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_bind_interdomain 0
64#define EVTCHNOP_bind_virq        1
65#define EVTCHNOP_bind_pirq        2
66#define EVTCHNOP_close            3
67#define EVTCHNOP_send             4
68#define EVTCHNOP_status           5
69#define EVTCHNOP_alloc_unbound    6
70#define EVTCHNOP_bind_ipi         7
71#define EVTCHNOP_bind_vcpu        8
72#define EVTCHNOP_unmask           9
73#define EVTCHNOP_reset           10
74/* ` } */
75
76#ifndef __XEN_EVTCHN_PORT_DEFINED__
77typedef uint32_t evtchn_port_t;
78DEFINE_XEN_GUEST_HANDLE(evtchn_port_t);
79#define __XEN_EVTCHN_PORT_DEFINED__ 1
80#endif
81
82/*
83 * EVTCHNOP_alloc_unbound: Allocate a port in domain <dom> and mark as
84 * accepting interdomain bindings from domain <remote_dom>. A fresh port
85 * is allocated in <dom> and returned as <port>.
86 * NOTES:
87 *  1. If the caller is unprivileged then <dom> must be DOMID_SELF.
88 *  2. <rdom> may be DOMID_SELF, allowing loopback connections.
89 */
90struct evtchn_alloc_unbound {
91    /* IN parameters */
92    domid_t dom, remote_dom;
93    /* OUT parameters */
94    evtchn_port_t port;
95};
96typedef struct evtchn_alloc_unbound evtchn_alloc_unbound_t;
97
98/*
99 * EVTCHNOP_bind_interdomain: Construct an interdomain event channel between
100 * the calling domain and <remote_dom>. <remote_dom,remote_port> must identify
101 * a port that is unbound and marked as accepting bindings from the calling
102 * domain. A fresh port is allocated in the calling domain and returned as
103 * <local_port>.
104 * NOTES:
105 *  1. <remote_dom> may be DOMID_SELF, allowing loopback connections.
106 */
107struct evtchn_bind_interdomain {
108    /* IN parameters. */
109    domid_t remote_dom;
110    evtchn_port_t remote_port;
111    /* OUT parameters. */
112    evtchn_port_t local_port;
113};
114typedef struct evtchn_bind_interdomain evtchn_bind_interdomain_t;
115
116/*
117 * EVTCHNOP_bind_virq: Bind a local event channel to VIRQ <irq> on specified
118 * vcpu.
119 * NOTES:
120 *  1. Virtual IRQs are classified as per-vcpu or global. See the VIRQ list
121 *     in xen.h for the classification of each VIRQ.
122 *  2. Global VIRQs must be allocated on VCPU0 but can subsequently be
123 *     re-bound via EVTCHNOP_bind_vcpu.
124 *  3. Per-vcpu VIRQs may be bound to at most one event channel per vcpu.
125 *     The allocated event channel is bound to the specified vcpu and the
126 *     binding cannot be changed.
127 */
128struct evtchn_bind_virq {
129    /* IN parameters. */
130    uint32_t virq; /* enum virq */
131    uint32_t vcpu;
132    /* OUT parameters. */
133    evtchn_port_t port;
134};
135typedef struct evtchn_bind_virq evtchn_bind_virq_t;
136
137/*
138 * EVTCHNOP_bind_pirq: Bind a local event channel to a real IRQ (PIRQ <irq>).
139 * NOTES:
140 *  1. A physical IRQ may be bound to at most one event channel per domain.
141 *  2. Only a sufficiently-privileged domain may bind to a physical IRQ.
142 */
143struct evtchn_bind_pirq {
144    /* IN parameters. */
145    uint32_t pirq;
146#define BIND_PIRQ__WILL_SHARE 1
147    uint32_t flags; /* BIND_PIRQ__* */
148    /* OUT parameters. */
149    evtchn_port_t port;
150};
151typedef struct evtchn_bind_pirq evtchn_bind_pirq_t;
152
153/*
154 * EVTCHNOP_bind_ipi: Bind a local event channel to receive events.
155 * NOTES:
156 *  1. The allocated event channel is bound to the specified vcpu. The binding
157 *     may not be changed.
158 */
159struct evtchn_bind_ipi {
160    uint32_t vcpu;
161    /* OUT parameters. */
162    evtchn_port_t port;
163};
164typedef struct evtchn_bind_ipi evtchn_bind_ipi_t;
165
166/*
167 * EVTCHNOP_close: Close a local event channel <port>. If the channel is
168 * interdomain then the remote end is placed in the unbound state
169 * (EVTCHNSTAT_unbound), awaiting a new connection.
170 */
171struct evtchn_close {
172    /* IN parameters. */
173    evtchn_port_t port;
174};
175typedef struct evtchn_close evtchn_close_t;
176
177/*
178 * EVTCHNOP_send: Send an event to the remote end of the channel whose local
179 * endpoint is <port>.
