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x86: Hyper-V: Integrate the clocksource with Hyper-V detection code

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The Hyper-V clocksource driver is best integrated with Hyper-V
detection code since: 

  (a) Linux guests running on Hyper-V require it

  (b) Integration into that code significanly reduces code size

Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: Haiyang Zhang <haiyangz@microsoft.com>
Cc: gregkh@suse.de
Cc: devel@linuxdriverproject.org
Cc: virtualization@lists.osdl.org
Link: http://lkml.kernel.org/r/1315434310-4827-1-git-send-email-kys@microsoft.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
This commit is contained in:
K. Y. Srinivasan
2011-09-07 15:25:10 -07:00
committed by Thomas Gleixner
parent ddf28352b8
commit 6f4151c89b
3 changed files with 24 additions and 102 deletions
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23
arch/x86/kernel/cpu/mshyperv.c
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@ -11,6 +11,8 @@
*/
#include <linux/types.h>
#include <linux/time.h>
#include <linux/clocksource.h>
#include <linux/module.h>
#include <asm/processor.h>
#include <asm/hypervisor.h>
@ -36,6 +38,25 @@ static bool __init ms_hyperv_platform(void)
!memcmp("Microsoft Hv", hyp_signature, 12);
}
static cycle_t read_hv_clock(struct clocksource *arg)
{
cycle_t current_tick;
/*
* Read the partition counter to get the current tick count. This count
* is set to 0 when the partition is created and is incremented in
* 100 nanosecond units.
*/
rdmsrl(HV_X64_MSR_TIME_REF_COUNT, current_tick);
return current_tick;
}
static struct clocksource hyperv_cs = {
.name = "hyperv_clocksource",
.rating = 400, /* use this when running on Hyperv*/
.read = read_hv_clock,
.mask = CLOCKSOURCE_MASK(64),
};
static void __init ms_hyperv_init_platform(void)
{
/*
@ -46,6 +67,8 @@ 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);
}
const __refconst struct hypervisor_x86 x86_hyper_ms_hyperv = {