44 lines
1.1 KiB
C
44 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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/*
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* ucall_exit_mmio_addr holds per-VM values (global data is duplicated by each
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* VM), it must not be accessed from host code.
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*/
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static vm_vaddr_t *ucall_exit_mmio_addr;
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void ucall_arch_init(struct kvm_vm *vm, vm_paddr_t mmio_gpa)
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{
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vm_vaddr_t mmio_gva = vm_vaddr_unused_gap(vm, vm->page_size, KVM_UTIL_MIN_VADDR);
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virt_map(vm, mmio_gva, mmio_gpa, 1);
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vm->ucall_mmio_addr = mmio_gpa;
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write_guest_global(vm, ucall_exit_mmio_addr, (vm_vaddr_t *)mmio_gva);
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}
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void ucall_arch_do_ucall(vm_vaddr_t uc)
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{
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WRITE_ONCE(*ucall_exit_mmio_addr, uc);
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}
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void *ucall_arch_get_ucall(struct kvm_vcpu *vcpu)
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{
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struct kvm_run *run = vcpu->run;
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if (run->exit_reason == KVM_EXIT_MMIO &&
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run->mmio.phys_addr == vcpu->vm->ucall_mmio_addr) {
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TEST_ASSERT(run->mmio.is_write && run->mmio.len == sizeof(uint64_t),
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"Unexpected ucall exit mmio address access");
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return (void *)(*((uint64_t *)run->mmio.data));
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}
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return NULL;
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}
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