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 
82 typedef uint32_t evtchn_port_t;
83 DEFINE_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  */
93 struct evtchn_alloc_unbound {
94     /* IN parameters */
95     domid_t dom, remote_dom;
96     /* OUT parameters */
97     evtchn_port_t port;
98 };
99 typedef 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  */
121 struct 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 };
128 typedef 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  */
142 struct 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 };
149 typedef 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  */
157 struct 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 };
165 typedef 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  */
173 struct evtchn_bind_ipi {
174     uint32_t vcpu;
175     /* OUT parameters. */
176     evtchn_port_t port;
177 };
178 typedef 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  */
185 struct evtchn_close {
186     /* IN parameters. */
187     evtchn_port_t port;
188 };
189 typedef 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  */
195 struct evtchn_send {
196     /* IN parameters. */
197     evtchn_port_t port;
198 };
199 typedef 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  */
209 struct 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 };
234 typedef 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  */
248 struct evtchn_bind_vcpu {
249     /* IN parameters. */
250     evtchn_port_t port;
251     uint32_t vcpu;
252 };
253 typedef 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  */
259 struct evtchn_unmask {
260     /* IN parameters. */
261     evtchn_port_t port;
262 };
263 typedef 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  */
275 struct evtchn_reset {
276     /* IN parameters. */
277     domid_t dom;
278 };
279 typedef 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  */
288 struct 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 };
297 typedef struct evtchn_init_control evtchn_init_control_t;
298 
299 /*
300  * EVTCHNOP_expand_array: add an additional page to the event array.
301  */
302 struct evtchn_expand_array {
303     /* IN parameters. */
304     uint64_t array_gfn;
305 };
306 typedef struct evtchn_expand_array evtchn_expand_array_t;
307 
308 /*
309  * EVTCHNOP_set_priority: set the priority for an event channel.
310  */
311 struct evtchn_set_priority {
312     /* IN parameters. */
313     evtchn_port_t port;
314     uint32_t priority;
315 };
316 typedef 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  */
324 struct evtchn_op {
325     uint32_t cmd; /* enum event_channel_op */
326     union {
327         struct evtchn_alloc_unbound    alloc_unbound;
328         struct evtchn_bind_interdomain bind_interdomain;
329         struct evtchn_bind_virq        bind_virq;
330         struct evtchn_bind_pirq        bind_pirq;
331         struct evtchn_bind_ipi         bind_ipi;
332         struct evtchn_close            close;
333         struct evtchn_send             send;
334         struct evtchn_status           status;
335         struct evtchn_bind_vcpu        bind_vcpu;
336         struct evtchn_unmask           unmask;
337     } u;
338 };
339 typedef struct evtchn_op evtchn_op_t;
340 DEFINE_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 
359 typedef 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 
371 struct evtchn_fifo_control_block {
372     uint32_t ready;
373     uint32_t _rsvd;
374     uint32_t head[EVTCHN_FIFO_MAX_QUEUES];
375 };
376 typedef 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