From: Olaf Hering <[mailto:olaf@aepfle.de]> Date: Mon, 4 Feb 2013 01:22:37 +0000 (-0800) Subject: x86: Hyper-V: register clocksource only if its advertised X-Git-Tag: v3.2.40~106 X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=12324875d79c23a13bbf66390b595a84337dc8d7;p=pandora-kernel.git x86: Hyper-V: register clocksource only if its advertised commit 32068f6527b8f1822a30671dedaf59c567325026 upstream. Enable hyperv_clocksource only if its advertised as a feature. XenServer 6 returns the signature which is checked in ms_hyperv_platform(), but it does not offer all features. Currently the clocksource is enabled unconditionally in ms_hyperv_init_platform(), and the result is a hanging guest. Hyper-V spec Bit 1 indicates the availability of Partition Reference Counter. Register the clocksource only if this bit is set. The guest in question prints this in dmesg: [ 0.000000] Hypervisor detected: Microsoft HyperV [ 0.000000] HyperV: features 0x70, hints 0x0 This bug can be reproduced easily be setting 'viridian=1' in a HVM domU .cfg file. A workaround without this patch is to boot the HVM guest with 'clocksource=jiffies'. Signed-off-by: Olaf Hering Link: http://lkml.kernel.org/r/1359940959-32168-1-git-send-email-kys@microsoft.com Signed-off-by: K. Y. Srinivasan Cc: Greg KH Signed-off-by: H. Peter Anvin Signed-off-by: Ben Hutchings --- Reading git-diff-tree failed