1 /*- 2 * SPDX-License-Identifier: BSD-2-Clause 3 * 4 * Copyright (c) 2025 The FreeBSD Foundation 5 * 6 * This software was developed by Konstantin Belousov <kib@FreeBSD.org> 7 * under sponsorship from the FreeBSD Foundation. 8 * 9 * Redistribution and use in source and binary forms, with or without 10 * modification, are permitted provided that the following conditions 11 * are met: 12 * 1. Redistributions of source code must retain the above copyright 13 * notice, this list of conditions and the following disclaimer. 14 * 2. Redistributions in binary form must reproduce the above copyright 15 * notice, this list of conditions and the following disclaimer in the 16 * documentation and/or other materials provided with the distribution. 17 * 18 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 19 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 20 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 21 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 22 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 23 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 24 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 25 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 26 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 27 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 28 * SUCH DAMAGE. 29 */ 30 31 #include <sys/types.h> 32 #include <sys/errno.h> 33 #include <sys/tree.h> 34 #include <machine/vmm.h> 35 36 #include <stdio.h> 37 38 #include "debug.h" 39 #include "mem.h" 40 41 static int 42 no_mem_handler(struct vcpu *vcpu __unused, int dir, uint64_t addr __unused, 43 int size, uint64_t *val, void *arg1 __unused, long arg2 __unused) 44 { 45 if (dir == MEM_F_READ) { 46 switch (size) { 47 case 1: 48 *val = 0xff; 49 break; 50 case 2: 51 *val = 0xffff; 52 break; 53 case 4: 54 *val = 0xffffffff; 55 break; 56 case 8: 57 *val = 0xffffffffffffffff; 58 break; 59 } 60 } 61 return (0); 62 } 63 64 static struct mem_range fb_entry = { 65 .handler = no_mem_handler, 66 .base = 0, 67 .size = 0xffffffffffffffff, 68 }; 69 70 /* 71 * x86 hardware ignores writes without receiver, and returns all 1's 72 * from reads without response to transaction. 73 */ 74 int 75 mmio_handle_non_backed_mem(struct vcpu *vcpu __unused, uint64_t paddr, 76 struct mem_range **mr_paramp) 77 { 78 *mr_paramp = &fb_entry; 79 EPRINTLN("Emulating access to non-existent address to %#lx\n", 80 paddr); 81 return (0); 82 } 83