From: Stephan Mueller <smueller@chronox.de>
Date: Mon, 2 May 2016 06:14:34 +0000 (-0400)
Subject: random: add interrupt callback to VMBus IRQ handler
X-Git-Tag: v4.7.2~106
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=107fc0ad657987e2ebb1aff11d8955d8076abde6;p=thirdparty%2Fkernel%2Fstable.git

random: add interrupt callback to VMBus IRQ handler

commit 4b44f2d18a330565227a7348844493c59366171e upstream.

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.

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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---

diff --git a/drivers/char/random.c b/drivers/char/random.c
index 87ab9f6b41126..1a4d6e3db6aab 100644
--- a/drivers/char/random.c
+++ b/drivers/char/random.c
@@ -949,6 +949,7 @@ void add_interrupt_randomness(int irq, int irq_flags)
 	/* award one bit for the contents of the fast pool */
 	credit_entropy_bits(r, credit + 1);
 }
+EXPORT_SYMBOL_GPL(add_interrupt_randomness);
 
 #ifdef CONFIG_BLOCK
 void add_disk_randomness(struct gendisk *disk)
diff --git a/drivers/hv/vmbus_drv.c b/drivers/hv/vmbus_drv.c
index 952f20fdc7e3f..e82f7e1c217cb 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);
 }