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#ifndef __XEN_BLKIF_H__
#define __XEN_BLKIF_H__
#include <xen/io/ring.h>
#include <xen/io/blkif.h>
#include <xen/io/protocols.h>
/* Not a real protocol. Used to generate ring structs which contain
* the elements common to all protocols only. This way we get a
* compiler-checkable way to use common struct elements, so we can
* avoid using switch(protocol) in a number of places. */
struct blkif_common_request {
char dummy;
};
struct blkif_common_response {
char dummy;
};
/* i386 protocol version */
#pragma pack(push, 4)
struct blkif_x86_32_request {
uint8_t operation; /* BLKIF_OP_??? */
uint8_t nr_segments; /* number of segments */
blkif_vdev_t handle; /* only for read/write requests */
uint64_t id; /* private guest value, echoed in resp */
blkif_sector_t sector_number;/* start sector idx on disk (r/w only) */
struct blkif_request_segment seg[BLKIF_MAX_SEGMENTS_PER_REQUEST];
};
struct blkif_x86_32_response {
uint64_t id; /* copied from request */
uint8_t operation; /* copied from request */
int16_t status; /* BLKIF_RSP_??? */
};
typedef struct blkif_x86_32_request blkif_x86_32_request_t;
typedef struct blkif_x86_32_response blkif_x86_32_response_t;
#pragma pack(pop)
/* x86_64 protocol version */
struct blkif_x86_64_request {
uint8_t operation; /* BLKIF_OP_??? */
uint8_t nr_segments; /* number of segments */
blkif_vdev_t handle; /* only for read/write requests */
uint64_t __attribute__((__aligned__(8))) id;
blkif_sector_t sector_number;/* start sector idx on disk (r/w only) */
struct blkif_request_segment seg[BLKIF_MAX_SEGMENTS_PER_REQUEST];
};
struct blkif_x86_64_response {
uint64_t __attribute__((__aligned__(8))) id;
uint8_t operation; /* copied from request */
int16_t status; /* BLKIF_RSP_??? */
};
typedef struct blkif_x86_64_request blkif_x86_64_request_t;
typedef struct blkif_x86_64_response blkif_x86_64_response_t;
DEFINE_RING_TYPES(blkif_common, struct blkif_common_request, struct blkif_common_response);
DEFINE_RING_TYPES(blkif_x86_32, struct blkif_x86_32_request, struct blkif_x86_32_response);
DEFINE_RING_TYPES(blkif_x86_64, struct blkif_x86_64_request, struct blkif_x86_64_response);
union blkif_back_rings {
blkif_back_ring_t native;
blkif_common_back_ring_t common;
blkif_x86_32_back_ring_t x86_32_part;
blkif_x86_64_back_ring_t x86_64_part;
};
typedef union blkif_back_rings blkif_back_rings_t;
enum blkif_protocol {
BLKIF_PROTOCOL_NATIVE = 1,
BLKIF_PROTOCOL_X86_32 = 2,
BLKIF_PROTOCOL_X86_64 = 3,
};
static inline void blkif_get_x86_32_req(blkif_request_t *dst, blkif_x86_32_request_t *src)
{
int i, n = BLKIF_MAX_SEGMENTS_PER_REQUEST;
dst->operation = src->operation;
dst->nr_segments = src->nr_segments;
dst->handle = src->handle;
dst->id = src->id;
dst->sector_number = src->sector_number;
if (src->operation == BLKIF_OP_DISCARD) {
struct blkif_request_discard *s = (void *)src;
struct blkif_request_discard *d = (void *)dst;
d->nr_sectors = s->nr_sectors;
return;
}
/* prevent the compiler from optimizing the code and using src->nr_segments instead */
barrier();
if (n > dst->nr_segments)
n = dst->nr_segments;
for (i = 0; i < n; i++)
dst->seg[i] = src->seg[i];
}
static inline void blkif_get_x86_64_req(blkif_request_t *dst, blkif_x86_64_request_t *src)
{
int i, n = BLKIF_MAX_SEGMENTS_PER_REQUEST;
dst->operation = src->operation;
dst->nr_segments = src->nr_segments;
dst->handle = src->handle;
dst->id = src->id;
dst->sector_number = src->sector_number;
if (src->operation == BLKIF_OP_DISCARD) {
struct blkif_request_discard *s = (void *)src;
struct blkif_request_discard *d = (void *)dst;
d->nr_sectors = s->nr_sectors;
return;
}
/* prevent the compiler from optimizing the code and using src->nr_segments instead */
barrier();
if (n > dst->nr_segments)
n = dst->nr_segments;
for (i = 0; i < n; i++)
dst->seg[i] = src->seg[i];
}
#endif /* __XEN_BLKIF_H__ */
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