8cfacf0790
Add a logical block size attribute as various guest side tools only increase the filesystem sector size based on it, not the advisory physical block size. For scsi we already have support for a different logical block size in place for CDROMs that we can built upon. Only my recent block device characteristics VPD page needs some fixups. Note that we leave the logial block size for CDROMs hardcoded as the 2k value is expected for it in general. For virtio-blk we already have a feature flag claiming to support a variable logical block size that was added for the s390 kuli hypervisor. Interestingly it does not actually change the units in which the protocol works, which is still fixed at 512 bytes, but only communicates a different minimum I/O granularity. So all we need to do in virtio is to add a trap for unaligned I/O and round down the device size to the next multiple of the logical block size. IDE does not support any other logical block size than 512 bytes. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
104 lines
2.8 KiB
C
104 lines
2.8 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 "virtio.h"
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#include "block.h"
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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_WCACHE 9 /* write cache enabled */
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#define VIRTIO_BLK_F_TOPOLOGY 10 /* Topology information is available */
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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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} __attribute__((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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/* 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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#ifdef __linux__
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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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DEFINE_PROP_BIT("scsi", _state, _field, VIRTIO_BLK_F_SCSI, true)
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#else
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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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#endif
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#endif
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