/usr/include/xen/io/libxenvchan.h is in libxen-dev 4.9.2-0ubuntu1.
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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 | /**
* @file
* @section AUTHORS
*
* Copyright (C) 2010 Rafal Wojtczuk <rafal@invisiblethingslab.com>
*
* Authors:
* Rafal Wojtczuk <rafal@invisiblethingslab.com>
* Daniel De Graaf <dgdegra@tycho.nsa.gov>
*
* @section LICENSE
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to
* deal in the Software without restriction, including without limitation the
* rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
* sell copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
* DEALINGS IN THE SOFTWARE.
*
* @section DESCRIPTION
*
* Originally borrowed from the Qubes OS Project, http://www.qubes-os.org,
* this code has been substantially rewritten to use the gntdev and gntalloc
* devices instead of raw MFNs and map_foreign_range.
*
* This is a library for inter-domain communication. A standard Xen ring
* buffer is used, with a datagram-based interface built on top. The grant
* reference and event channels are shared in XenStore under a user-specified
* path.
*
* The ring.h macros define an asymmetric interface to a shared data structure
* that assumes all rings reside in a single contiguous memory space. This is
* not suitable for vchan because the interface to the ring is symmetric except
* for the setup. Unlike the producer-consumer rings defined in ring.h, the
* size of the rings used in vchan are determined at execution time instead of
* compile time, so the macros in ring.h cannot be used to access the rings.
*/
#include <stdint.h>
#include <sys/types.h>
struct ring_shared {
uint32_t cons, prod;
};
#define VCHAN_NOTIFY_WRITE 0x1
#define VCHAN_NOTIFY_READ 0x2
/**
* vchan_interface: primary shared data structure
*/
struct vchan_interface {
/**
* Standard consumer/producer interface, one pair per buffer
* left is client write, server read
* right is client read, server write
*/
struct ring_shared left, right;
/**
* size of the rings, which determines their location
* 10 - at offset 1024 in ring's page
* 11 - at offset 2048 in ring's page
* 12+ - uses 2^(N-12) grants to describe the multi-page ring
* These should remain constant once the page is shared.
* Only one of the two orders can be 10 (or 11).
*/
uint16_t left_order, right_order;
/**
* Shutdown detection:
* 0: client (or server) has exited
* 1: client (or server) is connected
* 2: client has not yet connected
*/
uint8_t cli_live, srv_live;
/**
* Notification bits:
* VCHAN_NOTIFY_WRITE: send notify when data is written
* VCHAN_NOTIFY_READ: send notify when data is read (consumed)
* cli_notify is used for the client to inform the server of its action
*/
uint8_t cli_notify, srv_notify;
/**
* Grant list: ordering is left, right. Must not extend into actual ring
* or grow beyond the end of the initial shared page.
* These should remain constant once the page is shared, to allow
* for possible remapping by a client that restarts.
*/
uint32_t grants[0];
};
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