mirror of
https://github.com/qemu/qemu.git
synced 2024-12-16 07:53:36 +08:00
e4ec5ad464
Replay is capable of recording normal BH events, but sometimes there are single use callbacks scheduled with aio_bh_schedule_oneshot function. This patch enables recording and replaying such callbacks. Block layer uses these events for calling the completion function. Replaying these calls makes the execution deterministic. Signed-off-by: Pavel Dovgalyuk <Pavel.Dovgaluk@ispras.ru> Acked-by: Kevin Wolf <kwolf@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
319 lines
8.9 KiB
C
319 lines
8.9 KiB
C
/*
|
|
* Null block driver
|
|
*
|
|
* Authors:
|
|
* Fam Zheng <famz@redhat.com>
|
|
*
|
|
* Copyright (C) 2014 Red Hat, 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 "qemu/osdep.h"
|
|
#include "qapi/error.h"
|
|
#include "qapi/qmp/qdict.h"
|
|
#include "qapi/qmp/qstring.h"
|
|
#include "qemu/module.h"
|
|
#include "qemu/option.h"
|
|
#include "block/block_int.h"
|
|
#include "sysemu/replay.h"
|
|
|
|
#define NULL_OPT_LATENCY "latency-ns"
|
|
#define NULL_OPT_ZEROES "read-zeroes"
|
|
|
|
typedef struct {
|
|
int64_t length;
|
|
int64_t latency_ns;
|
|
bool read_zeroes;
|
|
} BDRVNullState;
|
|
|
|
static QemuOptsList runtime_opts = {
|
|
.name = "null",
|
|
.head = QTAILQ_HEAD_INITIALIZER(runtime_opts.head),
|
|
.desc = {
|
|
{
|
|
.name = BLOCK_OPT_SIZE,
|
|
.type = QEMU_OPT_SIZE,
|
|
.help = "size of the null block",
|
|
},
|
|
{
|
|
.name = NULL_OPT_LATENCY,
|
|
.type = QEMU_OPT_NUMBER,
|
|
.help = "nanoseconds (approximated) to wait "
|
|
"before completing request",
|
|
},
|
|
{
|
|
.name = NULL_OPT_ZEROES,
|
|
.type = QEMU_OPT_BOOL,
|
|
.help = "return zeroes when read",
|
|
},
|
|
{ /* end of list */ }
|
|
},
|
|
};
|
|
|
|
static void null_co_parse_filename(const char *filename, QDict *options,
|
|
Error **errp)
|
|
{
|
|
/* This functions only exists so that a null-co:// filename is accepted
|
|
* with the null-co driver. */
|
|
if (strcmp(filename, "null-co://")) {
|
|
error_setg(errp, "The only allowed filename for this driver is "
|
|
"'null-co://'");
|
|
return;
|
|
}
|
|
}
|
|
|
|
static void null_aio_parse_filename(const char *filename, QDict *options,
|
|
Error **errp)
|
|
{
|
|
/* This functions only exists so that a null-aio:// filename is accepted
|
|
* with the null-aio driver. */
|
|
if (strcmp(filename, "null-aio://")) {
|
|
error_setg(errp, "The only allowed filename for this driver is "
|
|
"'null-aio://'");
|
|
return;
|
|
}
|
|
}
|
|
|
|
static int null_file_open(BlockDriverState *bs, QDict *options, int flags,
|
|
Error **errp)
|
|
{
|
|
QemuOpts *opts;
|
|
BDRVNullState *s = bs->opaque;
|
|
int ret = 0;
|
|
|
|
opts = qemu_opts_create(&runtime_opts, NULL, 0, &error_abort);
|
|
qemu_opts_absorb_qdict(opts, options, &error_abort);
|
|
s->length =
|
|
qemu_opt_get_size(opts, BLOCK_OPT_SIZE, 1 << 30);
|
|
s->latency_ns =
|
|
