Merge remote-tracking branch 'remotes/philmd-gitlab/tags/renesas-20201027' into staging
[qemu.git] / hw / block / hd-geometry.c
1 /*
2 * Hard disk geometry utilities
3 *
4 * Copyright (C) 2012 Red Hat, Inc.
5 *
6 * This work is licensed under the terms of the GNU GPL, version 2 or later.
7 * See the COPYING file in the top-level directory.
8 *
9 * This file incorporates work covered by the following copyright and
10 * permission notice:
11 *
12 * Copyright (c) 2003 Fabrice Bellard
13 *
14 * Permission is hereby granted, free of charge, to any person obtaining a copy
15 * of this software and associated documentation files (the "Software"), to deal
16 * in the Software without restriction, including without limitation the rights
17 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
18 * copies of the Software, and to permit persons to whom the Software is
19 * furnished to do so, subject to the following conditions:
20 *
21 * The above copyright notice and this permission notice shall be included in
22 * all copies or substantial portions of the Software.
23 *
24 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
25 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
26 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
27 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
28 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
29 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
30 * THE SOFTWARE.
31 */
32
33 #include "qemu/osdep.h"
34 #include "sysemu/block-backend.h"
35 #include "qapi/qapi-types-block.h"
36 #include "qemu/bswap.h"
37 #include "hw/block/block.h"
38 #include "trace.h"
39
40 struct partition {
41 uint8_t boot_ind; /* 0x80 - active */
42 uint8_t head; /* starting head */
43 uint8_t sector; /* starting sector */
44 uint8_t cyl; /* starting cylinder */
45 uint8_t sys_ind; /* What partition type */
46 uint8_t end_head; /* end head */
47 uint8_t end_sector; /* end sector */
48 uint8_t end_cyl; /* end cylinder */
49 uint32_t start_sect; /* starting sector counting from 0 */
50 uint32_t nr_sects; /* nr of sectors in partition */
51 } QEMU_PACKED;
52
53 /* try to guess the disk logical geometry from the MSDOS partition table.
54 Return 0 if OK, -1 if could not guess */
55 static int guess_disk_lchs(BlockBackend *blk,
56 int *pcylinders, int *pheads, int *psectors)
57 {
58 uint8_t buf[BDRV_SECTOR_SIZE];
59 int i, heads, sectors, cylinders;
60 struct partition *p;
61 uint32_t nr_sects;
62 uint64_t nb_sectors;
63
64 blk_get_geometry(blk, &nb_sectors);
65
66 if (blk_pread(blk, 0, buf, BDRV_SECTOR_SIZE) < 0) {
67 return -1;
68 }
69 /* test msdos magic */
70 if (buf[510] != 0x55 || buf[511] != 0xaa) {
71 return -1;
72 }
73 for (i = 0; i < 4; i++) {
74 p = ((struct partition *)(buf + 0x1be)) + i;
75 nr_sects = le32_to_cpu(p->nr_sects);
76 if (nr_sects && p->end_head) {
77 /* We make the assumption that the partition terminates on
78 a cylinder boundary */
79 heads = p->end_head + 1;
80 sectors = p->end_sector & 63;
81 if (sectors == 0) {
82 continue;
83 }
84 cylinders = nb_sectors / (heads * sectors);
85 if (cylinders < 1 || cylinders > 16383) {
86 continue;
87 }
88 *pheads = heads;
89 *psectors = sectors;
90 *pcylinders = cylinders;
91 trace_hd_geometry_lchs_guess(blk, cylinders, heads, sectors);
92 return 0;
93 }
94 }
95 return -1;
96 }
97
98 static void guess_chs_for_size(BlockBackend *blk,
99 uint32_t *pcyls, uint32_t *pheads, uint32_t *psecs)
100 {
101 uint64_t nb_sectors;
102 int cylinders;
103
104 blk_get_geometry(blk, &nb_sectors);
105
106 cylinders = nb_sectors / (16 * 63);
107 if (cylinders > 16383) {
108 cylinders = 16383;
109 } else if (cylinders < 2) {
110 cylinders = 2;
111 }
112 *pcyls = cylinders;
113 *pheads = 16;
114 *psecs = 63;
115 }
116
117 void hd_geometry_guess(BlockBackend *blk,
118 uint32_t *pcyls, uint32_t *pheads, uint32_t *psecs,
119 int *ptrans)
120 {
121 int cylinders, heads, secs, translation;
122 HDGeometry geo;
123
124 /* Try to probe the backing device geometry, otherwise fallback
125 to the old logic. (as of 12/2014 probing only succeeds on DASDs) */
126 if (blk_probe_geometry(blk, &geo) == 0) {
127 *pcyls = geo.cylinders;
128 *psecs = geo.sectors;
129 *pheads = geo.heads;
130 translation = BIOS_ATA_TRANSLATION_NONE;
131 } else if (guess_disk_lchs(blk, &cylinders, &heads, &secs) < 0) {
132 /* no LCHS guess: use a standard physical disk geometry */
133 guess_chs_for_size(blk, pcyls, pheads, psecs);
134 translation = hd_bios_chs_auto_trans(*pcyls, *pheads, *psecs);
135 } else if (heads > 16) {
136 /* LCHS guess with heads > 16 means that a BIOS LBA
137 translation was active, so a standard physical disk
138 geometry is OK */
139 guess_chs_for_size(blk, pcyls, pheads, psecs);
140 translation = *pcyls * *pheads <= 131072
141 ? BIOS_ATA_TRANSLATION_LARGE
142 : BIOS_ATA_TRANSLATION_LBA;
143 } else {
144 /* LCHS guess with heads <= 16: use as physical geometry */
145 *pcyls = cylinders;
146 *pheads = heads;
147 *psecs = secs;
148 /* disable any translation to be in sync with
149 the logical geometry */
150 translation = BIOS_ATA_TRANSLATION_NONE;
151 }
152 if (ptrans) {
153 *ptrans = translation;
154 }
155 trace_hd_geometry_guess(blk, *pcyls, *pheads, *psecs, translation);
156 }
157
158 int hd_bios_chs_auto_trans(uint32_t cyls, uint32_t heads, uint32_t secs)
159 {
160 return cyls <= 1024 && heads <= 16 && secs <= 63
161 ? BIOS_ATA_TRANSLATION_NONE
162 : BIOS_ATA_TRANSLATION_LBA;
163 }