180 */
181struct evtchn_send {
182    /* IN parameters. */
183    evtchn_port_t port;
184};
185typedef struct evtchn_send evtchn_send_t;
186
187/*
188 * EVTCHNOP_status: Get the current status of the communication channel which
189 * has an endpoint at <dom, port>.
190 * NOTES:
191 *  1. <dom> may be specified as DOMID_SELF.
192 *  2. Only a sufficiently-privileged domain may obtain the status of an event
193 *     channel for which <dom> is not DOMID_SELF.
194 */
195struct evtchn_status {
196    /* IN parameters */
197    domid_t  dom;
198    evtchn_port_t port;
199    /* OUT parameters */
200#define EVTCHNSTAT_closed       0  /* Channel is not in use.                 */
201#define EVTCHNSTAT_unbound      1  /* Channel is waiting interdom connection.*/
202#define EVTCHNSTAT_interdomain  2  /* Channel is connected to remote domain. */
203#define EVTCHNSTAT_pirq         3  /* Channel is bound to a phys IRQ line.   */
204#define EVTCHNSTAT_virq         4  /* Channel is bound to a virtual IRQ line */
205#define EVTCHNSTAT_ipi          5  /* Channel is bound to a virtual IPI line */
206    uint32_t status;
207    uint32_t vcpu;                 /* VCPU to which this channel is bound.   */
208    union {
209        struct {
210            domid_t dom;
211        } unbound;                 /* EVTCHNSTAT_unbound */
212        struct {
213            domid_t dom;
214            evtchn_port_t port;
215        } interdomain;             /* EVTCHNSTAT_interdomain */
216        uint32_t pirq;             /* EVTCHNSTAT_pirq        */
217        uint32_t virq;             /* EVTCHNSTAT_virq        */
218    } u;
219};
220typedef struct evtchn_status evtchn_status_t;
221
222/*
223 * EVTCHNOP_bind_vcpu: Specify which vcpu a channel should notify when an
224 * event is pending.
225 * NOTES:
226 *  1. IPI-bound channels always notify the vcpu specified at bind time.
227 *     This binding cannot be changed.
228 *  2. Per-VCPU VIRQ channels always notify the vcpu specified at bind time.
229 *     This binding cannot be changed.
230 *  3. All other channels notify vcpu0 by default. This default is set when
231 *     the channel is allocated (a port that is freed and subsequently reused
232 *     has its binding reset to vcpu0).
233 */
234struct evtchn_bind_vcpu {
235    /* IN parameters. */
236    evtchn_port_t port;
237    uint32_t vcpu;
238};
239typedef struct evtchn_bind_vcpu evtchn_bind_vcpu_t;
240
241/*
242 * EVTCHNOP_unmask: Unmask the specified local event-channel port and deliver
243 * a notification to the appropriate VCPU if an event is pending.
244 */
245struct evtchn_unmask {
246    /* IN parameters. */
247    evtchn_port_t port;
248};
249typedef struct evtchn_unmask evtchn_unmask_t;
250
251/*
252 * EVTCHNOP_reset: Close all event channels associated with specified domain.
253 * NOTES:
254 *  1. <dom> may be specified as DOMID_SELF.
255 *  2. Only a sufficiently-privileged domain may specify other than DOMID_SELF.
256 */
257struct evtchn_reset {
258    /* IN parameters. */
259    domid_t dom;
260};
261typedef struct evtchn_reset evtchn_reset_t;
262
263/*
264 * ` enum neg_errnoval
265 * ` HYPERVISOR_event_channel_op_compat(struct evtchn_op *op)
266 * `
267 * Superceded by new event_channel_op() hypercall since 0x00030202.
268 */
269struct evtchn_op {
270    uint32_t cmd; /* enum event_channel_op */
271    union {
272        struct evtchn_alloc_unbound    alloc_unbound;
273        struct evtchn_bind_interdomain bind_interdomain;
274        struct evtchn_bind_virq        bind_virq;
275        struct evtchn_bind_pirq        bind_pirq;
276        struct evtchn_bind_ipi         bind_ipi;
277        struct evtchn_close            close;
278        struct evtchn_send             send;
279        struct evtchn_status           status;
280        struct evtchn_bind_vcpu        bind_vcpu;
281        struct evtchn_unmask           unmask;
282    } u;
283};
284typedef struct evtchn_op evtchn_op_t;
285DEFINE_XEN_GUEST_HANDLE(evtchn_op_t);
286
287#endif /* __XEN_PUBLIC_EVENT_CHANNEL_H__ */
288
289/*
290 * Local variables:
291 * mode: C
292 * c-set-style: "BSD"
293 * c-basic-offset: 4
294 * tab-width: 4
295 * indent-tabs-mode: nil
296 * End:
297 */
298