2019-08-14 12:33:20

by Tianyu Lan

[permalink] [raw]
Subject: [PATCH V2 0/2] clocksource/Hyper-V: Add Hyper-V specific sched clock

From: Tianyu Lan <[email protected]>

Hyper-V guests use the default native_sched_clock() in pv_ops.time.sched_clock
on x86. But native_sched_clock() directly uses the raw TSC value, which
can be discontinuous in a Hyper-V VM. Add the generic hv_setup_sched_clock()
to set the sched clock function appropriately. On x86, this sets
pv_ops.time.sched_clock to read the Hyper-V reference TSC value that is
scaled and adjusted to be continuous.

Also move the Hyper-V reference TSC initialization much earlier in the boot
process so no discontinuity is observed when pv_ops.time.sched_clock
calculates its offset. This earlier initialization requires that the Hyper-V TSC
page be allocated statically instead of with vmalloc(), so fixup the references
to the TSC page and the method of getting its physical address.

Change since v1:
- Update patch 1 commit log
- Remove and operation of tsc page's va with PAGE_MASK
in the read_hv_sched_clock_tsc().

Tianyu Lan (2):
clocksource/Hyper-v: Allocate Hyper-V tsc page statically
clocksource/Hyper-V: Add Hyper-V specific sched clock function

arch/x86/entry/vdso/vma.c | 2 +-
arch/x86/hyperv/hv_init.c | 2 --
arch/x86/kernel/cpu/mshyperv.c | 8 ++++++++
drivers/clocksource/hyperv_timer.c | 34 ++++++++++++++++------------------
include/asm-generic/mshyperv.h | 1 +
5 files changed, 26 insertions(+), 21 deletions(-)

--
2.14.5


2019-08-14 12:33:58

by Tianyu Lan

[permalink] [raw]
Subject: [PATCH V2 1/2] clocksource/Hyper-v: Allocate Hyper-V tsc page statically

From: Tianyu Lan <[email protected]>

Prepare to add Hyper-V sched clock callback and move Hyper-V
Reference TSC initialization much earlier in the boot process. Earlier
initialization is needed so that it happens while the timestamp value
is still 0 and no discontinuity in the timestamp will occur when
pv_ops.time.sched_clock calculates its offset. The earlier
initialization requires that the Hyper-V TSC page be allocated
statically instead of with vmalloc(), so fixup the references
to the TSC page and the method of getting its physical address.

Signed-off-by: Tianyu Lan <[email protected]>
---
Change since v1:
- Update commit log
- Remove and operation of tsc page's va with PAGE_MASK

arch/x86/entry/vdso/vma.c | 2 +-
drivers/clocksource/hyperv_timer.c | 12 ++++--------
2 files changed, 5 insertions(+), 9 deletions(-)

diff --git a/arch/x86/entry/vdso/vma.c b/arch/x86/entry/vdso/vma.c
index 349a61d8bf34..f5937742b290 100644
--- a/arch/x86/entry/vdso/vma.c
+++ b/arch/x86/entry/vdso/vma.c
@@ -122,7 +122,7 @@ static vm_fault_t vvar_fault(const struct vm_special_mapping *sm,

if (tsc_pg && vclock_was_used(VCLOCK_HVCLOCK))
return vmf_insert_pfn(vma, vmf->address,
- vmalloc_to_pfn(tsc_pg));
+ virt_to_phys(tsc_pg) >> PAGE_SHIFT);
}

return VM_FAULT_SIGBUS;
diff --git a/drivers/clocksource/hyperv_timer.c b/drivers/clocksource/hyperv_timer.c
index ba2c79e6a0ee..432aa331df04 100644
--- a/drivers/clocksource/hyperv_timer.c
+++ b/drivers/clocksource/hyperv_timer.c
@@ -214,17 +214,17 @@ EXPORT_SYMBOL_GPL(hyperv_cs);

