hyperv: Change hv_root_partition into a function

Introduce hv_curr_partition_type to store the partition type
as an enum.

Right now this is limited to guest or root partition, but there will
be oth

hyperv: Change hv_root_partition into a function

Introduce hv_curr_partition_type to store the partition type
as an enum.

Right now this is limited to guest or root partition, but there will
be other kinds in future and the enum is easily extensible.

Set up hv_curr_partition_type early in Hyper-V initialization with
hv_identify_partition_type(). hv_root_partition() just queries this
value, and shouldn't be called before that.

Making this check into a function sets the stage for adding a config
option to gate the compilation of root partition code. In particular,
hv_root_partition() can be stubbed out always be false if root
partition support isn't desired.

Signed-off-by: Nuno Das Neves <[email protected]>
Reviewed-by: Easwar Hariharan <[email protected]>
Reviewed-by: Michael Kelley <[email protected]>
Link: https://lore.kernel.org/r/1740167795-13296-3-git-send-email-nunodasneves@linux.microsoft.com
Signed-off-by: Wei Liu <[email protected]>
Message-ID: <1740167795-13296-3-git-send-email-nunodasneves@linux.microsoft.com>

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hyperv: Switch from hyperv-tlfs.h to hyperv/hvhdk.h

Switch to using hvhdk.h everywhere in the kernel. This header
includes all the new Hyper-V headers in include/hyperv, which form a
superset of the

hyperv: Switch from hyperv-tlfs.h to hyperv/hvhdk.h

Switch to using hvhdk.h everywhere in the kernel. This header
includes all the new Hyper-V headers in include/hyperv, which form a
superset of the definitions found in hyperv-tlfs.h.

This makes it easier to add new Hyper-V interfaces without being
restricted to those in the TLFS doc (reflected in hyperv-tlfs.h).

To be more consistent with the original Hyper-V code, the names of
some definitions are changed slightly. Update those where needed.

Update comments in mshyperv.h files to point to include/hyperv for
adding new definitions.

Signed-off-by: Nuno Das Neves <[email protected]>
Reviewed-by: Michael Kelley <[email protected]>
Reviewed-by: Easwar Hariharan <[email protected]>
Signed-off-by: Roman Kisel <[email protected]>
Reviewed-by: Easwar Hariharan <[email protected]>
Link: https://lore.kernel.org/r/1732577084-2122-5-git-send-email-nunodasneves@linux.microsoft.com
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Wei Liu <[email protected]>

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x86/hyperv: Fix hv tsc page based sched_clock for hibernation

read_hv_sched_clock_tsc() assumes that the Hyper-V clock counter is
bigger than the variable hv_sched_clock_offset, which is cached duri

x86/hyperv: Fix hv tsc page based sched_clock for hibernation

read_hv_sched_clock_tsc() assumes that the Hyper-V clock counter is
bigger than the variable hv_sched_clock_offset, which is cached during
early boot, but depending on the timing this assumption may be false
when a hibernated VM starts again (the clock counter starts from 0
again) and is resuming back (Note: hv_init_tsc_clocksource() is not
called during hibernation/resume); consequently,
read_hv_sched_clock_tsc() may return a negative integer (which is
interpreted as a huge positive integer since the return type is u64)
and new kernel messages are prefixed with huge timestamps before
read_hv_sched_clock_tsc() grows big enough (which typically takes
several seconds).

Fix the issue by saving the Hyper-V clock counter just before the
suspend, and using it to correct the hv_sched_clock_offset in
resume. This makes hv tsc page based sched_clock continuous and ensures
that post resume, it starts from where it left off during suspend.
Override x86_platform.save_sched_clock_state and
x86_platform.restore_sched_clock_state routines to correct this as soon
as possible.

Note: if Invariant TSC is available, the issue doesn't happen because
1) we don't register read_hv_sched_clock_tsc() for sched clock:
See commit e5313f1c5404 ("clocksource/drivers/hyper-v: Rework
clocksource and sched clock setup");
2) the common x86 code adjusts TSC similarly: see
__restore_processor_state() -> tsc_verify_tsc_adjust(true) and
x86_platform.restore_sched_clock_state().

