[PATCH] xen/events: Fix interrupt lost during irq_disable and irq_enable

[PATCH] xen/events: Fix interrupt lost during irq_disable and irq_enable

[Liu Shuo]

Here is a device has xen-pirq-MSI interrupt. Dom0 might lost interrupt
during driver irq_disable/irq_enable. Here is the scenario,
 1. irq_disable -> disable_dynirq -> mask_evtchn(irq channel)
 2. dev interrupt raised by HW and Xen mark its evtchn as pending
 3. irq_enable -> startup_pirq -> eoi_pirq ->
    clear_evtchn(channel of irq) -> clear pending status
 4. consume_one_event process the irq event without pending bit assert
    which result in interrupt lost once
 5. No HW interrupt raising anymore.

Now use enable_dynirq for enable_pirq of xen_pirq_chip to remove
eoi_pirq when irq_enable.

Signed-off-by: Liu Shuo <shuo.a.liu@intel.com>
---
 drivers/xen/events/events_base.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/xen/events/events_base.c b/drivers/xen/events/events_base.c
index bae1f5d3..2d43118 100644
--- a/drivers/xen/events/events_base.c
+++ b/drivers/xen/events/events_base.c
@@ -574,7 +574,7 @@ static void shutdown_pirq(struct irq_data *data)
 
 static void enable_pirq(struct irq_data *data)
 {
-	startup_pirq(data);
+	enable_dynirq(data);
 }
 
 static void disable_pirq(struct irq_data *data)
-- 
1.9.4

Re: [PATCH] xen/events: Fix interrupt lost during irq_disable and irq_enable

[Boris Ostrovsky]

On 07/29/2017 12:59 PM, Liu Shuo wrote:
> Here is a device has xen-pirq-MSI interrupt. Dom0 might lost interrupt
> during driver irq_disable/irq_enable. Here is the scenario,
>  1. irq_disable -> disable_dynirq -> mask_evtchn(irq channel)
>  2. dev interrupt raised by HW and Xen mark its evtchn as pending
>  3. irq_enable -> startup_pirq -> eoi_pirq ->
>     clear_evtchn(channel of irq) -> clear pending status
>  4. consume_one_event process the irq event without pending bit assert
>     which result in interrupt lost once
>  5. No HW interrupt raising anymore.
>
> Now use enable_dynirq for enable_pirq of xen_pirq_chip to remove
> eoi_pirq when irq_enable.
>
> Signed-off-by: Liu Shuo <shuo.a.liu@intel.com>

Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>

Re: [PATCH] xen/events: Fix interrupt lost during irq_disable and irq_enable

[Juergen Gross]

On 29/07/17 18:59, Liu Shuo wrote:
> Here is a device has xen-pirq-MSI interrupt. Dom0 might lost interrupt
> during driver irq_disable/irq_enable. Here is the scenario,
>  1. irq_disable -> disable_dynirq -> mask_evtchn(irq channel)
>  2. dev interrupt raised by HW and Xen mark its evtchn as pending
>  3. irq_enable -> startup_pirq -> eoi_pirq ->
>     clear_evtchn(channel of irq) -> clear pending status
>  4. consume_one_event process the irq event without pending bit assert
>     which result in interrupt lost once
>  5. No HW interrupt raising anymore.
> 
> Now use enable_dynirq for enable_pirq of xen_pirq_chip to remove
> eoi_pirq when irq_enable.
> 
> Signed-off-by: Liu Shuo <shuo.a.liu@intel.com>

Pushed to xen/tip.git for-linus-4.13b


Thanks,

Juergen