7f510c8f01
This is a license change only commit, which can be found upstream in the Xen tree as 937324f032f4f77866e80e39de0d697fa5131df1. Sponsored by: Citrix Systems R&D
102 lines
3.7 KiB
C
102 lines
3.7 KiB
C
/**
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* @file
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* @section AUTHORS
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*
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* Copyright (C) 2010 Rafal Wojtczuk <rafal@invisiblethingslab.com>
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*
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* Authors:
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* Rafal Wojtczuk <rafal@invisiblethingslab.com>
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* Daniel De Graaf <dgdegra@tycho.nsa.gov>
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*
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* @section LICENSE
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*
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* Permission is hereby granted, free of charge, to any person obtaining a copy
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* of this software and associated documentation files (the "Software"), to
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* deal in the Software without restriction, including without limitation the
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* rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
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* sell copies of the Software, and to permit persons to whom the Software is
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* furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be included in
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* all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
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* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
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* DEALINGS IN THE SOFTWARE.
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*
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* @section DESCRIPTION
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*
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* Originally borrowed from the Qubes OS Project, http://www.qubes-os.org,
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* this code has been substantially rewritten to use the gntdev and gntalloc
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* devices instead of raw MFNs and map_foreign_range.
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*
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* This is a library for inter-domain communication. A standard Xen ring
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* buffer is used, with a datagram-based interface built on top. The grant
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* reference and event channels are shared in XenStore under a user-specified
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* path.
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*
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* The ring.h macros define an asymmetric interface to a shared data structure
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* that assumes all rings reside in a single contiguous memory space. This is
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* not suitable for vchan because the interface to the ring is symmetric except
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* for the setup. Unlike the producer-consumer rings defined in ring.h, the
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* size of the rings used in vchan are determined at execution time instead of
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* compile time, so the macros in ring.h cannot be used to access the rings.
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*/
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#include <stdint.h>
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#include <sys/types.h>
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struct ring_shared {
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uint32_t cons, prod;
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};
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#define VCHAN_NOTIFY_WRITE 0x1
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#define VCHAN_NOTIFY_READ 0x2
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/**
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* vchan_interface: primary shared data structure
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*/
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struct vchan_interface {
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/**
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* Standard consumer/producer interface, one pair per buffer
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* left is client write, server read
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* right is client read, server write
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*/
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struct ring_shared left, right;
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/**
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* size of the rings, which determines their location
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* 10 - at offset 1024 in ring's page
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* 11 - at offset 2048 in ring's page
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* 12+ - uses 2^(N-12) grants to describe the multi-page ring
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* These should remain constant once the page is shared.
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* Only one of the two orders can be 10 (or 11).
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*/
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uint16_t left_order, right_order;
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/**
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* Shutdown detection:
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* 0: client (or server) has exited
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* 1: client (or server) is connected
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* 2: client has not yet connected
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*/
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uint8_t cli_live, srv_live;
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/**
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* Notification bits:
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* VCHAN_NOTIFY_WRITE: send notify when data is written
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* VCHAN_NOTIFY_READ: send notify when data is read (consumed)
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* cli_notify is used for the client to inform the server of its action
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*/
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uint8_t cli_notify, srv_notify;
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/**
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* Grant list: ordering is left, right. Must not extend into actual ring
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* or grow beyond the end of the initial shared page.
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* These should remain constant once the page is shared, to allow
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* for possible remapping by a client that restarts.
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*/
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uint32_t grants[0];
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};
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