Commit ddc9d357 authored by Dexuan Cui's avatar Dexuan Cui Committed by Sasha Levin
Browse files

Drivers: hv: vmbus: Ignore CHANNELMSG_TL_CONNECT_RESULT(23) 



When a Linux hv_sock app tries to connect to a Service GUID on which no
host app is listening, a recent host (RS3+) sends a
CHANNELMSG_TL_CONNECT_RESULT (23) message to Linux and this triggers such
a warning:

unknown msgtype=23
WARNING: CPU: 2 PID: 0 at drivers/hv/vmbus_drv.c:1031 vmbus_on_msg_dpc

Actually Linux can safely ignore the message because the Linux app's
connect() will time out in 2 seconds: see VSOCK_DEFAULT_CONNECT_TIMEOUT
and vsock_stream_connect(). We don't bother to make use of the message
because: 1) it's only supported on recent hosts; 2) a non-trivial effort
is required to use the message in Linux, but the benefit is small.

So, let's not see the warning by silently ignoring the message.

Signed-off-by: default avatarDexuan Cui <decui@microsoft.com>
Reviewed-by: default avatarMichael Kelley <mikelley@microsoft.com>
Signed-off-by: default avatarSasha Levin <sashal@kernel.org>
parent 382a4622

drivers/hv/channel_mgmt.c

+7 −14
Original line number Diff line number Diff line
@@ -1351,6 +1351,8 @@ channel_message_table[CHANNELMSG_COUNT] = { 
	{ CHANNELMSG_19,			0, NULL },

	{ CHANNELMSG_20,			0, NULL },

	{ CHANNELMSG_TL_CONNECT_REQUEST,	0, NULL },

	{ CHANNELMSG_22,			0, NULL },

	{ CHANNELMSG_TL_CONNECT_RESULT,		0, NULL },

};



/*
@@ -1362,25 +1364,16 @@ void vmbus_onmessage(void *context) 
{

	struct hv_message *msg = context;

	struct vmbus_channel_message_header *hdr;

	int size;



	hdr = (struct vmbus_channel_message_header *)msg->u.payload;

	size = msg->header.payload_size;



	trace_vmbus_on_message(hdr);



	if (hdr->msgtype >= CHANNELMSG_COUNT) {

		pr_err("Received invalid channel message type %d size %d\n",

			   hdr->msgtype, size);

		print_hex_dump_bytes("", DUMP_PREFIX_NONE,

				     (unsigned char *)msg->u.payload, size);

		return;

	}



	if (channel_message_table[hdr->msgtype].message_handler)

	/*

	 * vmbus_on_msg_dpc() makes sure the hdr->msgtype here can not go

	 * out of bound and the message_handler pointer can not be NULL.

	 */

	channel_message_table[hdr->msgtype].message_handler(hdr);

	else

		pr_err("Unhandled channel message type %d\n", hdr->msgtype);

}



/*

drivers/hv/vmbus_drv.c

+4 −0
Original line number Diff line number Diff line
@@ -1033,6 +1033,10 @@ void vmbus_on_msg_dpc(unsigned long data) 
	}



	entry = &channel_message_table[hdr->msgtype];



	if (!entry->message_handler)

		goto msg_handled;



	if (entry->handler_type	== VMHT_BLOCKING) {

		ctx = kmalloc(sizeof(*ctx), GFP_ATOMIC);

		if (ctx == NULL)

include/linux/hyperv.h

+2 −0
Original line number Diff line number Diff line
@@ -425,6 +425,8 @@ enum vmbus_channel_message_type { 
	CHANNELMSG_19				= 19,

	CHANNELMSG_20				= 20,

	CHANNELMSG_TL_CONNECT_REQUEST		= 21,

	CHANNELMSG_22				= 22,

	CHANNELMSG_TL_CONNECT_RESULT		= 23,

	CHANNELMSG_COUNT

};

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