From: Jianyong Wu <Jianyong.Wu@arm.com>
To: Marc Zyngier <maz@kernel.org>
Cc: "netdev@vger.kernel.org" <netdev@vger.kernel.org>,
"yangbo.lu@nxp.com" <yangbo.lu@nxp.com>,
"john.stultz@linaro.org" <john.stultz@linaro.org>,
"tglx@linutronix.de" <tglx@linutronix.de>,
"pbonzini@redhat.com" <pbonzini@redhat.com>,
"sean.j.christopherson@intel.com"
<sean.j.christopherson@intel.com>,
"richardcochran@gmail.com" <richardcochran@gmail.com>,
Mark Rutland <Mark.Rutland@arm.com>,
"will@kernel.org" <will@kernel.org>,
Suzuki Poulose <Suzuki.Poulose@arm.com>,
Steven Price <Steven.Price@arm.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"linux-arm-kernel@lists.infradead.org"
<linux-arm-kernel@lists.infradead.org>,
"kvmarm@lists.cs.columbia.edu" <kvmarm@lists.cs.columbia.edu>,
"kvm@vger.kernel.org" <kvm@vger.kernel.org>,
Steve Capper <Steve.Capper@arm.com>, Kaly Xin <Kaly.Xin@arm.com>,
Justin He <Justin.He@arm.com>, nd <nd@arm.com>
Subject: RE: [RFC PATCH v9 6/8] psci: Add hvc call service for ptp_kvm.
Date: Tue, 14 Jan 2020 10:34:51 +0000 [thread overview]
Message-ID: <HE1PR0801MB1676C93AF0AA7980F4A79B3FF4340@HE1PR0801MB1676.eurprd08.prod.outlook.com> (raw)
In-Reply-To: <22ba1283a7b82f018c1fdf85414e5bfe@kernel.org>
Hi Marc,
> -----Original Message-----
> From: Marc Zyngier <maz@kernel.org>
> Sent: Monday, January 13, 2020 7:16 PM
> 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;
> richardcochran@gmail.com; Mark Rutland <Mark.Rutland@arm.com>;
> will@kernel.org; Suzuki Poulose <Suzuki.Poulose@arm.com>; Steven Price
> <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 <Steve.Capper@arm.com>; Kaly Xin
> <Kaly.Xin@arm.com>; Justin He <Justin.He@arm.com>; nd <nd@arm.com>
> Subject: Re: [RFC PATCH v9 6/8] psci: Add hvc call service for ptp_kvm.
>
> Hi Jianyong,
>
> On 2020-01-13 10:30, Jianyong Wu wrote:
> > Hi Marc,
> >
> >> -----Original Message-----
> >> From: Marc Zyngier <maz@kernel.org>
> >> Sent: Friday, January 10, 2020 6:56 PM NV breaks that assumtion,
> >> because the guest hypervisor is using the physical counter. Also,
> >> let's not forget that the hypercall isn't Linux specific.
> >> I can write my own non-Linux guest and still use this hypercall.
> >> Nothing in
> >> there says that I can't use the physical counter if I want to.
> >>
> >> So somehow, you need to convey the the hypervisor the notion of
> >> *which*
> >> counter the guest uses.
> >>
> >> Does it make sense? Or am I missing something?
> >>
> > I know what you say. Let me try to solve this problem.
> > Step 0, summary out all the conditions we should process, which will
> > sever as branch condition.(now only normal virt and nested virt, I
> > think)
>
> No. You shouldn't think of the various use cases, but of which time
> references a guest can use. You don't need nested virt to use the physical
> counter, for example.
Ok,
>
> > Step 1, figure out the set of reference counter value used by guest
> > in all condition.
>
> That should be for the guest to tell you when it calls into the PV service.
>
Yeah
> > Step 2, determine which reference counter value will be used by
> guest
> > in a certain condition in hypercall.
> > In step 1, can we give the set only 2 elements that one is physical
> > counter the other is virtual counter?
>
> I don't think returning the two values is useful. Just return what the guest
> asks for.
>
> > For step 2, I have no idea for that now. can you give me some hint
> > about it?
>
> Just expand your SMC call to take a parameter indicating the reference
> counter, and return the sampled (or computed) value corresponding to that
> counter.
Get it, I'll try it.
Thanks
Jianyong
>
> M.
> --
> Jazz is not dead. It just smells funny...
next prev parent reply other threads:[~2020-01-14 10:35 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-12-10 3:40 [RFC PATCH v9 0/8] Enable ptp_kvm for arm64 Jianyong Wu
2019-12-10 3:40 ` [RFC PATCH v9 1/8] arm/arm64: smccc/psci: add arm_smccc_1_1_get_conduit() Jianyong Wu
2019-12-10 3:40 ` [RFC PATCH v9 2/8] psci: let arm_smccc_1_1_invoke available by modules Jianyong Wu
2019-12-10 3:40 ` [RFC PATCH v9 3/8] ptp: Reorganize ptp_kvm modules to make it arch-independent Jianyong Wu
2019-12-10 3:40 ` [RFC PATCH v9 4/8] time: Add mechanism to recognize clocksource in time_get_snapshot Jianyong Wu
2019-12-10 3:40 ` [RFC PATCH v9 5/8] clocksource: Add clocksource id for arm arch counter Jianyong Wu
2019-12-10 3:40 ` [RFC PATCH v9 6/8] psci: Add hvc call service for ptp_kvm Jianyong Wu
2020-01-07 9:16 ` Marc Zyngier
2020-01-09 5:45 ` Jianyong Wu
2020-01-09 9:16 ` Marc Zyngier
2020-01-10 9:51 ` Jianyong Wu
2020-01-10 10:56 ` Marc Zyngier
2020-01-13 10:30 ` Jianyong Wu
2020-01-13 11:16 ` Marc Zyngier
2020-01-14 10:34 ` Jianyong Wu [this message]
2019-12-10 3:40 ` [RFC PATCH v9 7/8] ptp: arm64: Enable ptp_kvm for arm64 Jianyong Wu
2020-01-07 9:29 ` Marc Zyngier
2020-01-09 5:59 ` Jianyong Wu
2020-01-09 9:24 ` Marc Zyngier
2020-01-09 9:46 ` Marc Zyngier
2020-01-10 10:15 ` Jianyong Wu
2020-01-10 10:15 ` Jianyong Wu
2020-01-10 10:35 ` Marc Zyngier
2020-01-13 10:37 ` Jianyong Wu
2020-01-13 11:21 ` Marc Zyngier
2020-01-14 10:22 ` Jianyong Wu
2019-12-10 3:40 ` [RFC PATCH v9 8/8] kvm: arm64: Add capability check extension for ptp_kvm Jianyong Wu
2020-01-06 9:38 ` [RFC PATCH v9 0/8] Enable ptp_kvm for arm64 Jianyong Wu
2020-01-07 8:15 ` Paolo Bonzini
2020-01-07 9:33 ` Marc Zyngier
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