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 #define EVTCHNOP_init_control 11
75 #define EVTCHNOP_expand_array 12
76 #define EVTCHNOP_set_priority 13
77 /* ` } */
78
79 typedef uint32_t evtchn_port_t;
80 DEFINE_XEN_GUEST_HANDLE(evtchn_port_t);
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 */
90 struct evtchn_alloc_unbound {
91 /* IN parameters */
92 domid_t dom, remote_dom;
93 /* OUT parameters */
94 evtchn_port_t port;
95 };
96 typedef 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 *
105 * In case the peer domain has already tried to set our event channel
106 * pending, before it was bound, EVTCHNOP_bind_interdomain always sets
107 * the local event channel pending.
108 *
109 * The usual pattern of use, in the guest's upcall (or subsequent
110 * handler) is as follows: (Re-enable the event channel for subsequent
111 * signalling and then) check for the existence of whatever condition
112 * is being waited for by other means, and take whatever action is
113 * needed (if any).
114 *
115 * NOTES:
116 * 1. <remote_dom> may be DOMID_SELF, allowing loopback connections.
117 */
118 struct evtchn_bind_interdomain {
119 /* IN parameters. */
120 domid_t remote_dom;
121 evtchn_port_t remote_port;
122 /* OUT parameters. */
123 evtchn_port_t local_port;
124 };
125 typedef struct evtchn_bind_interdomain evtchn_bind_interdomain_t;
126
127 /*
128 * EVTCHNOP_bind_virq: Bind a local event channel to VIRQ <irq> on specified
129 * vcpu.
130 * NOTES:
131 * 1. Virtual IRQs are classified as per-vcpu or global. See the VIRQ list
132 * in xen.h for the classification of each VIRQ.
133 * 2. Global VIRQs must be allocated on VCPU0 but can subsequently be
134 * re-bound via EVTCHNOP_bind_vcpu.
135 * 3. Per-vcpu VIRQs may be bound to at most one event channel per vcpu.
136 * The allocated event channel is bound to the specified vcpu and the
137 * binding cannot be changed.
138 */
139 struct evtchn_bind_virq {
140 /* IN parameters. */
141 uint32_t virq; /* enum virq */
142 uint32_t vcpu;
143 /* OUT parameters. */
144 evtchn_port_t port;
145 };
146 typedef struct evtchn_bind_virq evtchn_bind_virq_t;
147
148 /*
149 * EVTCHNOP_bind_pirq: Bind a local event channel to a real IRQ (PIRQ <irq>).
150 * NOTES:
151 * 1. A physical IRQ may be bound to at most one event channel per domain.
152 * 2. Only a sufficiently-privileged domain may bind to a physical IRQ.
153 */
154 struct evtchn_bind_pirq {
155 /* IN parameters. */
156 uint32_t pirq;
157 #define BIND_PIRQ__WILL_SHARE 1
158 uint32_t flags; /* BIND_PIRQ__* */
159 /* OUT parameters. */
160 evtchn_port_t port;
161 };
162 typedef struct evtchn_bind_pirq evtchn_bind_pirq_t;
163
164 /*
165 * EVTCHNOP_bind_ipi: Bind a local event channel to receive events.
166 * NOTES:
167 * 1. The allocated event channel is bound to the specified vcpu. The binding
168 * may not be changed.
169 */
170 struct evtchn_bind_ipi {
171 uint32_t vcpu;
172 /* OUT parameters. */
173 evtchn_port_t port;
174 };
175 typedef struct evtchn_bind_ipi evtchn_bind_ipi_t;
176
177 /*
178 * EVTCHNOP_close: Close a local event channel <port>. If the channel is
179 * interdomain then the remote end is placed in the unbound state
180 * (EVTCHNSTAT_unbound), awaiting a new connection.
181 */
182 struct evtchn_close {
183 /* IN parameters. */
184 evtchn_port_t port;
185 };
186 typedef struct evtchn_close evtchn_close_t;
187
188 /*
189 * EVTCHNOP_send: Send an event to the remote end of the channel whose local
190 * endpoint is <port>.