#ifdef CONFIG_HYPERV_TSCPAGE

-static struct ms_hyperv_tsc_page *tsc_pg;
+static struct ms_hyperv_tsc_page tsc_pg __aligned(PAGE_SIZE);

struct ms_hyperv_tsc_page *hv_get_tsc_page(void)
{
- return tsc_pg;
+ return &tsc_pg;
}
EXPORT_SYMBOL_GPL(hv_get_tsc_page);

static u64 notrace read_hv_sched_clock_tsc(void)
{
- u64 current_tick = hv_read_tsc_page(tsc_pg);
+ u64 current_tick = hv_read_tsc_page(&tsc_pg);

if (current_tick == U64_MAX)
hv_get_time_ref_count(current_tick);
@@ -280,12 +280,8 @@ static bool __init hv_init_tsc_clocksource(void)
if (!(ms_hyperv.features & HV_MSR_REFERENCE_TSC_AVAILABLE))
return false;

- tsc_pg = vmalloc(PAGE_SIZE);
- if (!tsc_pg)
- return false;
-
hyperv_cs = &hyperv_cs_tsc;
- phys_addr = page_to_phys(vmalloc_to_page(tsc_pg));
+ phys_addr = virt_to_phys(&tsc_pg);

/*
* The Hyper-V TLFS specifies to preserve the value of reserved
--
2.14.5

2019-08-14 12:34:04

by Tianyu Lan

[permalink] [raw]
Subject: [PATCH V2 2/2] clocksource/Hyper-V: Add Hyper-V specific sched clock function

From: Tianyu Lan <[email protected]>

Hyper-V guests use the default native_sched_clock() in pv_ops.time.sched_clock
on x86. But native_sched_clock() directly uses the raw TSC value, which
can be discontinuous in a Hyper-V VM. Add the generic hv_setup_sched_clock()
to set the sched clock function appropriately. On x86, this sets pv_ops.time.
sched_clock to read the Hyper-V reference TSC value that is scaled and adjusted
to be continuous.

Also move the Hyper-V reference TSC initialization much earlier in the boot
process so no discontinuity is observed when pv_ops.time.sched_clock
calculates its offset.

Reviewed-by: Michael Kelley <[email protected]>
Signed-off-by: Tianyu Lan <[email protected]>
---
arch/x86/hyperv/hv_init.c | 2 --
arch/x86/kernel/cpu/mshyperv.c | 8 ++++++++
drivers/clocksource/hyperv_timer.c | 22 ++++++++++++----------
include/asm-generic/mshyperv.h | 1 +
4 files changed, 21 insertions(+), 12 deletions(-)

diff --git a/arch/x86/hyperv/hv_init.c b/arch/x86/hyperv/hv_init.c
index 0d258688c8cf..866dfb3dca48 100644
--- a/arch/x86/hyperv/hv_init.c
+++ b/arch/x86/hyperv/hv_init.c
@@ -301,8 +301,6 @@ void __init hyperv_init(void)

x86_init.pci.arch_init = hv_pci_init;

- /* Register Hyper-V specific clocksource */
- hv_init_clocksource();
return;

remove_cpuhp_state:
diff --git a/arch/x86/kernel/cpu/mshyperv.c b/arch/x86/kernel/cpu/mshyperv.c
index 062f77279ce3..53afd33990eb 100644
--- a/arch/x86/kernel/cpu/mshyperv.c
+++ b/arch/x86/kernel/cpu/mshyperv.c
@@ -29,6 +29,7 @@
#include <asm/timer.h>
#include <asm/reboot.h>
#include <asm/nmi.h>
+#include <clocksource/hyperv_timer.h>

struct ms_hyperv_info ms_hyperv;
EXPORT_SYMBOL_GPL(ms_hyperv);
@@ -338,9 +339,16 @@ static void __init ms_hyperv_init_platform(void)
x2apic_phys = 1;
# endif

