diff options
| author | K. Y. Srinivasan <kys@microsoft.com> | 2011-09-07 15:25:10 -0700 |
|---|---|---|
| committer | Thomas Gleixner <tglx@linutronix.de> | 2011-09-08 10:33:59 +0200 |
| commit | 6f4151c89b7d036c755d8cf74729e09b76fa6676 (patch) | |
| tree | c86026f4c56764596f5425892850f89cbc77ffb3 /arch/x86/kernel/cpu/mshyperv.c | |
| parent | ddf28352b80c86754a6424e3a61e8bdf9213b3c7 (diff) | |
x86: Hyper-V: Integrate the clocksource with Hyper-V detection code
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>
Diffstat (limited to 'arch/x86/kernel/cpu/mshyperv.c')
| -rw-r--r-- | arch/x86/kernel/cpu/mshyperv.c | 23 |
1 files changed, 23 insertions, 0 deletions
diff --git a/arch/x86/kernel/cpu/mshyperv.c b/arch/x86/kernel/cpu/mshyperv.c index d944bf6c50e9..0a630dd4b620 100644 --- a/arch/x86/kernel/cpu/mshyperv.c +++ b/arch/x86/kernel/cpu/mshyperv.c @@ -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 = { |