Hi Marc, > -----Original Message----- > From: Marc Zyngier <m...@kernel.org> > Sent: Tuesday, November 24, 2020 5:05 PM > To: Jianyong Wu <jianyong...@arm.com> > Cc: net...@vger.kernel.org; yangbo...@nxp.com; john.stu...@linaro.org; > t...@linutronix.de; pbonz...@redhat.com; sean.j.christopher...@intel.com; > richardcoch...@gmail.com; Mark Rutland <mark.rutl...@arm.com>; > w...@kernel.org; Suzuki Poulose <suzuki.poul...@arm.com>; Andre > Przywara <andre.przyw...@arm.com>; Steven Price > <steven.pr...@arm.com>; linux-kernel@vger.kernel.org; linux-arm- > ker...@lists.infradead.org; kvm...@lists.cs.columbia.edu; > k...@vger.kernel.org; Steve Capper <steve.cap...@arm.com>; Justin He > <justin...@arm.com>; nd <n...@arm.com> > Subject: Re: [PATCH v15 7/9] ptp: arm/arm64: Enable ptp_kvm for > arm/arm64 > > Jianyong, > > On 2020-11-24 05:37, Jianyong Wu wrote: > > Hi Marc, > > [...] > > >> > + > >> arm_smccc_1_1_invoke(ARM_SMCCC_VENDOR_HYP_KVM_PTP_FU > >> NC_ID, > >> > + ARM_PTP_NONE_COUNTER, &hvc_res); > >> > >> I really don't see the need to use a non-architectural counter ID. > >> Using the virtual counter ID should just be fine, and shouldn't lead > >> to any issue. > >> > > > >> Am I missing something? > > > > In this function, no counter data is needed. If virtual counter ID is > > used here, user may be confused with why we get virtual counter > > data and do nothing with it. So I explicitly add a new "NONE" counter > > ID to make it clear. > > > > WDYT? > > ITIABI (I Think It's A Bad Idea). There are two counters, and the API > allows to retrieve the data for any of these two. If the "user" doesn't > want to do anything with the data, that's their problem. > > Here, you can just sue the virtual counter, and that will give you the > exact same semantic, without inventing non-architectural state. > OK, that's it.
Thanks Jianyong Wu > Thanks, > > M. > -- > Jazz is not dead. It just smells funny...
