1// SPDX-License-Identifier: GPL-2.0
2/*
3 * ucall support. A ucall is a "hypercall to userspace".
4 *
5 * Copyright (C) 2019 Red Hat, Inc.
6 */
7#include "kvm_util.h"
8
9void *ucall_arch_get_ucall(struct kvm_vcpu *vcpu)
10{
11	struct kvm_run *run = vcpu->run;
12
13	if (run->exit_reason == KVM_EXIT_S390_SIEIC &&
14	    run->s390_sieic.icptcode == 4 &&
15	    (run->s390_sieic.ipa >> 8) == 0x83 &&    /* 0x83 means DIAGNOSE */
16	    (run->s390_sieic.ipb >> 16) == 0x501) {
17		int reg = run->s390_sieic.ipa & 0xf;
18
19		return (void *)run->s.regs.gprs[reg];
20	}
21	return NULL;
22}
23