From: Daniel Lezcano <daniel.lezcano@linaro.org>
To: Michael Kelley <mikelley@microsoft.com>,
sthemmin@microsoft.com, kys@microsoft.com, wei.liu@kernel.org,
tglx@linutronix.de, mingo@redhat.com, bp@alien8.de,
hpa@zytor.com, arnd@arndb.de, linux-hyperv@vger.kernel.org
Cc: linux-kernel@vger.kernel.org, x86@kernel.org, linux-arch@vger.kernel.org
Subject: Re: [PATCH v2 09/10] clocksource/drivers/hyper-v: Set clocksource rating based on Hyper-V feature
Date: Mon, 1 Mar 2021 16:42:04 +0100 [thread overview]
Message-ID: <e6e2f860-d109-25c7-5892-ef9b06daaa7d@linaro.org> (raw)
In-Reply-To: <1614561332-2523-10-git-send-email-mikelley@microsoft.com>
On 01/03/2021 02:15, Michael Kelley wrote:
> On x86/x64, the TSC clocksource is available in a Hyper-V VM only if
> Hyper-V provides the TSC_INVARIANT flag. The rating on the Hyper-V
> Reference TSC page clocksource is currently set so that it will not
> override the TSC clocksource in this case. Alternatively, if the TSC
> clocksource is not available, then the Hyper-V clocksource is used.
>
> But on ARM64, the Hyper-V Reference TSC page clocksource should
> override the ARM arch counter, since the Hyper-V clocksource provides
> scaling and offsetting during live migrations that is not provided
> for the ARM arch counter.
>
> To get the needed behavior for both x86/x64 and ARM64, tweak the
> logic by defaulting the Hyper-V Reference TSC page clocksource
> rating to a large value that will always override. If the Hyper-V
> TSC_INVARIANT flag is set, then reduce the rating so that it will not
> override the TSC.
>
> While the logic for getting there is slightly different, the net
> result in the normal cases is no functional change.
>
> Signed-off-by: Michael Kelley <mikelley@microsoft.com>
Acked-by: Daniel Lezcano <daniel.lezcano@linaro.org>
[ ... ]
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next prev parent reply other threads:[~2021-03-01 15:42 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-01 1:15 [PATCH v2 00/10] Refactor arch specific Hyper-V code Michael Kelley
2021-03-01 1:15 ` [PATCH v2 01/10] Drivers: hv: vmbus: Move Hyper-V page allocator to arch neutral code Michael Kelley
2021-03-02 12:57 ` ** POTENTIAL FRAUD ALERT - RED HAT ** " Vitaly Kuznetsov
2021-03-02 17:42 ` Michael Kelley
2021-03-01 1:15 ` [PATCH v2 02/10] x86/hyper-v: Move hv_message_type to architecture neutral module Michael Kelley
2021-03-01 1:15 ` [PATCH v2 03/10] Drivers: hv: Redo Hyper-V synthetic MSR get/set functions Michael Kelley
2021-03-01 1:15 ` [PATCH v2 04/10] Drivers: hv: vmbus: Move hyperv_report_panic_msg to arch neutral code Michael Kelley
2021-03-01 1:15 ` [PATCH v2 05/10] Drivers: hv: vmbus: Handle auto EOI quirk inline Michael Kelley
2021-03-01 1:15 ` [PATCH v2 06/10] Drivers: hv: vmbus: Move handling of VMbus interrupts Michael Kelley
2021-03-01 1:15 ` [PATCH v2 07/10] clocksource/drivers/hyper-v: Handle vDSO differences inline Michael Kelley
2021-03-01 12:21 ` Daniel Lezcano
2021-03-02 1:29 ` Michael Kelley
2021-03-02 13:01 ` Daniel Lezcano
2021-03-01 1:15 ` [PATCH v2 08/10] clocksource/drivers/hyper-v: Handle sched_clock " Michael Kelley
2021-03-01 14:25 ` Daniel Lezcano
2021-03-02 1:38 ` Michael Kelley
2021-03-02 13:34 ` Daniel Lezcano
2021-03-01 1:15 ` [PATCH v2 09/10] clocksource/drivers/hyper-v: Set clocksource rating based on Hyper-V feature Michael Kelley
2021-03-01 15:42 ` Daniel Lezcano [this message]
2021-03-01 1:15 ` [PATCH v2 10/10] clocksource/drivers/hyper-v: Move handling of STIMER0 interrupts Michael Kelley
2021-03-01 18:44 ` Daniel Lezcano
2021-03-02 1:40 ` Michael Kelley
2021-03-01 11:30 ` [PATCH v2 00/10] Refactor arch specific Hyper-V code Wei Liu
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