gwj / at91sam9263 · Files

/*
 * Command line utility to exercise the QEMU I/O path.
 *
 * Copyright (C) 2009 Red Hat, Inc.
 * Copyright (c) 2003-2005 Silicon Graphics, Inc.
 *
 * 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 <sys/types.h>
#include <stdarg.h>
#include <stdio.h>
#include <getopt.h>

#include "qemu-common.h"
#include "block_int.h"
#include "cmd.h"

#define VERSION	"0.0.1"

#define CMD_NOFILE_OK	0x01

char *progname;
static BlockDriverState *bs;

static int misalign;

/*

 * Parse the pattern argument to various sub-commands.
 *
 * Because the pattern is used as an argument to memset it must evaluate
 * to an unsigned integer that fits into a single byte.
 */
static int parse_pattern(const char *arg)
{
	char *endptr = NULL;
	long pattern;

	pattern = strtol(arg, &endptr, 0);
	if (pattern < 0 || pattern > UCHAR_MAX || *endptr != '\0') {
		printf("%s is not a valid pattern byte\n", arg);
		return -1;
	}

	return pattern;
}

/*

 * Memory allocation helpers.
 *
 * Make sure memory is aligned by default, or purposefully misaligned if
 * that is specified on the command line.
 */

#define MISALIGN_OFFSET		16
static void *qemu_io_alloc(size_t len, int pattern)
{
	void *buf;

	if (misalign)
		len += MISALIGN_OFFSET;
	buf = qemu_memalign(512, len);
	memset(buf, pattern, len);
	if (misalign)
		buf += MISALIGN_OFFSET;
	return buf;
}

static void qemu_io_free(void *p)
{
	if (misalign)
		p -= MISALIGN_OFFSET;
	qemu_vfree(p);
}

static void

dump_buffer(const void *buffer, int64_t offset, int len)

{
	int i, j;

	const uint8_t *p;

	for (i = 0, p = buffer; i < len; i += 16) {

		const uint8_t *s = p;

		printf("%08llx:  ", (unsigned long long)offset + i);
		for (j = 0; j < 16 && i + j < len; j++, p++)
			printf("%02x ", *p);
		printf(" ");
		for (j = 0; j < 16 && i + j < len; j++, s++) {

			if (isalnum(*s))

				printf("%c", *s);
			else
				printf(".");
		}
		printf("\n");
	}
}

static void
print_report(const char *op, struct timeval *t, int64_t offset,
		int count, int total, int cnt, int Cflag)
{
	char s1[64], s2[64], ts[64];

	timestr(t, ts, sizeof(ts), Cflag ? VERBOSE_FIXED_TIME : 0);
	if (!Cflag) {
		cvtstr((double)total, s1, sizeof(s1));
		cvtstr(tdiv((double)total, *t), s2, sizeof(s2));
		printf("%s %d/%d bytes at offset %lld\n",
			op, total, count, (long long)offset);
		printf("%s, %d ops; %s (%s/sec and %.4f ops/sec)\n",
			s1, cnt, ts, s2, tdiv((double)cnt, *t));
	} else {/* bytes,ops,time,bytes/sec,ops/sec */
		printf("%d,%d,%s,%.3f,%.3f\n",
			total, cnt, ts,
			tdiv((double)total, *t),
			tdiv((double)cnt, *t));
	}
}

/*
 * Parse multiple length statements for vectored I/O, and construct an I/O
 * vector matching it.
 */
static void *
create_iovec(QEMUIOVector *qiov, char **argv, int nr_iov, int pattern)
{
	size_t *sizes = calloc(nr_iov, sizeof(size_t));
	size_t count = 0;
	void *buf, *p;
	int i;

	for (i = 0; i < nr_iov; i++) {
		char *arg = argv[i];
		long long len;

		len = cvtnum(arg);
		if (len < 0) {
			printf("non-numeric length argument -- %s\n", arg);
			return NULL;
		}

