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. <remote_dom> 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  */
386