Re: [PATCH v3 0/2] Drivers: hv: Move Hyper-V clock/timer code to separate clocksource driver

[Sasha Levin]

On Mon, May 27, 2019 at 02:59:07PM +0000, Michael Kelley wrote:
> This patch series moves Hyper-V clock/timer code to a separate Hyper-V
> clocksource driver. Previously, Hyper-V clock/timer code and data
> structures were mixed in with other Hyper-V code in the ISA independent
> drivers/hv code as well as in arch dependent code. The new Hyper-V
> clocksource driver is ISA independent, with a just few dependencies on
> arch specific functions. The patch series does not change any behavior
> or functionality -- it only reorganizes the existing code and fixes up
> the linkages. A few places outside of Hyper-V code are fixed up to use
> the new #include file structure.
>
> This restructuring is in response to Marc Zyngier's review comments
> on supporting Hyper-V running on ARM64, and is a good idea in general.
> It increases the amount of code shared between the x86 and ARM64
> architectures, and reduces the size of the new code for supporting
> Hyper-V on ARM64. A new version of the Hyper-V on ARM64 patches will
> follow once this clocksource restructuring is accepted.
>
> The code is diff'ed against Linux 5.2.0-rc1-next-20190524.
>
> Changes in v3:
> * Removed boolean argument to hv_init_clocksource(). Always call
> sched_clock_register, which is needed on ARM64 but a no-op on x86.
> * Removed separate cpuhp setup in hv_stimer_alloc() and instead
> directly call hv_stimer_init() and hv_stimer_cleanup() from
> corresponding VMbus functions.  This more closely matches original
> code and avoids clocksource stop/restart problems on ARM64 when
> VMbus code denies CPU offlining request.
>
> Changes in v2:
> * Revised commit short descriptions so the distinction between
> the first and second patches is clearer [GregKH]
> * Renamed new clocksource driver files and functions to use
> existing "timer" and "stimer" names instead of introducing
> "syntimer". [Vitaly Kuznetsov]
> * Introduced CONFIG_HYPER_TIMER to fix build problem when
> CONFIG_HYPERV=m [Vitaly Kuznetsov]
> * Added "Suggested-by: Marc Zyngier"
>
> Michael Kelley (2):
>  Drivers: hv: Create Hyper-V clocksource driver from existing
>    clockevents code
>  Drivers: hv: Move Hyper-V clocksource code to new clocksource driver
>
> MAINTAINERS                          |   2 +
> arch/x86/entry/vdso/vclock_gettime.c |   1 +
> arch/x86/entry/vdso/vma.c            |   2 +-
> arch/x86/hyperv/hv_init.c            |  91 +---------
> arch/x86/include/asm/hyperv-tlfs.h   |   6 +
> arch/x86/include/asm/mshyperv.h      |  81 ++-------
> arch/x86/kernel/cpu/mshyperv.c       |   2 +
> arch/x86/kvm/x86.c                   |   1 +
> drivers/clocksource/Makefile         |   1 +
> drivers/clocksource/hyperv_timer.c   | 321 +++++++++++++++++++++++++++++++++++
> drivers/hv/Kconfig                   |   3 +
> drivers/hv/hv.c                      | 156 +----------------
> drivers/hv/hv_util.c                 |   1 +
> drivers/hv/hyperv_vmbus.h            |   3 -
> drivers/hv/vmbus_drv.c               |  42 ++---
> include/clocksource/hyperv_timer.h   | 105 ++++++++++++
> 16 files changed, 484 insertions(+), 334 deletions(-)
> create mode 100644 drivers/clocksource/hyperv_timer.c
> create mode 100644 include/clocksource/hyperv_timer.h

Queued for hyperv-next, thanks!

--
Thanks,
Sasha