tests/boot-sector.c

   1 /*
   2  * QEMU boot sector testing helpers.
   3  *
   4  * Copyright (c) 2016 Red Hat Inc.
   5  *
   6  * Authors:
   7  *  Michael S. Tsirkin <mst@redhat.com>
   8  *  Victor Kaplansky <victork@redhat.com>
   9  *
  10  * This work is licensed under the terms of the GNU GPL, version 2 or later.
  11  * See the COPYING file in the top-level directory.
  12  */
  13 #include "qemu/osdep.h"
  14 #include "boot-sector.h"
  15 #include "qemu-common.h"
  16 #include "libqtest.h"
  17
  18 #define LOW(x) ((x) & 0xff)
  19 #define HIGH(x) ((x) >> 8)
  20
  21 #define SIGNATURE 0xdead
  22 #define SIGNATURE_OFFSET 0x10
  23 #define BOOT_SECTOR_ADDRESS 0x7c00
  24 #define SIGNATURE_ADDR (BOOT_SECTOR_ADDRESS + SIGNATURE_OFFSET)
  25
  26 /* x86 boot sector code: write SIGNATURE into memory,
  27  * then halt.
  28  */
  29 static uint8_t x86_boot_sector[512] = {
  30     /* The first sector will be placed at RAM address 00007C00, and
  31      * the BIOS transfers control to 00007C00
  32      */
  33
  34     /* Data Segment register should be initialized, since pxe
  35      * boot loader can leave it dirty.
  36      */
  37
  38     /* 7c00: move $0000,%ax */
  39     [0x00] = 0xb8,
  40     [0x01] = 0x00,
  41     [0x02] = 0x00,
  42     /* 7c03: move %ax,%ds */
  43     [0x03] = 0x8e,
  44     [0x04] = 0xd8,
  45
  46     /* 7c05: mov $0xdead,%ax */
  47     [0x05] = 0xb8,
  48     [0x06] = LOW(SIGNATURE),
  49     [0x07] = HIGH(SIGNATURE),
  50     /* 7c08:  mov %ax,0x7c10 */
  51     [0x08] = 0xa3,
  52     [0x09] = LOW(SIGNATURE_ADDR),
  53     [0x0a] = HIGH(SIGNATURE_ADDR),
  54
  55     /* 7c0b cli */
  56     [0x0b] = 0xfa,
  57     /* 7c0c: hlt */
  58     [0x0c] = 0xf4,
  59     /* 7c0e: jmp 0x7c07=0x7c0f-3 */
  60     [0x0d] = 0xeb,
  61     [0x0e] = LOW(-3),
  62     /* We mov 0xdead here: set value to make debugging easier */
  63     [SIGNATURE_OFFSET] = LOW(0xface),
  64     [SIGNATURE_OFFSET + 1] = HIGH(0xface),
  65     /* End of boot sector marker */
  66     [0x1FE] = 0x55,
  67     [0x1FF] = 0xAA,
  68 };
  69
  70 /* For s390x, use a mini "kernel" with the appropriate signature */
  71 static const uint8_t s390x_psw[] = {
  72     0x00, 0x08, 0x00, 0x00, 0x80, 0x01, 0x00, 0x00
  73 };
  74 static const uint8_t s390x_code[] = {
  75     0xa7, 0xf4, 0x00, 0x0a,                                /* j 0x10010 */
  76     0x00, 0x00, 0x00, 0x00,
  77     'S', '3', '9', '0',
  78     'E', 'P', 0x00, 0x01,
  79     0xa7, 0x38, HIGH(SIGNATURE_ADDR), LOW(SIGNATURE_ADDR), /* lhi r3,0x7c10 */
  80     0xa7, 0x48, LOW(SIGNATURE), HIGH(SIGNATURE),           /* lhi r4,0xadde */
  81     0x40, 0x40, 0x30, 0x00,                                /* sth r4,0(r3) */
  82     0xa7, 0xf4, 0xff, 0xfa                                 /* j 0x10010 */
  83 };
  84
  85 /* Create boot disk file.  */
  86 int boot_sector_init(char *fname)
  87 {
  88     int fd, ret;
  89     size_t len;
  90     char *boot_code;
  91     const char *arch = qtest_get_arch();
  92
  93     fd = mkstemp(fname);
  94     if (fd < 0) {
  95         fprintf(stderr, "Couldn't open \"%s\": %s", fname, strerror(errno));
  96         return 1;
  97     }
  98
  99     if (g_str_equal(arch, "i386") || g_str_equal(arch, "x86_64")) {
 100         /* Q35 requires a minimum 0x7e000 bytes disk (bug or feature?) */
 101         len = MAX(0x7e000, sizeof(x86_boot_sector));
 102         boot_code = g_malloc0(len);
 103         memcpy(boot_code, x86_boot_sector, sizeof(x86_boot_sector));
 104     } else if (g_str_equal(arch, "ppc64")) {
 105         /* For Open Firmware based system, use a Forth script */
 106         boot_code = g_strdup_printf("\\ Bootscript\n%x %x c! %x %x c!\n",
 107                                     LOW(SIGNATURE), SIGNATURE_ADDR,
 108                                     HIGH(SIGNATURE), SIGNATURE_ADDR + 1);
 109         len = strlen(boot_code);
 110     } else if (g_str_equal(arch, "s390x")) {
 111         len = 0x10000 + sizeof(s390x_code);
 112         boot_code = g_malloc0(len);
 113         memcpy(boot_code, s390x_psw, sizeof(s390x_psw));
 114         memcpy(&boot_code[0x10000], s390x_code, sizeof(s390x_code));
 115     } else {
 116         g_assert_not_reached();
 117     }
 118
 119     ret = write(fd, boot_code, len);
 120     close(fd);
 121
 122     g_free(boot_code);
 123
 124     if (ret != len) {
 125         fprintf(stderr, "Could not write \"%s\"", fname);
 126         return 1;
 127     }
 128
 129     return 0;
 130 }
 131
 132 /* Loop until signature in memory is OK.  */
 133 void boot_sector_test(void)
 134 {
 135     uint8_t signature_low;
 136     uint8_t signature_high;
 137     uint16_t signature;
 138     int i;
 139
 140     /* Wait at most 90 seconds */
 141 #define TEST_DELAY (1 * G_USEC_PER_SEC / 10)
 142 #define TEST_CYCLES MAX((90 * G_USEC_PER_SEC / TEST_DELAY), 1)
 143
 144     /* Poll until code has run and modified memory.  Once it has we know BIOS
 145      * initialization is done.  TODO: check that IP reached the halt
 146      * instruction.
 147      */
 148     for (i = 0; i < TEST_CYCLES; ++i) {
 149         signature_low = readb(SIGNATURE_ADDR);
 150         signature_high = readb(SIGNATURE_ADDR + 1);
 151         signature = (signature_high << 8) | signature_low;
 152         if (signature == SIGNATURE) {
 153             break;
 154         }
 155         g_usleep(TEST_DELAY);
 156     }
 157
 158     g_assert_cmphex(signature, ==, SIGNATURE);
 159 }
 160
 161 /* unlink boot disk file.  */
 162 void boot_sector_cleanup(const char *fname)
 163 {
 164     unlink(fname);
 165 }