+ /* Register Hyper-V specific clocksource */
+ hv_init_clocksource();
#endif
}

+void hv_setup_sched_clock(void *sched_clock)
+{
+ pv_ops.time.sched_clock = sched_clock;
+}
+
const __initconst struct hypervisor_x86 x86_hyper_ms_hyperv = {
.name = "Microsoft Hyper-V",
.detect = ms_hyperv_platform,
diff --git a/drivers/clocksource/hyperv_timer.c b/drivers/clocksource/hyperv_timer.c
index 432aa331df04..dad8af198e20 100644
--- a/drivers/clocksource/hyperv_timer.c
+++ b/drivers/clocksource/hyperv_timer.c
@@ -215,6 +215,7 @@ EXPORT_SYMBOL_GPL(hyperv_cs);
#ifdef CONFIG_HYPERV_TSCPAGE

static struct ms_hyperv_tsc_page tsc_pg __aligned(PAGE_SIZE);
+static u64 hv_sched_clock_offset __ro_after_init;

struct ms_hyperv_tsc_page *hv_get_tsc_page(void)
{
@@ -222,7 +223,7 @@ struct ms_hyperv_tsc_page *hv_get_tsc_page(void)
}
EXPORT_SYMBOL_GPL(hv_get_tsc_page);

-static u64 notrace read_hv_sched_clock_tsc(void)
+static u64 notrace read_hv_clock_tsc(struct clocksource *arg)
{
u64 current_tick = hv_read_tsc_page(&tsc_pg);

@@ -232,9 +233,9 @@ static u64 notrace read_hv_sched_clock_tsc(void)
return current_tick;
}

-static u64 read_hv_clock_tsc(struct clocksource *arg)
+static u64 read_hv_sched_clock_tsc(void)
{
- return read_hv_sched_clock_tsc();
+ return read_hv_clock_tsc(NULL) - hv_sched_clock_offset;
}

static struct clocksource hyperv_cs_tsc = {
@@ -246,7 +247,7 @@ static struct clocksource hyperv_cs_tsc = {
};
#endif

-static u64 notrace read_hv_sched_clock_msr(void)
+static u64 notrace read_hv_clock_msr(struct clocksource *arg)
{
u64 current_tick;
/*
@@ -258,9 +259,9 @@ static u64 notrace read_hv_sched_clock_msr(void)
return current_tick;
}

-static u64 read_hv_clock_msr(struct clocksource *arg)
+static u64 read_hv_sched_clock_msr(void)
{
- return read_hv_sched_clock_msr();
+ return read_hv_clock_msr(NULL) - hv_sched_clock_offset;
}

static struct clocksource hyperv_cs_msr = {
@@ -298,8 +299,9 @@ static bool __init hv_init_tsc_clocksource(void)
hv_set_clocksource_vdso(hyperv_cs_tsc);
clocksource_register_hz(&hyperv_cs_tsc, NSEC_PER_SEC/100);

- /* sched_clock_register is needed on ARM64 but is a no-op on x86 */
- sched_clock_register(read_hv_sched_clock_tsc, 64, HV_CLOCK_HZ);
+ hv_sched_clock_offset = hyperv_cs->read(hyperv_cs);
+ hv_setup_sched_clock(read_hv_sched_clock_tsc);
+
return true;
}
#else
@@ -329,7 +331,7 @@ void __init hv_init_clocksource(void)
hyperv_cs = &hyperv_cs_msr;
clocksource_register_hz(&hyperv_cs_msr, NSEC_PER_SEC/100);

- /* sched_clock_register is needed on ARM64 but is a no-op on x86 */
- sched_clock_register(read_hv_sched_clock_msr, 64, HV_CLOCK_HZ);
+ hv_sched_clock_offset = hyperv_cs->read(hyperv_cs);
+ hv_setup_sched_clock(read_hv_sched_clock_msr);
}
EXPORT_SYMBOL_GPL(hv_init_clocksource);
diff --git a/include/asm-generic/mshyperv.h b/include/asm-generic/mshyperv.h
index 0becb7d9704d..18d8e2d8210f 100644
--- a/include/asm-generic/mshyperv.h
+++ b/include/asm-generic/mshyperv.h
@@ -167,6 +167,7 @@ void hyperv_report_panic(struct pt_regs *regs, long err);
void hyperv_report_panic_msg(phys_addr_t pa, size_t size);
bool hv_is_hyperv_initialized(void);
void hyperv_cleanup(void);
+void hv_setup_sched_clock(void *sched_clock);
#else /* CONFIG_HYPERV */
static inline bool hv_is_hyperv_initialized(void) { return false; }
static inline void hyperv_cleanup(void) {}
--
2.14.5

