// SPDX-License-Identifier: GPL-2.0
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/*
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* ucall support. A ucall is a "hypercall to userspace".
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*
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* Copyright (C) 2019 Red Hat, Inc.
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*/
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#include "kvm_util.h"
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void ucall_init(struct kvm_vm *vm, void *arg)
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{
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}
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void ucall_uninit(struct kvm_vm *vm)
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{
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}
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void ucall(uint64_t cmd, int nargs, ...)
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{
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struct ucall uc = {
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.cmd = cmd,
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};
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va_list va;
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int i;
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nargs = nargs <= UCALL_MAX_ARGS ? nargs : UCALL_MAX_ARGS;
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va_start(va, nargs);
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for (i = 0; i < nargs; ++i)
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uc.args[i] = va_arg(va, uint64_t);
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va_end(va);
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/* Exit via DIAGNOSE 0x501 (normally used for breakpoints) */
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asm volatile ("diag 0,%0,0x501" : : "a"(&uc) : "memory");
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}
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uint64_t get_ucall(struct kvm_vm *vm, uint32_t vcpu_id, struct ucall *uc)
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{
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struct kvm_run *run = vcpu_state(vm, vcpu_id);
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struct ucall ucall = {};
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if (uc)
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memset(uc, 0, sizeof(*uc));
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if (run->exit_reason == KVM_EXIT_S390_SIEIC &&
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run->s390_sieic.icptcode == 4 &&
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(run->s390_sieic.ipa >> 8) == 0x83 && /* 0x83 means DIAGNOSE */
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(run->s390_sieic.ipb >> 16) == 0x501) {
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int reg = run->s390_sieic.ipa & 0xf;
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memcpy(&ucall, addr_gva2hva(vm, run->s.regs.gprs[reg]),
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sizeof(ucall));
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vcpu_run_complete_io(vm, vcpu_id);
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if (uc)
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memcpy(uc, &ucall, sizeof(ucall));
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}
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return ucall.cmd;
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}
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