--- zzzz-none-000/linux-3.10.107/drivers/hv/connection.c	2017-06-27 09:49:32.000000000 +0000
+++ scorpion-7490-727/linux-3.10.107/drivers/hv/connection.c	2021-02-04 17:41:59.000000000 +0000
@@ -58,6 +58,9 @@
 	case (VERSION_WIN8_1):
 		return VERSION_WIN8;
 
+	case (VERSION_WIN10):
+		return VERSION_WIN8_1;
+
 	case (VERSION_WS2008):
 	default:
 		return VERSION_INVAL;
@@ -78,13 +81,12 @@
 	msg->header.msgtype = CHANNELMSG_INITIATE_CONTACT;
 	msg->vmbus_version_requested = version;
 	msg->interrupt_page = virt_to_phys(vmbus_connection.int_page);
-	msg->monitor_page1 = virt_to_phys(vmbus_connection.monitor_pages);
-	msg->monitor_page2 = virt_to_phys(
-			(void *)((unsigned long)vmbus_connection.monitor_pages +
-				 PAGE_SIZE));
-
-	if (version == VERSION_WIN8_1)
-		msg->target_vcpu = hv_context.vp_index[smp_processor_id()];
+	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();
+	}
 
 	/*
 	 * Add to list before we send the request since we may
@@ -166,9 +168,10 @@
 	 * Setup the monitor notification facility. The 1st page for
 	 * parent->child and the 2nd page for child->parent
 	 */
-	vmbus_connection.monitor_pages =
-	(void *)__get_free_pages((GFP_KERNEL|__GFP_ZERO), 1);
-	if (vmbus_connection.monitor_pages == NULL) {
+	vmbus_connection.monitor_pages[0] = (void *)__get_free_pages((GFP_KERNEL|__GFP_ZERO), 0);
+	vmbus_connection.monitor_pages[1] = (void *)__get_free_pages((GFP_KERNEL|__GFP_ZERO), 0);
+	if ((vmbus_connection.monitor_pages[0] == NULL) ||
+	    (vmbus_connection.monitor_pages[1] == NULL)) {
 		ret = -ENOMEM;
 		goto cleanup;
 	}
@@ -192,7 +195,10 @@
 
 	do {
 		ret = vmbus_negotiate_version(msginfo, version);
-		if (ret == 0)
+		if (ret == -ETIMEDOUT)
+			goto cleanup;
+
+		if (vmbus_connection.conn_state == CONNECTED)
 			break;
 
 		version = vmbus_get_next_version(version);
@@ -213,26 +219,60 @@
 
 cleanup:
 	pr_err("Unable to connect to host\n");
+
 	vmbus_connection.conn_state = DISCONNECTED;
+	vmbus_disconnect();
+
+	kfree(msginfo);
+
+	return ret;
+}
 
-	if (vmbus_connection.work_queue)
+void vmbus_disconnect(void)
+{
+	/*
+	 * First send the unload request to the host.
+	 */
+	vmbus_initiate_unload();
+
+	if (vmbus_connection.work_queue) {
+		drain_workqueue(vmbus_connection.work_queue);
 		destroy_workqueue(vmbus_connection.work_queue);
+	}
 
 	if (vmbus_connection.int_page) {
 		free_pages((unsigned long)vmbus_connection.int_page, 0);
 		vmbus_connection.int_page = NULL;
 	}
 
-	if (vmbus_connection.monitor_pages) {
-		free_pages((unsigned long)vmbus_connection.monitor_pages, 1);
-		vmbus_connection.monitor_pages = NULL;
-	}
+	free_pages((unsigned long)vmbus_connection.monitor_pages[0], 0);
+	free_pages((unsigned long)vmbus_connection.monitor_pages[1], 0);
+	vmbus_connection.monitor_pages[0] = NULL;
+	vmbus_connection.monitor_pages[1] = NULL;
+}
 
-	kfree(msginfo);
+/*
+ * Map the given relid to the corresponding channel based on the
+ * per-cpu list of channels that have been affinitized to this CPU.
+ * This will be used in the channel callback path as we can do this
+ * mapping in a lock-free fashion.
+ */
+static struct vmbus_channel *pcpu_relid2channel(u32 relid)
+{
+	struct vmbus_channel *channel;
+	struct vmbus_channel *found_channel  = NULL;
+	int cpu = smp_processor_id();
+	struct list_head *pcpu_head = &hv_context.percpu_list[cpu];
 
-	return ret;
-}
+	list_for_each_entry(channel, pcpu_head, percpu_list) {
+		if (channel->offermsg.child_relid == relid) {
+			found_channel = channel;
+			break;
+		}
+	}
 
