48ff269272
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>
159 lines
4.6 KiB
C
159 lines
4.6 KiB
C
/*
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* Virtio Block Device
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*
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* Copyright IBM, Corp. 2007
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*
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* Authors:
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* Anthony Liguori <aliguori@us.ibm.com>
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*
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* This work is licensed under the terms of the GNU GPL, version 2. See
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* the COPYING file in the top-level directory.
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*
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*/
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#ifndef _QEMU_VIRTIO_BLK_H
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#define _QEMU_VIRTIO_BLK_H
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#include "hw/virtio/virtio.h"
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#include "hw/block/block.h"
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#include "sysemu/iothread.h"
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#define TYPE_VIRTIO_BLK "virtio-blk-device"
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#define VIRTIO_BLK(obj) \
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OBJECT_CHECK(VirtIOBlock, (obj), TYPE_VIRTIO_BLK)
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/* from Linux's linux/virtio_blk.h */
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/* The ID for virtio_block */
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#define VIRTIO_ID_BLOCK 2
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/* Feature bits */
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#define VIRTIO_BLK_F_BARRIER 0 /* Does host support barriers? */
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#define VIRTIO_BLK_F_SIZE_MAX 1 /* Indicates maximum segment size */
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#define VIRTIO_BLK_F_SEG_MAX 2 /* Indicates maximum # of segments */
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#define VIRTIO_BLK_F_GEOMETRY 4 /* Indicates support of legacy geometry */
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#define VIRTIO_BLK_F_RO 5 /* Disk is read-only */
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#define VIRTIO_BLK_F_BLK_SIZE 6 /* Block size of disk is available*/
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#define VIRTIO_BLK_F_SCSI 7 /* Supports scsi command passthru */
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/* #define VIRTIO_BLK_F_IDENTIFY 8 ATA IDENTIFY supported, DEPRECATED */
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#define VIRTIO_BLK_F_WCE 9 /* write cache enabled */
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#define VIRTIO_BLK_F_TOPOLOGY 10 /* Topology information is available */
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#define VIRTIO_BLK_F_CONFIG_WCE 11 /* write cache configurable */
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#define VIRTIO_BLK_ID_BYTES 20 /* ID string length */
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struct virtio_blk_config
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{
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uint64_t capacity;
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uint32_t size_max;
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uint32_t seg_max;
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uint16_t cylinders;
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uint8_t heads;
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uint8_t sectors;
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uint32_t blk_size;
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uint8_t physical_block_exp;
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uint8_t alignment_offset;
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uint16_t min_io_size;
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uint32_t opt_io_size;
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uint8_t wce;
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} QEMU_PACKED;
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/* These two define direction. */
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#define VIRTIO_BLK_T_IN 0
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#define VIRTIO_BLK_T_OUT 1
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/* This bit says it's a scsi command, not an actual read or write. */
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#define VIRTIO_BLK_T_SCSI_CMD 2
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/* Flush the volatile write cache */
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#define VIRTIO_BLK_T_FLUSH 4
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/* return the device ID string */
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#define VIRTIO_BLK_T_GET_ID 8
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/* Barrier before this op. */
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#define VIRTIO_BLK_T_BARRIER 0x80000000
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/* This is the first element of the read scatter-gather list. */
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struct virtio_blk_outhdr
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{
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/* VIRTIO_BLK_T* */
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uint32_t type;
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/* io priority. */
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uint32_t ioprio;
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/* Sector (ie. 512 byte offset) */
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uint64_t sector;
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};
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#define VIRTIO_BLK_S_OK 0
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#define VIRTIO_BLK_S_IOERR 1
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#define VIRTIO_BLK_S_UNSUPP 2
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/* This is the last element of the write scatter-gather list */
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struct virtio_blk_inhdr
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{
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unsigned char status;
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};
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/* SCSI pass-through header */
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struct virtio_scsi_inhdr
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{
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uint32_t errors;
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uint32_t data_len;
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uint32_t sense_len;
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uint32_t residual;
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};
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struct VirtIOBlkConf
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{
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BlockConf conf;
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IOThread *iothread;
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char *serial;
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uint32_t scsi;
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uint32_t config_wce;
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uint32_t data_plane;
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};
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struct VirtIOBlockDataPlane;
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typedef struct VirtIOBlock {
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VirtIODevice parent_obj;
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BlockDriverState *bs;
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VirtQueue *vq;
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void *rq;
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QEMUBH *bh;
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BlockConf *conf;
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VirtIOBlkConf blk;
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unsigned short sector_mask;
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bool original_wce;
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VMChangeStateEntry *change;
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#ifdef CONFIG_VIRTIO_BLK_DATA_PLANE
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Notifier migration_state_notifier;
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struct VirtIOBlockDataPlane *dataplane;
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#endif
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} VirtIOBlock;
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#define DEFINE_VIRTIO_BLK_FEATURES(_state, _field) \
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DEFINE_VIRTIO_COMMON_FEATURES(_state, _field)
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#ifdef __linux__
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#define DEFINE_VIRTIO_BLK_PROPERTIES(_state, _field) \
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DEFINE_BLOCK_PROPERTIES(_state, _field.conf), \
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DEFINE_BLOCK_CHS_PROPERTIES(_state, _field.conf), \
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DEFINE_PROP_STRING("serial", _state, _field.serial), \
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DEFINE_PROP_BIT("config-wce", _state, _field.config_wce, 0, true), \
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DEFINE_PROP_BIT("scsi", _state, _field.scsi, 0, true), \
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DEFINE_PROP_IOTHREAD("x-iothread", _state, _field.iothread)
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#else
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#define DEFINE_VIRTIO_BLK_PROPERTIES(_state, _field) \
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DEFINE_BLOCK_PROPERTIES(_state, _field.conf), \
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DEFINE_BLOCK_CHS_PROPERTIES(_state, _field.conf), \
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DEFINE_PROP_STRING("serial", _state, _field.serial), \
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DEFINE_PROP_BIT("config-wce", _state, _field.config_wce, 0, true), \
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DEFINE_PROP_IOTHREAD("x-iothread", _state, _field.iothread)
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#endif /* __linux__ */
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void virtio_blk_set_conf(DeviceState *dev, VirtIOBlkConf *blk);
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#endif
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