[MODERATED] [PATCH v6 32/43] MDSv6

[Andi Kleen <andi@firstfloor.org>]

Xen has its own call back system that multiplexes a single interrupt.

Most Xen handlers do not touch user data, but a few non performance
critical ones do. Add explicit clearing to those. The fast paths
for block and network IO are not impacted.

Signed-off-by: Andi Kleen <ak@linux.intel.com>
---
 drivers/input/misc/xen-kbdfront.c | 3 ++-
 drivers/video/fbdev/xen-fbfront.c | 2 ++
 drivers/xen/pvcalls-front.c       | 2 ++
 3 files changed, 6 insertions(+), 1 deletion(-)

diff --git a/drivers/input/misc/xen-kbdfront.c b/drivers/input/misc/xen-kbdfront.c
index 24bc5c5d876f..e7cf4fffcc8b 100644
--- a/drivers/input/misc/xen-kbdfront.c
+++ b/drivers/input/misc/xen-kbdfront.c
@@ -19,6 +19,7 @@
 #include <linux/input.h>
 #include <linux/input/mt.h>
 #include <linux/slab.h>
+#include <linux/clearcpu.h>
 
 #include <asm/xen/hypervisor.h>
 
@@ -193,7 +194,7 @@ static irqreturn_t input_handler(int rq, void *dev_id)
 	mb();			/* ensure we got ring contents */
 	page->in_cons = cons;
 	notify_remote_via_irq(info->irq);
-
+	lazy_clear_cpu();
 	return IRQ_HANDLED;
 }
 
diff --git a/drivers/video/fbdev/xen-fbfront.c b/drivers/video/fbdev/xen-fbfront.c
index 6a4bbc9e1fb0..55c4cefd6a24 100644
--- a/drivers/video/fbdev/xen-fbfront.c
+++ b/drivers/video/fbdev/xen-fbfront.c
@@ -28,6 +28,7 @@
 #include <linux/slab.h>
 #include <linux/vmalloc.h>
 #include <linux/mm.h>
+#include <linux/clearcpu.h>
 
 #include <asm/xen/hypervisor.h>
 
@@ -358,6 +359,7 @@ static irqreturn_t xenfb_event_handler(int rq, void *dev_id)
 	/* Flush dirty rectangle: */
 	xenfb_refresh(info, INT_MAX, INT_MAX, -INT_MAX, -INT_MAX);
 
+	lazy_clear_cpu();
 	return IRQ_HANDLED;
 }
 
diff --git a/drivers/xen/pvcalls-front.c b/drivers/xen/pvcalls-front.c
index 8a249c95c193..e01eb88cddfd 100644
--- a/drivers/xen/pvcalls-front.c
+++ b/drivers/xen/pvcalls-front.c
@@ -15,6 +15,7 @@
 #include <linux/module.h>
 #include <linux/net.h>
 #include <linux/socket.h>
+#include <linux/clearcpu.h>
 
 #include <net/sock.h>
 
@@ -219,6 +220,7 @@ static irqreturn_t pvcalls_front_event_handler(int irq, void *dev_id)
 			 */
 			smp_wmb();
 			bedata->rsp[req_id].req_id = req_id;
+			lazy_clear_cpu();
 		}
 
 		done = 1;
-- 
2.17.2