2019-08-16 15:01:16

by Daniel Lezcano

[permalink] [raw]
Subject: Re: [PATCH V2 1/2] clocksource/Hyper-v: Allocate Hyper-V tsc page statically

On 14/08/2019 14:32, [email protected] wrote:
> From: Tianyu Lan <[email protected]>
>
> Prepare to add Hyper-V sched clock callback and move Hyper-V
> Reference TSC initialization much earlier in the boot process. Earlier
> initialization is needed so that it happens while the timestamp value
> is still 0 and no discontinuity in the timestamp will occur when
> pv_ops.time.sched_clock calculates its offset. The earlier
> initialization requires that the Hyper-V TSC page be allocated
> statically instead of with vmalloc(), so fixup the references
> to the TSC page and the method of getting its physical address.
>
> Signed-off-by: Tianyu Lan <[email protected]>

Acked-by: Daniel Lezcano <[email protected]>

> ---
> Change since v1:
> - Update commit log
> - Remove and operation of tsc page's va with PAGE_MASK
>
> arch/x86/entry/vdso/vma.c | 2 +-
> drivers/clocksource/hyperv_timer.c | 12 ++++--------
> 2 files changed, 5 insertions(+), 9 deletions(-)
>
> diff --git a/arch/x86/entry/vdso/vma.c b/arch/x86/entry/vdso/vma.c
> index 349a61d8bf34..f5937742b290 100644
> --- a/arch/x86/entry/vdso/vma.c
> +++ b/arch/x86/entry/vdso/vma.c
> @@ -122,7 +122,7 @@ static vm_fault_t vvar_fault(const struct vm_special_mapping *sm,
>
> if (tsc_pg && vclock_was_used(VCLOCK_HVCLOCK))
> return vmf_insert_pfn(vma, vmf->address,
> - vmalloc_to_pfn(tsc_pg));
> + virt_to_phys(tsc_pg) >> PAGE_SHIFT);
> }
>
> return VM_FAULT_SIGBUS;
> diff --git a/drivers/clocksource/hyperv_timer.c b/drivers/clocksource/hyperv_timer.c
> index ba2c79e6a0ee..432aa331df04 100644
> --- a/drivers/clocksource/hyperv_timer.c
> +++ b/drivers/clocksource/hyperv_timer.c
> @@ -214,17 +214,17 @@ EXPORT_SYMBOL_GPL(hyperv_cs);
>
> #ifdef CONFIG_HYPERV_TSCPAGE
>
> -static struct ms_hyperv_tsc_page *tsc_pg;
> +static struct ms_hyperv_tsc_page tsc_pg __aligned(PAGE_SIZE);
>
> struct ms_hyperv_tsc_page *hv_get_tsc_page(void)
> {
> - return tsc_pg;
> + return &tsc_pg;
> }
> EXPORT_SYMBOL_GPL(hv_get_tsc_page);
>
> static u64 notrace read_hv_sched_clock_tsc(void)
> {
> - u64 current_tick = hv_read_tsc_page(tsc_pg);
> + u64 current_tick = hv_read_tsc_page(&tsc_pg);
>
> if (current_tick == U64_MAX)
> hv_get_time_ref_count(current_tick);
> @@ -280,12 +280,8 @@ static bool __init hv_init_tsc_clocksource(void)
> if (!(ms_hyperv.features & HV_MSR_REFERENCE_TSC_AVAILABLE))
> return false;
>
> - tsc_pg = vmalloc(PAGE_SIZE);
> - if (!tsc_pg)
> - return false;
> -
> hyperv_cs = &hyperv_cs_tsc;
> - phys_addr = page_to_phys(vmalloc_to_page(tsc_pg));
> + phys_addr = virt_to_phys(&tsc_pg);
>
> /*
> * The Hyper-V TLFS specifies to preserve the value of reserved
>


