From: Jianyong Wu <Jianyong.Wu@arm.com>
To: Marc Zyngier <maz@kernel.org>
Cc: Justin He <Justin.He@arm.com>,
"kvm@vger.kernel.org" <kvm@vger.kernel.org>,
"netdev@vger.kernel.org" <netdev@vger.kernel.org>,
"richardcochran@gmail.com" <richardcochran@gmail.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"sean.j.christopherson@intel.com"
<sean.j.christopherson@intel.com>,
Steven Price <Steven.Price@arm.com>,
Andre Przywara <Andre.Przywara@arm.com>,
"john.stultz@linaro.org" <john.stultz@linaro.org>,
"yangbo.lu@nxp.com" <yangbo.lu@nxp.com>,
"pbonzini@redhat.com" <pbonzini@redhat.com>,
"tglx@linutronix.de" <tglx@linutronix.de>, nd <nd@arm.com>,
"will@kernel.org" <will@kernel.org>,
"kvmarm@lists.cs.columbia.edu" <kvmarm@lists.cs.columbia.edu>,
"linux-arm-kernel@lists.infradead.org"
<linux-arm-kernel@lists.infradead.org>
Subject: RE: [PATCH v15 6/9] arm64/kvm: Add hypercall service for kvm ptp.
Date: Tue, 24 Nov 2020 05:11:52 +0000 [thread overview]
Message-ID: <HE1PR0802MB2555E9997B3DD956430F9185F4FB0@HE1PR0802MB2555.eurprd08.prod.outlook.com> (raw)
In-Reply-To: <276428d3d291f703e2f0c2c323194e98@kernel.org>
Hi Marc,
> -----Original Message-----
> From: Marc Zyngier <maz@kernel.org>
> Sent: Monday, November 23, 2020 7:59 PM
> To: Jianyong Wu <Jianyong.Wu@arm.com>
> Cc: Justin He <Justin.He@arm.com>; kvm@vger.kernel.org;
> netdev@vger.kernel.org; richardcochran@gmail.com; linux-
> kernel@vger.kernel.org; sean.j.christopherson@intel.com; Steven Price
> <Steven.Price@arm.com>; Andre Przywara <Andre.Przywara@arm.com>;
> john.stultz@linaro.org; yangbo.lu@nxp.com; pbonzini@redhat.com;
> tglx@linutronix.de; nd <nd@arm.com>; will@kernel.org;
> kvmarm@lists.cs.columbia.edu; linux-arm-kernel@lists.infradead.org
> Subject: Re: [PATCH v15 6/9] arm64/kvm: Add hypercall service for kvm ptp.
>
> On 2020-11-23 10:44, Marc Zyngier wrote:
> > On 2020-11-11 06:22, Jianyong Wu wrote:
> >> ptp_kvm will get this service through SMCC call.
> >> The service offers wall time and cycle count of host to guest.
> >> The caller must specify whether they want the host cycle count or the
> >> difference between host cycle count and cntvoff.
> >>
> >> Signed-off-by: Jianyong Wu <jianyong.wu@arm.com>
> >> ---
> >> arch/arm64/kvm/hypercalls.c | 61
> >> +++++++++++++++++++++++++++++++++++++
> >> include/linux/arm-smccc.h | 17 +++++++++++
> >> 2 files changed, 78 insertions(+)
> >>
> >> diff --git a/arch/arm64/kvm/hypercalls.c
> >> b/arch/arm64/kvm/hypercalls.c index b9d8607083eb..f7d189563f3d
> 100644
> >> --- a/arch/arm64/kvm/hypercalls.c
> >> +++ b/arch/arm64/kvm/hypercalls.c
> >> @@ -9,6 +9,51 @@
> >> #include <kvm/arm_hypercalls.h>
> >> #include <kvm/arm_psci.h>
> >>
> >> +static void kvm_ptp_get_time(struct kvm_vcpu *vcpu, u64 *val) {
> >> + struct system_time_snapshot systime_snapshot;
> >> + u64 cycles = ~0UL;
> >> + u32 feature;
> >> +
> >> + /*
> >> + * system time and counter value must captured in the same
> >> + * time to keep consistency and precision.