qemu_opt_get_number(opts, NULL_OPT_LATENCY, 0);
|
|
if (s->latency_ns < 0) {
|
|
error_setg(errp, "latency-ns is invalid");
|
|
ret = -EINVAL;
|
|
}
|
|
s->read_zeroes = qemu_opt_get_bool(opts, NULL_OPT_ZEROES, false);
|
|
qemu_opts_del(opts);
|
|
bs->supported_write_flags = BDRV_REQ_FUA;
|
|
return ret;
|
|
}
|
|
|
|
static int64_t null_getlength(BlockDriverState *bs)
|
|
{
|
|
BDRVNullState *s = bs->opaque;
|
|
return s->length;
|
|
}
|
|
|
|
static coroutine_fn int null_co_common(BlockDriverState *bs)
|
|
{
|
|
BDRVNullState *s = bs->opaque;
|
|
|
|
if (s->latency_ns) {
|
|
qemu_co_sleep_ns(QEMU_CLOCK_REALTIME, s->latency_ns);
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
static coroutine_fn int null_co_preadv(BlockDriverState *bs,
|
|
uint64_t offset, uint64_t bytes,
|
|
QEMUIOVector *qiov, int flags)
|
|
{
|
|
BDRVNullState *s = bs->opaque;
|
|
|
|
if (s->read_zeroes) {
|
|
qemu_iovec_memset(qiov, 0, 0, bytes);
|
|
}
|
|
|
|
return null_co_common(bs);
|
|
}
|
|
|
|
static coroutine_fn int null_co_pwritev(BlockDriverState *bs,
|
|
uint64_t offset, uint64_t bytes,
|
|
QEMUIOVector *qiov, int flags)
|
|
{
|
|
return null_co_common(bs);
|
|
}
|
|
|
|
static coroutine_fn int null_co_flush(BlockDriverState *bs)
|
|
{
|
|
return null_co_common(bs);
|
|
}
|
|
|
|
typedef struct {
|
|
BlockAIOCB common;
|
|
QEMUTimer timer;
|
|
} NullAIOCB;
|
|
|
|
static const AIOCBInfo null_aiocb_info = {
|
|
.aiocb_size = sizeof(NullAIOCB),
|
|
};
|
|
|
|
static void null_bh_cb(void *opaque)
|
|
{
|
|
NullAIOCB *acb = opaque;
|
|
acb->common.cb(acb->common.opaque, 0);
|
|
qemu_aio_unref(acb);
|
|
}
|
|
|
|
static void null_timer_cb(void *opaque)
|
|
{
|
|
NullAIOCB *acb = opaque;
|
|
acb->common.cb(acb->common.opaque, 0);
|
|
timer_deinit(&acb->timer);
|
|
qemu_aio_unref(acb);
|
|
}
|
|
|
|
static inline BlockAIOCB *null_aio_common(BlockDriverState *bs,
|
|
BlockCompletionFunc *cb,
|
|
void *opaque)
|
|
{
|
|
NullAIOCB *acb;
|
|
BDRVNullState *s = bs->opaque;
|
|
|
|
acb = qemu_aio_get(&null_aiocb_info, bs, cb, opaque);
|
|
/* Only emulate latency after vcpu is running. */
|
|
if (s->latency_ns) {
|
|
aio_timer_init(bdrv_get_aio_context(bs), &acb->timer,
|
|
QEMU_CLOCK_REALTIME, SCALE_NS,
|
|
null_timer_cb, acb);
|
|
timer_mod_ns(&acb->timer,
|
|
qemu_clock_get_ns(QEMU_CLOCK_REALTIME) + s->latency_ns);
|
|
} else {
|
|
replay_bh_schedule_oneshot_event(bdrv_get_aio_context(bs),
|
|
null_bh_cb, acb);
|
|
}
|
|
return &acb->common;
|
|
}
|
|
|
|
static BlockAIOCB *null_aio_preadv(BlockDriverState *bs,
|
|
uint64_t offset, uint64_t bytes,
|
|
QEMUIOVector *qiov, int flags,
|
|
BlockCompletionFunc *cb,
|
|
void *opaque)
|
|
{
|
|
BDRVNullState *s = bs->opaque;
|
|
|
|
if (s->read_zeroes) {
|
|
qemu_iovec_memset(qiov, 0, 0, bytes);
|
|
}
|
|
|
|
return null_aio_common(bs, cb, opaque);
|
|
}
|
|
|
|
static BlockAIOCB *null_aio_pwritev(BlockDriverState *bs,
|
|
uint64_t offset, uint64_t bytes,
|
|
