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From: Paolo Bonzini <pbonzini@redhat.com>
To: Jianyong Wu <jianyong.wu@arm.com>,
	netdev@vger.kernel.org, yangbo.lu@nxp.com,
	john.stultz@linaro.org, tglx@linutronix.de,
	sean.j.christopherson@intel.com, maz@kernel.org,
	richardcochran@gmail.com, Mark.Rutland@arm.com,
	Will.Deacon@arm.com, suzuki.poulose@arm.com
Cc: linux-kernel@vger.kernel.org, kvm@vger.kernel.org,
	Steve.Capper@arm.com, Kaly.Xin@arm.com, justin.he@arm.com,
	nd@arm.com, linux-arm-kernel@lists.infradead.org
Subject: Re: [RFC PATCH v3 4/6] psci: Add hvc call service for ptp_kvm.
Date: Wed, 18 Sep 2019 10:25:37 +0200	[thread overview]
Message-ID: <83ed7fac-277f-a31e-af37-8ec134f39d26@redhat.com> (raw)
In-Reply-To: <20190918080716.64242-5-jianyong.wu@arm.com>

On 18/09/19 10:07, Jianyong Wu wrote:
> +	case ARM_SMCCC_VENDOR_HYP_KVM_PTP_FUNC_ID:
> +		getnstimeofday(ts);

This is not Y2038-safe.  Please use ktime_get_real_ts64 instead, and
split the 64-bit seconds value between val[0] and val[1].

However, it seems to me that the new function is not needed and you can
just use ktime_get_snapshot.  You'll get the time in
systime_snapshot->real and the cycles value in systime_snapshot->cycles.

> +		get_current_counterval(&sc);
> +		val[0] = ts->tv_sec;
> +		val[1] = ts->tv_nsec;
> +		val[2] = sc.cycles;
> +		val[3] = 0;
> +		break;

This should return a guest-cycles value.  If the cycles values always
the same between the host and the guest on ARM, then okay.  If not, you
have to apply whatever offset exists.

Thanks,

Paolo


  reply	other threads:[~2019-09-18  8:25 UTC|newest]

Thread overview: 27+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-09-18  8:07 [RFC PATCH v3 0/6] Enable ptp_kvm for arm64 Jianyong Wu
2019-09-18  8:07 ` [RFC PATCH v3 1/6] psci: Export psci_ops.conduit symbol as modules will use it Jianyong Wu
2019-09-18  8:07 ` [RFC PATCH v3 2/6] ptp: Reorganize ptp_kvm modules to make it arch-independent Jianyong Wu
2019-09-18  8:07 ` [RFC PATCH v3 3/6] timekeeping: Expose API allowing retrival of current clocksource and counter value Jianyong Wu
2019-09-18  8:29   ` Paolo Bonzini
2019-09-18  8:07 ` [RFC PATCH v3 4/6] psci: Add hvc call service for ptp_kvm Jianyong Wu
2019-09-18  8:25   ` Paolo Bonzini [this message]
2019-09-18  9:57     ` Jianyong Wu (Arm Technology China)
2019-09-18 10:23       ` Paolo Bonzini
2019-09-19  9:46         ` Jianyong Wu (Arm Technology China)
2019-09-19 11:07           ` Paolo Bonzini
2019-09-19 11:39             ` Marc Zyngier
2019-09-19 12:13               ` Paolo Bonzini
2019-09-23  3:19                 ` Jianyong Wu (Arm Technology China)
2019-10-09  5:21                 ` Jianyong Wu (Arm Technology China)
2019-10-09  6:36                   ` Paolo Bonzini
2019-10-09  8:18                     ` Jianyong Wu (Arm Technology China)
2019-10-09  9:13                       ` Paolo Bonzini
2019-10-09 16:05                         ` John Stultz
2019-10-09 20:56                           ` Paolo Bonzini
2019-10-14  5:50                         ` Jianyong Wu (Arm Technology China)
2019-10-14  6:58                           ` Paolo Bonzini
2019-09-23  4:57             ` Jianyong Wu (Arm Technology China)
2019-09-24 14:20               ` Paolo Bonzini
2019-09-25 10:27                 ` Jianyong Wu (Arm Technology China)
2019-09-18  8:07 ` [RFC PATCH v3 5/6] ptp: arm64: Enable ptp_kvm for arm64 Jianyong Wu
2019-09-18  8:07 ` [RFC PATCH v3 6/6] kvm: arm64: Add capability check extension for ptp_kvm Jianyong Wu

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