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/*
* Copyright (c) 2008, XenSource Inc.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* * Neither the name of XenSource Inc. nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER
* OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
* PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
* LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
* NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
/* log.h: API for writelog communication */
#ifndef __LOG_H__
#define __LOG_H__ 1
#include <inttypes.h>
#include <xen/io/ring.h>
/* for wmb et al */
#include <xenctrl.h>
#define LOGCMD_SHMP "shmp"
#define LOGCMD_PEEK "peek"
#define LOGCMD_CLEAR "clrw"
#define LOGCMD_GET "getw"
#define LOGCMD_KICK "kick"
#define CTLRSPLEN_SHMP 256
#define CTLRSPLEN_PEEK 4
#define CTLRSPLEN_CLEAR 4
#define CTLRSPLEN_GET 4
#define CTLRSPLEN_KICK 0
/* shmregion is arbitrarily capped at 8 megs for a minimum of
* 64 MB of data per read (if there are no contiguous regions)
* In the off-chance that there is more dirty data, multiple
* reads must be done */
#define SHMSIZE (8 * 1024 * 1024)
#define SRINGSIZE 4096
/* The shared memory region is split up into 3 subregions:
* The first half is reserved for the dirty bitmap log.
* The second half begins with 1 page for read request descriptors,
* followed by a big area for supplying read data.
*/
static inline void* bmstart(void* shm)
{
return shm;
}
static inline void* bmend(void* shm)
{
return shm + SHMSIZE/2;
}
static inline void* sringstart(void* shm)
{
return bmend(shm);
}
static inline void* sdatastart(void* shm)
{
return sringstart(shm) + SRINGSIZE;
}
static inline void* sdataend(void* shm)
{
return shm + SHMSIZE;
}
/* format for messages between log client and server */
struct log_ctlmsg {
char msg[4];
char params[16];
};
/* extent descriptor */
struct disk_range {
uint64_t sector;
uint32_t count;
};
/* dirty write logging space. This is an extent ring at the front,
* full of disk_ranges plus a pointer into the data area */
/* I think I'd rather have the header in front of each data section to
* avoid having two separate spaces that can run out, but then I'd either
* lose page alignment on the data blocks or spend an entire page on the
* header */
struct log_extent {
uint64_t sector;
uint32_t count;
uint32_t offset; /* offset from start of data area to start of extent */
};
/* struct above should be 16 bytes, or 256 extents/page */
typedef struct log_extent log_request_t;
typedef struct log_extent log_response_t;
DEFINE_RING_TYPES(log, log_request_t, log_response_t);
#define LOG_HEADER_PAGES 4
#endif
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