Drivers: hv: vmbus: Force all channel messages to be delivered on CPU 0

Force all channel messages to be delivered on CPU0. These messages are not
performance critical and are used during the setup and teardown of the
channel.
Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/hv/connection.c

@@ -83,10 +83,13 @@ static int vmbus_negotiate_version(struct vmbus_channel_msginfo *msginfo,
 	msg->interrupt_page = virt_to_phys(vmbus_connection.int_page);
 	msg->monitor_page1 = virt_to_phys(vmbus_connection.monitor_pages[0]);
 	msg->monitor_page2 = virt_to_phys(vmbus_connection.monitor_pages[1]);
-	if (version >= VERSION_WIN8_1) {
-		msg->target_vcpu = hv_context.vp_index[get_cpu()];
-		put_cpu();
-	}
+	/*
+	 * We want all channel messages to be delivered on CPU 0.
+	 * This has been the behavior pre-win8. This is not
+	 * perf issue and having all channel messages delivered on CPU 0
+	 * would be ok.
+	 */
+	msg->target_vcpu = 0;
 
 	/*
 	 * Add to list before we send the request since we may