--
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Subject: [tip: timers/core] clocksource/drivers/hyperv: Allocate Hyper-V TSC page statically

The following commit has been merged into the timers/core branch of tip:

Commit-ID: adb87ff4f96c9700718e09c97a804124d5cd61ff
Gitweb: https://git.kernel.org/tip/adb87ff4f96c9700718e09c97a804124d5cd61ff
Author: Tianyu Lan <[email protected]>
AuthorDate: Wed, 14 Aug 2019 20:32:15 +08:00
Committer: Thomas Gleixner <[email protected]>
CommitterDate: Fri, 23 Aug 2019 16:59:53 +02:00

clocksource/drivers/hyperv: Allocate Hyper-V TSC page statically

Prepare to add Hyper-V sched clock callback and move Hyper-V Reference TSC
initialization much earlier in the boot process. Earlier initialization is
needed so that it happens while the timestamp value is still 0 and no
discontinuity in the timestamp will occur when pv_ops.time.sched_clock
calculates its offset.

The earlier initialization requires that the Hyper-V TSC page be allocated
statically instead of with vmalloc(), so fixup the references to the TSC
page and the method of getting its physical address.

Signed-off-by: Tianyu Lan <[email protected]>
Signed-off-by: Thomas Gleixner <[email protected]>
Acked-by: Daniel Lezcano <[email protected]>
Link: https://lkml.kernel.org/r/[email protected]
---
arch/x86/entry/vdso/vma.c | 2 +-
drivers/clocksource/hyperv_timer.c | 12 ++++--------
2 files changed, 5 insertions(+), 9 deletions(-)

diff --git a/arch/x86/entry/vdso/vma.c b/arch/x86/entry/vdso/vma.c
index 349a61d..f593774 100644
--- a/arch/x86/entry/vdso/vma.c
+++ b/arch/x86/entry/vdso/vma.c
@@ -122,7 +122,7 @@ static vm_fault_t vvar_fault(const struct vm_special_mapping *sm,

if (tsc_pg && vclock_was_used(VCLOCK_HVCLOCK))
return vmf_insert_pfn(vma, vmf->address,
- vmalloc_to_pfn(tsc_pg));
+ virt_to_phys(tsc_pg) >> PAGE_SHIFT);
}

return VM_FAULT_SIGBUS;
diff --git a/drivers/clocksource/hyperv_timer.c b/drivers/clocksource/hyperv_timer.c
index ba2c79e..432aa33 100644
--- a/drivers/clocksource/hyperv_timer.c
+++ b/drivers/clocksource/hyperv_timer.c
@@ -214,17 +214,17 @@ EXPORT_SYMBOL_GPL(hyperv_cs);

#ifdef CONFIG_HYPERV_TSCPAGE

-static struct ms_hyperv_tsc_page *tsc_pg;
+static struct ms_hyperv_tsc_page tsc_pg __aligned(PAGE_SIZE);

struct ms_hyperv_tsc_page *hv_get_tsc_page(void)
{
- return tsc_pg;
+ return &tsc_pg;
}
EXPORT_SYMBOL_GPL(hv_get_tsc_page);

static u64 notrace read_hv_sched_clock_tsc(void)
{
- u64 current_tick = hv_read_tsc_page(tsc_pg);
+ u64 current_tick = hv_read_tsc_page(&tsc_pg);

if (current_tick == U64_MAX)
hv_get_time_ref_count(current_tick);
@@ -280,12 +280,8 @@ static bool __init hv_init_tsc_clocksource(void)
if (!(ms_hyperv.features & HV_MSR_REFERENCE_TSC_AVAILABLE))
return false;

