qemu/include/hw/virtio/virtio-blk.h
Stefan Hajnoczi 48ff269272 dataplane: replace internal thread with IOThread
Today virtio-blk dataplane uses a 1:1 device-per-thread model.  Now that
IOThreads have been introduced we can generalize this to N:M devices per
threads.

This patch drops thread code from dataplane in favor of running inside
an IOThread AioContext.

As a bonus we solve the case where a guest keeps submitting I/O requests
while dataplane is trying to stop.  Previously the dataplane thread
would continue to process requests until the request gave it a break.
Now we can shut down in bounded time thanks to
aio_context_acquire/release.

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2014-03-13 14:42:24 +01:00

159 lines
4.6 KiB
C

/*
* Virtio Block Device
*
* Copyright IBM, Corp. 2007
*
* Authors:
* Anthony Liguori <aliguori@us.ibm.com>
*
* This work is licensed under the terms of the GNU GPL, version 2. See
* the COPYING file in the top-level directory.
*
*/
#ifndef _QEMU_VIRTIO_BLK_H
#define _QEMU_VIRTIO_BLK_H
#include "hw/virtio/virtio.h"
#include "hw/block/block.h"
#include "sysemu/iothread.h"
#define TYPE_VIRTIO_BLK "virtio-blk-device"
#define VIRTIO_BLK(obj) \
OBJECT_CHECK(VirtIOBlock, (obj), TYPE_VIRTIO_BLK)
/* from Linux's linux/virtio_blk.h */
/* The ID for virtio_block */
#define VIRTIO_ID_BLOCK 2
/* Feature bits */
#define VIRTIO_BLK_F_BARRIER 0 /* Does host support barriers? */
#define VIRTIO_BLK_F_SIZE_MAX 1 /* Indicates maximum segment size */
#define VIRTIO_BLK_F_SEG_MAX 2 /* Indicates maximum # of segments */
#define VIRTIO_BLK_F_GEOMETRY 4 /* Indicates support of legacy geometry */
#define VIRTIO_BLK_F_RO 5 /* Disk is read-only */
#define VIRTIO_BLK_F_BLK_SIZE 6 /* Block size of disk is available*/
#define VIRTIO_BLK_F_SCSI 7 /* Supports scsi command passthru */
/* #define VIRTIO_BLK_F_IDENTIFY 8 ATA IDENTIFY supported, DEPRECATED */
#define VIRTIO_BLK_F_WCE 9 /* write cache enabled */
#define VIRTIO_BLK_F_TOPOLOGY 10 /* Topology information is available */
#define VIRTIO_BLK_F_CONFIG_WCE 11 /* write cache configurable */
#define VIRTIO_BLK_ID_BYTES 20 /* ID string length */
struct virtio_blk_config
{
uint64_t capacity;
uint32_t size_max;
uint32_t seg_max;
uint16_t cylinders;
uint8_t heads;
uint8_t sectors;
uint32_t blk_size;
uint8_t physical_block_exp;
uint8_t alignment_offset;
uint16_t min_io_size;
uint32_t opt_io_size;
uint8_t wce;
} QEMU_PACKED;
/* These two define direction. */
#define VIRTIO_BLK_T_IN 0
#define VIRTIO_BLK_T_OUT 1
/* This bit says it's a scsi command, not an actual read or write. */
#define VIRTIO_BLK_T_SCSI_CMD 2
/* Flush the volatile write cache */
#define VIRTIO_BLK_T_FLUSH 4
/* return the device ID string */
#define VIRTIO_BLK_T_GET_ID 8
/* Barrier before this op. */
#define VIRTIO_BLK_T_BARRIER 0x80000000
/* This is the first element of the read scatter-gather list. */
struct virtio_blk_outhdr
{
/* VIRTIO_BLK_T* */
uint32_t type;
/* io priority. */
uint32_t ioprio;
/* Sector (ie. 512 byte offset) */
uint64_t sector;
};
#define VIRTIO_BLK_S_OK 0
#define VIRTIO_BLK_S_IOERR 1
#define VIRTIO_BLK_S_UNSUPP 2
/* This is the last element of the write scatter-gather list */
struct virtio_blk_inhdr
{
unsigned char status;
};
/* SCSI pass-through header */
struct virtio_scsi_inhdr
{
uint32_t errors;
uint32_t data_len;
uint32_t sense_len;
uint32_t residual;
};
struct VirtIOBlkConf
{
BlockConf conf;
IOThread *iothread;
char *serial;
uint32_t scsi;
uint32_t config_wce;
uint32_t data_plane;
};
struct VirtIOBlockDataPlane;
typedef struct VirtIOBlock {
VirtIODevice parent_obj;
BlockDriverState *bs;
VirtQueue *vq;
void *rq;
QEMUBH *bh;
BlockConf *conf;
VirtIOBlkConf blk;
unsigned short sector_mask;
bool original_wce;
VMChangeStateEntry *change;
#ifdef CONFIG_VIRTIO_BLK_DATA_PLANE
Notifier migration_state_notifier;
struct VirtIOBlockDataPlane *dataplane;
#endif
} VirtIOBlock;
#define DEFINE_VIRTIO_BLK_FEATURES(_state, _field) \
DEFINE_VIRTIO_COMMON_FEATURES(_state, _field)
#ifdef __linux__
#define DEFINE_VIRTIO_BLK_PROPERTIES(_state, _field) \
DEFINE_BLOCK_PROPERTIES(_state, _field.conf), \
DEFINE_BLOCK_CHS_PROPERTIES(_state, _field.conf), \
DEFINE_PROP_STRING("serial", _state, _field.serial), \
DEFINE_PROP_BIT("config-wce", _state, _field.config_wce, 0, true), \
DEFINE_PROP_BIT("scsi", _state, _field.scsi, 0, true), \
DEFINE_PROP_IOTHREAD("x-iothread", _state, _field.iothread)
#else
#define DEFINE_VIRTIO_BLK_PROPERTIES(_state, _field) \
DEFINE_BLOCK_PROPERTIES(_state, _field.conf), \
DEFINE_BLOCK_CHS_PROPERTIES(_state, _field.conf), \
DEFINE_PROP_STRING("serial", _state, _field.serial), \
DEFINE_PROP_BIT("config-wce", _state, _field.config_wce, 0, true), \
DEFINE_PROP_IOTHREAD("x-iothread", _state, _field.iothread)
#endif /* __linux__ */
void virtio_blk_set_conf(DeviceState *dev, VirtIOBlkConf *blk);
#endif