Cc: [email protected]
Fixes: 1349401ff1aa ("clocksource/drivers/hyper-v: Suspend/resume Hyper-V clocksource for hibernation")
Co-developed-by: Dexuan Cui <[email protected]>
Signed-off-by: Dexuan Cui <[email protected]>
Signed-off-by: Naman Jain <[email protected]>
Reviewed-by: Michael Kelley <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Wei Liu <[email protected]>
Message-ID: <[email protected]>

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clocksource: hyper-v: Use lapic timer in a TDX VM without paravisor

In a TDX VM without paravisor, currently the default timer is the Hyper-V
timer, which depends on the slow VM Reference Counter MS

clocksource: hyper-v: Use lapic timer in a TDX VM without paravisor

In a TDX VM without paravisor, currently the default timer is the Hyper-V
timer, which depends on the slow VM Reference Counter MSR: the Hyper-V TSC
page is not enabled in such a VM because the VM uses Invariant TSC as a
better clocksource and it's challenging to mark the Hyper-V TSC page shared
in very early boot.

Lower the rating of the Hyper-V timer so the local APIC timer becomes the
the default timer in such a VM, and print a warning in case Invariant TSC
is unavailable in such a VM. This change should cause no perceivable
performance difference.

Cc: [email protected] # 6.6+
Reviewed-by: Roman Kisel <[email protected]>
Signed-off-by: Dexuan Cui <[email protected]>
Reviewed-by: Michael Kelley <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Wei Liu <[email protected]>
Message-ID: <[email protected]>

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hyperv-tlfs: Change prefix of generic HV_REGISTER_* MSRs to HV_MSR_*

The HV_REGISTER_ are used as arguments to hv_set/get_register(), which
delegate to arch-specific mechanisms for getting/setting s

hyperv-tlfs: Change prefix of generic HV_REGISTER_* MSRs to HV_MSR_*

The HV_REGISTER_ are used as arguments to hv_set/get_register(), which
delegate to arch-specific mechanisms for getting/setting synthetic
Hyper-V MSRs.

On arm64, HV_REGISTER_ defines are synthetic VP registers accessed via
the get/set vp registers hypercalls. The naming matches the TLFS
document, although these register names are not specific to arm64.

However, on x86 the prefix HV_REGISTER_ indicates Hyper-V MSRs accessed
via rdmsrl()/wrmsrl(). This is not consistent with the TLFS doc, where
HV_REGISTER_ is *only* used for used for VP register names used by
the get/set register hypercalls.

To fix this inconsistency and prevent future confusion, change the
arch-generic aliases used by callers of hv_set/get_register() to have
the prefix HV_MSR_ instead of HV_REGISTER_.

Use the prefix HV_X64_MSR_ for the x86-only Hyper-V MSRs. On x86, the
generic HV_MSR_'s point to the corresponding HV_X64_MSR_.

Move the arm64 HV_REGISTER_* defines to the asm-generic hyperv-tlfs.h,
since these are not specific to arm64. On arm64, the generic HV_MSR_'s
point to the corresponding HV_REGISTER_.

While at it, rename hv_get/set_registers() and related functions to
hv_get/set_msr(), hv_get/set_nested_msr(), etc. These are only used for
Hyper-V MSRs and this naming makes that clear.

Signed-off-by: Nuno Das Neves <[email protected]>
Reviewed-by: Wei Liu <[email protected]>
Reviewed-by: Michael Kelley <[email protected]>
Link: https://lore.kernel.org/r/1708440933-27125-1-git-send-email-nunodasneves@linux.microsoft.com
Signed-off-by: Wei Liu <[email protected]>
Message-ID: <1708440933-27125-1-git-send-email-nunodasneves@linux.microsoft.com>

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clocksource: hyper-v: Mark hyperv tsc page unencrypted in sev-snp enlightened guest

Hyper-V tsc page is shared with hypervisor and mark the page
unencrypted in sev-snp enlightened guest when it's us

clocksource: hyper-v: Mark hyperv tsc page unencrypted in sev-snp enlightened guest

Hyper-V tsc page is shared with hypervisor and mark the page
unencrypted in sev-snp enlightened guest when it's used.

