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Subject[PATCH] xen/events: don't use chip_data for legacy IRQs
Date
Since commit c330fb1ddc0a ("XEN uses irqdesc::irq_data_common::handler_data to store a per interrupt XEN data pointer which contains XEN specific information.")
Xen is using the chip_data pointer for storing IRQ specific data. When
running as a HVM domain this can result in problems for legacy IRQs, as
those might use chip_data for their own purposes.

Use a local array for this purpose in case of legacy IRQs, avoiding the
double use.

Cc: stable@vger.kernel.org
Fixes: c330fb1ddc0a ("XEN uses irqdesc::irq_data_common::handler_data to store a per interrupt XEN data pointer which contains XEN specific information.")
Signed-off-by: Juergen Gross <jgross@suse.com>
---
drivers/xen/events/events_base.c | 29 +++++++++++++++++++++--------
1 file changed, 21 insertions(+), 8 deletions(-)

diff --git a/drivers/xen/events/events_base.c b/drivers/xen/events/events_base.c
index 90b8f56fbadb..6f02c18fa65c 100644
--- a/drivers/xen/events/events_base.c
+++ b/drivers/xen/events/events_base.c
@@ -92,6 +92,8 @@ static bool (*pirq_needs_eoi)(unsigned irq);
/* Xen will never allocate port zero for any purpose. */
#define VALID_EVTCHN(chn) ((chn) != 0)

+static struct irq_info *legacy_info_ptrs[NR_IRQS_LEGACY];
+
static struct irq_chip xen_dynamic_chip;
static struct irq_chip xen_percpu_chip;
static struct irq_chip xen_pirq_chip;
@@ -156,7 +158,18 @@ int get_evtchn_to_irq(evtchn_port_t evtchn)
/* Get info for IRQ */
struct irq_info *info_for_irq(unsigned irq)
{
- return irq_get_chip_data(irq);
+ if (irq < nr_legacy_irqs())
+ return legacy_info_ptrs[irq];
+ else
+ return irq_get_chip_data(irq);
+}
+
+static void set_info_for_irq(unsigned int irq, struct irq_info *info)
+{
+ if (irq < nr_legacy_irqs())
+ legacy_info_ptrs[irq] = info;
+ else
+ irq_set_chip_data(irq, info);
}

/* Constructors for packed IRQ information. */
@@ -377,7 +390,7 @@ static void xen_irq_init(unsigned irq)
info->type = IRQT_UNBOUND;
info->refcnt = -1;

- irq_set_chip_data(irq, info);
+ set_info_for_irq(irq, info);

list_add_tail(&info->list, &xen_irq_list_head);
}
@@ -426,14 +439,14 @@ static int __must_check xen_allocate_irq_gsi(unsigned gsi)

static void xen_free_irq(unsigned irq)
{
- struct irq_info *info = irq_get_chip_data(irq);
+ struct irq_info *info = info_for_irq(irq);

if (WARN_ON(!info))
return;

list_del(&info->list);

- irq_set_chip_data(irq, NULL);
+ set_info_for_irq(irq, NULL);

WARN_ON(info->refcnt > 0);

@@ -603,7 +616,7 @@ EXPORT_SYMBOL_GPL(xen_irq_from_gsi);
static void __unbind_from_irq(unsigned int irq)
{
evtchn_port_t evtchn = evtchn_from_irq(irq);
- struct irq_info *info = irq_get_chip_data(irq);
+ struct irq_info *info = info_for_irq(irq);

if (info->refcnt > 0) {
info->refcnt--;
@@ -1108,7 +1121,7 @@ int bind_ipi_to_irqhandler(enum ipi_vector ipi,

void unbind_from_irqhandler(unsigned int irq, void *dev_id)
{
- struct irq_info *info = irq_get_chip_data(irq);
+ struct irq_info *info = info_for_irq(irq);

if (WARN_ON(!info))
return;
@@ -1142,7 +1155,7 @@ int evtchn_make_refcounted(evtchn_port_t evtchn)
if (irq == -1)
return -ENOENT;

- info = irq_get_chip_data(irq);
+ info = info_for_irq(irq);

if (!info)
return -ENOENT;
@@ -1170,7 +1183,7 @@ int evtchn_get(evtchn_port_t evtchn)
if (irq == -1)
goto done;

- info = irq_get_chip_data(irq);
+ info = info_for_irq(irq);

if (!info)
goto done;
--
2.26.2
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