xen/events: don't unmask an event channel when an eoi is pending
commit 25da4618af240fbec6112401498301a6f2bc9702 upstream.
An event channel should be kept masked when an eoi is pending for it.
When being migrated to another cpu it might be unmasked, though.
In order to avoid this keep three different flags for each event channel
to be able to distinguish "normal" masking/unmasking from eoi related
masking/unmasking and temporary masking. The event channel should only
be able to generate an interrupt if all flags are cleared.
Cc: stable@vger.kernel.org
Fixes: 54c9de89895e ("xen/events: add a new "late EOI" evtchn framework")
Reported-by: Julien Grall <julien@xen.org>
Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Julien Grall <jgrall@amazon.com>
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Tested-by: Ross Lagerwall <ross.lagerwall@citrix.com>
Link: https://lore.kernel.org/r/20210306161833.4552-3-jgross@suse.com
[boris -- corrected Fixed tag format]
Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/drivers/xen/events/events_2l.c b/drivers/xen/events/events_2l.c
index cf3f579..77cc80b 100644
--- a/drivers/xen/events/events_2l.c
+++ b/drivers/xen/events/events_2l.c
@@ -76,12 +76,6 @@
return sync_test_bit(port, BM(&s->evtchn_pending[0]));
}
-static bool evtchn_2l_test_and_set_mask(unsigned port)
-{
- struct shared_info *s = HYPERVISOR_shared_info;
- return sync_test_and_set_bit(port, BM(&s->evtchn_mask[0]));
-}
-
static void evtchn_2l_mask(unsigned port)
{
struct shared_info *s = HYPERVISOR_shared_info;
@@ -375,7 +369,6 @@
.clear_pending = evtchn_2l_clear_pending,
.set_pending = evtchn_2l_set_pending,
.is_pending = evtchn_2l_is_pending,
- .test_and_set_mask = evtchn_2l_test_and_set_mask,
.mask = evtchn_2l_mask,
.unmask = evtchn_2l_unmask,
.handle_events = evtchn_2l_handle_events,
diff --git a/drivers/xen/events/events_base.c b/drivers/xen/events/events_base.c
index 2e4c4ab..9025a06 100644
--- a/drivers/xen/events/events_base.c
+++ b/drivers/xen/events/events_base.c
@@ -99,6 +99,7 @@
* evtchn_rwlock
* IRQ-desc lock
* percpu eoi_list_lock
+ * irq_info->lock
*/
static LIST_HEAD(xen_irq_list_head);
@@ -220,6 +221,8 @@
info->irq = irq;
info->evtchn = evtchn;
info->cpu = cpu;
+ info->mask_reason = EVT_MASK_REASON_EXPLICIT;
+ spin_lock_init(&info->lock);
ret = set_evtchn_to_irq(evtchn, irq);
if (ret < 0)
@@ -367,6 +370,34 @@
return ret;
}
+static void do_mask(struct irq_info *info, u8 reason)
+{
+ unsigned long flags;
+
+ spin_lock_irqsave(&info->lock, flags);
+
+ if (!info->mask_reason)
+ mask_evtchn(info->evtchn);
+
+ info->mask_reason |= reason;
+
+ spin_unlock_irqrestore(&info->lock, flags);
+}
+
+static void do_unmask(struct irq_info *info, u8 reason)
+{
+ unsigned long flags;
+
+ spin_lock_irqsave(&info->lock, flags);
+
+ info->mask_reason &= ~reason;
+
+ if (!info->mask_reason)
+ unmask_evtchn(info->evtchn);
+
+ spin_unlock_irqrestore(&info->lock, flags);
+}
+
#ifdef CONFIG_X86
static bool pirq_check_eoi_map(unsigned irq)
{
@@ -494,7 +525,7 @@
}
info->eoi_time = 0;
- unmask_evtchn(evtchn);
+ do_unmask(info, EVT_MASK_REASON_EOI_PENDING);
}
static void xen_irq_lateeoi_worker(struct work_struct *work)
@@ -681,7 +712,8 @@
static void eoi_pirq(struct irq_data *data)
{
- int evtchn = evtchn_from_irq(data->irq);
+ struct irq_info *info = info_for_irq(data->irq);
