1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * ucall support. A ucall is a "hypercall to userspace".
4 *
5 * Copyright (C) 2018, Red Hat, Inc.
6 */
7 #include "kvm_util.h"
8
9 vm_vaddr_t *ucall_exit_mmio_addr;
10
11 void ucall_arch_init(struct kvm_vm *vm, vm_paddr_t mmio_gpa)
12 {
13 vm_vaddr_t mmio_gva = vm_vaddr_unused_gap(vm, vm->page_size, KVM_UTIL_MIN_VADDR);
14
15 virt_map(vm, mmio_gva, mmio_gpa, 1);
16
17 vm->ucall_mmio_addr = mmio_gpa;
18
19 write_guest_global(vm, ucall_exit_mmio_addr, (vm_vaddr_t *)mmio_gva);
20 }
21
22 void *ucall_arch_get_ucall(struct kvm_vcpu *vcpu)
23 {
24 struct kvm_run *run = vcpu->run;
25
26 if (run->exit_reason == KVM_EXIT_MMIO &&
27 run->mmio.phys_addr == vcpu->vm->ucall_mmio_addr) {
28 TEST_ASSERT(run->mmio.is_write && run->mmio.len == sizeof(uint64_t),
29 "Unexpected ucall exit mmio address access");
30 return (void *)(*((uint64_t *)run->mmio.data));
31 }
32
33 return NULL;
34 }
35
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