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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [xen stable-4.13] evtchn: convert per-channel lock to be IRQ-safe
commit 21054297bf832d8eacd73dc428f55168522b0d86
Author: Jan Beulich <jbeulich@xxxxxxxx>
AuthorDate: Tue Sep 22 16:26:01 2020 +0200
Commit: Jan Beulich <jbeulich@xxxxxxxx>
CommitDate: Tue Sep 22 16:26:01 2020 +0200
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@xxxxxxxx>
Acked-by: Julien Grall <jgrall@xxxxxxxxxx>
---
xen/common/event_channel.c | 73 ++++++++++++++++++++++++++++------------------
1 file changed, 44 insertions(+), 29 deletions(-)
diff --git a/xen/common/event_channel.c b/xen/common/event_channel.c
index 6a566917b1..0e550e9c7a 100644
--- a/xen/common/event_channel.c
+++ b/xen/common/event_channel.c
@@ -248,6 +248,7 @@ static long evtchn_alloc_unbound(evtchn_alloc_unbound_t
*alloc)
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_alloc_unbound_t
*alloc)
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_alloc_unbound_t
*alloc)
}
-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(evtchn_bind_interdomain_t *bind)
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(evtchn_bind_interdomain_t *bind)
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(evtchn_bind_interdomain_t *bind)
*/
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 *bind,
evtchn_port_t port)
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 *bind,
evtchn_port_t port)
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_ipi_t *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_ipi_t *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_pirq_t *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_pirq_t *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 port1, bool guest)
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 port1, bool guest)
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 port1, bool guest)
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, unsigned int lport)
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, unsigned int lport)
}
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 domain *ld,
int lport)
{
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 domain *ld, int
lport)
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)
--
generated by git-patchbot for /home/xen/git/xen.git#stable-4.13
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