		/* should be SIZE_T_MAX, but that doesn't exist */
		if (len > UINT_MAX) {
			printf("too large length argument -- %s\n", arg);
			return NULL;
		}

		if (len & 0x1ff) {
			printf("length argument %lld is not sector aligned\n",
				len);
			return NULL;
		}

		sizes[i] = len;
		count += len;
	}

	qemu_iovec_init(qiov, nr_iov);

	buf = p = qemu_io_alloc(count, pattern);

	for (i = 0; i < nr_iov; i++) {
		qemu_iovec_add(qiov, p, sizes[i]);
		p += sizes[i];
	}

	free(sizes);
	return buf;
}

static int do_read(char *buf, int64_t offset, int count, int *total)
{
	int ret;

	ret = bdrv_read(bs, offset >> 9, (uint8_t *)buf, count >> 9);
	if (ret < 0)
		return ret;
	*total = count;
	return 1;
}

static int do_write(char *buf, int64_t offset, int count, int *total)
{
	int ret;

	ret = bdrv_write(bs, offset >> 9, (uint8_t *)buf, count >> 9);
	if (ret < 0)
		return ret;
	*total = count;
	return 1;
}

static int do_pread(char *buf, int64_t offset, int count, int *total)
{
	*total = bdrv_pread(bs, offset, (uint8_t *)buf, count);
	if (*total < 0)
		return *total;
	return 1;
}

static int do_pwrite(char *buf, int64_t offset, int count, int *total)
{
	*total = bdrv_pwrite(bs, offset, (uint8_t *)buf, count);
	if (*total < 0)
		return *total;
	return 1;
}

static int do_load_vmstate(char *buf, int64_t offset, int count, int *total)
{
	*total = bdrv_load_vmstate(bs, (uint8_t *)buf, offset, count);
	if (*total < 0)
		return *total;
	return 1;
}

static int do_save_vmstate(char *buf, int64_t offset, int count, int *total)
{
	*total = bdrv_save_vmstate(bs, (uint8_t *)buf, offset, count);
	if (*total < 0)
		return *total;
	return 1;
}

#define NOT_DONE 0x7fffffff
static void aio_rw_done(void *opaque, int ret)
{
	*(int *)opaque = ret;
}

static int do_aio_readv(QEMUIOVector *qiov, int64_t offset, int *total)
{
	BlockDriverAIOCB *acb;
	int async_ret = NOT_DONE;

	acb = bdrv_aio_readv(bs, offset >> 9, qiov, qiov->size >> 9,
			     aio_rw_done, &async_ret);
	if (!acb)
		return -EIO;

	while (async_ret == NOT_DONE)
		qemu_aio_wait();

	*total = qiov->size;
	return async_ret < 0 ? async_ret : 1;
}

static int do_aio_writev(QEMUIOVector *qiov, int64_t offset, int *total)
{
	BlockDriverAIOCB *acb;
	int async_ret = NOT_DONE;

	acb = bdrv_aio_writev(bs, offset >> 9, qiov, qiov->size >> 9,
			      aio_rw_done, &async_ret);
	if (!acb)
		return -EIO;

	while (async_ret == NOT_DONE)
		qemu_aio_wait();

	*total = qiov->size;

	return async_ret < 0 ? async_ret : 1;
}


static const cmdinfo_t read_cmd;

static void
read_help(void)
{
	printf(
"\n"
" reads a range of bytes from the given offset\n"
"\n"
" Example:\n"
" 'read -v 512 1k' - dumps 1 kilobyte read from 512 bytes into the file\n"
"\n"
" Reads a segment of the currently open file, optionally dumping it to the\n"
" standard output stream (with -v option) for subsequent inspection.\n"

" -b, -- read from the VM state rather than the virtual disk\n"

" -C, -- report statistics in a machine parsable format\n"
" -l, -- length for pattern verification (only with -P)\n"

" -p, -- use bdrv_pread to read the file\n"

" -P, -- use a pattern to verify read data\n"

" -q, -- quite mode, do not show I/O statistics\n"

" -s, -- start offset for pattern verification (only with -P)\n"
" -v, -- dump buffer to standard output\n"

"\n");
}

static int
read_f(int argc, char **argv)
{
	struct timeval t1, t2;
	int Cflag = 0, pflag = 0, qflag = 0, vflag = 0;

	int Pflag = 0, sflag = 0, lflag = 0, bflag = 0;

	int c, cnt;
	char *buf;
	int64_t offset;

	int count;
        /* Some compilers get confused and warn if this is not initialized.  */
        int total = 0;

	int pattern = 0, pattern_offset = 0, pattern_count = 0;

	while ((c = getopt(argc, argv, "bCl:pP:qs:v")) != EOF) {

		switch (c) {

		case 'b':
			bflag = 1;
			break;

		case 'C':
			Cflag = 1;
			break;

