From: Dave P Martin <Dave.Martin@arm.com>
To: Marc Zyngier <Marc.Zyngier@arm.com>
Cc: "tokamoto@jp.fujitsu.com" <tokamoto@jp.fujitsu.com>,
Christoffer Dall <cdall@kernel.org>,
Ard Biesheuvel <ard.biesheuvel@linaro.org>,
Catalin Marinas <Catalin.Marinas@arm.com>,
Will Deacon <Will.Deacon@arm.com>,
Zhang Lei <zhang.lei@jp.fujitsu.com>,
Julien Grall <Julien.Grall@arm.com>,
"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 v7 16/27] KVM: arm64: Factor out core register ID enumeration
Date: Tue, 2 Apr 2019 09:54:19 +0000 [thread overview]
Message-ID: <20190402095416.GV27348@e103592.cambridge.arm.com> (raw)
In-Reply-To: <865zrw69cd.wl-marc.zyngier@arm.com>
On Tue, Apr 02, 2019 at 10:32:34AM +0100, Marc Zyngier wrote:
> On Tue, 02 Apr 2019 09:59:19 +0100,
> Dave Martin <Dave.Martin@arm.com> wrote:
> >
> > On Tue, Apr 02, 2019 at 03:41:56AM +0100, Marc Zyngier wrote:
[...]
> > > diff --git a/arch/arm64/kvm/guest.c b/arch/arm64/kvm/guest.c
> > > index 086ab0508d69..4f7b26bbf671 100644
> > > --- a/arch/arm64/kvm/guest.c
> > > +++ b/arch/arm64/kvm/guest.c
> > > @@ -604,22 +604,22 @@ int kvm_arm_copy_reg_indices(struct kvm_vcpu *vcpu, u64 __user *uindices)
[...]
> > > ret = kvm_arm_copy_fw_reg_indices(vcpu, uindices);
> > > -if (ret)
> > > +if (ret < 0)
> > > return ret;
> > > uindices += kvm_arm_get_fw_num_regs(vcpu);
> > >
> > > ret = copy_timer_indices(vcpu, uindices);
> > > -if (ret)
> > > +if (ret < 0)
> > > return ret;
> > > uindices += NUM_TIMER_REGS;
> >
> > For these two, the interface is not really the same. These don't
> > return the number of registers, so return 0 on success. "< 0" here
> > could be a trap for the future, though the risk looks low.
>
> I realised that, but since they all return a negative value on error,
> I went for a similar error handling.
Sure, this is more potential future maintenance thing -- and anyway not
a big deal.
I agree that your changes look like they work.
> > I can have a go at some rework on top to make this more consistent,
> > but I'd rather not muddy the water further for the moment.
> >
> > Any view on that?
>
> I don't think there is any urgency on that front. For now, I'd like to
> make sure things do not regress. Once we're sure we have something
> stable, we'll be able to make it shiny.
Agreed.
I won't worry about this for now, but we can discuss it later.