+ int evtchn = info ? info->evtchn : 0;
struct physdev_eoi eoi = { .irq = pirq_from_irq(data->irq) };
int rc = 0;
@@ -690,14 +722,13 @@
if (unlikely(irqd_is_setaffinity_pending(data)) &&
likely(!irqd_irq_disabled(data))) {
- int masked = test_and_set_mask(evtchn);
+ do_mask(info, EVT_MASK_REASON_TEMPORARY);
clear_evtchn(evtchn);
irq_move_masked_irq(data);
- if (!masked)
- unmask_evtchn(evtchn);
+ do_unmask(info, EVT_MASK_REASON_TEMPORARY);
} else
clear_evtchn(evtchn);
@@ -750,7 +781,8 @@
goto err;
out:
- unmask_evtchn(evtchn);
+ do_unmask(info, EVT_MASK_REASON_EXPLICIT);
+
eoi_pirq(irq_get_irq_data(irq));
return 0;
@@ -777,7 +809,7 @@
if (!VALID_EVTCHN(evtchn))
return;
- mask_evtchn(evtchn);
+ do_mask(info, EVT_MASK_REASON_EXPLICIT);
xen_evtchn_close(evtchn);
xen_irq_info_cleanup(info);
}
@@ -1636,10 +1668,10 @@
}
/* Rebind an evtchn so that it gets delivered to a specific cpu */
-static int xen_rebind_evtchn_to_cpu(int evtchn, unsigned int tcpu)
+static int xen_rebind_evtchn_to_cpu(struct irq_info *info, unsigned int tcpu)
{
struct evtchn_bind_vcpu bind_vcpu;
- int masked;
+ evtchn_port_t evtchn = info ? info->evtchn : 0;
if (!VALID_EVTCHN(evtchn))
return -1;
@@ -1655,7 +1687,7 @@
* Mask the event while changing the VCPU binding to prevent
* it being delivered on an unexpected VCPU.
*/
- masked = test_and_set_mask(evtchn);
+ do_mask(info, EVT_MASK_REASON_TEMPORARY);
/*
* If this fails, it usually just indicates that we're dealing with a
@@ -1665,8 +1697,7 @@
if (HYPERVISOR_event_channel_op(EVTCHNOP_bind_vcpu, &bind_vcpu) >= 0)
bind_evtchn_to_cpu(evtchn, tcpu);
- if (!masked)
- unmask_evtchn(evtchn);
+ do_unmask(info, EVT_MASK_REASON_TEMPORARY);
return 0;
}
@@ -1675,7 +1706,7 @@
bool force)
{
unsigned tcpu = cpumask_first_and(dest, cpu_online_mask);
- int ret = xen_rebind_evtchn_to_cpu(evtchn_from_irq(data->irq), tcpu);
+ int ret = xen_rebind_evtchn_to_cpu(info_for_irq(data->irq), tcpu);
if (!ret)
irq_data_update_effective_affinity(data, cpumask_of(tcpu));
@@ -1694,37 +1725,39 @@
static void enable_dynirq(struct irq_data *data)
{
- int evtchn = evtchn_from_irq(data->irq);
+ struct irq_info *info = info_for_irq(data->irq);
+ evtchn_port_t evtchn = info ? info->evtchn : 0;
if (VALID_EVTCHN(evtchn))
- unmask_evtchn(evtchn);
+ do_unmask(info, EVT_MASK_REASON_EXPLICIT);
}
static void disable_dynirq(struct irq_data *data)
{
- int evtchn = evtchn_from_irq(data->irq);
+ struct irq_info *info = info_for_irq(data->irq);
+ evtchn_port_t evtchn = info ? info->evtchn : 0;
if (VALID_EVTCHN(evtchn))
- mask_evtchn(evtchn);
+ do_mask(info, EVT_MASK_REASON_EXPLICIT);
}
static void ack_dynirq(struct irq_data *data)
{
- int evtchn = evtchn_from_irq(data->irq);
+ struct irq_info *info = info_for_irq(data->irq);
+ evtchn_port_t evtchn = info ? info->evtchn : 0;
if (!VALID_EVTCHN(evtchn))
return;
if (unlikely(irqd_is_setaffinity_pending(data)) &&
likely(!irqd_irq_disabled(data))) {
- int masked = test_and_set_mask(evtchn);
+ do_mask(info, EVT_MASK_REASON_TEMPORARY);
clear_evtchn(evtchn);
irq_move_masked_irq(data);
- if (!masked)
- unmask_evtchn(evtchn);
+ do_unmask(info, EVT_MASK_REASON_TEMPORARY);
} else
clear_evtchn(evtchn);
}
@@ -1735,18 +1768,39 @@
ack_dynirq(data);
}
+static void lateeoi_ack_dynirq(struct irq_data *data)
+{
+ struct irq_info *info = info_for_irq(data->irq);
