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Subject[PATCH 10/14] xen: events: maintain a list of Xen interrupts
Date
In a PVHVM kernel not all interrupts are Xen interrupts (APIC interrupts can also be present).

Currently we get away with walking over all interrupts because the
lookup in the irq_info array simply returns IRQT_UNBOUND and we ignore
it. However this array will be going away in a future patch so we need
to manually track which interrupts have been allocated by the Xen
events infrastructure.

Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
---
drivers/xen/events.c | 59 +++++++++++++++++++++++++++++++++++++------------
1 files changed, 44 insertions(+), 15 deletions(-)
diff --git a/drivers/xen/events.c b/drivers/xen/events.c
index cf372d4..e119989 100644
--- a/drivers/xen/events.c
+++ b/drivers/xen/events.c
@@ -56,6 +56,8 @@
*/
static DEFINE_SPINLOCK(irq_mapping_update_lock);

+static LIST_HEAD(xen_irq_list_head);
+
/* IRQ <-> VIRQ mapping. */
static DEFINE_PER_CPU(int [NR_VIRQS], virq_to_irq) = {[0 ... NR_VIRQS-1] = -1};

@@ -85,7 +87,9 @@ enum xen_irq_type {
*/
struct irq_info
{
+ struct list_head list;
enum xen_irq_type type; /* type */
+ unsigned irq;
unsigned short evtchn; /* event channel */
unsigned short cpu; /* cpu bound */

@@ -135,6 +139,7 @@ static void xen_irq_info_common_init(struct irq_info *info,
BUG_ON(info->type != IRQT_UNBOUND && info->type != type);

info->type = type;
+ info->irq = irq;
info->evtchn = evtchn;
info->cpu = cpu;

@@ -311,10 +316,11 @@ static void init_evtchn_cpu_bindings(void)
{
int i;
#ifdef CONFIG_SMP
- struct irq_desc *desc;
+ struct irq_info *info;

/* By default all event channels notify CPU#0. */
- for_each_irq_desc(i, desc) {
+ list_for_each_entry(info, &xen_irq_list_head, list) {
+ struct irq_desc *desc = irq_to_desc(info->irq);
cpumask_copy(desc->irq_data.affinity, cpumask_of(0));
}
#endif
@@ -397,6 +403,21 @@ static void unmask_evtchn(int port)
put_cpu();
}

+static void xen_irq_init(unsigned irq)
+{
+ struct irq_info *info;
+ struct irq_desc *desc = irq_to_desc(irq);
+
+ /* By default all event channels notify CPU#0. */
+ cpumask_copy(desc->irq_data.affinity, cpumask_of(0));
+
+ info = &irq_info[irq];
+
+ info->type = IRQT_UNBOUND;
+
+ list_add_tail(&info->list, &xen_irq_list_head);
+}
+
static int xen_allocate_irq_dynamic(void)
{
int first = 0;
@@ -426,6 +447,8 @@ retry:
if (irq < 0)
panic("No available IRQ to bind to: increase nr_irqs!\n");

+ xen_irq_init(irq);
+
return irq;
}

@@ -444,18 +467,25 @@ static int xen_allocate_irq_gsi(unsigned gsi)

/* Legacy IRQ descriptors are already allocated by the arch. */
if (gsi < NR_IRQS_LEGACY)
- return gsi;
+ irq = gsi;
+ else
+ irq = irq_alloc_desc_at(gsi, -1);

- irq = irq_alloc_desc_at(gsi, -1);
if (irq < 0)
panic("Unable to allocate to IRQ%d (%d)\n", gsi, irq);

+ xen_irq_init(irq);
+
return irq;
}

static void xen_free_irq(unsigned irq)
{
- irq_info[irq].type = IRQT_UNBOUND;
+ struct irq_info *info = &irq_info[irq];
+
+ info->type = IRQT_UNBOUND;
+
+ list_del(&info->list);

/* Legacy IRQ descriptors are managed by the arch. */
if (irq < NR_IRQS_LEGACY)
@@ -586,16 +616,14 @@ static void ack_pirq(struct irq_data *data)

static int find_irq_by_gsi(unsigned gsi)
{
- int irq;
-
- for (irq = 0; irq < nr_irqs; irq++) {
- struct irq_info *info = info_for_irq(irq);
+ struct irq_info *info;

- if (info == NULL || info->type != IRQT_PIRQ)
+ list_for_each_entry(info, &xen_irq_list_head, list) {
+ if (info->type != IRQT_PIRQ)
continue;

- if (gsi_from_irq(irq) == gsi)
- return irq;
+ if (info->u.pirq.gsi == gsi)
+ return info->irq;
}

return -1;
@@ -1374,7 +1402,8 @@ void xen_poll_irq(int irq)

void xen_irq_resume(void)
{
- unsigned int cpu, irq, evtchn;
+ unsigned int cpu, evtchn;
+ struct irq_info *info;

init_evtchn_cpu_bindings();

@@ -1383,8 +1412,8 @@ void xen_irq_resume(void)
mask_evtchn(evtchn);

/* No IRQ <-> event-channel mappings. */
- for (irq = 0; irq < nr_irqs; irq++)
- irq_info[irq].evtchn = 0; /* zap event-channel binding */
+ list_for_each_entry(info, &xen_irq_list_head, list)
+ info->evtchn = 0; /* zap event-channel binding */

for (evtchn = 0; evtchn < NR_EVENT_CHANNELS; evtchn++)
evtchn_to_irq[evtchn] = -1;
--
1.5.6.5


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