Drivers: hv: vmbus: Specify the target CPU that should receive notification

During the initial VMBUS connect phase, starting with WS2012 R2, we should
specify the VPCU in the guest that should receive the notification. Fix this
issue. This fix is required to properly connect to the host in the kexeced
kernel.

Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Cc: <stable@vger.kernel.org>        [3.9+]
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/hv/connection.c

@@ -78,6 +78,8 @@ 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)
+		msg->target_vcpu = hv_context.vp_index[smp_processor_id()];
 
 	/*
 	 * Add to list before we send the request since we may

include/linux/hyperv.h

@@ -875,7 +875,7 @@ struct vmbus_channel_relid_released {
 struct vmbus_channel_initiate_contact {
 	struct vmbus_channel_message_header header;
 	u32 vmbus_version_requested;
-	u32 padding2;
+	u32 target_vcpu; /* The VCPU the host should respond to */
 	u64 interrupt_page;
 	u64 monitor_page1;
 	u64 monitor_page2;