+ evtchn_port_t evtchn = info ? info->evtchn : 0;
+
+ if (VALID_EVTCHN(evtchn)) {
+ do_mask(info, EVT_MASK_REASON_EOI_PENDING);
+ clear_evtchn(evtchn);
+ }
+}
+
+static void lateeoi_mask_ack_dynirq(struct irq_data *data)
+{
+ struct irq_info *info = info_for_irq(data->irq);
+ evtchn_port_t evtchn = info ? info->evtchn : 0;
+
+ if (VALID_EVTCHN(evtchn)) {
+ do_mask(info, EVT_MASK_REASON_EXPLICIT);
+ clear_evtchn(evtchn);
+ }
+}
+
static int retrigger_dynirq(struct irq_data *data)
{
- unsigned int evtchn = evtchn_from_irq(data->irq);
- int masked;
+ struct irq_info *info = info_for_irq(data->irq);
+ evtchn_port_t evtchn = info ? info->evtchn : 0;
if (!VALID_EVTCHN(evtchn))
return 0;
- masked = test_and_set_mask(evtchn);
+ do_mask(info, EVT_MASK_REASON_TEMPORARY);
set_evtchn(evtchn);
- if (!masked)
- unmask_evtchn(evtchn);
+ do_unmask(info, EVT_MASK_REASON_TEMPORARY);
return 1;
}
@@ -1952,8 +2006,8 @@
.irq_mask = disable_dynirq,
.irq_unmask = enable_dynirq,
- .irq_ack = mask_ack_dynirq,
- .irq_mask_ack = mask_ack_dynirq,
+ .irq_ack = lateeoi_ack_dynirq,
+ .irq_mask_ack = lateeoi_mask_ack_dynirq,
.irq_set_affinity = set_affinity_irq,
.irq_retrigger = retrigger_dynirq,
diff --git a/drivers/xen/events/events_fifo.c b/drivers/xen/events/events_fifo.c
index 3346252..360a7f8 100644
--- a/drivers/xen/events/events_fifo.c
+++ b/drivers/xen/events/events_fifo.c
@@ -209,12 +209,6 @@
return sync_test_bit(EVTCHN_FIFO_BIT(PENDING, word), BM(word));
}
-static bool evtchn_fifo_test_and_set_mask(unsigned port)
-{
- event_word_t *word = event_word_from_port(port);
- return sync_test_and_set_bit(EVTCHN_FIFO_BIT(MASKED, word), BM(word));
-}
-
static void evtchn_fifo_mask(unsigned port)
{
event_word_t *word = event_word_from_port(port);
@@ -420,7 +414,6 @@
.clear_pending = evtchn_fifo_clear_pending,
.set_pending = evtchn_fifo_set_pending,
.is_pending = evtchn_fifo_is_pending,
- .test_and_set_mask = evtchn_fifo_test_and_set_mask,
.mask = evtchn_fifo_mask,
.unmask = evtchn_fifo_unmask,
.handle_events = evtchn_fifo_handle_events,
diff --git a/drivers/xen/events/events_internal.h b/drivers/xen/events/events_internal.h
index 6ccebc4..dd3748e 100644
--- a/drivers/xen/events/events_internal.h
+++ b/drivers/xen/events/events_internal.h
@@ -33,13 +33,18 @@
struct list_head eoi_list;
short refcnt;
short spurious_cnt;
- enum xen_irq_type type; /* type */
+ short type; /* type */
+ u8 mask_reason; /* Why is event channel masked */
+#define EVT_MASK_REASON_EXPLICIT 0x01
+#define EVT_MASK_REASON_TEMPORARY 0x02
+#define EVT_MASK_REASON_EOI_PENDING 0x04
unsigned irq;
unsigned int evtchn; /* event channel */
unsigned short cpu; /* cpu bound */
unsigned short eoi_cpu; /* EOI must happen on this cpu */
unsigned int irq_epoch; /* If eoi_cpu valid: irq_epoch of event */
u64 eoi_time; /* Time in jiffies when to EOI. */
+ spinlock_t lock;
union {
unsigned short virq;
@@ -71,7 +76,6 @@
void (*clear_pending)(unsigned port);
void (*set_pending)(unsigned port);
bool (*is_pending)(unsigned port);
- bool (*test_and_set_mask)(unsigned port);
void (*mask)(unsigned port);
void (*unmask)(unsigned port);
@@ -136,11 +140,6 @@
return evtchn_ops->is_pending(port);
}
-static inline bool test_and_set_mask(unsigned port)
-{
- return evtchn_ops->test_and_set_mask(port);
-}
-
static inline void mask_evtchn(unsigned port)
{
return evtchn_ops->mask(port);
