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hv: export current Hyper-V clocksource

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As a preparation to implementing Hyper-V PTP device supporting
.getcrosststamp we need to export a reference to the current Hyper-V
clocksource in use (MSR or TSC page).

Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Vitaly Kuznetsov 2017-02-04 09:57:13 -07:00 committed by Greg Kroah-Hartman
parent 9b06e1018a
commit dee863b571
2 changed files with 12 additions and 4 deletions
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13
arch/x86/hyperv/hv_init.c
View file

@ -99,6 +99,9 @@ static struct clocksource hyperv_cs_msr = {
};
static void *hypercall_pg;
struct clocksource *hyperv_cs;
EXPORT_SYMBOL_GPL(hyperv_cs);
/*
* This function is to be invoked early in the boot sequence after the
* hypervisor has been detected.
@ -141,10 +144,10 @@ void hyperv_init(void)
union hv_x64_msr_hypercall_contents tsc_msr;
tsc_pg = __vmalloc(PAGE_SIZE, GFP_KERNEL, PAGE_KERNEL);
if (!tsc_pg) {
clocksource_register_hz(&hyperv_cs_msr, NSEC_PER_SEC/100);
return;
}
if (!tsc_pg)
goto register_msr_cs;
hyperv_cs = &hyperv_cs_tsc;
rdmsrl(HV_X64_MSR_REFERENCE_TSC, tsc_msr.as_uint64);
@ -161,6 +164,8 @@ void hyperv_init(void)
* the partition counter.
*/
register_msr_cs:
hyperv_cs = &hyperv_cs_msr;
if (ms_hyperv.features & HV_X64_MSR_TIME_REF_COUNT_AVAILABLE)
clocksource_register_hz(&hyperv_cs_msr, NSEC_PER_SEC/100);
}

3
arch/x86/include/asm/mshyperv.h
View file

@ -3,6 +3,7 @@
#include <linux/types.h>
#include <linux/interrupt.h>
#include <linux/clocksource.h>
#include <asm/hyperv.h>
/*
@ -168,6 +169,8 @@ void hv_setup_crash_handler(void (*handler)(struct pt_regs *regs));
void hv_remove_crash_handler(void);
#if IS_ENABLED(CONFIG_HYPERV)
extern struct clocksource *hyperv_cs;
void hyperv_init(void);
void hyperv_report_panic(struct pt_regs *regs);
bool hv_is_hypercall_page_setup(void);