Cheers
---Dave
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next prev parent reply other threads:[~2019-04-02 9:54 UTC|newest]
Thread overview: 115+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-03-29 13:00 [PATCH v7 00/27] KVM: arm64: SVE guest support Dave Martin
2019-03-29 13:00 ` [PATCH v7 01/27] KVM: Documentation: Document arm64 core registers in detail Dave Martin
2019-04-24 9:25 ` Alex Bennée
2019-03-29 13:00 ` [PATCH v7 02/27] arm64: fpsimd: Always set TIF_FOREIGN_FPSTATE on task state flush Dave Martin
2019-03-29 13:00 ` [PATCH v7 03/27] KVM: arm64: Delete orphaned declaration for __fpsimd_enabled() Dave Martin
2019-03-29 13:00 ` [PATCH v7 04/27] KVM: arm64: Refactor kvm_arm_num_regs() for easier maintenance Dave Martin
2019-03-29 13:00 ` [PATCH v7 05/27] KVM: arm64: Add missing #includes to kvm_host.h Dave Martin
2019-03-29 13:00 ` [PATCH v7 06/27] arm64/sve: Clarify role of the VQ map maintenance functions Dave Martin
2019-04-04 21:21 ` Andrew Jones
2019-03-29 13:00 ` [PATCH v7 07/27] arm64/sve: Check SVE virtualisability Dave Martin
2019-04-04 21:21 ` Andrew Jones
2019-04-05 9:35 ` Dave Martin
2019-03-29 13:00 ` [PATCH v7 08/27] arm64/sve: Enable SVE state tracking for non-task contexts Dave Martin
2019-03-29 13:00 ` [PATCH v7 09/27] KVM: arm64: Add a vcpu flag to control SVE visibility for the guest Dave Martin
2019-04-03 19:14 ` Andrew Jones
2019-04-04 3:17 ` Marc Zyngier
2019-04-04 7:53 ` Dave Martin
2019-04-04 21:15 ` Andrew Jones
2019-03-29 13:00 ` [PATCH v7 10/27] KVM: arm64: Propagate vcpu into read_id_reg() Dave Martin
2019-04-04 21:15 ` Andrew Jones
2019-03-29 13:00 ` [PATCH v7 11/27] KVM: arm64: Support runtime sysreg visibility filtering Dave Martin
2019-04-03 19:17 ` Andrew Jones
2019-04-24 9:39 ` Alex Bennée
2019-04-24 13:47 ` Dave Martin
2019-04-24 13:47 ` Dave Martin
2019-03-29 13:00 ` [PATCH v7 12/27] KVM: arm64/sve: System register context switch and access support Dave Martin
2019-04-03 19:39 ` Andrew Jones
2019-04-04 8:06 ` Dave Martin
2019-04-04 8:32 ` Andrew Jones
2019-04-04 8:47 ` Dave Martin
2019-04-04 8:59 ` Andrew Jones
2019-04-24 15:21 ` Alex Bennée
2019-04-25 13:28 ` Dave Martin
2019-04-25 13:28 ` Dave Martin
2019-03-29 13:00 ` [PATCH v7 13/27] KVM: arm64/sve: Context switch the SVE registers Dave Martin
2019-04-03 20:01 ` Andrew Jones
2019-04-04 8:10 ` Dave Martin
2019-04-04 8:35 ` Andrew Jones
2019-04-04 8:36 ` Dave Martin
2019-04-24 14:51 ` Alex Bennée
2019-04-25 13:35 ` Dave Martin
2019-04-25 13:35 ` Dave Martin
2019-03-29 13:00 ` [PATCH v7 14/27] KVM: Allow 2048-bit register access via ioctl interface Dave Martin
2019-04-04 21:11 ` Andrew Jones
2019-03-29 13:00 ` [PATCH v7 15/27] KVM: arm64: Add missing #include of <linux/string.h> in guest.c Dave Martin
2019-03-29 13:00 ` [PATCH v7 16/27] KVM: arm64: Factor out core register ID enumeration Dave Martin
2019-04-02 2:41 ` Marc Zyngier
2019-04-02 8:59 ` Dave Martin
2019-04-02 9:32 ` Marc Zyngier
2019-04-02 9:54 ` Dave P Martin [this message]
