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#ifdef __XEN__
78#define EVTCHNOP_reset_cont      14
79#endif
80/* ` } */
81
82typedef uint32_t evtchn_port_t;
83DEFINE_XEN_GUEST_HANDLE(evtchn_port_t);
84
85/*
86 * EVTCHNOP_alloc_unbound: Allocate a port in domain <dom> and mark as
87 * accepting interdomain bindings from domain <remote_dom>. A fresh port
88 * is allocated in <dom> and returned as <port>.
89 * NOTES:
90 *  1. If the caller is unprivileged then <dom> must be DOMID_SELF.
91 *  2. <remote_dom> may be DOMID_SELF, allowing loopback connections.
92 */
93struct evtchn_alloc_unbound {
94    /* IN parameters */
95    domid_t dom, remote_dom;
96    /* OUT parameters */
97    evtchn_port_t port;
98};
99typedef struct evtchn_alloc_unbound evtchn_alloc_unbound_t;
100
101/*
102 * EVTCHNOP_bind_interdomain: Construct an interdomain event channel between
103 * the calling domain and <remote_dom>. <remote_dom,remote_port> must identify
104 * a port that is unbound and marked as accepting bindings from the calling
105 * domain. A fresh port is allocated in the calling domain and returned as
106 * <local_port>.
107 *
108 * In case the peer domain has already tried to set our event channel
109 * pending, before it was bound, EVTCHNOP_bind_interdomain always sets
110 * the local event channel pending.
111 *
112 * The usual pattern of use, in the guest's upcall (or subsequent
113 * handler) is as follows: (Re-enable the event channel for subsequent
114 * signalling and then) check for the existence of whatever condition
115 * is being waited for by other means, and take whatever action is
116 * needed (if any).
117 *
118 * NOTES:
119 *  1. <remote_dom> may be DOMID_SELF, allowing loopback connections.
120 */
121struct evtchn_bind_interdomain {
122    /* IN parameters. */
123    domid_t remote_dom;
124    evtchn_port_t remote_port;
125    /* OUT parameters. */
126    evtchn_port_t local_port;
127};
128typedef struct evtchn_bind_interdomain evtchn_bind_interdomain_t;
129
130/*
131 * EVTCHNOP_bind_virq: Bind a local event channel to VIRQ <irq> on specified
132 * vcpu.
133 * NOTES:
134 *  1. Virtual IRQs are classified as per-vcpu or global. See the VIRQ list
135 *     in xen.h for the classification of each VIRQ.
136 *  2. Global VIRQs must be allocated on VCPU0 but can subsequently be
137 *     re-bound via EVTCHNOP_bind_vcpu.
138 *  3. Per-vcpu VIRQs may be bound to at most one event channel per vcpu.
139 *     The allocated event channel is bound to the specified vcpu and the
140 *     binding cannot be changed.
141 */
142struct evtchn_bind_virq {
143    /* IN parameters. */
144    uint32_t virq; /* enum virq */
145    uint32_t vcpu;
146    /* OUT parameters. */
147    evtchn_port_t port;
148};
149typedef struct evtchn_bind_virq evtchn_bind_virq_t;
150
151/*
152 * EVTCHNOP_bind_pirq: Bind a local event channel to a real IRQ (PIRQ <irq>).
153 * NOTES:
154 *  1. A physical IRQ may be bound to at most one event channel per domain.
155 *  2. Only a sufficiently-privileged domain may bind to a physical IRQ.
156 */
157struct evtchn_bind_pirq {
158    /* IN parameters. */
159    uint32_t pirq;
160#define BIND_PIRQ__WILL_SHARE 1
161    uint32_t flags; /* BIND_PIRQ__* */
162    /* OUT parameters. */
163    evtchn_port_t port;
164};
165typedef struct evtchn_bind_pirq evtchn_bind_pirq_t;
166
167/*
168 * EVTCHNOP_bind_ipi: Bind a local event channel to receive events.
169 * NOTES:
170 *  1. The allocated event channel is bound to the specified vcpu. The binding
171 *     may not be changed.
