1 /******************************************************************************
4 * Event channels between domains.
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24 * Copyright (c) 2003-2004, K A Fraser.
27 #ifndef __XEN_PUBLIC_EVENT_CHANNEL_H__
28 #define __XEN_PUBLIC_EVENT_CHANNEL_H__
33 * `incontents 150 evtchn Event Channels
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.
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).
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.
50 * Event channels are represented by the evtchn_* fields in
51 * struct shared_info and struct vcpu_info.
56 * ` HYPERVISOR_event_channel_op(enum event_channel_op cmd, void *args)
58 * @cmd == EVTCHNOP_* (event-channel operation).
59 * @args == struct evtchn_* Operation-specific extra arguments (NULL if none).
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
78 #define EVTCHNOP_reset_cont 14
82 typedef uint32_t evtchn_port_t;
83 DEFINE_XEN_GUEST_HANDLE(evtchn_port_t);
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>.
90 * 1. If the caller is unprivileged then <dom> must be DOMID_SELF.
91 * 2. <remote_dom> may be DOMID_SELF, allowing loopback connections.
93 struct evtchn_alloc_unbound {
95 domid_t dom, remote_dom;
99 typedef struct evtchn_alloc_unbound evtchn_alloc_unbound_t;
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
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.
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
119 * 1. <remote_dom> may be DOMID_SELF, allowing loopback connections.
121 struct evtchn_bind_interdomain {
124 evtchn_port_t remote_port;
125 /* OUT parameters. */
126 evtchn_port_t local_port;
128 typedef struct evtchn_bind_interdomain evtchn_bind_interdomain_t;
131 * EVTCHNOP_bind_virq: Bind a local event channel to VIRQ <irq> on specified
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.
142 struct evtchn_bind_virq {
144 uint32_t virq; /* enum virq */
146 /* OUT parameters. */
149 typedef struct evtchn_bind_virq evtchn_bind_virq_t;
152 * EVTCHNOP_bind_pirq: Bind a local event channel to a real IRQ (PIRQ <irq>).
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.
157 struct evtchn_bind_pirq {
160 #define BIND_PIRQ__WILL_SHARE 1
161 uint32_t flags; /* BIND_PIRQ__* */
162 /* OUT parameters. */
165 typedef struct evtchn_bind_pirq evtchn_bind_pirq_t;
168 * EVTCHNOP_bind_ipi: Bind a local event channel to receive events.
170 * 1. The allocated event channel is bound to the specified vcpu. The binding
171 * may not be changed.
173 struct evtchn_bind_ipi {
175 /* OUT parameters. */
178 typedef struct evtchn_bind_ipi evtchn_bind_ipi_t;
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.
185 struct evtchn_close {
189 typedef struct evtchn_close evtchn_close_t;
192 * EVTCHNOP_send: Send an event to the remote end of the channel whose local
193 * endpoint is <port>.
199 typedef struct evtchn_send evtchn_send_t;
202 * EVTCHNOP_status: Get the current status of the communication channel which
203 * has an endpoint at <dom, port>.
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.
209 struct evtchn_status {
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 */
221 uint32_t vcpu; /* VCPU to which this channel is bound. */
225 } unbound; /* EVTCHNSTAT_unbound */
229 } interdomain; /* EVTCHNSTAT_interdomain */
230 uint32_t pirq; /* EVTCHNSTAT_pirq */
231 uint32_t virq; /* EVTCHNSTAT_virq */
234 typedef struct evtchn_status evtchn_status_t;
237 * EVTCHNOP_bind_vcpu: Specify which vcpu a channel should notify when an
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).
248 struct evtchn_bind_vcpu {
253 typedef struct evtchn_bind_vcpu evtchn_bind_vcpu_t;
256 * EVTCHNOP_unmask: Unmask the specified local event-channel port and deliver
257 * a notification to the appropriate VCPU if an event is pending.
259 struct evtchn_unmask {
263 typedef struct evtchn_unmask evtchn_unmask_t;
266 * EVTCHNOP_reset: Close all event channels associated with specified domain.
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.
275 struct evtchn_reset {
279 typedef struct evtchn_reset evtchn_reset_t;
282 * EVTCHNOP_init_control: initialize the control block for the FIFO ABI.
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.
288 struct evtchn_init_control {
290 uint64_t control_gfn;
293 /* OUT parameters. */
297 typedef struct evtchn_init_control evtchn_init_control_t;
300 * EVTCHNOP_expand_array: add an additional page to the event array.
302 struct evtchn_expand_array {
306 typedef struct evtchn_expand_array evtchn_expand_array_t;
309 * EVTCHNOP_set_priority: set the priority for an event channel.
311 struct evtchn_set_priority {
316 typedef struct evtchn_set_priority evtchn_set_priority_t;
319 * ` enum neg_errnoval
320 * ` HYPERVISOR_event_channel_op_compat(struct evtchn_op *op)
322 * Superceded by new event_channel_op() hypercall since 0x00030202.
325 uint32_t cmd; /* enum event_channel_op */
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;
334 evtchn_status_t status;
335 evtchn_bind_vcpu_t bind_vcpu;
336 evtchn_unmask_t unmask;
339 typedef struct evtchn_op evtchn_op_t;
340 DEFINE_XEN_GUEST_HANDLE(evtchn_op_t);
346 #define EVTCHN_2L_NR_CHANNELS (sizeof(xen_ulong_t) * sizeof(xen_ulong_t) * 64)
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
357 #define EVTCHN_FIFO_MAX_QUEUES (EVTCHN_FIFO_PRIORITY_MIN + 1)
359 typedef uint32_t event_word_t;
361 #define EVTCHN_FIFO_PENDING 31
362 #define EVTCHN_FIFO_MASKED 30
363 #define EVTCHN_FIFO_LINKED 29
364 #define EVTCHN_FIFO_BUSY 28
366 #define EVTCHN_FIFO_LINK_BITS 17
367 #define EVTCHN_FIFO_LINK_MASK ((1 << EVTCHN_FIFO_LINK_BITS) - 1)
369 #define EVTCHN_FIFO_NR_CHANNELS (1 << EVTCHN_FIFO_LINK_BITS)
371 struct evtchn_fifo_control_block {
374 uint32_t head[EVTCHN_FIFO_MAX_QUEUES];
376 typedef struct evtchn_fifo_control_block evtchn_fifo_control_block_t;
378 #endif /* __XEN_PUBLIC_EVENT_CHANNEL_H__ */
383 * c-file-style: "BSD"
386 * indent-tabs-mode: nil