Reviewed-by: Dexuan Cui <[email protected]>
Reviewed-by: Michael Kelley <[email protected]>
Signed-off-by: Tianyu Lan <[email protected]>
Signed-off-by: Wei Liu <[email protected]>
Link: https://lore.kernel.org/r/[email protected]

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clocksource/drivers/hyper-v: Rework clocksource and sched clock setup

Current code assigns either the Hyper-V TSC page or MSR-based ref counter
as the sched clock. This may be sub-optimal in two cas

clocksource/drivers/hyper-v: Rework clocksource and sched clock setup

Current code assigns either the Hyper-V TSC page or MSR-based ref counter
as the sched clock. This may be sub-optimal in two cases. First, if there
is hardware support to ensure consistent TSC frequency across live
migrations and Hyper-V is using that support, the raw TSC is a faster
source of time than the Hyper-V TSC page. Second, the MSR-based ref
counter is relatively slow because reads require a trap to the hypervisor.
As such, it should never be used as the sched clock. The native sched
clock based on the raw TSC or jiffies is much better.

Rework the sched clock setup so it is set to the TSC page only if
Hyper-V indicates that the TSC may have inconsistent frequency across
live migrations. Also, remove the code that sets the sched clock to
the MSR-based ref counter. In the cases where it is not set, the sched
clock will then be the native sched clock.

As part of the rework, always enable both the TSC page clocksource and
the MSR-based ref counter clocksource. Set the ratings so the TSC page
clocksource is preferred. While the MSR-based ref counter clocksource
is unlikely to ever be the default, having it available for manual
selection is convenient for development purposes.

Signed-off-by: Michael Kelley <[email protected]>
Reviewed-by: Dexuan Cui <[email protected]>
Signed-off-by: Daniel Lezcano <[email protected]>
Link: https://lore.kernel.org/r/[email protected]

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clocksource: hyper-v: Provide noinstr sched_clock()

With the intent to provide local_clock_noinstr(), a variant of
local_clock() that's safe to be called from noinstr code (with the
assumption that

clocksource: hyper-v: Provide noinstr sched_clock()

With the intent to provide local_clock_noinstr(), a variant of
local_clock() that's safe to be called from noinstr code (with the
assumption that any such code will already be non-preemptible),
prepare for things by making the Hyper-V TSC and MSR sched_clock
implementations noinstr.

Signed-off-by: Peter Zijlstra (Intel) <[email protected]>
Co-developed-by: Michael Kelley <[email protected]>
Signed-off-by: Michael Kelley <[email protected]>
Signed-off-by: Peter Zijlstra (Intel) <[email protected]>
Tested-by: Michael Kelley <[email protected]> # Hyper-V
Link: https://lore.kernel.org/r/[email protected]

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clocksource: hyper-v: Adjust hv_read_tsc_page_tsc() to avoid special casing U64_MAX

Currently hv_read_tsc_page_tsc() (ab)uses the (valid) time value of
U64_MAX as an error return. This breaks the cl

clocksource: hyper-v: Adjust hv_read_tsc_page_tsc() to avoid special casing U64_MAX

Currently hv_read_tsc_page_tsc() (ab)uses the (valid) time value of
U64_MAX as an error return. This breaks the clean wrap-around of the
clock.

Modify the function signature to return a boolean state and provide
another u64 pointer to store the actual time on success. This obviates
the need to steal one time value and restores the full counter width.

Signed-off-by: Peter Zijlstra (Intel) <[email protected]>
Reviewed-by: Michael Kelley <[email protected]>
Tested-by: Michael Kelley <[email protected]> # Hyper-V
Link: https://lore.kernel.org/r/[email protected]

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clocksource: hyper-v: make sure Invariant-TSC is used if it is available

If Hyper-V TSC page is unavailable and Invariant-TSC is available,
currently hyperv_cs_msr (rather than Invariant-TSC) is use

clocksource: hyper-v: make sure Invariant-TSC is used if it is available

If Hyper-V TSC page is unavailable and Invariant-TSC is available,
currently hyperv_cs_msr (rather than Invariant-TSC) is used by default.

