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      1 /* $NetBSD: xenring.h,v 1.8 2024/07/16 22:44:38 riastradh Exp $ */
      2 
      3 /*
      4  * Glue goop for xbd ring request/response protocol structures.
      5  *
      6  * These are used only from __XEN_INTERFACE_VERSION__ >= 0x00030201
      7  * prior to which they were part of the public XEN api.
      8  */
      9 
     10 #ifndef _XEN_RING_H
     11 #define _XEN_RING_H
     12 
     13 #if (__XEN_INTERFACE_VERSION__ >= 0x00030201) && \
     14 	(__XEN_INTERFACE_VERSION < 0x00030208)
     15 
     16 #include <xen/include/public/io/ring.h>
     17 
     18 /*
     19  * Undo namespace damage from xen/include/public/io/ring.h
     20  * The proper fix is to get upstream to stop assuming that all OSs use
     21  * mb(), rmb(), wmb().
     22  */
     23 #undef xen_mb
     24 #undef xen_rmb
     25 #undef xen_wmb
     26 
     27 void xen_mb(void);
     28 #define xen_rmb() membar_acquire()
     29 #define xen_wmb() membar_release()
     30 
     31 /*
     32  * Define ring types. These were previously part of the public API.
     33  * Not anymore.
     34  */
     35 /* i386 requests/responses */
     36 struct blkif_x86_32_request {
     37     uint8_t        operation;    /* BLKIF_OP_???                         */
     38     uint8_t        nr_segments;  /* number of segments                   */
     39     blkif_vdev_t   handle;       /* only for read/write requests         */
     40     uint64_t       id;           /* private guest value, echoed in resp  */
     41     blkif_sector_t sector_number;/* start sector idx on disk (r/w only)  */
     42     struct blkif_request_segment seg[BLKIF_MAX_SEGMENTS_PER_REQUEST];
     43 } __packed;
     44 typedef struct blkif_x86_32_request blkif_x86_32_request_t;
     45 
     46 struct blkif_x86_32_response {
     47     uint64_t        id;              /* copied from request */
     48     uint8_t         operation;       /* copied from request */
     49     uint8_t         _pad;
     50     int16_t         status;          /* BLKIF_RSP_???       */
     51 } __packed;
     52 typedef struct blkif_x86_32_response blkif_x86_32_response_t;
     53 
     54 struct blkif_x86_32_request_indirect {
     55     uint8_t        operation;    /* BLKIF_OP_INDIRECT                    */
     56     uint8_t        indirect_op;  /* BLKIF_OP_{READ/WRITE}                */
     57     uint16_t       nr_segments;  /* number of segments                   */
     58     uint64_t       id;		 /* private guest value, echoed in resp  */
     59     blkif_sector_t sector_number;/* start sector idx on disk (r/w only)  */
     60     blkif_vdev_t   handle;       /* only for read/write requests         */
     61     uint16_t	   _pad2;
     62     grant_ref_t    indirect_grefs[BLKIF_MAX_INDIRECT_PAGES_PER_REQUEST];
     63     uint64_t       _pad3;	 /* make it 64 byte aligned */
     64 } __packed;
     65 typedef struct blkif_x86_32_request_indirect blkif_x86_32_request_indirect_t;
     66 
     67 /* amd64-type requests/responses (always used in frontends ) */
     68 
     69 struct blkif_x86_64_request {
     70     uint8_t        operation;    /* BLKIF_OP_???                         */
     71     uint8_t        nr_segments;  /* number of segments                   */
     72     blkif_vdev_t   handle;       /* only for read/write requests         */
     73     uint64_t __attribute__((__aligned__(8))) id;/* private guest value, echoed in resp  */
     74     blkif_sector_t sector_number;/* start sector idx on disk (r/w only)  */
     75     struct blkif_request_segment seg[BLKIF_MAX_SEGMENTS_PER_REQUEST];
     76 };
     77 typedef struct blkif_x86_64_request blkif_x86_64_request_t;
     78 
     79 struct blkif_x86_64_response {
     80     uint64_t __attribute__((__aligned__(8))) id; /* copied from request */
     81     uint8_t         operation;       /* copied from request */
     82     int16_t         status;          /* BLKIF_RSP_???       */
     83 };
     84 typedef struct blkif_x86_64_response blkif_x86_64_response_t;
     85 
     86 struct blkif_x86_64_request_indirect {
     87     uint8_t        operation;    /* BLKIF_OP_INDIRECT                    */
     88     uint8_t        indirect_op;  /* BLKIF_OP_{READ/WRITE}                */
     89     uint16_t       nr_segments;  /* number of segments                   */
     90     uint32_t       _pad1;
     91     uint64_t       id;           /* private guest value, echoed in resp  */
     92     blkif_sector_t sector_number;/* start sector idx on disk (r/w only)  */
     93     blkif_vdev_t   handle;       /* only for read/write requests         */
     94     uint16_t	   _pad2;
     95     grant_ref_t    indirect_grefs[BLKIF_MAX_INDIRECT_PAGES_PER_REQUEST];
     96     uint32_t       _pad3;	 /* make it 64 byte aligned */
     97 } __packed;
     98 typedef struct blkif_x86_64_request_indirect blkif_x86_64_request_indirect_t;
     99 
    100 CTASSERT(sizeof(struct blkif_x86_32_request_indirect)
    101 	== sizeof(struct blkif_x86_64_request_indirect));
    102 CTASSERT(sizeof(struct blkif_request_indirect)
    103 	== sizeof(struct blkif_x86_64_request_indirect));
    104 
    105 DEFINE_RING_TYPES(blkif_x86_32, struct blkif_x86_32_request, struct blkif_x86_32_response);
    106 DEFINE_RING_TYPES(blkif_x86_64, struct blkif_x86_64_request, struct blkif_x86_64_response);
    107 
    108 union blkif_back_ring_proto {
    109 	blkif_back_ring_t ring_n; /* native/common members */
    110 	blkif_x86_32_back_ring_t ring_32;
    111 	blkif_x86_64_back_ring_t ring_64;
    112 };
    113 typedef union blkif_back_ring_proto blkif_back_ring_proto_t;
    114 
    115 #endif /* __XEN_INTERFACE_VERSION__ */
    116 
    117 #endif /* _XEN_RING_H_ */
    118