1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * (C) 2003 - Rolf Neugebauer - Intel Research Cambridge
4 * (C) 2005 - Grzegorz Milos - Intel Research Cambridge
5 * (C) 2020 - EPAM Systems Inc.
6 *
7 * File: events.c [1]
8 * Author: Rolf Neugebauer (neugebar@dcs.gla.ac.uk)
9 * Changes: Grzegorz Milos (gm281@cam.ac.uk)
10 *
11 * Date: Jul 2003, changes Jun 2005
12 *
13 * Description: Deals with events received on event channels
14 *
15 * [1] - http://xenbits.xen.org/gitweb/?p=mini-os.git;a=summary
16 */
17 #include <common.h>
18 #include <log.h>
19
20 #include <asm/io.h>
21 #include <asm/xen/system.h>
22
23 #include <xen/events.h>
24 #include <xen/hvm.h>
25
26 #if IS_ENABLED(CONFIG_XEN_SERIAL)
27 extern u32 console_evtchn;
28 #endif /* IS_ENABLED(CONFIG_XEN_SERIAL) */
29
30 #define NR_EVS 1024
31
32 /**
33 * struct _ev_action - represents a event handler.
34 *
35 * Chaining or sharing is not allowed
36 */
37 struct _ev_action {
38 void (*handler)(evtchn_port_t port, struct pt_regs *regs, void *data);
39 void *data;
40 u32 count;
41 };
42
43 static struct _ev_action ev_actions[NR_EVS];
44 void default_handler(evtchn_port_t port, struct pt_regs *regs, void *data);
45
46 static unsigned long bound_ports[NR_EVS / (8 * sizeof(unsigned long))];
47
unbind_all_ports(void)48 void unbind_all_ports(void)
49 {
50 int i;
51 int cpu = 0;
52 struct shared_info *s = HYPERVISOR_shared_info;
53 struct vcpu_info *vcpu_info = &s->vcpu_info[cpu];
54
55 for (i = 0; i < NR_EVS; i++) {
56 #if IS_ENABLED(CONFIG_XEN_SERIAL)
57 if (i == console_evtchn)
58 continue;
59 #endif /* IS_ENABLED(CONFIG_XEN_SERIAL) */
60
61 if (test_and_clear_bit(i, bound_ports)) {
62 printf("port %d still bound!\n", i);
63 unbind_evtchn(i);
64 }
65 }
66 vcpu_info->evtchn_upcall_pending = 0;
67 vcpu_info->evtchn_pending_sel = 0;
68 }
69
do_event(evtchn_port_t port,struct pt_regs * regs)70 int do_event(evtchn_port_t port, struct pt_regs *regs)
71 {
72 struct _ev_action *action;
73
74 clear_evtchn(port);
75
76 if (port >= NR_EVS) {
77 printk("WARN: do_event(): Port number too large: %d\n", port);
78 return 1;
79 }
80
81 action = &ev_actions[port];
82 action->count++;
83
84 /* call the handler */
85 action->handler(port, regs, action->data);
86
87 return 1;
88 }
89
bind_evtchn(evtchn_port_t port,void (* handler)(evtchn_port_t,struct pt_regs *,void *),void * data)90 evtchn_port_t bind_evtchn(evtchn_port_t port,
91 void (*handler)(evtchn_port_t, struct pt_regs *, void *),
92 void *data)
93 {
94 if (ev_actions[port].handler != default_handler)
95 printf("WARN: Handler for port %d already registered, replacing\n",
96 port);
97
98 ev_actions[port].data = data;
99 wmb();
100 ev_actions[port].handler = handler;
101 synch_set_bit(port, bound_ports);
102
103 return port;
104 }
105
106 /**
107 * unbind_evtchn() - Unbind event channel for selected port
108 */
unbind_evtchn(evtchn_port_t port)109 void unbind_evtchn(evtchn_port_t port)
110 {
111 struct evtchn_close close;
112 int rc;
113
114 if (ev_actions[port].handler == default_handler)
115 debug("Default handler for port %d when unbinding\n", port);
116 mask_evtchn(port);
117 clear_evtchn(port);
118
119 ev_actions[port].handler = default_handler;
120 wmb();
121 ev_actions[port].data = NULL;
122 synch_clear_bit(port, bound_ports);
123
124 close.port = port;
125 rc = HYPERVISOR_event_channel_op(EVTCHNOP_close, &close);
126 if (rc)
127 printf("WARN: close_port %d failed rc=%d. ignored\n", port, rc);
128 }
129
default_handler(evtchn_port_t port,struct pt_regs * regs,void * ignore)130 void default_handler(evtchn_port_t port, struct pt_regs *regs, void *ignore)
131 {
132 debug("[Port %d] - event received\n", port);
133 }
134
135 /**
136 * evtchn_alloc_unbound() - Create a port available to the pal for
137 * exchanging notifications.
138 *
139 * Unfortunate confusion of terminology: the port is unbound as far
140 * as Xen is concerned, but we automatically bind a handler to it.
141 *
142 * Return: The result of the hypervisor call.
143 */
evtchn_alloc_unbound(domid_t pal,void (* handler)(evtchn_port_t,struct pt_regs *,void *),void * data,evtchn_port_t * port)144 int evtchn_alloc_unbound(domid_t pal,
145 void (*handler)(evtchn_port_t, struct pt_regs *, void *),
146 void *data, evtchn_port_t *port)
147 {
148 int rc;
149
150 struct evtchn_alloc_unbound op;
151
152 op.dom = DOMID_SELF;
153 op.remote_dom = pal;
154 rc = HYPERVISOR_event_channel_op(EVTCHNOP_alloc_unbound, &op);
155 if (rc) {
156 printf("ERROR: alloc_unbound failed with rc=%d", rc);
157 return rc;
158 }
159 if (!handler)
160 handler = default_handler;
161 *port = bind_evtchn(op.port, handler, data);
162 return rc;
163 }
164
165 /**
166 * eventchn_poll() - Event channel polling function
167 *
168 * Check and process any pending events
169 */
eventchn_poll(void)170 void eventchn_poll(void)
171 {
172 do_hypervisor_callback(NULL);
173 }
174
175 /**
176 * init_events() - Initialize event handler
177 *
178 * Initially all events are without a handler and disabled.
179 */
init_events(void)180 void init_events(void)
181 {
182 int i;
183
184 debug("%s\n", __func__);
185
186 for (i = 0; i < NR_EVS; i++) {
187 ev_actions[i].handler = default_handler;
188 mask_evtchn(i);
189 }
190 }
191
192 /**
193 * fini_events() - Close all ports
194 *
195 * Mask and clear event channels. Close port using EVTCHNOP_close
196 * hypercall.
197 */
fini_events(void)198 void fini_events(void)
199 {
200 debug("%s\n", __func__);
201 /* Dealloc all events */
202 unbind_all_ports();
203 }
204