Use Invariant-TSC by default by downgrading hyperv_cs_msr.rating in
hv_init_tsc_clocksource(), if Invariant-TSC is available.

Signed-off-by: Dexuan Cui <[email protected]>
Reviewed-by: Michael Kelley <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Wei Liu <[email protected]>

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drivers/clocksource/hyper-v: non ACPI support in hyperv clock

Add a placeholder function for the hv_setup_stimer0_irq API to accommodate
systems without ACPI support. Since this function is not util

drivers/clocksource/hyper-v: non ACPI support in hyperv clock

Add a placeholder function for the hv_setup_stimer0_irq API to accommodate
systems without ACPI support. Since this function is not utilized on
x86/x64 systems and non-ACPI support is only intended for x86/x64 systems,
a placeholder function is sufficient for now and can be improved upon if
necessary in the future.

Signed-off-by: Saurabh Sengar <[email protected]>
Reviewed-by: Michael Kelley <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Wei Liu <[email protected]>

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clocksource: hyper-v: Add TSC page support for root partition

Microsoft Hypervisor root partition has to map the TSC page specified
by the hypervisor, instead of providing the page to the hypervisor

clocksource: hyper-v: Add TSC page support for root partition

Microsoft Hypervisor root partition has to map the TSC page specified
by the hypervisor, instead of providing the page to the hypervisor like
it's done in the guest partitions.

However, it's too early to map the page when the clock is initialized, so, the
actual mapping is happening later.

Signed-off-by: Stanislav Kinsburskiy <[email protected]>
CC: "K. Y. Srinivasan" <[email protected]>
CC: Haiyang Zhang <[email protected]>
CC: Wei Liu <[email protected]>
CC: Dexuan Cui <[email protected]>
CC: Thomas Gleixner <[email protected]>
CC: Ingo Molnar <[email protected]>
CC: Borislav Petkov <[email protected]>
CC: Dave Hansen <[email protected]>
CC: [email protected]
CC: "H. Peter Anvin" <[email protected]>
CC: Daniel Lezcano <[email protected]>
CC: [email protected]
CC: [email protected]
Reviewed-by: Michael Kelley <[email protected]>
Reviewed-by: Anirudh Rayabharam <[email protected]>
Link: https://lore.kernel.org/r/166759443644.385891.15921594265843430260.stgit@skinsburskii-cloud-desktop.internal.cloudapp.net
Signed-off-by: Wei Liu <[email protected]>

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clocksource: hyper-v: Use TSC PFN getter to map vvar page

Instead of converting the virtual address to physical directly.

This is a precursor patch for the upcoming support for TSC page mapping int

clocksource: hyper-v: Use TSC PFN getter to map vvar page

Instead of converting the virtual address to physical directly.

This is a precursor patch for the upcoming support for TSC page mapping into
Microsoft Hypervisor root partition, where TSC PFN will be defined by the
hypervisor and thus can't be obtained by linear translation of the physical
address.

Signed-off-by: Stanislav Kinsburskiy <[email protected]>
CC: Andy Lutomirski <[email protected]>
CC: Thomas Gleixner <[email protected]>
CC: Ingo Molnar <[email protected]>
CC: Borislav Petkov <[email protected]>
CC: Dave Hansen <[email protected]>
CC: [email protected]
CC: "H. Peter Anvin" <[email protected]>
CC: "K. Y. Srinivasan" <[email protected]>
CC: Haiyang Zhang <[email protected]>
CC: Wei Liu <[email protected]>
CC: Dexuan Cui <[email protected]>
CC: Daniel Lezcano <[email protected]>
CC: [email protected]
CC: [email protected]
Reviewed-by: Michael Kelley <[email protected]>
Reviewed-by: Anirudh Rayabharam <[email protected]>
Link: https://lore.kernel.org/r/166749833939.218190.14095015146003109462.stgit@skinsburskii-cloud-desktop.internal.cloudapp.net
Signed-off-by: Wei Liu <[email protected]>

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clocksource: hyper-v: Introduce TSC PFN getter

And rework the code to use it instead of the physical address, which isn't
required by itself.

This is a cleanup and precursor patch for upcoming supp

clocksource: hyper-v: Introduce TSC PFN getter

And rework the code to use it instead of the physical address, which isn't
required by itself.