		case 'l':
			lflag = 1;
			pattern_count = cvtnum(optarg);
			if (pattern_count < 0) {
				printf("non-numeric length argument -- %s\n", optarg);
				return 0;
			}
			break;

		case 'p':
			pflag = 1;
			break;

		case 'P':
			Pflag = 1;

			pattern = parse_pattern(optarg);
			if (pattern < 0)
				return 0;

			break;

		case 'q':
			qflag = 1;
			break;

		case 's':
			sflag = 1;
			pattern_offset = cvtnum(optarg);
			if (pattern_offset < 0) {
				printf("non-numeric length argument -- %s\n", optarg);
				return 0;
			}
			break;

		case 'v':
			vflag = 1;
			break;
		default:
			return command_usage(&read_cmd);
		}
	}

	if (optind != argc - 2)
		return command_usage(&read_cmd);

	if (bflag && pflag) {
		printf("-b and -p cannot be specified at the same time\n");
		return 0;
	}

	offset = cvtnum(argv[optind]);
	if (offset < 0) {
		printf("non-numeric length argument -- %s\n", argv[optind]);
		return 0;
	}

	optind++;
	count = cvtnum(argv[optind]);
	if (count < 0) {
		printf("non-numeric length argument -- %s\n", argv[optind]);
		return 0;
	}

    if (!Pflag && (lflag || sflag)) {
        return command_usage(&read_cmd);
    }

    if (!lflag) {
        pattern_count = count - pattern_offset;
    }

    if ((pattern_count < 0) || (pattern_count + pattern_offset > count))  {
        printf("pattern verfication range exceeds end of read data\n");
        return 0;
    }

	if (!pflag)
		if (offset & 0x1ff) {
			printf("offset %lld is not sector aligned\n",
				(long long)offset);
			return 0;

		if (count & 0x1ff) {
			printf("count %d is not sector aligned\n",
				count);
			return 0;
		}
	}

	buf = qemu_io_alloc(count, 0xab);

	gettimeofday(&t1, NULL);
	if (pflag)
		cnt = do_pread(buf, offset, count, &total);

	else if (bflag)
		cnt = do_load_vmstate(buf, offset, count, &total);

	else
		cnt = do_read(buf, offset, count, &total);
	gettimeofday(&t2, NULL);

	if (cnt < 0) {
		printf("read failed: %s\n", strerror(-cnt));

		goto out;

	}

	if (Pflag) {

		void* cmp_buf = malloc(pattern_count);
		memset(cmp_buf, pattern, pattern_count);
		if (memcmp(buf + pattern_offset, cmp_buf, pattern_count)) {

			printf("Pattern verification failed at offset %lld, "
				"%d bytes\n",

				(long long) offset + pattern_offset, pattern_count);

		}
		free(cmp_buf);
	}

	if (qflag)

		goto out;

        if (vflag)
		dump_buffer(buf, offset, count);

	/* Finally, report back -- -C gives a parsable format */
	t2 = tsub(t2, t1);
	print_report("read", &t2, offset, count, total, cnt, Cflag);

out:

	qemu_io_free(buf);

	return 0;
}

static const cmdinfo_t read_cmd = {
	.name		= "read",
	.altname	= "r",
	.cfunc		= read_f,
	.argmin		= 2,
	.argmax		= -1,

	.args		= "[-abCpqv] [-P pattern [-s off] [-l len]] off len",

	.oneline	= "reads a number of bytes at a specified offset",
	.help		= read_help,
};

static const cmdinfo_t readv_cmd;

static void
readv_help(void)
{
	printf(
"\n"
" reads a range of bytes from the given offset into multiple buffers\n"
"\n"
" Example:\n"
" 'readv -v 512 1k 1k ' - dumps 2 kilobytes read from 512 bytes into the file\n"
"\n"
" Reads a segment of the currently open file, optionally dumping it to the\n"
" standard output stream (with -v option) for subsequent inspection.\n"
" Uses multiple iovec buffers if more than one byte range is specified.\n"
" -C, -- report statistics in a machine parsable format\n"

" -P, -- use a pattern to verify read data\n"

" -v, -- dump buffer to standard output\n"
" -q, -- quite mode, do not show I/O statistics\n"
"\n");
}

static int
readv_f(int argc, char **argv)
{
	struct timeval t1, t2;
	int Cflag = 0, qflag = 0, vflag = 0;
	int c, cnt;

	char *buf;

	int64_t offset;

	int total;
	int nr_iov;

