diff options
| author | Olaf Hering <[mailto:olaf@aepfle.de]> | 2013-02-03 17:22:37 -0800 |
|---|---|---|
| committer | Ben Hutchings <ben@decadent.org.uk> | 2013-03-06 03:23:56 +0000 |
| commit | 12324875d79c23a13bbf66390b595a84337dc8d7 (patch) | |
| tree | 17eabe572ec02bed1cac3f617b81ff6cd9f714b1 /arch | |
| parent | 7366b52c44b46c073a4bf1285ca09ca6ce5d9b39 (diff) | |
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 <olaf@aepfle.de>
Link: http://lkml.kernel.org/r/1359940959-32168-1-git-send-email-kys@microsoft.com
Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Cc: Greg KH <gregkh@linuxfoundation.org>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/x86/kernel/cpu/mshyperv.c | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/arch/x86/kernel/cpu/mshyperv.c b/arch/x86/kernel/cpu/mshyperv.c index 0a630dd4b620..646d192b18a2 100644 --- a/arch/x86/kernel/cpu/mshyperv.c +++ b/arch/x86/kernel/cpu/mshyperv.c @@ -68,7 +68,8 @@ static void __init ms_hyperv_init_platform(void) printk(KERN_INFO "HyperV: features 0x%x, hints 0x%x\n", ms_hyperv.features, ms_hyperv.hints); - clocksource_register_hz(&hyperv_cs, NSEC_PER_SEC/100); + if (ms_hyperv.features & HV_X64_MSR_TIME_REF_COUNT_AVAILABLE) + clocksource_register_hz(&hyperv_cs, NSEC_PER_SEC/100); } const __refconst struct hypervisor_x86 x86_hyper_ms_hyperv = { |