This is a cleanup and precursor patch for upcoming support for TSC page
mapping into Microsoft Hypervisor root partition, where TSC PFN will be
defined by the hypervisor and not by the kernel.

Signed-off-by: Stanislav Kinsburskiy <[email protected]>
CC: "K. Y. Srinivasan" <[email protected]>
CC: Haiyang Zhang <[email protected]>
CC: Wei Liu <[email protected]>
CC: Dexuan Cui <[email protected]>
CC: Daniel Lezcano <[email protected]>
CC: Thomas Gleixner <[email protected]>
CC: [email protected]
CC: [email protected]
Reviewed-by: Michael Kelley <[email protected]>
Reviewed-by: Anirudh Rayabharam <[email protected]>
Link: https://lore.kernel.org/r/166749833420.218190.2102763345349472395.stgit@skinsburskii-cloud-desktop.internal.cloudapp.net
Signed-off-by: Wei Liu <[email protected]>

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clocksource: hyper-v: Introduce a pointer to TSC page

Will be used later keep the address of the remapped page for the root
partition as it will be Microsoft Hypervisor defined (and thus won't be a

clocksource: hyper-v: Introduce a pointer to TSC page

Will be used later keep the address of the remapped page for the root
partition as it will be Microsoft Hypervisor defined (and thus won't be a
static address).

Signed-off-by: Stanislav Kinsburskiy <[email protected]>
CC: "K. Y. Srinivasan" <[email protected]>
CC: Haiyang Zhang <[email protected]>
CC: Wei Liu <[email protected]>
CC: Dexuan Cui <[email protected]>
CC: Daniel Lezcano <[email protected]>
CC: Thomas Gleixner <[email protected]>
CC: [email protected]
CC: [email protected]
Reviewed-by: Michael Kelley <[email protected]>
Reviewed-by: Anirudh Rayabharam <[email protected]>
Link: https://lore.kernel.org/r/166749832893.218190.16503272948154953294.stgit@skinsburskii-cloud-desktop.internal.cloudapp.net
Signed-off-by: Wei Liu <[email protected]>

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clocksource/drivers/hyperv: add data structure for reference TSC MSR

Add a data structure to represent the reference TSC MSR similar to
other MSRs. This simplifies the code for updating the MSR.

Si

clocksource/drivers/hyperv: add data structure for reference TSC MSR

Add a data structure to represent the reference TSC MSR similar to
other MSRs. This simplifies the code for updating the MSR.

Signed-off-by: Anirudh Rayabharam <[email protected]>
Reviewed-by: Michael Kelley <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Wei Liu <[email protected]>

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clocksource: hyper-v: unexport __init-annotated hv_init_clocksource()

EXPORT_SYMBOL and __init is a bad combination because the .init.text
section is freed up after the initialization. Hence, module

clocksource: hyper-v: unexport __init-annotated hv_init_clocksource()

EXPORT_SYMBOL and __init is a bad combination because the .init.text
section is freed up after the initialization. Hence, modules cannot
use symbols annotated __init. The access to a freed symbol may end up
with kernel panic.

modpost used to detect it, but it has been broken for a decade.

Recently, I fixed modpost so it started to warn it again, then this
showed up in linux-next builds.

There are two ways to fix it:

- Remove __init
- Remove EXPORT_SYMBOL

I chose the latter for this case because the only in-tree call-site,
arch/x86/kernel/cpu/mshyperv.c is never compiled as modular.
(CONFIG_HYPERVISOR_GUEST is boolean)

Fixes: dd2cb348613b ("clocksource/drivers: Continue making Hyper-V clocksource ISA agnostic")
Reported-by: Stephen Rothwell <[email protected]>
Signed-off-by: Masahiro Yamada <[email protected]>
Reviewed-by: Vitaly Kuznetsov <[email protected]>
Reviewed-by: Michael Kelley <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Wei Liu <[email protected]>

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drivers: hv: Decouple Hyper-V clock/timer code from VMbus drivers

Hyper-V clock/timer code in hyperv_timer.c is mostly independent from
other VMbus drivers, but building for ARM64 without hyperv_tim

drivers: hv: Decouple Hyper-V clock/timer code from VMbus drivers

Hyper-V clock/timer code in hyperv_timer.c is mostly independent from
other VMbus drivers, but building for ARM64 without hyperv_timer.c
shows some remaining entanglements. A default implementation of
hv_read_reference_counter can just read a Hyper-V synthetic register
and be independent of hyperv_timer.c, so move this code out and into
hv_common.c. Then it can be used by the timesync driver even if
hyperv_timer.c isn't built on a particular architecture. If
hyperv_timer.c *is* built, it can override with a faster implementation.

