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 /* 10 * ucall_exit_mmio_addr holds per-VM values (global data is duplicated by each 11 * VM), it must not be accessed from host code. 12 */ 13 static vm_vaddr_t *ucall_exit_mmio_addr; 14 15 void ucall_arch_init(struct kvm_vm *vm, vm_paddr_t mmio_gpa) 16 { 17 vm_vaddr_t mmio_gva = vm_vaddr_unused_gap(vm, vm->page_size, KVM_UTIL_MIN_VADDR); 18 19 virt_map(vm, mmio_gva, mmio_gpa, 1); 20 21 vm->ucall_mmio_addr = mmio_gpa; 22 23 write_guest_global(vm, ucall_exit_mmio_addr, (vm_vaddr_t *)mmio_gva); 24 } 25 26 void ucall_arch_do_ucall(vm_vaddr_t uc) 27 { 28 WRITE_ONCE(*ucall_exit_mmio_addr, uc); 29 } 30 31 void *ucall_arch_get_ucall(struct kvm_vcpu *vcpu) 32 { 33 struct kvm_run *run = vcpu->run; 34 35 if (run->exit_reason == KVM_EXIT_MMIO && 36 run->mmio.phys_addr == vcpu->vm->ucall_mmio_addr) { 37 TEST_ASSERT(run->mmio.is_write && run->mmio.len == sizeof(uint64_t), 38 "Unexpected ucall exit mmio address access"); 39 return (void *)(*((uint64_t *)run->mmio.data)); 40 } 41 42 return NULL; 43 } 44