[PATCH 0/2] clocksource/Hyper-V: Add Hyper-V specific sched clock function

[lantianyu1986@gmail.com]

From: Tianyu Lan <Tianyu.Lan@microsoft.com>

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.

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