2019-03-29 13:00 ` [PATCH v7 17/27] KVM: arm64: Reject ioctl access to FPSIMD V-regs on SVE vcpus Dave Martin
2019-04-03 20:15 ` Andrew Jones
2019-04-24 13:45 ` Alex Bennée
2019-03-29 13:00 ` [PATCH v7 18/27] KVM: arm64/sve: Add SVE support to register access ioctl interface Dave Martin
2019-04-04 13:57 ` Andrew Jones
2019-04-04 14:50 ` Dave Martin
2019-04-04 16:25 ` Andrew Jones
2019-04-04 16:56 ` Dave Martin
2019-03-29 13:00 ` [PATCH v7 19/27] KVM: arm64: Enumerate SVE register indices for KVM_GET_REG_LIST Dave Martin
2019-04-04 14:08 ` Andrew Jones
2019-04-05 9:35 ` Dave Martin
2019-04-05 9:45 ` Andrew Jones
2019-04-05 11:11 ` Dave Martin
2019-03-29 13:00 ` [PATCH v7 20/27] arm64/sve: In-kernel vector length availability query interface Dave Martin
2019-04-04 14:20 ` Andrew Jones
2019-04-05 9:35 ` Dave Martin
2019-04-05 9:54 ` Andrew Jones
2019-04-05 11:13 ` Dave Martin
2019-03-29 13:00 ` [PATCH v7 21/27] KVM: arm/arm64: Add hook for arch-specific KVM initialisation Dave Martin
2019-04-04 14:25 ` Andrew Jones
2019-04-04 14:53 ` Dave Martin
2019-04-04 16:33 ` Andrew Jones
2019-04-05 9:36 ` Dave Martin
2019-04-05 10:40 ` Andrew Jones
2019-04-05 11:14 ` Dave Martin
2019-03-29 13:00 ` [PATCH v7 22/27] KVM: arm/arm64: Add KVM_ARM_VCPU_FINALIZE ioctl Dave Martin
2019-04-04 15:07 ` Andrew Jones
2019-04-04 16:47 ` Dave Martin
2019-03-29 13:00 ` [PATCH v7 23/27] KVM: arm64/sve: Add pseudo-register for the guest's vector lengths Dave Martin
2019-04-04 20:18 ` Andrew Jones
2019-04-05 9:36 ` Dave Martin
2019-04-05 10:14 ` Andrew Jones
2019-04-05 12:54 ` Dave Martin
2019-04-05 15:33 ` Andrew Jones
2019-04-10 12:42 ` Dave Martin
2019-04-10 12:42 ` Dave Martin
2019-04-04 20:31 ` Andrew Jones
2019-04-05 9:36 ` Dave Martin
2019-04-05 10:22 ` Andrew Jones
2019-04-05 14:06 ` Dave Martin
2019-04-05 15:41 ` Andrew Jones
2019-04-10 12:35 ` Dave Martin
2019-04-10 12:35 ` Dave Martin
2019-03-29 13:00 ` [PATCH v7 24/27] KVM: arm64/sve: Allow userspace to enable SVE for vcpus Dave Martin
2019-04-04 20:36 ` Andrew Jones
2019-03-29 13:00 ` [PATCH v7 25/27] KVM: arm64: Add a capability to advertise SVE support Dave Martin
2019-04-04 20:39 ` Andrew Jones
2019-03-29 13:00 ` [PATCH v7 26/27] KVM: Document errors for KVM_GET_ONE_REG and KVM_SET_ONE_REG Dave Martin
2019-04-03 20:27 ` Andrew Jones
2019-04-04 8:35 ` Dave Martin
2019-04-04 9:34 ` Andrew Jones
2019-04-04 9:38 ` Dave P Martin
2019-04-04 9:45 ` Andrew Jones
2019-03-29 13:00 ` [PATCH v7 27/27] KVM: arm64/sve: Document KVM API extensions for SVE Dave Martin
2019-04-04 21:09 ` Andrew Jones
2019-04-05 9:36 ` Dave Martin
2019-04-05 10:39 ` Andrew Jones
2019-04-05 13:00 ` Dave Martin
2019-04-05 15:38 ` Andrew Jones
2019-04-10 12:34 ` Dave Martin
2019-04-10 12:34 ` Dave Martin
2019-03-29 14:56 ` [PATCH v7 00/27] KVM: arm64: SVE guest support Marc Zyngier
2019-03-29 15:06 ` Dave Martin
2019-04-05 16:41 ` Dave Martin
2019-04-25 10:33 ` Alex Bennée
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