Naman Jain bacd0498de x86/hyperv: Fix hv tsc page based sched_clock for hibernation ... commit bcc80dec91 upstream. 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 e5313f1c54 ("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: stable@vger.kernel.org Fixes: 1349401ff1 ("clocksource/drivers/hyper-v: Suspend/resume Hyper-V clocksource for hibernation") Co-developed-by: Dexuan Cui <decui@microsoft.com> Signed-off-by: Dexuan Cui <decui@microsoft.com> Signed-off-by: Naman Jain <namjain@linux.microsoft.com> Reviewed-by: Michael Kelley <mhklinux@outlook.com> Link: https://lore.kernel.org/r/20240917053917.76787-1-namjain@linux.microsoft.com Signed-off-by: Wei Liu <wei.liu@kernel.org> Message-ID: <20240917053917.76787-1-namjain@linux.microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>		2024-12-27 14:02:15 +01:00
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arm_arch_timer.h	KVM: arm64: timers: Use CNTPOFF_EL2 to offset the physical timer	2023-03-30 19:01:09 +01:00
hyperv_timer.h	x86/hyperv: Fix hv tsc page based sched_clock for hibernation	2024-12-27 14:02:15 +01:00
pxa.h	treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 441	2019-06-05 17:37:17 +02:00
samsung_pwm.h	clocksource/drivers/samsung_pwm: Constify passed structure	2021-06-04 10:12:11 +02:00
timer-davinci.h	clocksource/drivers/davinci: Add support for clockevents	2019-06-25 20:46:14 +02:00
timer-goldfish.h	clocksource/drivers: Add a goldfish-timer clocksource	2022-04-11 11:48:01 +02:00
timer-riscv.h	RISC-V: KVM: Add timer functionality	2021-10-04 16:07:16 +05:30
timer-ti-dm.h	clocksource/drivers/timer-ti-dm: Make timer_get_irq static	2022-12-02 13:16:46 +01:00
timer-xilinx.h	pwm: xilinx: Fix u32 overflow issue in 32-bit width PWM mode.	2024-06-03 13:07:56 +02:00