QEMUIOVector *qiov, int flags,
|
|
BlockCompletionFunc *cb,
|
|
void *opaque)
|
|
{
|
|
return null_aio_common(bs, cb, opaque);
|
|
}
|
|
|
|
static BlockAIOCB *null_aio_flush(BlockDriverState *bs,
|
|
BlockCompletionFunc *cb,
|
|
void *opaque)
|
|
{
|
|
return null_aio_common(bs, cb, opaque);
|
|
}
|
|
|
|
static int null_reopen_prepare(BDRVReopenState *reopen_state,
|
|
BlockReopenQueue *queue, Error **errp)
|
|
{
|
|
return 0;
|
|
}
|
|
|
|
static int coroutine_fn null_co_block_status(BlockDriverState *bs,
|
|
bool want_zero, int64_t offset,
|
|
int64_t bytes, int64_t *pnum,
|
|
int64_t *map,
|
|
BlockDriverState **file)
|
|
{
|
|
BDRVNullState *s = bs->opaque;
|
|
int ret = BDRV_BLOCK_OFFSET_VALID;
|
|
|
|
*pnum = bytes;
|
|
*map = offset;
|
|
*file = bs;
|
|
|
|
if (s->read_zeroes) {
|
|
ret |= BDRV_BLOCK_ZERO;
|
|
}
|
|
return ret;
|
|
}
|
|
|
|
static void null_refresh_filename(BlockDriverState *bs)
|
|
{
|
|
const QDictEntry *e;
|
|
|
|
for (e = qdict_first(bs->full_open_options); e;
|
|
e = qdict_next(bs->full_open_options, e))
|
|
{
|
|
/* These options can be ignored */
|
|
if (strcmp(qdict_entry_key(e), "filename") &&
|
|
strcmp(qdict_entry_key(e), "driver") &&
|
|
strcmp(qdict_entry_key(e), NULL_OPT_LATENCY))
|
|
{
|
|
return;
|
|
}
|
|
}
|
|
|
|
snprintf(bs->exact_filename, sizeof(bs->exact_filename), "%s://",
|
|
bs->drv->format_name);
|
|
}
|
|
|
|
static const char *const null_strong_runtime_opts[] = {
|
|
BLOCK_OPT_SIZE,
|
|
NULL_OPT_ZEROES,
|
|
|
|
NULL
|
|
};
|
|
|
|
static BlockDriver bdrv_null_co = {
|
|
.format_name = "null-co",
|
|
.protocol_name = "null-co",
|
|
.instance_size = sizeof(BDRVNullState),
|
|
|
|
.bdrv_file_open = null_file_open,
|
|
.bdrv_parse_filename = null_co_parse_filename,
|
|
.bdrv_getlength = null_getlength,
|
|
|
|
.bdrv_co_preadv = null_co_preadv,
|
|
.bdrv_co_pwritev = null_co_pwritev,
|
|
.bdrv_co_flush_to_disk = null_co_flush,
|
|
.bdrv_reopen_prepare = null_reopen_prepare,
|
|
|
|
.bdrv_co_block_status = null_co_block_status,
|
|
|
|
.bdrv_refresh_filename = null_refresh_filename,
|
|
.strong_runtime_opts = null_strong_runtime_opts,
|
|
};
|
|
|
|
static BlockDriver bdrv_null_aio = {
|
|
.format_name = "null-aio",
|
|
.protocol_name = "null-aio",
|
|
.instance_size = sizeof(BDRVNullState),
|
|
|
|
.bdrv_file_open = null_file_open,
|
|
.bdrv_parse_filename = null_aio_parse_filename,
|
|
.bdrv_getlength = null_getlength,
|
|
|
|
.bdrv_aio_preadv = null_aio_preadv,
|
|
.bdrv_aio_pwritev = null_aio_pwritev,
|
|
.bdrv_aio_flush = null_aio_flush,
|
|
.bdrv_reopen_prepare = null_reopen_prepare,
|
|
|
|
.bdrv_co_block_status = null_co_block_status,
|
|
|
|
.bdrv_refresh_filename = null_refresh_filename,
|
|
.strong_runtime_opts = null_strong_runtime_opts,
|
|
};
|
|
|
|
static void bdrv_null_init(void)
|
|
{
|
|
bdrv_register(&bdrv_null_co);
|
|
bdrv_register(&bdrv_null_aio);
|
|
}
|
|
|
|
block_init(bdrv_null_init);
|