1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
|
From: Jan Beulich <jbeulich@suse.com>
Subject: evtchn: convert per-channel lock to be IRQ-safe
... in order for send_guest_{global,vcpu}_virq() to be able to make use
of it.
This is part of XSA-343.
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Acked-by: Julien Grall <jgrall@amazon.com>
---
v6: New.
---
TBD: This is the "dumb" conversion variant. In a couple of cases the
slightly simpler spin_{,un}lock_irq() could apparently be used.
--- a/xen/common/event_channel.c
+++ b/xen/common/event_channel.c
@@ -248,6 +248,7 @@ static long evtchn_alloc_unbound(evtchn_
int port;
domid_t dom = alloc->dom;
long rc;
+ unsigned long flags;
d = rcu_lock_domain_by_any_id(dom);
if ( d == NULL )
@@ -263,14 +264,14 @@ static long evtchn_alloc_unbound(evtchn_
if ( rc )
goto out;
- spin_lock(&chn->lock);
+ spin_lock_irqsave(&chn->lock, flags);
chn->state = ECS_UNBOUND;
if ( (chn->u.unbound.remote_domid = alloc->remote_dom) == DOMID_SELF )
chn->u.unbound.remote_domid = current->domain->domain_id;
evtchn_port_init(d, chn);
- spin_unlock(&chn->lock);
+ spin_unlock_irqrestore(&chn->lock, flags);
alloc->port = port;
@@ -283,26 +284,32 @@ static long evtchn_alloc_unbound(evtchn_
}
-static void double_evtchn_lock(struct evtchn *lchn, struct evtchn *rchn)
+static unsigned long double_evtchn_lock(struct evtchn *lchn,
+ struct evtchn *rchn)
{
- if ( lchn < rchn )
+ unsigned long flags;
+
+ if ( lchn <= rchn )
{
- spin_lock(&lchn->lock);
- spin_lock(&rchn->lock);
+ spin_lock_irqsave(&lchn->lock, flags);
+ if ( lchn != rchn )
+ spin_lock(&rchn->lock);
}
else
{
- if ( lchn != rchn )
- spin_lock(&rchn->lock);
+ spin_lock_irqsave(&rchn->lock, flags);
spin_lock(&lchn->lock);
}
+
+ return flags;
}
-static void double_evtchn_unlock(struct evtchn *lchn, struct evtchn *rchn)
+static void double_evtchn_unlock(struct evtchn *lchn, struct evtchn *rchn,
+ unsigned long flags)
{
- spin_unlock(&lchn->lock);
if ( lchn != rchn )
- spin_unlock(&rchn->lock);
+ spin_unlock(&lchn->lock);
+ spin_unlock_irqrestore(&rchn->lock, flags);
}
static long evtchn_bind_interdomain(evtchn_bind_interdomain_t *bind)
@@ -312,6 +319,7 @@ static long evtchn_bind_interdomain(evtc
int lport, rport = bind->remote_port;
domid_t rdom = bind->remote_dom;
long rc;
+ unsigned long flags;
if ( rdom == DOMID_SELF )
rdom = current->domain->domain_id;
@@ -347,7 +355,7 @@ static long evtchn_bind_interdomain(evtc
if ( rc )
goto out;
- double_evtchn_lock(lchn, rchn);
+ flags = double_evtchn_lock(lchn, rchn);
lchn->u.interdomain.remote_dom = rd;
lchn->u.interdomain.remote_port = rport;
@@ -364,7 +372,7 @@ static long evtchn_bind_interdomain(evtc
*/
evtchn_port_set_pending(ld, lchn->notify_vcpu_id, lchn);
- double_evtchn_unlock(lchn, rchn);
+ double_evtchn_unlock(lchn, rchn, flags);
bind->local_port = lport;
@@ -387,6 +395,7 @@ int evtchn_bind_virq(evtchn_bind_virq_t
struct domain *d = current->domain;
int virq = bind->virq, vcpu = bind->vcpu;
int rc = 0;
+ unsigned long flags;
if ( (virq < 0) || (virq >= ARRAY_SIZE(v->virq_to_evtchn)) )
return -EINVAL;
@@ -424,14 +433,14 @@ int evtchn_bind_virq(evtchn_bind_virq_t
chn = evtchn_from_port(d, port);
- spin_lock(&chn->lock);
+ spin_lock_irqsave(&chn->lock, flags);
chn->state = ECS_VIRQ;
chn->notify_vcpu_id = vcpu;
chn->u.virq = virq;
evtchn_port_init(d, chn);
- spin_unlock(&chn->lock);
+ spin_unlock_irqrestore(&chn->lock, flags);
v->virq_to_evtchn[virq] = bind->port = port;
@@ -448,6 +457,7 @@ static long evtchn_bind_ipi(evtchn_bind_
struct domain *d = current->domain;
