From: Pavel Tatashin <pasha.tatashin@soleen.com>
To: Wei Liu <wei.liu@kernel.org>
Cc: Linux on Hyper-V List <linux-hyperv@vger.kernel.org>,
virtualization@lists.linux-foundation.org,
Linux Kernel List <linux-kernel@vger.kernel.org>,
Michael Kelley <mikelley@microsoft.com>,
Vineeth Pillai <viremana@linux.microsoft.com>,
Sunil Muthuswamy <sunilmut@microsoft.com>,
Nuno Das Neves <nunodasneves@linux.microsoft.com>,
Daniel Lezcano <daniel.lezcano@linaro.org>,
"K. Y. Srinivasan" <kys@microsoft.com>,
Haiyang Zhang <haiyangz@microsoft.com>,
Stephen Hemminger <sthemmin@microsoft.com>,
Thomas Gleixner <tglx@linutronix.de>
Subject: Re: [PATCH v5 05/16] clocksource/hyperv: use MSR-based access if running as root
Date: Wed, 20 Jan 2021 11:13:28 -0500 [thread overview]
Message-ID: <CA+CK2bBTjUWEOrFKi4pYpEe355sve6b7AjKGc7cQRRe3c-DTrQ@mail.gmail.com> (raw)
In-Reply-To: <20210120120058.29138-6-wei.liu@kernel.org>
On Wed, Jan 20, 2021 at 7:01 AM Wei Liu <wei.liu@kernel.org> wrote:
>
> When Linux runs as the root partition, the setup required for TSC page
> is different.
Why would we need a TSC page as a clock source for root partition at
all? I think the above can be removed.
Luckily Linux also has access to the MSR based
> clocksource. We can just disable the TSC page clocksource if Linux is
> the root partition.
>
> Signed-off-by: Wei Liu <wei.liu@kernel.org>
> Acked-by: Daniel Lezcano <daniel.lezcano@linaro.org>
> ---
> drivers/clocksource/hyperv_timer.c | 3 +++
> 1 file changed, 3 insertions(+)
>
> diff --git a/drivers/clocksource/hyperv_timer.c b/drivers/clocksource/hyperv_timer.c
> index ba04cb381cd3..269a691bd2c4 100644
> --- a/drivers/clocksource/hyperv_timer.c
> +++ b/drivers/clocksource/hyperv_timer.c
> @@ -426,6 +426,9 @@ static bool __init hv_init_tsc_clocksource(void)
> if (!(ms_hyperv.features & HV_MSR_REFERENCE_TSC_AVAILABLE))
> return false;
>
> + if (hv_root_partition)
> + return false;
> +
Reviewed-by: Pavel Tatashin <pasha.tatashin@soleen.com>
WARNING: multiple messages have this Message-ID (diff)
From: Pavel Tatashin <pasha.tatashin@soleen.com>
To: Wei Liu <wei.liu@kernel.org>
Cc: Linux on Hyper-V List <linux-hyperv@vger.kernel.org>,
Stephen Hemminger <sthemmin@microsoft.com>,
Haiyang Zhang <haiyangz@microsoft.com>,
Daniel Lezcano <daniel.lezcano@linaro.org>,
Linux Kernel List <linux-kernel@vger.kernel.org>,
Michael Kelley <mikelley@microsoft.com>,
Nuno Das Neves <nunodasneves@linux.microsoft.com>,
Sunil Muthuswamy <sunilmut@microsoft.com>,
virtualization@lists.linux-foundation.org,
Vineeth Pillai <viremana@linux.microsoft.com>,
Thomas Gleixner <tglx@linutronix.de>
Subject: Re: [PATCH v5 05/16] clocksource/hyperv: use MSR-based access if running as root
Date: Wed, 20 Jan 2021 11:13:28 -0500 [thread overview]
Message-ID: <CA+CK2bBTjUWEOrFKi4pYpEe355sve6b7AjKGc7cQRRe3c-DTrQ@mail.gmail.com> (raw)
In-Reply-To: <20210120120058.29138-6-wei.liu@kernel.org>
On Wed, Jan 20, 2021 at 7:01 AM Wei Liu <wei.liu@kernel.org> wrote:
>
> When Linux runs as the root partition, the setup required for TSC page
> is different.
