xen/events: use a common cpu hotplug hook for event channels

Today only fifo event channels have a cpu hotplug callback. In order
to prepare for more percpu (de)init work move that callback into
events_base.c and add percpu_init() and percpu_deinit() hooks to
struct evtchn_ops.

This is part of XSA-332.

Cc: stable@vger.kernel.org
Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Wei Liu <wl@xen.org>

1 files changed, 25 insertions, 0 deletions

diff --git a/drivers/xen/events/events_base.c b/drivers/xen/events/events_base.c
index 1eba8bc209ad..9cbfea5e9a08 100644
--- a/drivers/xen/events/events_base.c
+++ b/drivers/xen/events/events_base.c
@@ -34,6 +34,7 @@
 #include <linux/irqnr.h>
 #include <linux/pci.h>
 #include <linux/spinlock.h>
+#include <linux/cpuhotplug.h>
 
 #ifdef CONFIG_X86
 #include <asm/desc.h>
@@ -1830,6 +1831,26 @@ static inline void xen_alloc_callback_vector(void) {}
 static bool fifo_events = true;
 module_param(fifo_events, bool, 0);
 
+static int xen_evtchn_cpu_prepare(unsigned int cpu)
+{
+	int ret = 0;
+
+	if (evtchn_ops->percpu_init)
+		ret = evtchn_ops->percpu_init(cpu);
+
+	return ret;
+}
+
+static int xen_evtchn_cpu_dead(unsigned int cpu)
+{
+	int ret = 0;
+
+	if (evtchn_ops->percpu_deinit)
+		ret = evtchn_ops->percpu_deinit(cpu);
+
+	return ret;
+}
+
 void __init xen_init_IRQ(void)
 {
 	int ret = -EINVAL;
@@ -1840,6 +1861,10 @@ void __init xen_init_IRQ(void)
 	if (ret < 0)
 		xen_evtchn_2l_init();
 
+	cpuhp_setup_state_nocalls(CPUHP_XEN_EVTCHN_PREPARE,
+				  "xen/evtchn:prepare",
+				  xen_evtchn_cpu_prepare, xen_evtchn_cpu_dead);
+
 	evtchn_to_irq = kcalloc(EVTCHN_ROW(xen_evtchn_max_channels()),
 				sizeof(*evtchn_to_irq), GFP_KERNEL);
 	BUG_ON(!evtchn_to_irq);