60 lines
1.1 KiB
C
60 lines
1.1 KiB
C
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// 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 = min(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_vcpu *vcpu, struct ucall *uc)
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{
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struct kvm_run *run = vcpu->run;
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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(vcpu, ®s);
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memcpy(&ucall, addr_gva2hva(vcpu->vm, (vm_vaddr_t)regs.rdi),
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sizeof(ucall));
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vcpu_run_complete_io(vcpu);
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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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