85f2a4320e
Ensure the out value 'uc' in get_ucall() is properly reporting UCALL_NONE if the call fails. The return value will be correctly reported, however, the out parameter 'uc' will not be. Clear the struct to ensure the correct value is being reported in the out parameter. Signed-off-by: Aaron Lewis <aaronlewis@google.com> Reviewed-by: Andrew Jones <drjones@redhat.com> Reviewed-by: Alexander Graf <graf@amazon.com> Message-Id: <20201012194716.3950330-3-aaronlewis@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
59 lines
1.2 KiB
C
59 lines
1.2 KiB
C
// 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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