Why would we need a TSC page as a clock source for root partition at
all? I think the above can be removed.
Luckily Linux also has access to the MSR based
> clocksource. We can just disable the TSC page clocksource if Linux is
> the root partition.
>
> Signed-off-by: Wei Liu <wei.liu@kernel.org>
> Acked-by: Daniel Lezcano <daniel.lezcano@linaro.org>
> ---
> drivers/clocksource/hyperv_timer.c | 3 +++
> 1 file changed, 3 insertions(+)
>
> diff --git a/drivers/clocksource/hyperv_timer.c b/drivers/clocksource/hyperv_timer.c
> index ba04cb381cd3..269a691bd2c4 100644
> --- a/drivers/clocksource/hyperv_timer.c
> +++ b/drivers/clocksource/hyperv_timer.c
> @@ -426,6 +426,9 @@ static bool __init hv_init_tsc_clocksource(void)
> if (!(ms_hyperv.features & HV_MSR_REFERENCE_TSC_AVAILABLE))
> return false;
>
> + if (hv_root_partition)
> + return false;
> +
Reviewed-by: Pavel Tatashin <pasha.tatashin@soleen.com>
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next prev parent reply other threads:[~2021-01-20 16:18 UTC|newest]
Thread overview: 95+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-01-20 12:00 [PATCH v5 00/16] Introducing Linux root partition support for Microsoft Hypervisor Wei Liu
2021-01-20 12:00 ` [PATCH v5 01/16] asm-generic/hyperv: change HV_CPU_POWER_MANAGEMENT to HV_CPU_MANAGEMENT Wei Liu
2021-01-20 15:57 ` Pavel Tatashin
2021-01-20 15:57 ` Pavel Tatashin
2021-01-26 0:25 ` Michael Kelley
2021-01-26 0:25 ` Michael Kelley via Virtualization
2021-01-20 12:00 ` [PATCH v5 02/16] x86/hyperv: detect if Linux is the root partition Wei Liu
2021-01-20 16:03 ` Pavel Tatashin
2021-01-20 16:03 ` Pavel Tatashin
2021-01-26 15:06 ` Wei Liu
2021-01-26 0:31 ` Michael Kelley
2021-01-26 0:31 ` Michael Kelley via Virtualization
2021-01-26 15:15 ` Wei Liu
2021-01-26 15:24 ` Wei Liu
2021-01-20 12:00 ` [PATCH v5 03/16] Drivers: hv: vmbus: skip VMBus initialization if Linux is root Wei Liu
2021-01-20 16:06 ` Pavel Tatashin
2021-01-20 16:06 ` Pavel Tatashin
2021-01-26 0:32 ` Michael Kelley
2021-01-26 0:32 ` Michael Kelley via Virtualization
2021-01-20 12:00 ` [PATCH v5 04/16] iommu/hyperv: don't setup IRQ remapping when running as root Wei Liu
2021-01-20 12:00 ` Wei Liu
2021-01-20 16:08 ` Pavel Tatashin
2021-01-20 16:08 ` Pavel Tatashin
2021-01-20 16:08 ` Pavel Tatashin
2021-01-26 0:33 ` Michael Kelley
2021-01-26 0:33 ` Michael Kelley via Virtualization
2021-01-26 0:33 ` Michael Kelley via iommu
2021-01-20 12:00 ` [PATCH v5 05/16] clocksource/hyperv: use MSR-based access if " Wei Liu
2021-01-20 16:13 ` Pavel Tatashin [this message]
2021-01-20 16:13 ` Pavel Tatashin
2021-01-26 15:19 ` Wei Liu
2021-01-26 0:34 ` Michael Kelley
2021-01-26 0:34 ` Michael Kelley via Virtualization
2021-01-20 12:00 ` [PATCH v5 06/16] x86/hyperv: allocate output arg pages if required Wei Liu
2021-01-20 15:12 ` kernel test robot
2021-01-20 15:12 ` kernel test robot