191 */
192 struct evtchn_send {
193 /* IN parameters. */
194 evtchn_port_t port;
195 };
196 typedef struct evtchn_send evtchn_send_t;
197
198 /*
199 * EVTCHNOP_status: Get the current status of the communication channel which
200 * has an endpoint at <dom, port>.
201 * NOTES:
202 * 1. <dom> may be specified as DOMID_SELF.
203 * 2. Only a sufficiently-privileged domain may obtain the status of an event
204 * channel for which <dom> is not DOMID_SELF.
205 */
206 struct evtchn_status {
207 /* IN parameters */
208 domid_t dom;
209 evtchn_port_t port;
210 /* OUT parameters */
211 #define EVTCHNSTAT_closed 0 /* Channel is not in use. */
212 #define EVTCHNSTAT_unbound 1 /* Channel is waiting interdom connection.*/
213 #define EVTCHNSTAT_interdomain 2 /* Channel is connected to remote domain. */
214 #define EVTCHNSTAT_pirq 3 /* Channel is bound to a phys IRQ line. */
215 #define EVTCHNSTAT_virq 4 /* Channel is bound to a virtual IRQ line */
216 #define EVTCHNSTAT_ipi 5 /* Channel is bound to a virtual IPI line */
217 uint32_t status;
218 uint32_t vcpu; /* VCPU to which this channel is bound. */
219 union {
220 struct {
221 domid_t dom;
222 } unbound; /* EVTCHNSTAT_unbound */
223 struct {
224 domid_t dom;
225 evtchn_port_t port;
226 } interdomain; /* EVTCHNSTAT_interdomain */
227 uint32_t pirq; /* EVTCHNSTAT_pirq */
228 uint32_t virq; /* EVTCHNSTAT_virq */
229 } u;
230 };
231 typedef struct evtchn_status evtchn_status_t;
232
233 /*
234 * EVTCHNOP_bind_vcpu: Specify which vcpu a channel should notify when an
235 * event is pending.
236 * NOTES:
237 * 1. IPI-bound channels always notify the vcpu specified at bind time.
238 * This binding cannot be changed.
239 * 2. Per-VCPU VIRQ channels always notify the vcpu specified at bind time.
240 * This binding cannot be changed.
241 * 3. All other channels notify vcpu0 by default. This default is set when
242 * the channel is allocated (a port that is freed and subsequently reused
243 * has its binding reset to vcpu0).
244 */
245 struct evtchn_bind_vcpu {
246 /* IN parameters. */
247 evtchn_port_t port;
248 uint32_t vcpu;
249 };
250 typedef struct evtchn_bind_vcpu evtchn_bind_vcpu_t;
251
252 /*
253 * EVTCHNOP_unmask: Unmask the specified local event-channel port and deliver
254 * a notification to the appropriate VCPU if an event is pending.
255 */
256 struct evtchn_unmask {
257 /* IN parameters. */
258 evtchn_port_t port;
259 };
260 typedef struct evtchn_unmask evtchn_unmask_t;
261
262 /*
263 * EVTCHNOP_reset: Close all event channels associated with specified domain.
264 * NOTES:
265 * 1. <dom> may be specified as DOMID_SELF.
266 * 2. Only a sufficiently-privileged domain may specify other than DOMID_SELF.
267 * 3. Destroys all control blocks and event array, resets event channel
268 * operations to 2-level ABI if called with <dom> == DOMID_SELF and FIFO
269 * ABI was used. Guests should not bind events during EVTCHNOP_reset call
270 * as these events are likely to be lost.
271 */
272 struct evtchn_reset {
273 /* IN parameters. */
274 domid_t dom;
275 };
276 typedef struct evtchn_reset evtchn_reset_t;
277
278 /*
279 * EVTCHNOP_init_control: initialize the control block for the FIFO ABI.
