qemu/include/hw/block/block.h
Kevin Wolf 307a5f60eb block: Add qdev_prop_drive_iothread property type
Some qdev block devices have support for iothreads and take care of the
AioContext they are running in, but most devices don't know about any of
this. For the latter category, the qdev drive property must make sure
that their BlockBackend is in the main AioContext.

Unfortunately, while the current code just does the same thing for
devices that do support iothreads, this is not correct and it would show
as soon as we actually try to keep a consistent AioContext assignment
across all nodes and users of a block graph subtree: If a node is
already in a non-default AioContext because of one of its users,
attaching a new device should still be possible if that device can work
in the same AioContext. Switching the node back to the main context
first and only then into the device AioContext causes failure (because
the existing user wouldn't allow the switch to the main context).

So devices that support iothreads need a different kind of drive
property that leaves the node in its current AioContext, but by using
this type, the device promises to check later that it can work with this
context.

This patch adds the qdev infrastructure that allows devices to signal
that they handle iothreads and qdev should leave the AioContext alone.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2019-06-04 15:22:22 +02:00

98 lines
3.3 KiB
C

/*
* Common code for block device models
*
* Copyright (C) 2012 Red Hat, Inc.
* Copyright (c) 2003-2008 Fabrice Bellard
*
* This work is licensed under the terms of the GNU GPL, version 2 or
* later. See the COPYING file in the top-level directory.
*/
#ifndef HW_BLOCK_H
#define HW_BLOCK_H
#include "exec/hwaddr.h"
#include "qapi/qapi-types-block-core.h"
/* Configuration */
typedef struct BlockConf {
BlockBackend *blk;
uint16_t physical_block_size;
uint16_t logical_block_size;
uint16_t min_io_size;
uint32_t opt_io_size;
int32_t bootindex;
uint32_t discard_granularity;
/* geometry, not all devices use this */
uint32_t cyls, heads, secs;
OnOffAuto wce;
bool share_rw;
BlockdevOnError rerror;
BlockdevOnError werror;
} BlockConf;
static inline unsigned int get_physical_block_exp(BlockConf *conf)
{
unsigned int exp = 0, size;
for (size = conf->physical_block_size;
size > conf->logical_block_size;
size >>= 1) {
exp++;
}
return exp;
}
#define DEFINE_BLOCK_PROPERTIES_BASE(_state, _conf) \
DEFINE_PROP_BLOCKSIZE("logical_block_size", _state, \
_conf.logical_block_size), \
DEFINE_PROP_BLOCKSIZE("physical_block_size", _state, \
_conf.physical_block_size), \
DEFINE_PROP_UINT16("min_io_size", _state, _conf.min_io_size, 0), \
DEFINE_PROP_UINT32("opt_io_size", _state, _conf.opt_io_size, 0), \
DEFINE_PROP_UINT32("discard_granularity", _state, \
_conf.discard_granularity, -1), \
DEFINE_PROP_ON_OFF_AUTO("write-cache", _state, _conf.wce, \
ON_OFF_AUTO_AUTO), \
DEFINE_PROP_BOOL("share-rw", _state, _conf.share_rw, false)
#define DEFINE_BLOCK_PROPERTIES(_state, _conf) \
DEFINE_PROP_DRIVE("drive", _state, _conf.blk), \
DEFINE_BLOCK_PROPERTIES_BASE(_state, _conf)
#define DEFINE_BLOCK_CHS_PROPERTIES(_state, _conf) \
DEFINE_PROP_UINT32("cyls", _state, _conf.cyls, 0), \
DEFINE_PROP_UINT32("heads", _state, _conf.heads, 0), \
DEFINE_PROP_UINT32("secs", _state, _conf.secs, 0)
#define DEFINE_BLOCK_ERROR_PROPERTIES(_state, _conf) \
DEFINE_PROP_BLOCKDEV_ON_ERROR("rerror", _state, _conf.rerror, \
BLOCKDEV_ON_ERROR_AUTO), \
DEFINE_PROP_BLOCKDEV_ON_ERROR("werror", _state, _conf.werror, \
BLOCKDEV_ON_ERROR_AUTO)
/* Backend access helpers */
bool blk_check_size_and_read_all(BlockBackend *blk, void *buf, hwaddr size,
Error **errp);
/* Configuration helpers */
bool blkconf_geometry(BlockConf *conf, int *trans,
unsigned cyls_max, unsigned heads_max, unsigned secs_max,
Error **errp);
void blkconf_blocksizes(BlockConf *conf);
bool blkconf_apply_backend_options(BlockConf *conf, bool readonly,
bool resizable, Error **errp);
/* Hard disk geometry */
void hd_geometry_guess(BlockBackend *blk,
uint32_t *pcyls, uint32_t *pheads, uint32_t *psecs,
int *ptrans);
int hd_bios_chs_auto_trans(uint32_t cyls, uint32_t heads, uint32_t secs);
#endif