Also provide stubs for stimer functions called by the VMbus driver when
hyperv_timer.c isn't built.

No functional changes.

Signed-off-by: Michael Kelley <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Wei Liu <[email protected]>

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clocksource/drivers/hyper-v: Re-enable VDSO_CLOCKMODE_HVCLOCK on X86

Mohammed reports (https://bugzilla.kernel.org/show_bug.cgi?id=213029)
the commit e4ab4658f1cf ("clocksource/drivers/hyper-v: Hand

clocksource/drivers/hyper-v: Re-enable VDSO_CLOCKMODE_HVCLOCK on X86

Mohammed reports (https://bugzilla.kernel.org/show_bug.cgi?id=213029)
the commit e4ab4658f1cf ("clocksource/drivers/hyper-v: Handle vDSO
differences inline") broke vDSO on x86. The problem appears to be that
VDSO_CLOCKMODE_HVCLOCK is an enum value in 'enum vdso_clock_mode' and
'#ifdef VDSO_CLOCKMODE_HVCLOCK' branch evaluates to false (it is not
a define).

Use a dedicated HAVE_VDSO_CLOCKMODE_HVCLOCK define instead.

Fixes: e4ab4658f1cf ("clocksource/drivers/hyper-v: Handle vDSO differences inline")
Reported-by: Mohammed Gamal <[email protected]>
Suggested-by: Thomas Gleixner <[email protected]>
Signed-off-by: Vitaly Kuznetsov <[email protected]>
Signed-off-by: Thomas Gleixner <[email protected]>
Reviewed-by: Michael Kelley <[email protected]>
Link: https://lore.kernel.org/r/[email protected]

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timekeeping, clocksource: Fix various typos in comments

Fix ~56 single-word typos in timekeeping & clocksource code comments.

Signed-off-by: Ingo Molnar <[email protected]>
Cc: Thomas Gleixner <tglx

timekeeping, clocksource: Fix various typos in comments

Fix ~56 single-word typos in timekeeping & clocksource code comments.

Signed-off-by: Ingo Molnar <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: John Stultz <[email protected]>
Cc: Stephen Boyd <[email protected]>
Cc: Daniel Lezcano <[email protected]>
Cc: [email protected]

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clocksource/drivers/hyper-v: Move handling of STIMER0 interrupts

STIMER0 interrupts are most naturally modeled as per-cpu IRQs. But
because x86/x64 doesn't have per-cpu IRQs, the core STIMER0 interr

clocksource/drivers/hyper-v: Move handling of STIMER0 interrupts

STIMER0 interrupts are most naturally modeled as per-cpu IRQs. But
because x86/x64 doesn't have per-cpu IRQs, the core STIMER0 interrupt
handling machinery is done in code under arch/x86 and Linux IRQs are
not used. Adding support for ARM64 means adding equivalent code
using per-cpu IRQs under arch/arm64.

A better model is to treat per-cpu IRQs as the normal path (which it is
for modern architectures), and the x86/x64 path as the exception. Do this
by incorporating standard Linux per-cpu IRQ allocation into the main
SITMER0 driver code, and bypass it in the x86/x64 exception case. For
x86/x64, special case code is retained under arch/x86, but no STIMER0
interrupt handling code is needed under arch/arm64.

No functional change.

