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

From: Michael Kelley
Date: Mon May 27 2019 - 11:02:26 EST

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

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