From: Mark Rutland <mark.rutland@arm.com>
To: Michael Kelley <mikelley@microsoft.com>
Cc: will@kernel.org, catalin.marinas@arm.com,
lorenzo.pieralisi@arm.com, sudeep.holla@arm.com,
linux-arm-kernel@lists.infradead.org,
linux-kernel@vger.kernel.org, linux-hyperv@vger.kernel.org,
linux-efi@vger.kernel.org, arnd@arndb.de, wei.liu@kernel.org,
ardb@kernel.org, daniel.lezcano@linaro.org, kys@microsoft.com
Subject: Re: [PATCH v10 3/7] arm64: hyperv: Add Hyper-V clocksource/clockevent support
Date: Fri, 14 May 2021 13:37:11 +0100 [thread overview]
Message-ID: <20210514123711.GB30645@C02TD0UTHF1T.local> (raw)
In-Reply-To: <1620841067-46606-4-git-send-email-mikelley@microsoft.com>
Hi Michael,
On Wed, May 12, 2021 at 10:37:43AM -0700, Michael Kelley wrote:
> Add architecture specific definitions and functions needed
> by the architecture independent Hyper-V clocksource driver.
> Update the Hyper-V clocksource driver to be initialized
> on ARM64.
Previously we've said that for a clocksource we must use the architected
counter, since that's necessary for things like the VDSO to work
correctly and efficiently.
Given that, I'm a bit confused that we're registering a per-cpu
clocksource that is in part based on the architected counter. Likewise,
I don't entirely follow why it's necessary to PV the clock_event_device.
Are the architected counter and timer reliable without this PV
infrastructure? Why do we need to PV either of those?
Thanks,
Mark.
>
> Signed-off-by: Michael Kelley <mikelley@microsoft.com>
> Reviewed-by: Sunil Muthuswamy <sunilmut@microsoft.com>
> ---
> arch/arm64/include/asm/mshyperv.h | 12 ++++++++++++
> drivers/clocksource/hyperv_timer.c | 14 ++++++++++++++
> 2 files changed, 26 insertions(+)
>
> diff --git a/arch/arm64/include/asm/mshyperv.h b/arch/arm64/include/asm/mshyperv.h
> index c448704..b17299c 100644
> --- a/arch/arm64/include/asm/mshyperv.h
> +++ b/arch/arm64/include/asm/mshyperv.h
> @@ -21,6 +21,7 @@
> #include <linux/types.h>
> #include <linux/arm-smccc.h>
> #include <asm/hyperv-tlfs.h>
> +#include <clocksource/arm_arch_timer.h>
>
> /*
> * Declare calls to get and set Hyper-V VP register values on ARM64, which
> @@ -41,6 +42,17 @@ static inline u64 hv_get_register(unsigned int reg)
> return hv_get_vpreg(reg);
> }
>
> +/* Define the interrupt ID used by STIMER0 Direct Mode interrupts. This
> + * value can't come from ACPI tables because it is needed before the
> + * Linux ACPI subsystem is initialized.
> + */
> +#define HYPERV_STIMER0_VECTOR 31
> +
> +static inline u64 hv_get_raw_timer(void)
> +{
> + return arch_timer_read_counter();
> +}
> +
> /* SMCCC hypercall parameters */
> #define HV_SMCCC_FUNC_NUMBER 1
> #define HV_FUNC_ID ARM_SMCCC_CALL_VAL( \
> diff --git a/drivers/clocksource/hyperv_timer.c b/drivers/clocksource/hyperv_timer.c
> index 977fd05..270ad9c 100644
> --- a/drivers/clocksource/hyperv_timer.c
> +++ b/drivers/clocksource/hyperv_timer.c
> @@ -569,3 +569,17 @@ void __init hv_init_clocksource(void)
> hv_setup_sched_clock(read_hv_sched_clock_msr);
> }
> EXPORT_SYMBOL_GPL(hv_init_clocksource);
> +
> +/* Initialize everything on ARM64 */
> +static int __init hyperv_timer_init(struct acpi_table_header *table)
> +{
> + if (!hv_is_hyperv_initialized())
> + return -EINVAL;
> +
> + hv_init_clocksource();
> + if (hv_stimer_alloc(true))
> + return -EINVAL;
> +
> + return 0;
> +}
> +TIMER_ACPI_DECLARE(hyperv, ACPI_SIG_GTDT, hyperv_timer_init);
> --
> 1.8.3.1
>
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next prev parent reply other threads:[~2021-05-14 12:39 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-05-12 17:37 [PATCH v10 0/7] Enable Linux guests on Hyper-V on ARM64 Michael Kelley
2021-05-12 17:37 ` [PATCH v10 1/7] asm-generic: hyperv: Fix incorrect architecture dependencies Michael Kelley
2021-05-12 17:37 ` [PATCH v10 2/7] arm64: hyperv: Add Hyper-V hypercall and register access utilities Michael Kelley
2021-05-14 12:52 ` Mark Rutland
2021-05-14 15:14 ` Michael Kelley
2021-05-17 11:44 ` Mark Rutland
2021-05-17 16:41 ` Michael Kelley
2021-05-12 17:37 ` [PATCH v10 3/7] arm64: hyperv: Add Hyper-V clocksource/clockevent support Michael Kelley
2021-05-14 12:37 ` Mark Rutland [this message]
2021-05-14 15:35 ` Michael Kelley
2021-05-17 13:08 ` Mark Rutland
2021-05-17 17:27 ` Michael Kelley
2021-05-18 17:00 ` Mark Rutland
2021-06-08 15:36 ` Michael Kelley
2021-06-10 16:45 ` Mark Rutland
2021-06-14 2:42 ` Michael Kelley
2021-06-16 20:17 ` Michael Kelley
2021-06-22 9:54 ` Mark Rutland
2021-06-23 8:56 ` Marc Zyngier
2021-06-28 2:21 ` Michael Kelley
2021-05-12 17:37 ` [PATCH v10 4/7] arm64: hyperv: Add kexec and panic handlers Michael Kelley
2021-05-12 17:37 ` [PATCH v10 5/7] arm64: hyperv: Initialize hypervisor on boot Michael Kelley
2021-05-13 15:16 ` Wei Liu
2021-05-12 17:37 ` [PATCH v10 6/7] arm64: efi: Export screen_info Michael Kelley
2021-05-12 17:37 ` [PATCH v10 7/7] Drivers: hv: Enable Hyper-V code to be built on ARM64 Michael Kelley
2021-05-13 13:17 ` [PATCH v10 0/7] Enable Linux guests on Hyper-V " Sudeep Holla
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