On 06/19/2015 05:06 PM, David Vrabel wrote:
On 19/06/15 17:02, Boris Ostrovsky wrote:
On 06/19/2015 11:15 AM, Ross Lagerwall wrote:
When a CPU is offlined, there may be unprocessed events on a port for
that CPU. If the port is subsequently reused on a different CPU, it
could be in an unexpected state with the link bit set, resulting in
interrupts being missed. Fix this by consuming any unprocessed events
for a particular CPU when that CPU dies.
Signed-off-by: Ross Lagerwall <ross.lagerw...@citrix.com>
---
drivers/xen/events/events_fifo.c | 23 ++++++++++++++++++-----
1 file changed, 18 insertions(+), 5 deletions(-)
diff --git a/drivers/xen/events/events_fifo.c
b/drivers/xen/events/events_fifo.c
index 417415d..1dd0ba12 100644
--- a/drivers/xen/events/events_fifo.c
+++ b/drivers/xen/events/events_fifo.c
@@ -281,7 +281,8 @@ static void handle_irq_for_port(unsigned port)
static void consume_one_event(unsigned cpu,
struct evtchn_fifo_control_block *control_block,
- unsigned priority, unsigned long *ready)
+ unsigned priority, unsigned long *ready,
+ bool drop)
{
struct evtchn_fifo_queue *q = &per_cpu(cpu_queue, cpu);
uint32_t head;
@@ -313,13 +314,17 @@ static void consume_one_event(unsigned cpu,
if (head == 0)
clear_bit(priority, ready);
- if (evtchn_fifo_is_pending(port) && !evtchn_fifo_is_masked(port))
- handle_irq_for_port(port);
+ if (evtchn_fifo_is_pending(port) && !evtchn_fifo_is_masked(port)) {
+ if (unlikely(drop))
+ pr_warn("Dropping pending event for port %u\n", port);
Maybe pr_info (or pr_notice)?
We want a warning here because we think this shouldn't happen -- if it
does we actually need to retrigger the event on its new CPU.
Also, why not do this (testing for unprocessed events) in
xen_evtchn_close()?
We can't do anything about them when closing because they may be in the
middle of a queue.
David
Ping. Is this change OK?
--
Ross Lagerwall
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