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>
60 lines
1.2 KiB
C
60 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) 2018, Red Hat, Inc.
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*/
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#include "kvm_util.h"
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#define UCALL_PIO_PORT ((uint16_t)0x1000)
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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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asm volatile("in %[port], %%al"
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: : [port] "d" (UCALL_PIO_PORT), "D" (&uc) : "rax", "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_IO && run->io.port == UCALL_PIO_PORT) {
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struct kvm_regs regs;
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vcpu_regs_get(vm, vcpu_id, ®s);
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memcpy(&ucall, addr_gva2hva(vm, (vm_vaddr_t)regs.rdi),
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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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