eec7f96c2c
QEMU has a policy of keeping a stable guest device ABI. When new guest device
features are introduced they must not change hardware info seen by existing
guests. This is important because operating systems or applications may
"fingerprint" the hardware and refuse to run when the hardware changes. To
always get the latest guest device ABI, run with x86 machine type "pc".
This patch hides the new VIRTIO_BLK_F_CONFIG_WCE virtio feature bit from
existing machine types. Only pc-1.2 and later will expose this feature
by default.
For more info on the VIRTIO_BLK_F_CONFIG_WCE feature bit, see:
commit 13e3dce068
Author: Paolo Bonzini <pbonzini@redhat.com>
Date: Thu Aug 9 16:07:19 2012 +0200
virtio-blk: support VIRTIO_BLK_F_CONFIG_WCE
Also rename VIRTIO_BLK_F_WCACHE to VIRTIO_BLK_F_WCE for consistency with
the spec.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Anthony Liguori <aliguori@us.ibm.com> reported:
This broke qemu-test because it changed the pc-1.0 machine type:
Setting guest RANDOM seed to 47167
*** Running tests ***
Running test /tests/finger-print.sh... OK
--- fingerprints/pc-1.0.x86_64 2011-12-18 13:08:40.000000000 -0600
+++ fingerprint.txt 2012-08-12 13:30:48.000000000 -0500
@@ -55,7 +55,7 @@
/sys/bus/pci/devices/0000:00:06.0/subsystem_device=0x0002
/sys/bus/pci/devices/0000:00:06.0/class=0x010000
/sys/bus/pci/devices/0000:00:06.0/revision=0x00
-/sys/bus/pci/devices/0000:00:06.0/virtio/host-features=0x710006d4
+/sys/bus/pci/devices/0000:00:06.0/virtio/host-features=0x71000ed4
/sys/class/dmi/id/bios_vendor=Bochs
/sys/class/dmi/id/bios_date=01/01/2007
/sys/class/dmi/id/bios_version=Bochs
Guest fingerprint changed for pc-1.0!
Reported-by: Anthony Liguori <aliguori@us.ibm.com>
Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
114 lines
2.9 KiB
C
114 lines
2.9 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 "hw/block-common.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_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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char *serial;
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uint32_t scsi;
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uint32_t config_wce;
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};
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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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