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