1251767Sgibbs/** 2251767Sgibbs * @file 3251767Sgibbs * @section AUTHORS 4251767Sgibbs * 5251767Sgibbs * Copyright (C) 2010 Rafal Wojtczuk <rafal@invisiblethingslab.com> 6251767Sgibbs * 7251767Sgibbs * Authors: 8251767Sgibbs * Rafal Wojtczuk <rafal@invisiblethingslab.com> 9251767Sgibbs * Daniel De Graaf <dgdegra@tycho.nsa.gov> 10251767Sgibbs * 11251767Sgibbs * @section LICENSE 12251767Sgibbs * 13251767Sgibbs * This library is free software; you can redistribute it and/or 14251767Sgibbs * modify it under the terms of the GNU Lesser General Public 15251767Sgibbs * License as published by the Free Software Foundation; either 16251767Sgibbs * version 2.1 of the License, or (at your option) any later version. 17251767Sgibbs * 18251767Sgibbs * This library is distributed in the hope that it will be useful, 19251767Sgibbs * but WITHOUT ANY WARRANTY; without even the implied warranty of 20251767Sgibbs * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 21251767Sgibbs * Lesser General Public License for more details. 22251767Sgibbs * 23251767Sgibbs * You should have received a copy of the GNU Lesser General Public 24251767Sgibbs * License along with this library; if not, write to the Free Software 25251767Sgibbs * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA 26251767Sgibbs * 27251767Sgibbs * @section DESCRIPTION 28251767Sgibbs * 29251767Sgibbs * Originally borrowed from the Qubes OS Project, http://www.qubes-os.org, 30251767Sgibbs * this code has been substantially rewritten to use the gntdev and gntalloc 31251767Sgibbs * devices instead of raw MFNs and map_foreign_range. 32251767Sgibbs * 33251767Sgibbs * This is a library for inter-domain communication. A standard Xen ring 34251767Sgibbs * buffer is used, with a datagram-based interface built on top. The grant 35251767Sgibbs * reference and event channels are shared in XenStore under a user-specified 36251767Sgibbs * path. 37251767Sgibbs * 38251767Sgibbs * The ring.h macros define an asymmetric interface to a shared data structure 39251767Sgibbs * that assumes all rings reside in a single contiguous memory space. This is 40251767Sgibbs * not suitable for vchan because the interface to the ring is symmetric except 41251767Sgibbs * for the setup. Unlike the producer-consumer rings defined in ring.h, the 42251767Sgibbs * size of the rings used in vchan are determined at execution time instead of 43251767Sgibbs * compile time, so the macros in ring.h cannot be used to access the rings. 44251767Sgibbs */ 45251767Sgibbs 46251767Sgibbs#include <stdint.h> 47251767Sgibbs#include <sys/types.h> 48251767Sgibbs 49251767Sgibbsstruct ring_shared { 50251767Sgibbs uint32_t cons, prod; 51251767Sgibbs}; 52251767Sgibbs 53251767Sgibbs#define VCHAN_NOTIFY_WRITE 0x1 54251767Sgibbs#define VCHAN_NOTIFY_READ 0x2 55251767Sgibbs 56251767Sgibbs/** 57251767Sgibbs * vchan_interface: primary shared data structure 58251767Sgibbs */ 59251767Sgibbsstruct vchan_interface { 60251767Sgibbs /** 61251767Sgibbs * Standard consumer/producer interface, one pair per buffer 62251767Sgibbs * left is client write, server read 63251767Sgibbs * right is client read, server write 64251767Sgibbs */ 65251767Sgibbs struct ring_shared left, right; 66251767Sgibbs /** 67251767Sgibbs * size of the rings, which determines their location 68251767Sgibbs * 10 - at offset 1024 in ring's page 69251767Sgibbs * 11 - at offset 2048 in ring's page 70251767Sgibbs * 12+ - uses 2^(N-12) grants to describe the multi-page ring 71251767Sgibbs * These should remain constant once the page is shared. 72251767Sgibbs * Only one of the two orders can be 10 (or 11). 73251767Sgibbs */ 74251767Sgibbs uint16_t left_order, right_order; 75251767Sgibbs /** 76251767Sgibbs * Shutdown detection: 77251767Sgibbs * 0: client (or server) has exited 78251767Sgibbs * 1: client (or server) is connected 79251767Sgibbs * 2: client has not yet connected 80251767Sgibbs */ 81251767Sgibbs uint8_t cli_live, srv_live; 82251767Sgibbs /** 83251767Sgibbs * Notification bits: 84251767Sgibbs * VCHAN_NOTIFY_WRITE: send notify when data is written 85251767Sgibbs * VCHAN_NOTIFY_READ: send notify when data is read (consumed) 86251767Sgibbs * cli_notify is used for the client to inform the server of its action 87251767Sgibbs */ 88251767Sgibbs uint8_t cli_notify, srv_notify; 89251767Sgibbs /** 90251767Sgibbs * Grant list: ordering is left, right. Must not extend into actual ring 91251767Sgibbs * or grow beyond the end of the initial shared page. 92251767Sgibbs * These should remain constant once the page is shared, to allow 93251767Sgibbs * for possible remapping by a client that restarts. 94251767Sgibbs */ 95251767Sgibbs uint32_t grants[0]; 96251767Sgibbs}; 97251767Sgibbs 98