KVM: SVM: Prepare for SEV-ES exit handling in the sev.c file

This is a pre-patch to consolidate some exit handling code into callable
functions. Follow-on patches for SEV-ES exit handling will then be able
to use them from the sev.c file.
Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
Message-Id: <5b8b0ffca8137f3e1e257f83df9f5c881c8a96a3.1607620209.git.thomas.lendacky@amd.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

arch/x86/kvm/svm/svm.c

@@ -3097,6 +3097,43 @@ static void dump_vmcb(struct kvm_vcpu *vcpu)
 	       "excp_to:", save->last_excp_to);
 }
 
+static int svm_handle_invalid_exit(struct kvm_vcpu *vcpu, u64 exit_code)
+{
+	if (exit_code < ARRAY_SIZE(svm_exit_handlers) &&
+	    svm_exit_handlers[exit_code])
+		return 0;
+
+	vcpu_unimpl(vcpu, "svm: unexpected exit reason 0x%llx\n", exit_code);
+	dump_vmcb(vcpu);
+	vcpu->run->exit_reason = KVM_EXIT_INTERNAL_ERROR;
+	vcpu->run->internal.suberror = KVM_INTERNAL_ERROR_UNEXPECTED_EXIT_REASON;
+	vcpu->run->internal.ndata = 2;
+	vcpu->run->internal.data[0] = exit_code;
+	vcpu->run->internal.data[1] = vcpu->arch.last_vmentry_cpu;
+
+	return -EINVAL;
+}
+
+static int svm_invoke_exit_handler(struct vcpu_svm *svm, u64 exit_code)
+{
+	if (svm_handle_invalid_exit(&svm->vcpu, exit_code))
+		return 0;
+
+#ifdef CONFIG_RETPOLINE
+	if (exit_code == SVM_EXIT_MSR)
+		return msr_interception(svm);
+	else if (exit_code == SVM_EXIT_VINTR)
+		return interrupt_window_interception(svm);
+	else if (exit_code == SVM_EXIT_INTR)
+		return intr_interception(svm);
+	else if (exit_code == SVM_EXIT_HLT)
+		return halt_interception(svm);
+	else if (exit_code == SVM_EXIT_NPF)
+		return npf_interception(svm);
+#endif
+	return svm_exit_handlers[exit_code](svm);
+}
+
 static void svm_get_exit_info(struct kvm_vcpu *vcpu, u64 *info1, u64 *info2,
 			      u32 *intr_info, u32 *error_code)
 {
@@ -3163,32 +3200,7 @@ static int handle_exit(struct kvm_vcpu *vcpu, fastpath_t exit_fastpath)
 	if (exit_fastpath != EXIT_FASTPATH_NONE)
 		return 1;
 
-	if (exit_code >= ARRAY_SIZE(svm_exit_handlers)
-	    || !svm_exit_handlers[exit_code]) {
-		vcpu_unimpl(vcpu, "svm: unexpected exit reason 0x%x\n", exit_code);
-		dump_vmcb(vcpu);
-		vcpu->run->exit_reason = KVM_EXIT_INTERNAL_ERROR;
-		vcpu->run->internal.suberror =
-			KVM_INTERNAL_ERROR_UNEXPECTED_EXIT_REASON;
-		vcpu->run->internal.ndata = 2;
-		vcpu->run->internal.data[0] = exit_code;
-		vcpu->run->internal.data[1] = vcpu->arch.last_vmentry_cpu;
-		return 0;
-	}
-
-#ifdef CONFIG_RETPOLINE
-	if (exit_code == SVM_EXIT_MSR)
-		return msr_interception(svm);
-	else if (exit_code == SVM_EXIT_VINTR)
-		return interrupt_window_interception(svm);
-	else if (exit_code == SVM_EXIT_INTR)
-		return intr_interception(svm);
-	else if (exit_code == SVM_EXIT_HLT)
-		return halt_interception(svm);
-	else if (exit_code == SVM_EXIT_NPF)
-		return npf_interception(svm);
-#endif
-	return svm_exit_handlers[exit_code](svm);
+	return svm_invoke_exit_handler(svm, exit_code);
 }
 
 static void reload_tss(struct kvm_vcpu *vcpu)