+	return found_channel;
+}
 
 /*
  * relid2channel - Get the channel object given its
@@ -243,12 +283,26 @@
 	struct vmbus_channel *channel;
 	struct vmbus_channel *found_channel  = NULL;
 	unsigned long flags;
+	struct list_head *cur, *tmp;
+	struct vmbus_channel *cur_sc;
 
 	spin_lock_irqsave(&vmbus_connection.channel_lock, flags);
 	list_for_each_entry(channel, &vmbus_connection.chn_list, listentry) {
 		if (channel->offermsg.child_relid == relid) {
 			found_channel = channel;
 			break;
+		} else if (!list_empty(&channel->sc_list)) {
+			/*
+			 * Deal with sub-channels.
+			 */
+			list_for_each_safe(cur, tmp, &channel->sc_list) {
+				cur_sc = list_entry(cur, struct vmbus_channel,
+							sc_list);
+				if (cur_sc->offermsg.child_relid == relid) {
+					found_channel = cur_sc;
+					break;
+				}
+			}
 		}
 	}
 	spin_unlock_irqrestore(&vmbus_connection.channel_lock, flags);
@@ -262,7 +316,6 @@
 static void process_chn_event(u32 relid)
 {
 	struct vmbus_channel *channel;
-	unsigned long flags;
 	void *arg;
 	bool read_state;
 	u32 bytes_to_read;
@@ -271,23 +324,20 @@
 	 * Find the channel based on this relid and invokes the
 	 * channel callback to process the event
 	 */
-	channel = relid2channel(relid);
+	channel = pcpu_relid2channel(relid);
 
-	if (!channel) {
-		pr_err("channel not found for relid - %u\n", relid);
+	if (!channel)
 		return;
-	}
 
 	/*
 	 * A channel once created is persistent even when there
 	 * is no driver handling the device. An unloading driver
-	 * sets the onchannel_callback to NULL under the
-	 * protection of the channel inbound_lock. Thus, checking
-	 * and invoking the driver specific callback takes care of
-	 * orderly unloading of the driver.
+	 * sets the onchannel_callback to NULL on the same CPU
+	 * as where this interrupt is handled (in an interrupt context).
+	 * Thus, checking and invoking the driver specific callback takes
+	 * care of orderly unloading of the driver.
 	 */
 
-	spin_lock_irqsave(&channel->inbound_lock, flags);
 	if (channel->onchannel_callback != NULL) {
 		arg = channel->channel_callback_context;
 		read_state = channel->batched_reading;
@@ -312,11 +362,7 @@
 			else
 				bytes_to_read = 0;
 		} while (read_state && (bytes_to_read != 0));
-	} else {
-		pr_err("no channel callback for relid - %u\n", relid);
 	}
-
-	spin_unlock_irqrestore(&channel->inbound_lock, flags);
 }
 
 /*
@@ -333,8 +379,7 @@
 	int cpu = smp_processor_id();
 	union hv_synic_event_flags *event;
 
-	if ((vmbus_proto_version == VERSION_WS2008) ||
-		(vmbus_proto_version == VERSION_WIN7)) {
+	if (vmbus_proto_version < VERSION_WIN8) {
 		maxdword = MAX_NUM_CHANNELS_SUPPORTED >> 5;
 		recv_int_page = vmbus_connection.recv_int_page;
 	} else {
@@ -384,6 +429,7 @@
 	union hv_connection_id conn_id;
 	int ret = 0;
 	int retries = 0;
+	u32 msec = 1;
 
 	conn_id.asu32 = 0;
 	conn_id.u.id = VMBUS_MESSAGE_CONNECTION_ID;
@@ -393,13 +439,20 @@
 	 * insufficient resources. Retry the operation a couple of
 	 * times before giving up.
 	 */
-	while (retries < 10) {
+	while (retries < 20) {
 		ret = hv_post_message(conn_id, 1, buffer, buflen);
 
 		switch (ret) {
+		case HV_STATUS_INVALID_CONNECTION_ID:
+			/*
+			 * We could get this if we send messages too
+			 * frequently.
+			 */
+			ret = -EAGAIN;
+			break;
+		case HV_STATUS_INSUFFICIENT_MEMORY:
 		case HV_STATUS_INSUFFICIENT_BUFFERS:
 			ret = -ENOMEM;
-		case -ENOMEM:
 			break;
 		case HV_STATUS_SUCCESS:
 			return ret;
@@ -409,7 +462,9 @@
 		}
 
 		retries++;
-		msleep(100);
+		msleep(msec);
+		if (msec < 2048)
+			msec *= 2;
 	}
 	return ret;
 }