280 *
281 * Note: any events that are currently pending will not be resent and
282 * will be lost. Guests should call this before binding any event to
283 * avoid losing any events.
284 */
285 struct evtchn_init_control {
286 /* IN parameters. */
287 uint64_t control_gfn;
288 uint32_t offset;
289 uint32_t vcpu;
290 /* OUT parameters. */
291 uint8_t link_bits;
292 uint8_t _pad[7];
293 };
294 typedef struct evtchn_init_control evtchn_init_control_t;
295
296 /*
297 * EVTCHNOP_expand_array: add an additional page to the event array.
298 */
299 struct evtchn_expand_array {
300 /* IN parameters. */
301 uint64_t array_gfn;
302 };
303 typedef struct evtchn_expand_array evtchn_expand_array_t;
304
305 /*
306 * EVTCHNOP_set_priority: set the priority for an event channel.
307 */
308 struct evtchn_set_priority {
309 /* IN parameters. */
310 uint32_t port;
311 uint32_t priority;
312 };
313 typedef struct evtchn_set_priority evtchn_set_priority_t;
314
315 /*
316 * ` enum neg_errnoval
317 * ` HYPERVISOR_event_channel_op_compat(struct evtchn_op *op)
318 * `
319 * Superceded by new event_channel_op() hypercall since 0x00030202.
320 */
321 struct evtchn_op {
322 uint32_t cmd; /* enum event_channel_op */
323 union {
324 struct evtchn_alloc_unbound alloc_unbound;
325 struct evtchn_bind_interdomain bind_interdomain;
326 struct evtchn_bind_virq bind_virq;
327 struct evtchn_bind_pirq bind_pirq;
328 struct evtchn_bind_ipi bind_ipi;
329 struct evtchn_close close;
330 struct evtchn_send send;
331 struct evtchn_status status;
332 struct evtchn_bind_vcpu bind_vcpu;
333 struct evtchn_unmask unmask;
334 } u;
335 };
336 typedef struct evtchn_op evtchn_op_t;
337 DEFINE_XEN_GUEST_HANDLE(evtchn_op_t);
338
339 /*
340 * 2-level ABI
341 */
342
343 #define EVTCHN_2L_NR_CHANNELS (sizeof(xen_ulong_t) * sizeof(xen_ulong_t) * 64)
344
345 /*
346 * FIFO ABI
347 */
348
349 /* Events may have priorities from 0 (highest) to 15 (lowest). */
350 #define EVTCHN_FIFO_PRIORITY_MAX 0
351 #define EVTCHN_FIFO_PRIORITY_DEFAULT 7
352 #define EVTCHN_FIFO_PRIORITY_MIN 15
353
354 #define EVTCHN_FIFO_MAX_QUEUES (EVTCHN_FIFO_PRIORITY_MIN + 1)
355
356 typedef uint32_t event_word_t;
357
358 #define EVTCHN_FIFO_PENDING 31
359 #define EVTCHN_FIFO_MASKED 30
360 #define EVTCHN_FIFO_LINKED 29
361 #define EVTCHN_FIFO_BUSY 28
362
363 #define EVTCHN_FIFO_LINK_BITS 17
364 #define EVTCHN_FIFO_LINK_MASK ((1 << EVTCHN_FIFO_LINK_BITS) - 1)
365
366 #define EVTCHN_FIFO_NR_CHANNELS (1 << EVTCHN_FIFO_LINK_BITS)
367
368 struct evtchn_fifo_control_block {
369 uint32_t ready;
370 uint32_t _rsvd;
371 uint32_t head[EVTCHN_FIFO_MAX_QUEUES];
372 };
373 typedef struct evtchn_fifo_control_block evtchn_fifo_control_block_t;
374
375 #endif /* __XEN_PUBLIC_EVENT_CHANNEL_H__ */
376
377 /*
378 * Local variables:
379 * mode: C
380 * c-file-style: "BSD"
381 * c-basic-offset: 4
382 * tab-width: 4
383 * indent-tabs-mode: nil
384 * End:
385 */
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