	QEMUIOVector qiov;

	int pattern = 0;
	int Pflag = 0;

	while ((c = getopt(argc, argv, "CP:qv")) != EOF) {

		switch (c) {
		case 'C':
			Cflag = 1;
			break;

		case 'P':
			Pflag = 1;

			pattern = parse_pattern(optarg);
			if (pattern < 0)
				return 0;

			break;

		case 'q':
			qflag = 1;
			break;
		case 'v':
			vflag = 1;
			break;
		default:
			return command_usage(&readv_cmd);
		}
	}

	if (optind > argc - 2)
		return command_usage(&readv_cmd);


	offset = cvtnum(argv[optind]);
	if (offset < 0) {
		printf("non-numeric length argument -- %s\n", argv[optind]);
		return 0;
	}
	optind++;

	if (offset & 0x1ff) {
		printf("offset %lld is not sector aligned\n",
			(long long)offset);
		return 0;
	}

	nr_iov = argc - optind;

	buf = create_iovec(&qiov, &argv[optind], nr_iov, 0xab);

	gettimeofday(&t1, NULL);
	cnt = do_aio_readv(&qiov, offset, &total);
	gettimeofday(&t2, NULL);

	if (cnt < 0) {
		printf("readv failed: %s\n", strerror(-cnt));

		goto out;

	}

	if (Pflag) {

		void* cmp_buf = malloc(qiov.size);
		memset(cmp_buf, pattern, qiov.size);
		if (memcmp(buf, cmp_buf, qiov.size)) {

			printf("Pattern verification failed at offset %lld, "

				"%zd bytes\n",
				(long long) offset, qiov.size);

		}
		free(cmp_buf);
	}

	if (qflag)

		goto out;

        if (vflag)
		dump_buffer(buf, offset, qiov.size);

	/* Finally, report back -- -C gives a parsable format */
	t2 = tsub(t2, t1);
	print_report("read", &t2, offset, qiov.size, total, cnt, Cflag);

out:

	qemu_io_free(buf);
	return 0;
}

static const cmdinfo_t readv_cmd = {
	.name		= "readv",
	.cfunc		= readv_f,
	.argmin		= 2,
	.argmax		= -1,

	.args		= "[-Cqv] [-P pattern ] off len [len..]",

	.oneline	= "reads a number of bytes at a specified offset",
	.help		= readv_help,
};

static const cmdinfo_t write_cmd;

static void
write_help(void)
{
	printf(
"\n"
" writes a range of bytes from the given offset\n"
"\n"
" Example:\n"
" 'write 512 1k' - writes 1 kilobyte at 512 bytes into the open file\n"
"\n"
" Writes into a segment of the currently open file, using a buffer\n"
" filled with a set pattern (0xcdcdcdcd).\n"

" -b, -- write to the VM state rather than the virtual disk\n"

" -p, -- use bdrv_pwrite to write the file\n"
" -P, -- use different pattern to fill file\n"
" -C, -- report statistics in a machine parsable format\n"
" -q, -- quite mode, do not show I/O statistics\n"
"\n");
}

static int
write_f(int argc, char **argv)
{
	struct timeval t1, t2;

	int Cflag = 0, pflag = 0, qflag = 0, bflag = 0;

	int c, cnt;
	char *buf;
	int64_t offset;

	int count;
        /* Some compilers get confused and warn if this is not initialized.  */
        int total = 0;

	int pattern = 0xcd;

	while ((c = getopt(argc, argv, "bCpP:q")) != EOF) {

		switch (c) {

		case 'b':
			bflag = 1;
			break;

		case 'C':
			Cflag = 1;
			break;
		case 'p':
			pflag = 1;
			break;
		case 'P':

			pattern = parse_pattern(optarg);
			if (pattern < 0)
				return 0;

			break;
		case 'q':
			qflag = 1;
			break;
		default:
			return command_usage(&write_cmd);
		}
	}

	if (optind != argc - 2)
		return command_usage(&write_cmd);

	if (bflag && pflag) {
		printf("-b and -p cannot be specified at the same time\n");
		return 0;
	}

	offset = cvtnum(argv[optind]);
	if (offset < 0) {
		printf("non-numeric length argument -- %s\n", argv[optind]);
		return 0;
	}

