xen/events: reset affinity of 2-level event when tearing it down

When creating a new event channel with 2-level events the affinity
needs to be reset initially in order to avoid using an old affinity
from earlier usage of the event channel port. So when tearing an event
channel down reset all affinity bits.

The same applies to the affinity when onlining a vcpu: all old
affinity settings for this vcpu must be reset. As percpu events get
initialized before the percpu event channel hook is called,
resetting of the affinities happens after offlining a vcpu (this is
working, as initial percpu memory is zeroed out).

Cc: stable@vger.kernel.org
Reported-by: Julien Grall <julien@xen.org>
Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Julien Grall <jgrall@amazon.com>
Link: https://lore.kernel.org/r/20210306161833.4552-2-jgross@suse.com
Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>

diff --git a/drivers/xen/events/events_2l.c b/drivers/xen/events/events_2l.c
index da87f3a1e351b0bb2794b11aa900dc540d09351b..a7f413c5c1908c84763bbd96c8b54ca326064a78 100644 (file)
--- a/drivers/xen/events/events_2l.c
+++ b/drivers/xen/events/events_2l.c
@@ -47,6 +47,11 @@ static unsigned evtchn_2l_max_channels(void)
        return EVTCHN_2L_NR_CHANNELS;
 }
 
+static void evtchn_2l_remove(evtchn_port_t evtchn, unsigned int cpu)
+{
+       clear_bit(evtchn, BM(per_cpu(cpu_evtchn_mask, cpu)));
+}
+
 static void evtchn_2l_bind_to_cpu(evtchn_port_t evtchn, unsigned int cpu,
                                  unsigned int old_cpu)
 {
@@ -355,9 +360,18 @@ static void evtchn_2l_resume(void)
                                EVTCHN_2L_NR_CHANNELS/BITS_PER_EVTCHN_WORD);
 }
 
+static int evtchn_2l_percpu_deinit(unsigned int cpu)
+{
+       memset(per_cpu(cpu_evtchn_mask, cpu), 0, sizeof(xen_ulong_t) *
+                       EVTCHN_2L_NR_CHANNELS/BITS_PER_EVTCHN_WORD);
+
+       return 0;
+}
+
 static const struct evtchn_ops evtchn_ops_2l = {
        .max_channels      = evtchn_2l_max_channels,
        .nr_channels       = evtchn_2l_max_channels,
+       .remove            = evtchn_2l_remove,
        .bind_to_cpu       = evtchn_2l_bind_to_cpu,
        .clear_pending     = evtchn_2l_clear_pending,
        .set_pending       = evtchn_2l_set_pending,
@@ -367,6 +381,7 @@ static const struct evtchn_ops evtchn_ops_2l = {
        .unmask            = evtchn_2l_unmask,
        .handle_events     = evtchn_2l_handle_events,
        .resume            = evtchn_2l_resume,
+       .percpu_deinit     = evtchn_2l_percpu_deinit,
 };
 
 void __init xen_evtchn_2l_init(void)

diff --git a/drivers/xen/events/events_base.c b/drivers/xen/events/events_base.c
index adb7260e94b232d6ffe334cb2b5f6c023092c432..7e23808892a72df355ababb747d9ab2f0bb86b28 100644 (file)
--- a/drivers/xen/events/events_base.c
+++ b/drivers/xen/events/events_base.c
@@ -377,6 +377,7 @@ static int xen_irq_info_pirq_setup(unsigned irq,
 static void xen_irq_info_cleanup(struct irq_info *info)
 {
        set_evtchn_to_irq(info->evtchn, -1);
+       xen_evtchn_port_remove(info->evtchn, info->cpu);
        info->evtchn = 0;
        channels_on_cpu_dec(info);
 }

diff --git a/drivers/xen/events/events_internal.h b/drivers/xen/events/events_internal.h
index 0a97c0549db761fdf3f4ffdec0ff22401df427be..18a4090d07099e834fa4ff1c0a4cffac2459d40d 100644 (file)
--- a/drivers/xen/events/events_internal.h
+++ b/drivers/xen/events/events_internal.h
@@ -14,6 +14,7 @@ struct evtchn_ops {
        unsigned (*nr_channels)(void);
 
        int (*setup)(evtchn_port_t port);
+       void (*remove)(evtchn_port_t port, unsigned int cpu);
        void (*bind_to_cpu)(evtchn_port_t evtchn, unsigned int cpu,
                            unsigned int old_cpu);
 
@@ -54,6 +55,13 @@ static inline int xen_evtchn_port_setup(evtchn_port_t evtchn)
        return 0;
 }
 
+static inline void xen_evtchn_port_remove(evtchn_port_t evtchn,
+                                         unsigned int cpu)
+{
+       if (evtchn_ops->remove)
+               evtchn_ops->remove(evtchn, cpu);
+}
+
 static inline void xen_evtchn_port_bind_to_cpu(evtchn_port_t evtchn,
                                               unsigned int cpu,
                                               unsigned int old_cpu)