172 */
173struct evtchn_bind_ipi {
174    uint32_t vcpu;
175    /* OUT parameters. */
176    evtchn_port_t port;
177};
178typedef struct evtchn_bind_ipi evtchn_bind_ipi_t;
179
180/*
181 * EVTCHNOP_close: Close a local event channel <port>. If the channel is
182 * interdomain then the remote end is placed in the unbound state
183 * (EVTCHNSTAT_unbound), awaiting a new connection.
184 */
185struct evtchn_close {
186    /* IN parameters. */
187    evtchn_port_t port;
188};
189typedef struct evtchn_close evtchn_close_t;
190
191/*
192 * EVTCHNOP_send: Send an event to the remote end of the channel whose local
193 * endpoint is <port>.
194 */
195struct evtchn_send {
196    /* IN parameters. */
197    evtchn_port_t port;
198};
199typedef struct evtchn_send evtchn_send_t;
200
201/*
202 * EVTCHNOP_status: Get the current status of the communication channel which
203 * has an endpoint at <dom, port>.
204 * NOTES:
205 *  1. <dom> may be specified as DOMID_SELF.
206 *  2. Only a sufficiently-privileged domain may obtain the status of an event
207 *     channel for which <dom> is not DOMID_SELF.
208 */
209struct evtchn_status {
210    /* IN parameters */
211    domid_t  dom;
212    evtchn_port_t port;
213    /* OUT parameters */
214#define EVTCHNSTAT_closed       0  /* Channel is not in use.                 */
215#define EVTCHNSTAT_unbound      1  /* Channel is waiting interdom connection.*/
216#define EVTCHNSTAT_interdomain  2  /* Channel is connected to remote domain. */
217#define EVTCHNSTAT_pirq         3  /* Channel is bound to a phys IRQ line.   */
218#define EVTCHNSTAT_virq         4  /* Channel is bound to a virtual IRQ line */
219#define EVTCHNSTAT_ipi          5  /* Channel is bound to a virtual IPI line */
220    uint32_t status;
221    uint32_t vcpu;                 /* VCPU to which this channel is bound.   */
222    union {
223        struct {
224            domid_t dom;
225        } unbound;                 /* EVTCHNSTAT_unbound */
226        struct {
227            domid_t dom;
228            evtchn_port_t port;
229        } interdomain;             /* EVTCHNSTAT_interdomain */
230        uint32_t pirq;             /* EVTCHNSTAT_pirq        */
231        uint32_t virq;             /* EVTCHNSTAT_virq        */
232    } u;
233};
234typedef struct evtchn_status evtchn_status_t;
235
236/*
237 * EVTCHNOP_bind_vcpu: Specify which vcpu a channel should notify when an
238 * event is pending.
239 * NOTES:
240 *  1. IPI-bound channels always notify the vcpu specified at bind time.
241 *     This binding cannot be changed.
242 *  2. Per-VCPU VIRQ channels always notify the vcpu specified at bind time.
243 *     This binding cannot be changed.
244 *  3. All other channels notify vcpu0 by default. This default is set when
245 *     the channel is allocated (a port that is freed and subsequently reused
246 *     has its binding reset to vcpu0).
247 */
248struct evtchn_bind_vcpu {
249    /* IN parameters. */
250    evtchn_port_t port;
251    uint32_t vcpu;
252};
253typedef struct evtchn_bind_vcpu evtchn_bind_vcpu_t;
254
255/*
256 * EVTCHNOP_unmask: Unmask the specified local event-channel port and deliver
257 * a notification to the appropriate VCPU if an event is pending.
258 */
259struct evtchn_unmask {
260    /* IN parameters. */
261    evtchn_port_t port;
262};
263typedef struct evtchn_unmask evtchn_unmask_t;
264
265/*
266 * EVTCHNOP_reset: Close all event channels associated with specified domain.
267 * NOTES:
268 *  1. <dom> may be specified as DOMID_SELF.
269 *  2. Only a sufficiently-privileged domain may specify other than DOMID_SELF.
270 *  3. Destroys all control blocks and event array, resets event channel
271 *     operations to 2-level ABI if called with <dom> == DOMID_SELF and FIFO
272 *     ABI was used. Guests should not bind events during EVTCHNOP_reset call
273 *     as these events are likely to be lost.