	optind++;
	count = cvtnum(argv[optind]);
	if (count < 0) {
		printf("non-numeric length argument -- %s\n", argv[optind]);
		return 0;
	}

	if (!pflag) {
		if (offset & 0x1ff) {
			printf("offset %lld is not sector aligned\n",
				(long long)offset);
			return 0;
		}

		if (count & 0x1ff) {
			printf("count %d is not sector aligned\n",
				count);
			return 0;
		}
	}

	buf = qemu_io_alloc(count, pattern);

	gettimeofday(&t1, NULL);
	if (pflag)
		cnt = do_pwrite(buf, offset, count, &total);

	else if (bflag)
		cnt = do_save_vmstate(buf, offset, count, &total);

	else
		cnt = do_write(buf, offset, count, &total);
	gettimeofday(&t2, NULL);

	if (cnt < 0) {
		printf("write failed: %s\n", strerror(-cnt));

		goto out;

	}

	if (qflag)

		goto out;

	/* Finally, report back -- -C gives a parsable format */
	t2 = tsub(t2, t1);
	print_report("wrote", &t2, offset, count, total, cnt, Cflag);

out:

	qemu_io_free(buf);

	return 0;
}

static const cmdinfo_t write_cmd = {
	.name		= "write",
	.altname	= "w",
	.cfunc		= write_f,
	.argmin		= 2,
	.argmax		= -1,

	.args		= "[-abCpq] [-P pattern ] off len",

	.oneline	= "writes a number of bytes at a specified offset",
	.help		= write_help,
};

static const cmdinfo_t writev_cmd;

static void
writev_help(void)
{
	printf(
"\n"
" writes a range of bytes from the given offset source from multiple buffers\n"
"\n"
" Example:\n"
" 'write 512 1k 1k' - writes 2 kilobytes at 512 bytes into the open file\n"
"\n"
" Writes into a segment of the currently open file, using a buffer\n"
" filled with a set pattern (0xcdcdcdcd).\n"
" -P, -- use different pattern to fill file\n"
" -C, -- report statistics in a machine parsable format\n"
" -q, -- quite mode, do not show I/O statistics\n"
"\n");
}

static int
writev_f(int argc, char **argv)
{
	struct timeval t1, t2;
	int Cflag = 0, qflag = 0;
	int c, cnt;

	char *buf;

	int64_t offset;

	int total;
	int nr_iov;

	int pattern = 0xcd;
	QEMUIOVector qiov;

	while ((c = getopt(argc, argv, "CqP:")) != EOF) {
		switch (c) {
		case 'C':
			Cflag = 1;
			break;
		case 'q':
			qflag = 1;
			break;
		case 'P':

			pattern = parse_pattern(optarg);
			if (pattern < 0)
				return 0;

			break;
		default:
			return command_usage(&writev_cmd);
		}
	}

	if (optind > argc - 2)
		return command_usage(&writev_cmd);

	offset = cvtnum(argv[optind]);
	if (offset < 0) {
		printf("non-numeric length argument -- %s\n", argv[optind]);
		return 0;
	}
	optind++;

	if (offset & 0x1ff) {
		printf("offset %lld is not sector aligned\n",
			(long long)offset);
		return 0;
	}

	nr_iov = argc - optind;

	buf = create_iovec(&qiov, &argv[optind], nr_iov, pattern);

	gettimeofday(&t1, NULL);
	cnt = do_aio_writev(&qiov, offset, &total);
	gettimeofday(&t2, NULL);

	if (cnt < 0) {
		printf("writev failed: %s\n", strerror(-cnt));

		goto out;

	}

	if (qflag)

		goto out;

	/* Finally, report back -- -C gives a parsable format */
	t2 = tsub(t2, t1);
	print_report("wrote", &t2, offset, qiov.size, total, cnt, Cflag);

out:

	qemu_io_free(buf);
	return 0;
}

static const cmdinfo_t writev_cmd = {
	.name		= "writev",
	.cfunc		= writev_f,
	.argmin		= 2,
	.argmax		= -1,
	.args		= "[-Cq] [-P pattern ] off len [len..]",
	.oneline	= "writes a number of bytes at a specified offset",
	.help		= writev_help,
};

struct aio_ctx {
	QEMUIOVector qiov;
	int64_t offset;
	char *buf;
	int qflag;
	int vflag;
	int Cflag;
	int Pflag;
	int pattern;
	struct timeval t1;
};

static void
aio_write_done(void *opaque, int ret)
{
	struct aio_ctx *ctx = opaque;
	struct timeval t2;

	gettimeofday(&t2, NULL);


	if (ret < 0) {
		printf("aio_write failed: %s\n", strerror(-ret));

		goto out;

