1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * ucall support. A ucall is a "hypercall to userspace".
4 *
5 */
6 #include "kvm_util.h"
7
8 /*
9 * ucall_exit_mmio_addr holds per-VM values (global data is duplicated by each
10 * VM), it must not be accessed from host code.
11 */
12 vm_vaddr_t *ucall_exit_mmio_addr;
13
ucall_arch_init(struct kvm_vm * vm,vm_paddr_t mmio_gpa)14 void ucall_arch_init(struct kvm_vm *vm, vm_paddr_t mmio_gpa)
15 {
16 vm_vaddr_t mmio_gva = vm_vaddr_unused_gap(vm, vm->page_size, KVM_UTIL_MIN_VADDR);
17
18 virt_map(vm, mmio_gva, mmio_gpa, 1);
19
20 vm->ucall_mmio_addr = mmio_gpa;
21
22 write_guest_global(vm, ucall_exit_mmio_addr, (vm_vaddr_t *)mmio_gva);
23 }
24
ucall_arch_get_ucall(struct kvm_vcpu * vcpu)25 void *ucall_arch_get_ucall(struct kvm_vcpu *vcpu)
26 {
27 struct kvm_run *run = vcpu->run;
28
29 if (run->exit_reason == KVM_EXIT_MMIO &&
30 run->mmio.phys_addr == vcpu->vm->ucall_mmio_addr) {
31 TEST_ASSERT(run->mmio.is_write && run->mmio.len == sizeof(uint64_t),
32 "Unexpected ucall exit mmio address access");
33
34 return (void *)(*((uint64_t *)run->mmio.data));
35 }
36
37 return NULL;
38 }
39