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* [PATCH v6] clocksource/drivers: Suspend/resume Hyper-V clocksource for hibernation
@ 2019-11-20  7:12 Dexuan Cui
  2019-12-04 16:05 ` Daniel Lezcano
  0 siblings, 1 reply; 2+ messages in thread
From: Dexuan Cui @ 2019-11-20  7:12 UTC (permalink / raw)
  To: arnd, bp, daniel.lezcano, haiyangz, hpa, kys, linux-hyperv,
	linux-kernel, mingo, sashal, sthemmin, tglx, x86, mikelley,
	Alexander.Levin, vkuznets
  Cc: linux-arch, Dexuan Cui

This is needed for hibernation, e.g. when we resume the old kernel, we need
to disable the "current" kernel's TSC page and then resume the old kernel's.

Signed-off-by: Dexuan Cui <decui@microsoft.com>
Reviewed-by: Michael Kelley <mikelley@microsoft.com>
---

This patch is part of the v5 patchset:
  https://lkml.org/lkml/2019/9/5/1158
  https://lkml.org/lkml/2019/9/5/1161

  Actually v6 is the same as v1 (v2~v5 were posted with the other patches).

  Please pick up this patch into the tip.git tree, probably onto the branch
timers/core.

 drivers/clocksource/hyperv_timer.c | 25 +++++++++++++++++++++++++
 1 file changed, 25 insertions(+)

diff --git a/drivers/clocksource/hyperv_timer.c b/drivers/clocksource/hyperv_timer.c
index 287d8d58c21a..1aec08e82b7a 100644
--- a/drivers/clocksource/hyperv_timer.c
+++ b/drivers/clocksource/hyperv_timer.c
@@ -330,12 +330,37 @@ static u64 read_hv_sched_clock_tsc(void)
 	return read_hv_clock_tsc(NULL) - hv_sched_clock_offset;
 }
 
+static void suspend_hv_clock_tsc(struct clocksource *arg)
+{
+	u64 tsc_msr;
+
+	/* Disable the TSC page */
+	hv_get_reference_tsc(tsc_msr);
+	tsc_msr &= ~BIT_ULL(0);
+	hv_set_reference_tsc(tsc_msr);
+}
+
+
+static void resume_hv_clock_tsc(struct clocksource *arg)
+{
+	phys_addr_t phys_addr = virt_to_phys(&tsc_pg);
+	u64 tsc_msr;
+
+	/* Re-enable the TSC page */
+	hv_get_reference_tsc(tsc_msr);
+	tsc_msr &= GENMASK_ULL(11, 0);
+	tsc_msr |= BIT_ULL(0) | (u64)phys_addr;
+	hv_set_reference_tsc(tsc_msr);
+}
+
 static struct clocksource hyperv_cs_tsc = {
 	.name	= "hyperv_clocksource_tsc_page",
 	.rating	= 400,
 	.read	= read_hv_clock_tsc,
 	.mask	= CLOCKSOURCE_MASK(64),
 	.flags	= CLOCK_SOURCE_IS_CONTINUOUS,
+	.suspend= suspend_hv_clock_tsc,
+	.resume	= resume_hv_clock_tsc,
 };
 
 static u64 notrace read_hv_clock_msr(struct clocksource *arg)
-- 
2.19.1


^ permalink raw reply	[flat|nested] 2+ messages in thread

* Re: [PATCH v6] clocksource/drivers: Suspend/resume Hyper-V clocksource for hibernation
  2019-11-20  7:12 [PATCH v6] clocksource/drivers: Suspend/resume Hyper-V clocksource for hibernation Dexuan Cui
@ 2019-12-04 16:05 ` Daniel Lezcano
  0 siblings, 0 replies; 2+ messages in thread
From: Daniel Lezcano @ 2019-12-04 16:05 UTC (permalink / raw)
  To: decui, arnd, bp, haiyangz, hpa, kys, linux-hyperv, linux-kernel,
	mingo, sashal, sthemmin, tglx, x86, mikelley, Alexander.Levin,
	vkuznets
  Cc: linux-arch

On 20/11/2019 08:12, Dexuan Cui wrote:
> This is needed for hibernation, e.g. when we resume the old kernel, we need
> to disable the "current" kernel's TSC page and then resume the old kernel's.
> 
> Signed-off-by: Dexuan Cui <decui@microsoft.com>
> Reviewed-by: Michael Kelley <mikelley@microsoft.com>
> ---
> 
> This patch is part of the v5 patchset:
>   https://lkml.org/lkml/2019/9/5/1158
>   https://lkml.org/lkml/2019/9/5/1161
> 
>   Actually v6 is the same as v1 (v2~v5 were posted with the other patches).
> 
>   Please pick up this patch into the tip.git tree, probably onto the branch
> timers/core.

Applied, thanks!


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^ permalink raw reply	[flat|nested] 2+ messages in thread

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2019-11-20  7:12 [PATCH v6] clocksource/drivers: Suspend/resume Hyper-V clocksource for hibernation Dexuan Cui
2019-12-04 16:05 ` Daniel Lezcano

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