	}

	if (ctx->qflag) {

		goto out;

	}

	/* Finally, report back -- -C gives a parsable format */
	t2 = tsub(t2, ctx->t1);

	print_report("wrote", &t2, ctx->offset, ctx->qiov.size,
		     ctx->qiov.size, 1, ctx->Cflag);

out:

	qemu_io_free(ctx->buf);
	free(ctx);
}

static const cmdinfo_t aio_read_cmd;

static void
aio_read_done(void *opaque, int ret)
{
	struct aio_ctx *ctx = opaque;
	struct timeval t2;

	gettimeofday(&t2, NULL);

	if (ret < 0) {
		printf("readv failed: %s\n", strerror(-ret));

		goto out;

	}

	if (ctx->Pflag) {

		void *cmp_buf = malloc(ctx->qiov.size);

		memset(cmp_buf, ctx->pattern, ctx->qiov.size);
		if (memcmp(ctx->buf, cmp_buf, ctx->qiov.size)) {

			printf("Pattern verification failed at offset %lld, "

				"%zd bytes\n",
				(long long) ctx->offset, ctx->qiov.size);

		}
		free(cmp_buf);
	}

	if (ctx->qflag) {

		goto out;

	}

	if (ctx->vflag) {
		dump_buffer(ctx->buf, ctx->offset, ctx->qiov.size);
	}

	/* Finally, report back -- -C gives a parsable format */
	t2 = tsub(t2, ctx->t1);

	print_report("read", &t2, ctx->offset, ctx->qiov.size,
		     ctx->qiov.size, 1, ctx->Cflag);

out:

	qemu_io_free(ctx->buf);
	free(ctx);
}

static void
aio_read_help(void)
{
	printf(
"\n"
" asynchronously reads a range of bytes from the given offset\n"
"\n"
" Example:\n"
" 'aio_read -v 512 1k 1k ' - dumps 2 kilobytes read from 512 bytes into the file\n"
"\n"
" Reads a segment of the currently open file, optionally dumping it to the\n"
" standard output stream (with -v option) for subsequent inspection.\n"
" The read is performed asynchronously and should the aio_flush command \n"
" should be used to ensure all outstanding aio requests have been completed\n"
" -C, -- report statistics in a machine parsable format\n"
" -P, -- use a pattern to verify read data\n"
" -v, -- dump buffer to standard output\n"
" -q, -- quite mode, do not show I/O statistics\n"
"\n");
}

static int
aio_read_f(int argc, char **argv)
{

	int nr_iov, c;

	struct aio_ctx *ctx = calloc(1, sizeof(struct aio_ctx));
	BlockDriverAIOCB *acb;

	while ((c = getopt(argc, argv, "CP:qv")) != EOF) {
		switch (c) {
		case 'C':
			ctx->Cflag = 1;
			break;
		case 'P':
			ctx->Pflag = 1;

			ctx->pattern = parse_pattern(optarg);
			if (ctx->pattern < 0)
				return 0;

			break;
		case 'q':
			ctx->qflag = 1;
			break;
		case 'v':
			ctx->vflag = 1;
			break;
		default:

			free(ctx);

			return command_usage(&aio_read_cmd);
		}
	}

	if (optind > argc - 2) {
		free(ctx);

		return command_usage(&aio_read_cmd);

	}

	ctx->offset = cvtnum(argv[optind]);
	if (ctx->offset < 0) {
		printf("non-numeric length argument -- %s\n", argv[optind]);

		free(ctx);

		return 0;
	}
	optind++;

	if (ctx->offset & 0x1ff) {
		printf("offset %lld is not sector aligned\n",
			(long long)ctx->offset);

		free(ctx);

		return 0;
	}

	nr_iov = argc - optind;

	ctx->buf = create_iovec(&ctx->qiov, &argv[optind], nr_iov, 0xab);

	gettimeofday(&ctx->t1, NULL);
	acb = bdrv_aio_readv(bs, ctx->offset >> 9, &ctx->qiov,
			      ctx->qiov.size >> 9, aio_read_done, ctx);