int port, vcpu = bind->vcpu;
long rc = 0;
+ unsigned long flags;
if ( domain_vcpu(d, vcpu) == NULL )
return -ENOENT;
@@ -459,13 +469,13 @@ static long evtchn_bind_ipi(evtchn_bind_
chn = evtchn_from_port(d, port);
- spin_lock(&chn->lock);
+ spin_lock_irqsave(&chn->lock, flags);
chn->state = ECS_IPI;
chn->notify_vcpu_id = vcpu;
evtchn_port_init(d, chn);
- spin_unlock(&chn->lock);
+ spin_unlock_irqrestore(&chn->lock, flags);
bind->port = port;
@@ -509,6 +519,7 @@ static long evtchn_bind_pirq(evtchn_bind
struct pirq *info;
int port = 0, pirq = bind->pirq;
long rc;
+ unsigned long flags;
if ( (pirq < 0) || (pirq >= d->nr_pirqs) )
return -EINVAL;
@@ -541,14 +552,14 @@ static long evtchn_bind_pirq(evtchn_bind
goto out;
}
- spin_lock(&chn->lock);
+ spin_lock_irqsave(&chn->lock, flags);
chn->state = ECS_PIRQ;
chn->u.pirq.irq = pirq;
link_pirq_port(port, chn, v);
evtchn_port_init(d, chn);
- spin_unlock(&chn->lock);
+ spin_unlock_irqrestore(&chn->lock, flags);
bind->port = port;
@@ -569,6 +580,7 @@ int evtchn_close(struct domain *d1, int
struct evtchn *chn1, *chn2;
int port2;
long rc = 0;
+ unsigned long flags;
again:
spin_lock(&d1->event_lock);
@@ -668,14 +680,14 @@ int evtchn_close(struct domain *d1, int
BUG_ON(chn2->state != ECS_INTERDOMAIN);
BUG_ON(chn2->u.interdomain.remote_dom != d1);
- double_evtchn_lock(chn1, chn2);
+ flags = double_evtchn_lock(chn1, chn2);
evtchn_free(d1, chn1);
chn2->state = ECS_UNBOUND;
chn2->u.unbound.remote_domid = d1->domain_id;
- double_evtchn_unlock(chn1, chn2);
+ double_evtchn_unlock(chn1, chn2, flags);
goto out;
@@ -683,9 +695,9 @@ int evtchn_close(struct domain *d1, int
BUG();
}
- spin_lock(&chn1->lock);
+ spin_lock_irqsave(&chn1->lock, flags);
evtchn_free(d1, chn1);
- spin_unlock(&chn1->lock);
+ spin_unlock_irqrestore(&chn1->lock, flags);
out:
if ( d2 != NULL )
@@ -705,13 +717,14 @@ int evtchn_send(struct domain *ld, unsig
struct evtchn *lchn, *rchn;
struct domain *rd;
int rport, ret = 0;
+ unsigned long flags;
if ( !port_is_valid(ld, lport) )
return -EINVAL;
lchn = evtchn_from_port(ld, lport);
- spin_lock(&lchn->lock);
+ spin_lock_irqsave(&lchn->lock, flags);
/* Guest cannot send via a Xen-attached event channel. */
if ( unlikely(consumer_is_xen(lchn)) )
@@ -746,7 +759,7 @@ int evtchn_send(struct domain *ld, unsig
}
out:
- spin_unlock(&lchn->lock);
+ spin_unlock_irqrestore(&lchn->lock, flags);
return ret;
}
@@ -1238,6 +1251,7 @@ int alloc_unbound_xen_event_channel(
{
struct evtchn *chn;
int port, rc;
+ unsigned long flags;
spin_lock(&ld->event_lock);
@@ -1250,14 +1264,14 @@ int alloc_unbound_xen_event_channel(
if ( rc )
goto out;
- spin_lock(&chn->lock);
+ spin_lock_irqsave(&chn->lock, flags);
chn->state = ECS_UNBOUND;
chn->xen_consumer = get_xen_consumer(notification_fn);
chn->notify_vcpu_id = lvcpu;
chn->u.unbound.remote_domid = remote_domid;
- spin_unlock(&chn->lock);
+ spin_unlock_irqrestore(&chn->lock, flags);
write_atomic(&ld->xen_evtchns, ld->xen_evtchns + 1);
@@ -1280,11 +1294,12 @@ void notify_via_xen_event_channel(struct
{
struct evtchn *lchn, *rchn;
struct domain *rd;
+ unsigned long flags;
ASSERT(port_is_valid(ld, lport));
lchn = evtchn_from_port(ld, lport);
- spin_lock(&lchn->lock);
+ spin_lock_irqsave(&lchn->lock, flags);
if ( likely(lchn->state == ECS_INTERDOMAIN) )
{
@@ -1294,7 +1309,7 @@ void notify_via_xen_event_channel(struct
evtchn_port_set_pending(rd, rchn->notify_vcpu_id, rchn);
}
- spin_unlock(&lchn->lock);
+ spin_unlock_irqrestore(&lchn->lock, flags);
}
void evtchn_check_pollers(struct domain *d, unsigned int port)
|