Signed-off-by: Michael Kelley <[email protected]>
Acked-by: Daniel Lezcano <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Wei Liu <[email protected]>

show more ...

clocksource/drivers/hyper-v: Set clocksource rating based on Hyper-V feature

On x86/x64, the TSC clocksource is available in a Hyper-V VM only if
Hyper-V provides the TSC_INVARIANT flag. The rating

clocksource/drivers/hyper-v: Set clocksource rating based on Hyper-V feature

On x86/x64, the TSC clocksource is available in a Hyper-V VM only if
Hyper-V provides the TSC_INVARIANT flag. The rating on the Hyper-V
Reference TSC page clocksource is currently set so that it will not
override the TSC clocksource in this case. Alternatively, if the TSC
clocksource is not available, then the Hyper-V clocksource is used.

But on ARM64, the Hyper-V Reference TSC page clocksource should
override the ARM arch counter, since the Hyper-V clocksource provides
scaling and offsetting during live migrations that is not provided
for the ARM arch counter.

To get the needed behavior for both x86/x64 and ARM64, tweak the
logic by defaulting the Hyper-V Reference TSC page clocksource
rating to a large value that will always override. If the Hyper-V
TSC_INVARIANT flag is set, then reduce the rating so that it will not
override the TSC.

While the logic for getting there is slightly different, the net
result in the normal cases is no functional change.

Signed-off-by: Michael Kelley <[email protected]>
Acked-by: Daniel Lezcano <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Wei Liu <[email protected]>

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clocksource/drivers/hyper-v: Handle sched_clock differences inline

While the Hyper-V Reference TSC code is architecture neutral, the
pv_ops.time.sched_clock() function is implemented for x86/x64, bu

clocksource/drivers/hyper-v: Handle sched_clock differences inline

While the Hyper-V Reference TSC code is architecture neutral, the
pv_ops.time.sched_clock() function is implemented for x86/x64, but not
for ARM64. Current code calls a utility function under arch/x86 (and
coming, under arch/arm64) to handle the difference.

Change this approach to handle the difference inline based on whether
GENERIC_SCHED_CLOCK is present. The new approach removes code under
arch/* since the difference is tied more to the specifics of the Linux
implementation than to the architecture.

No functional change.

Signed-off-by: Michael Kelley <[email protected]>
Reviewed-by: Boqun Feng <[email protected]>
Acked-by: Daniel Lezcano <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Wei Liu <[email protected]>

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clocksource/drivers/hyper-v: Handle vDSO differences inline

While the driver for the Hyper-V Reference TSC and STIMERs is architecture
neutral, vDSO is implemented for x86/x64, but not for ARM64. C

clocksource/drivers/hyper-v: Handle vDSO differences inline

While the driver for the Hyper-V Reference TSC and STIMERs is architecture
neutral, vDSO is implemented for x86/x64, but not for ARM64. Current code
calls into utility functions under arch/x86 (and coming, under arch/arm64)
to handle the difference.

Change this approach to handle the difference inline based on whether
VDSO_CLOCK_MODE_HVCLOCK is present. The new approach removes code under
arch/* since the difference is tied more to the specifics of the Linux
implementation than to the architecture.

No functional change.

Signed-off-by: Michael Kelley <[email protected]>
Reviewed-by: Boqun Feng <[email protected]>
Acked-by: Daniel Lezcano <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Wei Liu <[email protected]>

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Drivers: hv: Redo Hyper-V synthetic MSR get/set functions

Current code defines a separate get and set macro for each Hyper-V
synthetic MSR used by the VMbus driver. Furthermore, the get macro
can't

Drivers: hv: Redo Hyper-V synthetic MSR get/set functions

Current code defines a separate get and set macro for each Hyper-V
synthetic MSR used by the VMbus driver. Furthermore, the get macro
can't be converted to a standard function because the second argument
is modified in place, which is somewhat bad form.

Redo this by providing a single get and a single set function that
take a parameter specifying the MSR to be operated on. Fixup usage
of the get function. Calling locations are no more complex than before,
but the code under arch/x86 and the upcoming code under arch/arm64
is significantly simplified.

Also standardize the names of Hyper-V synthetic MSRs that are
architecture neutral. But keep the old x86-specific names as aliases
that can be removed later when all references (particularly in KVM
code) have been cleaned up in a separate patch series.

No functional change.

Signed-off-by: Michael Kelley <[email protected]>
Reviewed-by: Boqun Feng <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Wei Liu <[email protected]>

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