From 4b44f2d18a330565227a7348844493c59366171e Mon Sep 17 00:00:00 2001
From: Stephan Mueller <smueller@chronox.de>
Date: Mon, 2 May 2016 02:14:34 -0400
Subject: random: add interrupt callback to VMBus IRQ handler

The Hyper-V Linux Integration Services use the VMBus implementation for
communication with the Hypervisor. VMBus registers its own interrupt
handler that completely bypasses the common Linux interrupt handling.
This implies that the interrupt entropy collector is not triggered.

This patch adds the interrupt entropy collection callback into the VMBus
interrupt handler function.

Cc: stable@kernel.org
Signed-off-by: Stephan Mueller <stephan.mueller@atsec.com>
Signed-off-by: Stephan Mueller <smueller@chronox.de>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
---
 drivers/hv/vmbus_drv.c | 3 +++
 1 file changed, 3 insertions(+)

(limited to 'drivers/hv')

diff --git a/drivers/hv/vmbus_drv.c b/drivers/hv/vmbus_drv.c
index 952f20fdc7e3..e82f7e1c217c 100644
--- a/drivers/hv/vmbus_drv.c
+++ b/drivers/hv/vmbus_drv.c
@@ -42,6 +42,7 @@
 #include <linux/screen_info.h>
 #include <linux/kdebug.h>
 #include <linux/efi.h>
+#include <linux/random.h>
 #include "hyperv_vmbus.h"
 
 static struct acpi_device  *hv_acpi_dev;
@@ -806,6 +807,8 @@ static void vmbus_isr(void)
 		else
 			tasklet_schedule(hv_context.msg_dpc[cpu]);
 	}
+
+	add_interrupt_randomness(HYPERVISOR_CALLBACK_VECTOR, 0);
 }
 
 
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