From: Tianyu Lan <redacted> Sent: Monday, July 29, 2019 12:53 AM
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.
Signed-off-by: Tianyu Lan <redacted>
---
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(-)
Reviewed-by: Michael Kelley <redacted>