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
no_mem_handler(struct vcpu * vcpu __unused,int dir,uint64_t addr __unused,int size,uint64_t * val,void * arg1 __unused,long arg2 __unused)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
mmio_handle_non_backed_mem(struct vcpu * vcpu __unused,uint64_t paddr,struct mem_range ** mr_paramp)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