> >> + */
> >> + ktime_get_snapshot(&systime_snapshot);
> >> +
> >> + // binding ptp_kvm clocksource to arm_arch_counter
> >> + if (systime_snapshot.cs_id != CSID_ARM_ARCH_COUNTER)
> >> + return;
> >> +
> >> + val[0] = upper_32_bits(systime_snapshot.real);
> >> + val[1] = lower_32_bits(systime_snapshot.real);
> >
> > What is the endianness of these values? I can't see it defined
> > anywhere, and this is likely not to work if guest and hypervisor don't
> > align.
>
> Scratch that. This is all passed via registers, so the endianness of the data is
> irrelevant. Please discard any comment about endianness I made in this
> review.
>
Yeah, these data process and transfer are no relationship with endianness. Thanks.
> The documentation aspect still requires to be beefed up.
So the endianness description will be "no endianness restriction".
Thanks
Jianyong
>
> Thanks,
>
> M.
> --
> Jazz is not dead. It just smells funny...
next prev parent reply other threads:[~2020-11-24 5:12 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-11-11 6:22 [PATCH v15 0/9] Enable ptp_kvm for arm/arm64 Jianyong Wu
2020-11-11 6:22 ` [PATCH v15 1/9] arm64: Probe for the presence of KVM hypervisor Jianyong Wu
2020-11-11 6:22 ` [PATCH v15 2/9] arm/arm64: KVM: Advertise KVM UID to guests via SMCCC Jianyong Wu
2020-11-11 6:22 ` [PATCH v15 3/9] ptp: Reorganize ptp_kvm module to make it arch-independent Jianyong Wu
2020-11-11 13:10 ` kernel test robot
2020-11-11 14:36 ` kernel test robot
2020-11-11 6:22 ` [PATCH v15 4/9] time: Add mechanism to recognize clocksource in time_get_snapshot Jianyong Wu
2020-11-11 6:22 ` [PATCH v15 5/9] clocksource: Add clocksource id for arm arch counter Jianyong Wu
2020-11-11 6:22 ` [PATCH v15 6/9] arm64/kvm: Add hypercall service for kvm ptp Jianyong Wu
2020-11-23 10:44 ` Marc Zyngier
2020-11-23 11:59 ` Marc Zyngier
2020-11-24 5:11 ` Jianyong Wu [this message]
2020-11-24 5:20 ` Jianyong Wu
2020-11-24 9:07 ` Marc Zyngier
2020-11-24 10:14 ` Jianyong Wu
2020-11-11 6:22 ` [PATCH v15 7/9] ptp: arm/arm64: Enable ptp_kvm for arm/arm64 Jianyong Wu
2020-11-11 8:52 ` kernel test robot
2020-11-11 13:44 ` kernel test robot
2020-11-23 10:49 ` Marc Zyngier
2020-11-24 5:37 ` Jianyong Wu
2020-11-24 9:04 ` Marc Zyngier
2020-11-24 10:18 ` Jianyong Wu
2020-11-11 6:22 ` [PATCH v15 8/9] doc: add ptp_kvm introduction for arm64 support Jianyong Wu
2020-11-23 10:58 ` Marc Zyngier
2020-11-24 5:21 ` Jianyong Wu
2020-11-11 6:22 ` [PATCH v15 9/9] arm64: Add kvm capability check extension for ptp_kvm Jianyong Wu
2020-11-23 9:26 ` [PATCH v15 0/9] Enable ptp_kvm for arm/arm64 Jianyong Wu
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=HE1PR0802MB2555E9997B3DD956430F9185F4FB0@HE1PR0802MB2555.eurprd08.prod.outlook.com \
--to=jianyong.wu@arm.com \
--cc=Andre.Przywara@arm.com \
--cc=Justin.He@arm.com \
--cc=Steven.Price@arm.com \
--cc=john.stultz@linaro.org \
--cc=kvm@vger.kernel.org \
--cc=kvmarm@lists.cs.columbia.edu \
--cc=linux-arm-kernel@lists.infradead.org \
--cc=linux-kernel@vger.kernel.org \
--cc=maz@kernel.org \
--cc=nd@arm.com \
--cc=netdev@vger.kernel.org \
--cc=pbonzini@redhat.com \
--cc=richardcochran@gmail.com \
--cc=sean.j.christopherson@intel.com \
--cc=tglx@linutronix.de \
--cc=will@kernel.org \
--cc=yangbo.lu@nxp.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).