- tsc_pg = vmalloc(PAGE_SIZE);
- if (!tsc_pg)
- return false;
-
hyperv_cs = &hyperv_cs_tsc;
- phys_addr = page_to_phys(vmalloc_to_page(tsc_pg));
+ phys_addr = virt_to_phys(&tsc_pg);

/*
* The Hyper-V TLFS specifies to preserve the value of reserved

Subject: [tip: timers/core] clocksource/drivers/hyperv: Add Hyper-V specific sched clock function

The following commit has been merged into the timers/core branch of tip:

Commit-ID: bd00cd52d5be655a2f217e2ed74b91a71cb2b14f
Gitweb: https://git.kernel.org/tip/bd00cd52d5be655a2f217e2ed74b91a71cb2b14f
Author: Tianyu Lan <[email protected]>
AuthorDate: Wed, 14 Aug 2019 20:32:16 +08:00
Committer: Thomas Gleixner <[email protected]>
CommitterDate: Fri, 23 Aug 2019 16:59:54 +02:00

clocksource/drivers/hyperv: Add Hyper-V specific sched clock function

Hyper-V guests use the default native_sched_clock() in
pv_ops.time.sched_clock on x86. But native_sched_clock() directly uses the
raw TSC value, which can be discontinuous in a Hyper-V VM.

Add the generic hv_setup_sched_clock() to set the sched clock function
appropriately. On x86, this sets pv_ops.time.sched_clock to read the
Hyper-V reference TSC value that is scaled and adjusted to be continuous.

Also move the Hyper-V reference TSC initialization much earlier in the boot
process so no discontinuity is observed when pv_ops.time.sched_clock
calculates its offset.

[ tglx: Folded build fix ]

Signed-off-by: Tianyu Lan <[email protected]>
Signed-off-by: Thomas Gleixner <[email protected]>
Reviewed-by: Michael Kelley <[email protected]>
Link: https://lkml.kernel.org/r/[email protected]
---
arch/x86/hyperv/hv_init.c | 2 --
arch/x86/kernel/cpu/mshyperv.c | 8 ++++++++
drivers/clocksource/hyperv_timer.c | 22 ++++++++++++----------
include/asm-generic/mshyperv.h | 1 +
4 files changed, 21 insertions(+), 12 deletions(-)

diff --git a/arch/x86/hyperv/hv_init.c b/arch/x86/hyperv/hv_init.c
index 0d25868..866dfb3 100644
--- a/arch/x86/hyperv/hv_init.c
+++ b/arch/x86/hyperv/hv_init.c
@@ -301,8 +301,6 @@ void __init hyperv_init(void)

x86_init.pci.arch_init = hv_pci_init;

- /* Register Hyper-V specific clocksource */
- hv_init_clocksource();
return;

remove_cpuhp_state:
diff --git a/arch/x86/kernel/cpu/mshyperv.c b/arch/x86/kernel/cpu/mshyperv.c
index 062f772..53afd33 100644
--- a/arch/x86/kernel/cpu/mshyperv.c
+++ b/arch/x86/kernel/cpu/mshyperv.c
@@ -29,6 +29,7 @@
#include <asm/timer.h>
#include <asm/reboot.h>
#include <asm/nmi.h>
+#include <clocksource/hyperv_timer.h>

struct ms_hyperv_info ms_hyperv;
EXPORT_SYMBOL_GPL(ms_hyperv);
@@ -338,9 +339,16 @@ static void __init ms_hyperv_init_platform(void)
x2apic_phys = 1;
# endif

+ /* Register Hyper-V specific clocksource */
+ hv_init_clocksource();
#endif
}

+void hv_setup_sched_clock(void *sched_clock)
+{
+ pv_ops.time.sched_clock = sched_clock;
+}
+
const __initconst struct hypervisor_x86 x86_hyper_ms_hyperv = {
.name = "Microsoft Hyper-V",
.detect = ms_hyperv_platform,
diff --git a/drivers/clocksource/hyperv_timer.c b/drivers/clocksource/hyperv_timer.c
index 432aa33..c322ab4 100644
--- a/drivers/clocksource/hyperv_timer.c
+++ b/drivers/clocksource/hyperv_timer.c
@@ -22,6 +22,7 @@
#include <asm/mshyperv.h>

static struct clock_event_device __percpu *hv_clock_event;
+static u64 hv_sched_clock_offset __ro_after_init;

