2017-07-29 17:04:10

by Shuo Liu

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

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 <[email protected]>
---
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

2017-07-31 13:58:35

by Boris Ostrovsky

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

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 <[email protected]>

Reviewed-by: Boris Ostrovsky <[email protected]>

2017-08-11 14:50:12

by Jürgen Groß

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

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 <[email protected]>

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


Thanks,

Juergen