2021-01-20 15:12 ` kernel test robot
2021-01-20 19:44 ` Pavel Tatashin
2021-01-20 19:44 ` Pavel Tatashin
2021-01-26 0:41 ` Michael Kelley
2021-01-26 0:41 ` Michael Kelley via Virtualization
2021-01-26 18:09 ` Wei Liu
2021-01-20 12:00 ` [PATCH v5 07/16] x86/hyperv: extract partition ID from Microsoft Hypervisor if necessary Wei Liu
2021-01-26 0:48 ` Michael Kelley
2021-01-26 0:48 ` Michael Kelley via Virtualization
2021-02-02 15:03 ` Wei Liu
2021-02-04 16:33 ` Michael Kelley
2021-02-04 16:33 ` Michael Kelley via Virtualization
2021-01-20 12:00 ` [PATCH v5 08/16] x86/hyperv: handling hypercall page setup for root Wei Liu
2021-01-26 0:49 ` Michael Kelley
2021-01-26 0:49 ` Michael Kelley via Virtualization
2021-01-20 12:00 ` [PATCH v5 09/16] x86/hyperv: provide a bunch of helper functions Wei Liu
2021-01-26 1:20 ` Michael Kelley
2021-01-26 1:20 ` Michael Kelley via Virtualization
2021-02-02 16:19 ` Wei Liu
2021-01-20 12:00 ` [PATCH v5 10/16] x86/hyperv: implement and use hv_smp_prepare_cpus Wei Liu
2021-01-26 1:21 ` Michael Kelley
2021-01-26 1:21 ` Michael Kelley via Virtualization
2021-01-20 12:00 ` [PATCH v5 11/16] asm-generic/hyperv: update hv_msi_entry Wei Liu
2021-01-26 1:22 ` Michael Kelley
2021-01-26 1:22 ` Michael Kelley via Virtualization
2021-01-20 12:00 ` [PATCH v5 12/16] asm-generic/hyperv: update hv_interrupt_entry Wei Liu
2021-01-26 1:23 ` Michael Kelley
2021-01-26 1:23 ` Michael Kelley via Virtualization
2021-01-20 12:00 ` [PATCH v5 13/16] asm-generic/hyperv: introduce hv_device_id and auxiliary structures Wei Liu
2021-01-26 1:26 ` Michael Kelley
2021-01-26 1:26 ` Michael Kelley via Virtualization
2021-02-02 17:02 ` Wei Liu
2021-02-03 13:26 ` Wei Liu
2021-02-03 13:49 ` Arnd Bergmann
2021-02-03 14:09 ` Wei Liu
2021-02-04 16:46 ` Michael Kelley
2021-02-04 16:46 ` Michael Kelley via Virtualization
2021-01-20 12:00 ` [PATCH v5 14/16] asm-generic/hyperv: import data structures for mapping device interrupts Wei Liu
2021-01-26 1:27 ` Michael Kelley
2021-01-26 1:27 ` Michael Kelley via Virtualization
2021-01-20 12:00 ` [PATCH v5 15/16] x86/hyperv: implement an MSI domain for root partition Wei Liu
2021-01-27 5:47 ` Michael Kelley
2021-01-27 5:47 ` Michael Kelley via Virtualization
2021-02-02 17:31 ` Wei Liu
2021-02-02 18:15 ` Michael Kelley
2021-02-02 18:15 ` Michael Kelley via Virtualization
2021-02-02 18:16 ` Wei Liu
2021-01-20 12:00 ` [PATCH v5 16/16] iommu/hyperv: setup an IO-APIC IRQ remapping " Wei Liu
2021-01-20 12:00 ` Wei Liu
2021-01-27 5:47 ` Michael Kelley
2021-01-27 5:47 ` Michael Kelley via Virtualization
2021-01-27 5:47 ` Michael Kelley via iommu
2021-02-03 12:47 ` Wei Liu
2021-02-03 12:47 ` Wei Liu
2021-02-04 16:41 ` Michael Kelley
2021-02-04 16:41 ` Michael Kelley via Virtualization
2021-02-04 16:41 ` Michael Kelley via iommu
2021-02-04 16:48 ` Wei Liu
2021-02-04 16:48 ` Wei Liu
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