From: Richard Cochran <richardcochran@gmail.com>
To: Jianyong Wu <jianyong.wu@arm.com>
Cc: netdev@vger.kernel.org, yangbo.lu@nxp.com,
john.stultz@linaro.org, tglx@linutronix.de, pbonzini@redhat.com,
sean.j.christopherson@intel.com, maz@kernel.org,
Mark.Rutland@arm.com, will@kernel.org, suzuki.poulose@arm.com,
steven.price@arm.com, linux-kernel@vger.kernel.org,
linux-arm-kernel@lists.infradead.org,
kvmarm@lists.cs.columbia.edu, kvm@vger.kernel.org,
Steve.Capper@arm.com, Kaly.Xin@arm.com, justin.he@arm.com,
Wei.Chen@arm.com, nd@arm.com
Subject: Re: [RFC PATCH v12 10/11] arm64: add mechanism to let user choose which counter to return
Date: Sat, 23 May 2020 18:47:21 -0700 [thread overview]
Message-ID: <20200524014721.GB335@localhost> (raw)
In-Reply-To: <20200522083724.38182-11-jianyong.wu@arm.com>
On Fri, May 22, 2020 at 04:37:23PM +0800, Jianyong Wu wrote:
> To use this feature, you should call PTP_EXTTS_REQUEST(2) ioctl with flag
> set bit PTP_KVM_ARM_PHY_COUNTER in its argument then call
> PTP_SYS_OFFSET_PRECISE(2) ioctl to get the cross timestamp and phyical
> counter will return. If the bit not set or no call for PTP_EXTTS_REQUEST2,
> virtual counter will return by default.
I'm sorry, but NAK on this completely bizarre twisting of the user
space API.
> diff --git a/drivers/ptp/ptp_chardev.c b/drivers/ptp/ptp_chardev.c
> index fef72f29f3c8..8b0a7b328bcd 100644
> --- a/drivers/ptp/ptp_chardev.c
> +++ b/drivers/ptp/ptp_chardev.c
> @@ -123,6 +123,9 @@ long ptp_ioctl(struct posix_clock *pc, unsigned int cmd, unsigned long arg)
> struct timespec64 ts;
> int enable, err = 0;
>
> +#ifdef CONFIG_ARM64
> + static long flag;
> +#endif
> switch (cmd) {
>
> case PTP_CLOCK_GETCAPS:
> @@ -149,6 +152,24 @@ long ptp_ioctl(struct posix_clock *pc, unsigned int cmd, unsigned long arg)
> err = -EFAULT;
> break;
> }
> +
> +#ifdef CONFIG_ARM64
> + /*
> + * Just using this ioctl to tell kvm ptp driver to get PHC
> + * with physical counter, so if bit PTP_KVM_ARM_PHY_COUNTER
> + * is set then just exit directly.
> + * In most cases, we just need virtual counter from host and
> + * there is limited scenario using this to get physical counter
> + * in guest.
> + * Be careful to use this as there is no way to set it back
> + * unless you reinstall the module.
> + * This is only for arm64.
> + */
> + if (req.extts.flags & PTP_KVM_ARM_PHY_COUNTER) {
> + flag = 1;
> + break;
> + }
> +#endif
This file contains the generic PTP Hardware Clock character device
implementation. It is no place for platform specific hacks.
Sorry,
Richard
next prev parent reply other threads:[~2020-05-24 1:47 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-05-22 8:37 [RFC PATCH v12 0/11] Enable ptp_kvm for arm64 Jianyong Wu
2020-05-22 8:37 ` [RFC PATCH v12 01/11] arm64: Probe for the presence of KVM hypervisor services during boot Jianyong Wu
2020-05-22 8:37 ` [RFC PATCH v12 02/11] arm/arm64: KVM: Advertise KVM UID to guests via SMCCC Jianyong Wu
2020-05-22 8:37 ` [RFC PATCH v12 03/11] psci: export smccc conduit get helper Jianyong Wu
2020-05-22 13:12 ` Sudeep Holla
2020-05-25 1:37 ` Jianyong Wu
2020-05-26 10:10 ` Sudeep Holla
2020-05-27 1:18 ` Jianyong Wu
2020-05-22 8:37 ` [RFC PATCH v12 04/11] ptp: Reorganize ptp_kvm modules to make it arch-independent Jianyong Wu
2020-05-22 8:37 ` [RFC PATCH v12 05/11] time: Add mechanism to recognize clocksource in time_get_snapshot Jianyong Wu
2020-05-28 16:36 ` Thomas Gleixner
2020-05-29 1:05 ` Jianyong Wu
2020-05-22 8:37 ` [RFC PATCH v12 06/11] clocksource: Add clocksource id for arm arch counter Jianyong Wu
2020-05-22 8:37 ` [RFC PATCH v12 07/11] psci: Add hypercall service for kvm ptp Jianyong Wu
2020-05-22 14:18 ` Steven Price
2020-05-25 2:11 ` Jianyong Wu
2020-05-26 11:02 ` Steven Price
2020-05-27 6:06 ` Jianyong Wu
2020-05-22 8:37 ` [RFC PATCH v12 08/11] ptp: arm64: Enable ptp_kvm for arm/arm64 Jianyong Wu
2020-05-22 8:37 ` [RFC PATCH v12 09/11] ptp: extend input argument for getcrosstimestamp API Jianyong Wu
2020-05-24 1:42 ` Richard Cochran
2020-05-22 8:37 ` [RFC PATCH v12 10/11] arm64: add mechanism to let user choose which counter to return Jianyong Wu
2020-05-24 1:47 ` Richard Cochran [this message]
2020-05-24 2:11 ` Richard Cochran
2020-05-25 4:50 ` Jianyong Wu
2020-05-25 6:16 ` Richard Cochran
2020-05-25 6:29 ` Jianyong Wu
2020-05-25 9:17 ` Marc Zyngier
2020-05-25 14:18 ` Jianyong Wu
2020-05-25 15:28 ` Marc Zyngier
2020-05-22 8:37 ` [RFC PATCH v12 11/11] arm64: Add kvm capability check extension for ptp_kvm Jianyong Wu
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