Drivers: hv: vss: run only on supported host versions
authorOlaf Hering <olaf@aepfle.de>
Tue, 15 Dec 2015 00:01:42 +0000 (16:01 -0800)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Thu, 15 Sep 2016 06:27:40 +0000 (08:27 +0200)
commitbf59c816fb104b2e92d29f8c13f1118f4c5333c4
tree6941ef4a1efde2e20b38705ad1094f2bf74c1263
parentc1d32939e9e1951eaf7af573b15d54d8495aafff
Drivers: hv: vss: run only on supported host versions

[ Upstream commit ed9ba608e4851144af8c7061cbb19f751c73e998 ]

The Backup integration service on WS2012 has appearently trouble to
negotiate with a guest which does not support the provided util version.
Currently the VSS driver supports only version 5/0. A WS2012 offers only
version 1/x and 3/x, and vmbus_prep_negotiate_resp correctly returns an
empty icframe_vercnt/icmsg_vercnt. But the host ignores that and
continues to send ICMSGTYPE_NEGOTIATE messages. The result are weird
errors during boot and general misbehaviour.

Check the Windows version to work around the host bug, skip hv_vss_init
on WS2012 and older.

Signed-off-by: Olaf Hering <olaf@aepfle.de>
Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
drivers/hv/hv_snapshot.c