274 */
275struct evtchn_reset {
276    /* IN parameters. */
277    domid_t dom;
278};
279typedef struct evtchn_reset evtchn_reset_t;
280
281/*
282 * EVTCHNOP_init_control: initialize the control block for the FIFO ABI.
283 *
284 * Note: any events that are currently pending will not be resent and
285 * will be lost.  Guests should call this before binding any event to
286 * avoid losing any events.
287 */
288struct evtchn_init_control {
289    /* IN parameters. */
290    uint64_t control_gfn;
291    uint32_t offset;
292    uint32_t vcpu;
293    /* OUT parameters. */
294    uint8_t link_bits;
295    uint8_t _pad[7];
296};
297typedef struct evtchn_init_control evtchn_init_control_t;
298
299/*
300 * EVTCHNOP_expand_array: add an additional page to the event array.
301 */
302struct evtchn_expand_array {
303    /* IN parameters. */
304    uint64_t array_gfn;
305};
306typedef struct evtchn_expand_array evtchn_expand_array_t;
307
308/*
309 * EVTCHNOP_set_priority: set the priority for an event channel.
310 */
311struct evtchn_set_priority {
312    /* IN parameters. */
313    evtchn_port_t port;
314    uint32_t priority;
315};
316typedef struct evtchn_set_priority evtchn_set_priority_t;
317
318/*
319 * ` enum neg_errnoval
320 * ` HYPERVISOR_event_channel_op_compat(struct evtchn_op *op)
321 * `
322 * Superceded by new event_channel_op() hypercall since 0x00030202.
323 */
324struct evtchn_op {
325    uint32_t cmd; /* enum event_channel_op */
326    union {
327        evtchn_alloc_unbound_t    alloc_unbound;
328        evtchn_bind_interdomain_t bind_interdomain;
329        evtchn_bind_virq_t        bind_virq;
330        evtchn_bind_pirq_t        bind_pirq;
331        evtchn_bind_ipi_t         bind_ipi;
332        evtchn_close_t            close;
333        evtchn_send_t             send;
334        evtchn_status_t           status;
335        evtchn_bind_vcpu_t        bind_vcpu;
336        evtchn_unmask_t           unmask;
337    } u;
338};
339typedef struct evtchn_op evtchn_op_t;
340DEFINE_XEN_GUEST_HANDLE(evtchn_op_t);
341
342/*
343 * 2-level ABI
344 */
345
346#define EVTCHN_2L_NR_CHANNELS (sizeof(xen_ulong_t) * sizeof(xen_ulong_t) * 64)
347
348/*
349 * FIFO ABI
350 */
351
352/* Events may have priorities from 0 (highest) to 15 (lowest). */
353#define EVTCHN_FIFO_PRIORITY_MAX     0
354#define EVTCHN_FIFO_PRIORITY_DEFAULT 7
355#define EVTCHN_FIFO_PRIORITY_MIN     15
356
357#define EVTCHN_FIFO_MAX_QUEUES (EVTCHN_FIFO_PRIORITY_MIN + 1)
358
359typedef uint32_t event_word_t;
360
361#define EVTCHN_FIFO_PENDING 31
362#define EVTCHN_FIFO_MASKED  30
363#define EVTCHN_FIFO_LINKED  29
364#define EVTCHN_FIFO_BUSY    28
365
366#define EVTCHN_FIFO_LINK_BITS 17
367#define EVTCHN_FIFO_LINK_MASK ((1 << EVTCHN_FIFO_LINK_BITS) - 1)
368
369#define EVTCHN_FIFO_NR_CHANNELS (1 << EVTCHN_FIFO_LINK_BITS)
370
371struct evtchn_fifo_control_block {
372    uint32_t ready;
373    uint32_t _rsvd;
374    uint32_t head[EVTCHN_FIFO_MAX_QUEUES];
375};
376typedef struct evtchn_fifo_control_block evtchn_fifo_control_block_t;
377
378#endif /* __XEN_PUBLIC_EVENT_CHANNEL_H__ */
379
380/*
381 * Local variables:
382 * mode: C
383 * c-file-style: "BSD"
384 * c-basic-offset: 4
385 * tab-width: 4
386 * indent-tabs-mode: nil
387 * End:
388 */
389