_EXIT_DONE;
 		break;
 	}
 	case SVM_EXIT_READ_DR0 ... SVM_EXIT_READ_DR7: {
 		u32 dr_bits = 1 << (exit_code - SVM_EXIT_READ_DR0);
 		if (svm->nested.intercept_dr_read & dr_bits)
-			vmexit = true;
+			vmexit = NESTED_EXIT_DONE;
 		break;
 	}
 	case SVM_EXIT_WRITE_DR0 ... SVM_EXIT_WRITE_DR7: {
 		u32 dr_bits = 1 << (exit_code - SVM_EXIT_WRITE_DR0);
 		if (svm->nested.intercept_dr_write & dr_bits)
-			vmexit = true;
+			vmexit = NESTED_EXIT_DONE;
 		break;
 	}
 	case SVM_EXIT_EXCP_BASE ... SVM_EXIT_EXCP_BASE + 0x1f: {
 		u32 excp_bits = 1 << (exit_code - SVM_EXIT_EXCP_BASE);
 		if (svm->nested.intercept_exceptions & excp_bits)
-			vmexit = true;
+			vmexit = NESTED_EXIT_DONE;
 		break;
 	}
 	default: {
 		u64 exit_bits = 1ULL << (exit_code - SVM_EXIT_INTR);
 		nsvm_printk("exit code: 0x%x\n", exit_code);
 		if (svm->nested.intercept & exit_bits)
-			vmexit = true;
+			vmexit = NESTED_EXIT_DONE;
 	}
 	}
 
-	if (vmexit) {
+	if (vmexit == NESTED_EXIT_DONE) {
 		nsvm_printk("#VMEXIT reason=%04x\n", exit_code);
 		nested_svm_vmexit(svm);
 	}
@@ -2312,10 +2324,18 @@ static int handle_exit(struct kvm_run *kvm_run, struct kvm_vcpu *vcpu)
 	trace_kvm_exit(exit_code, svm->vmcb->save.rip);
 
 	if (is_nested(svm)) {
+		int vmexit;
+
 		nsvm_printk("nested handle_exit: 0x%x | 0x%lx | 0x%lx | 0x%lx\n",
 			    exit_code, svm->vmcb->control.exit_info_1,
 			    svm->vmcb->control.exit_info_2, svm->vmcb->save.rip);
-		if (nested_svm_exit_handled(svm, true))
+
+		vmexit = nested_svm_exit_special(svm);
+
+		if (vmexit == NESTED_EXIT_CONTINUE)
+			vmexit = nested_svm_exit_handled(svm);
+
+		if (vmexit == NESTED_EXIT_DONE)
 			return 1;
 	}