/*
* If false, we're using the old mechanism for stimer0 interrupts
@@ -222,7 +223,7 @@ struct ms_hyperv_tsc_page *hv_get_tsc_page(void)
}
EXPORT_SYMBOL_GPL(hv_get_tsc_page);

-static u64 notrace read_hv_sched_clock_tsc(void)
+static u64 notrace read_hv_clock_tsc(struct clocksource *arg)
{
u64 current_tick = hv_read_tsc_page(&tsc_pg);

@@ -232,9 +233,9 @@ static u64 notrace read_hv_sched_clock_tsc(void)
return current_tick;
}

-static u64 read_hv_clock_tsc(struct clocksource *arg)
+static u64 read_hv_sched_clock_tsc(void)
{
- return read_hv_sched_clock_tsc();
+ return read_hv_clock_tsc(NULL) - hv_sched_clock_offset;
}

static struct clocksource hyperv_cs_tsc = {
@@ -246,7 +247,7 @@ static struct clocksource hyperv_cs_tsc = {
};
#endif

-static u64 notrace read_hv_sched_clock_msr(void)
+static u64 notrace read_hv_clock_msr(struct clocksource *arg)
{
u64 current_tick;
/*
@@ -258,9 +259,9 @@ static u64 notrace read_hv_sched_clock_msr(void)
return current_tick;
}

-static u64 read_hv_clock_msr(struct clocksource *arg)
+static u64 read_hv_sched_clock_msr(void)
{
- return read_hv_sched_clock_msr();
+ return read_hv_clock_msr(NULL) - hv_sched_clock_offset;
}

static struct clocksource hyperv_cs_msr = {
@@ -298,8 +299,9 @@ static bool __init hv_init_tsc_clocksource(void)
hv_set_clocksource_vdso(hyperv_cs_tsc);
clocksource_register_hz(&hyperv_cs_tsc, NSEC_PER_SEC/100);

- /* sched_clock_register is needed on ARM64 but is a no-op on x86 */
- sched_clock_register(read_hv_sched_clock_tsc, 64, HV_CLOCK_HZ);
+ hv_sched_clock_offset = hyperv_cs->read(hyperv_cs);
+ hv_setup_sched_clock(read_hv_sched_clock_tsc);
+
return true;
}
#else
@@ -329,7 +331,7 @@ void __init hv_init_clocksource(void)
hyperv_cs = &hyperv_cs_msr;
clocksource_register_hz(&hyperv_cs_msr, NSEC_PER_SEC/100);

- /* sched_clock_register is needed on ARM64 but is a no-op on x86 */
- sched_clock_register(read_hv_sched_clock_msr, 64, HV_CLOCK_HZ);
+ hv_sched_clock_offset = hyperv_cs->read(hyperv_cs);
+ hv_setup_sched_clock(read_hv_sched_clock_msr);
}
EXPORT_SYMBOL_GPL(hv_init_clocksource);
diff --git a/include/asm-generic/mshyperv.h b/include/asm-generic/mshyperv.h
index 0becb7d..18d8e2d 100644
--- a/include/asm-generic/mshyperv.h
+++ b/include/asm-generic/mshyperv.h
@@ -167,6 +167,7 @@ void hyperv_report_panic(struct pt_regs *regs, long err);
void hyperv_report_panic_msg(phys_addr_t pa, size_t size);
bool hv_is_hyperv_initialized(void);
void hyperv_cleanup(void);
+void hv_setup_sched_clock(void *sched_clock);
#else /* CONFIG_HYPERV */
static inline bool hv_is_hyperv_initialized(void) { return false; }
static inline void hyperv_cleanup(void) {}