1 /****************************************************************************** 2 * event_channel.h 3 * 4 * Event channels between domains. 5 * 6 * Permission is hereby granted, free of charge, to any person obtaining a copy 7 * of this software and associated documentation files (the "Software"), to 8 * deal in the Software without restriction, including without limitation the 9 * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or 10 * sell copies of the Software, and to permit persons to whom the Software is 11 * furnished to do so, subject to the following conditions: 12 * 13 * The above copyright notice and this permission notice shall be included in 14 * all copies or substantial portions of the Software. 15 * 16 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR 17 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 18 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE 19 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER 20 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING 21 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER 22 * DEALINGS IN THE SOFTWARE. 23 * 24 * Copyright (c) 2003-2004, K A Fraser. 25 */ 26 27 #ifndef __XEN_PUBLIC_EVENT_CHANNEL_H__ 28 #define __XEN_PUBLIC_EVENT_CHANNEL_H__ 29 30 #include "xen.h" 31 32 /* 33 * `incontents 150 evtchn Event Channels 34 * 35 * Event channels are the basic primitive provided by Xen for event 36 * notifications. An event is the Xen equivalent of a hardware 37 * interrupt. They essentially store one bit of information, the event 38 * of interest is signalled by transitioning this bit from 0 to 1. 39 * 40 * Notifications are received by a guest via an upcall from Xen, 41 * indicating when an event arrives (setting the bit). Further 42 * notifications are masked until the bit is cleared again (therefore, 43 * guests must check the value of the bit after re-enabling event 44 * delivery to ensure no missed notifications). 45 * 46 * Event notifications can be masked by setting a flag; this is 47 * equivalent to disabling interrupts and can be used to ensure 48 * atomicity of certain operations in the guest kernel. 49 * 50 * Event channels are represented by the evtchn_* fields in 51 * struct shared_info and struct vcpu_info. 52 */ 53 54 /* 55 * ` enum neg_errnoval 56 * ` HYPERVISOR_event_channel_op(enum event_channel_op cmd, VOID *args) 57 * ` 58 * @cmd == EVTCHNOP_* (event-channel operation). 59 * @args == struct evtchn_* Operation-specific extra arguments (NULL if none). 60 */ 61 62 /* ` enum event_channel_op { // EVTCHNOP_* => struct evtchn_* */ 63 #define EVTCHNOP_close 3 64 #define EVTCHNOP_send 4 65 #define EVTCHNOP_alloc_unbound 6 66 /* ` } */ 67 68 typedef UINT32 evtchn_port_t; 69 DEFINE_XEN_GUEST_HANDLE(evtchn_port_t); 70 71 /* 72 * EVTCHNOP_alloc_unbound: Allocate a port in domain <dom> and mark as 73 * accepting interdomain bindings from domain <remote_dom>. A fresh port 74 * is allocated in <dom> and returned as <port>. 75 * NOTES: 76 * 1. If the caller is unprivileged then <dom> must be DOMID_SELF. 77 * 2. <rdom> may be DOMID_SELF, allowing loopback connections. 78 */ 79 struct evtchn_alloc_unbound { 80 /* IN parameters */ 81 domid_t dom, remote_dom; 82 /* OUT parameters */ 83 evtchn_port_t port; 84 }; 85 typedef struct evtchn_alloc_unbound evtchn_alloc_unbound_t; 86 87 /* 88 * EVTCHNOP_close: Close a local event channel <port>. If the channel is 89 * interdomain then the remote end is placed in the unbound state 90 * (EVTCHNSTAT_unbound), awaiting a new connection. 91 */ 92 struct evtchn_close { 93 /* IN parameters. */ 94 evtchn_port_t port; 95 }; 96 typedef struct evtchn_close evtchn_close_t; 97 98 /* 99 * EVTCHNOP_send: Send an event to the remote end of the channel whose local 100 * endpoint is <port>. 101 */ 102 struct evtchn_send { 103 /* IN parameters. */ 104 evtchn_port_t port; 105 }; 106 typedef struct evtchn_send evtchn_send_t; 107 108 #endif /* __XEN_PUBLIC_EVENT_CHANNEL_H__ */ 109 110 /* 111 * Local variables: 112 * mode: C 113 * c-file-style: "BSD" 114 * c-basic-offset: 4 115 * tab-width: 4 116 * indent-tabs-mode: nil 117 * End: 118 */ 119