Revision 9c5a8433cee3f03ecd67de0046c41ed9b01d1993 authored by Eric Blake on 11 June 2018, 21:39:26 UTC, committed by Michael Roth on 21 June 2018, 01:45:07 UTC
Commit a290f085 exposed a latent bug in qemu-img map introduced during the conversion of block status to be byte-based. Earlier in commit 5e344dd8, the internal interface get_block_status() switched to take byte-based parameters, but still called a sector-based block layer function; as such, rounding was added in the lone caller to obey the contract. However, commit 237d78f8 changed get_block_status() to truly be byte-based, at which point rounding to sector boundaries can result in calling bdrv_block_status() with 'bytes == 0' (a coding error) when the boundary between data and a hole falls mid-sector (true for the past-EOF implicit hole present in POSIX files). Fix things by removing the rounding that is now no longer necessary. See also https://bugzilla.redhat.com/1589738 Fixes: 237d78f8 Reported-by: Dan Kenigsberg <danken@redhat.com> Reported-by: Nir Soffer <nsoffer@redhat.com> Reported-by: Maor Lipchuk <mlipchuk@redhat.com> CC: qemu-stable@nongnu.org Signed-off-by: Eric Blake <eblake@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com> (cherry picked from commit e0b371ed5e2db079051139136fd0478728b6a58f) Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
1 parent d8a919f
boot-sector.c
/*
* QEMU boot sector testing helpers.
*
* Copyright (c) 2016 Red Hat Inc.
*
* Authors:
* Michael S. Tsirkin <mst@redhat.com>
* Victor Kaplansky <victork@redhat.com>
*
* This work is licensed under the terms of the GNU GPL, version 2 or later.
* See the COPYING file in the top-level directory.
*/
#include "qemu/osdep.h"
#include "boot-sector.h"
#include "qemu-common.h"
#include "libqtest.h"
#define LOW(x) ((x) & 0xff)
#define HIGH(x) ((x) >> 8)
#define SIGNATURE 0xdead
#define SIGNATURE_OFFSET 0x10
#define BOOT_SECTOR_ADDRESS 0x7c00
#define SIGNATURE_ADDR (BOOT_SECTOR_ADDRESS + SIGNATURE_OFFSET)
/* x86 boot sector code: write SIGNATURE into memory,
* then halt.
*/
static uint8_t x86_boot_sector[512] = {
/* The first sector will be placed at RAM address 00007C00, and
* the BIOS transfers control to 00007C00
*/
/* Data Segment register should be initialized, since pxe
* boot loader can leave it dirty.
*/
/* 7c00: move $0000,%ax */
[0x00] = 0xb8,
[0x01] = 0x00,
[0x02] = 0x00,
/* 7c03: move %ax,%ds */
[0x03] = 0x8e,
[0x04] = 0xd8,
/* 7c05: mov $0xdead,%ax */
[0x05] = 0xb8,
[0x06] = LOW(SIGNATURE),
[0x07] = HIGH(SIGNATURE),
/* 7c08: mov %ax,0x7c10 */
[0x08] = 0xa3,
[0x09] = LOW(SIGNATURE_ADDR),
[0x0a] = HIGH(SIGNATURE_ADDR),
/* 7c0b cli */
[0x0b] = 0xfa,
/* 7c0c: hlt */
[0x0c] = 0xf4,
/* 7c0e: jmp 0x7c07=0x7c0f-3 */
[0x0d] = 0xeb,
[0x0e] = LOW(-3),
/* We mov 0xdead here: set value to make debugging easier */
[SIGNATURE_OFFSET] = LOW(0xface),
[SIGNATURE_OFFSET + 1] = HIGH(0xface),
/* End of boot sector marker */
[0x1FE] = 0x55,
[0x1FF] = 0xAA,
};
/* For s390x, use a mini "kernel" with the appropriate signature */
static const uint8_t s390x_psw[] = {
0x00, 0x08, 0x00, 0x00, 0x80, 0x01, 0x00, 0x00
};
static const uint8_t s390x_code[] = {
0xa7, 0xf4, 0x00, 0x0a, /* j 0x10010 */
0x00, 0x00, 0x00, 0x00,
'S', '3', '9', '0',
'E', 'P', 0x00, 0x01,
0xa7, 0x38, HIGH(SIGNATURE_ADDR), LOW(SIGNATURE_ADDR), /* lhi r3,0x7c10 */
0xa7, 0x48, LOW(SIGNATURE), HIGH(SIGNATURE), /* lhi r4,0xadde */
0x40, 0x40, 0x30, 0x00, /* sth r4,0(r3) */
0xa7, 0xf4, 0xff, 0xfa /* j 0x10010 */
};
/* Create boot disk file. */
int boot_sector_init(char *fname)
{
int fd, ret;
size_t len;
char *boot_code;
const char *arch = qtest_get_arch();
fd = mkstemp(fname);
if (fd < 0) {
fprintf(stderr, "Couldn't open \"%s\": %s", fname, strerror(errno));
return 1;
}
if (g_str_equal(arch, "i386") || g_str_equal(arch, "x86_64")) {
/* Q35 requires a minimum 0x7e000 bytes disk (bug or feature?) */
len = MAX(0x7e000, sizeof(x86_boot_sector));
boot_code = g_malloc0(len);
memcpy(boot_code, x86_boot_sector, sizeof(x86_boot_sector));
} else if (g_str_equal(arch, "ppc64")) {
/* For Open Firmware based system, use a Forth script */
boot_code = g_strdup_printf("\\ Bootscript\n%x %x c! %x %x c!\n",
LOW(SIGNATURE), SIGNATURE_ADDR,
HIGH(SIGNATURE), SIGNATURE_ADDR + 1);
len = strlen(boot_code);
} else if (g_str_equal(arch, "s390x")) {
len = 0x10000 + sizeof(s390x_code);
boot_code = g_malloc0(len);
memcpy(boot_code, s390x_psw, sizeof(s390x_psw));
memcpy(&boot_code[0x10000], s390x_code, sizeof(s390x_code));
} else {
g_assert_not_reached();
}
ret = write(fd, boot_code, len);
close(fd);
g_free(boot_code);
if (ret != len) {
fprintf(stderr, "Could not write \"%s\"", fname);
return 1;
}
return 0;
}
/* Loop until signature in memory is OK. */
void boot_sector_test(void)
{
uint8_t signature_low;
uint8_t signature_high;
uint16_t signature;
int i;
/* Wait at most 600 seconds (test is slow with TCI and --enable-debug) */
#define TEST_DELAY (1 * G_USEC_PER_SEC / 10)
#define TEST_CYCLES MAX((600 * G_USEC_PER_SEC / TEST_DELAY), 1)
/* Poll until code has run and modified memory. Once it has we know BIOS
* initialization is done. TODO: check that IP reached the halt
* instruction.
*/
for (i = 0; i < TEST_CYCLES; ++i) {
signature_low = readb(SIGNATURE_ADDR);
signature_high = readb(SIGNATURE_ADDR + 1);
signature = (signature_high << 8) | signature_low;
if (signature == SIGNATURE) {
break;
}
g_usleep(TEST_DELAY);
}
g_assert_cmphex(signature, ==, SIGNATURE);
}
/* unlink boot disk file. */
void boot_sector_cleanup(const char *fname)
{
unlink(fname);
}
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