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
9 void *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
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