@@ -345,6 +345,15 @@ irqreturn_t xen_debug_interrupt(int irq, void *dev_id)
return IRQ_HANDLED;
}
+static void evtchn_2l_resume(void)
+{
+ int i;
+
+ for_each_online_cpu(i)
+ memset(per_cpu(cpu_evtchn_mask, i), 0, sizeof(xen_ulong_t) *
+ EVTCHN_2L_NR_CHANNELS/BITS_PER_EVTCHN_WORD);
+}
+
static const struct evtchn_ops evtchn_ops_2l = {
.max_channels = evtchn_2l_max_channels,
.nr_channels = evtchn_2l_max_channels,
@@ -356,6 +365,7 @@ static const struct evtchn_ops evtchn_ops_2l = {
.mask = evtchn_2l_mask,
.unmask = evtchn_2l_unmask,
.handle_events = evtchn_2l_handle_events,
+ .resume = evtchn_2l_resume,
};
void __init xen_evtchn_2l_init(void)
@@ -1278,8 +1278,9 @@ void rebind_evtchn_irq(int evtchn, int irq)
mutex_unlock(&irq_mapping_update_lock);
- /* new event channels are always bound to cpu 0 */
- irq_set_affinity(irq, cpumask_of(0));
+ bind_evtchn_to_cpu(evtchn, info->cpu);
+ /* This will be deferred until interrupt is processed */
+ irq_set_affinity(irq, cpumask_of(info->cpu));
/* Unmask the event channel. */
enable_irq(irq);
This is a note to let you know that I have just added a patch titled xen/events: Clear cpu_evtchn_mask before resuming to the linux-3.16.y-queue branch of the 3.16.y-ckt extended stable tree which can be found at: http://kernel.ubuntu.com/git/ubuntu/linux.git/log/?h=linux-3.16.y-queue This patch is scheduled to be released in version 3.16.7-ckt12. If you, or anyone else, feels it should not be added to this tree, please reply to this email. For more information about the 3.16.y-ckt tree, see https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable Thanks. -Luis ------ From 06e826e09ff64c46ea6469d13f540ef35116f464 Mon Sep 17 00:00:00 2001 From: Boris Ostrovsky <boris.ostrovsky@oracle.com> Date: Wed, 29 Apr 2015 17:10:12 -0400 Subject: xen/events: Clear cpu_evtchn_mask before resuming commit 5cec98834989a014a9560b1841649eaca95cf00e upstream. When a guest is resumed, the hypervisor may change event channel assignments. If this happens and the guest uses 2-level events it is possible for the interrupt to be claimed by wrong VCPU since cpu_evtchn_mask bits may be stale. This can happen even though evtchn_2l_bind_to_cpu() attempts to clear old bits: irq_info that is passed in is not necessarily the original one (from pre-migration times) but instead is freshly allocated during resume and so any information about which CPU the channel was bound to is lost. Thus we should clear the mask during resume. We also need to make sure that bits for xenstore and console channels are set when these two subsystems are resumed. While rebind_evtchn_irq() (which is invoked for both of them on a resume) calls irq_set_affinity(), the latter will in fact postpone setting affinity until handling the interrupt. But because cpu_evtchn_mask will have bits for these two cleared we won't be able to take the interrupt. With that in mind, we need to bind those two channels explicitly in rebind_evtchn_irq(). We will keep irq_set_affinity() so that we have a pass through generic irq affinity code later, in case something needs to be updated there as well. (Also replace cpumask_of(0) with cpumask_of(info->cpu) in rebind_evtchn_irq(): it should be set to zero in preceding xen_irq_info_evtchn_setup().) Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com> Reported-by: Annie Li <annie.li@oracle.com> Signed-off-by: David Vrabel <david.vrabel@citrix.com> Signed-off-by: Luis Henriques <luis.henriques@canonical.com> --- drivers/xen/events/events_2l.c | 10 ++++++++++ drivers/xen/events/events_base.c | 5 +++-- 2 files changed, 13 insertions(+), 2 deletions(-)