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 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 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