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 87ab9f6b411260c3836df5558bbabc87cf885e09..1a4d6e3db6aabf7f63f62e94d8bdd8664201276c 100644 (file)
--- 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 952f20fdc7e3fbe37dd11b3225e038861f5b2a3b..e82f7e1c217cbfcfb39ed9c0e87876c78f3a22b5 100644 (file)
--- 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);
 }