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 #define UCALL_PIO_PORT ((uint16_t)0x1000) 10 11 void ucall_arch_init(struct kvm_vm *vm, vm_paddr_t mmio_gpa) 12 { 13 } 14 15 void ucall_arch_do_ucall(vm_vaddr_t uc) 16 { 17 asm volatile("in %[port], %%al" 18 : : [port] "d" (UCALL_PIO_PORT), "D" (uc) : "rax", "memory"); 19 } 20 21 void *ucall_arch_get_ucall(struct kvm_vcpu *vcpu) 22 { 23 struct kvm_run *run = vcpu->run; 24 25 if (run->exit_reason == KVM_EXIT_IO && run->io.port == UCALL_PIO_PORT) { 26 struct kvm_regs regs; 27 28 vcpu_regs_get(vcpu, ®s); 29 return (void *)regs.rdi; 30 } 31 return NULL; 32 } 33