linux-kernel - Re: [PATCH] KVM: x86/xsave: Remove 'return void' expression for 'void function'

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Message-ID: <ZWi3g6Mh9L8Lglxj@google.com>
Date:   Thu, 30 Nov 2023 08:25:39 -0800
From:   Sean Christopherson <seanjc@...gle.com>
To:     Like Xu <like.xu.linux@...il.com>
Cc:     Paolo Bonzini <pbonzini@...hat.com>, kvm@...r.kernel.org,
        linux-kernel@...r.kernel.org, Maxim Levitsky <mlevitsk@...hat.com>
Subject: Re: [PATCH] KVM: x86/xsave: Remove 'return void' expression for 'void function'

On Thu, Nov 30, 2023, Like Xu wrote:
> On 26/10/2023 9:10 am, Sean Christopherson wrote:
> > On Wed, Oct 25, 2023, Sean Christopherson wrote:
> > > On Wed, Oct 25, 2023, Like Xu wrote:
> > > > Emm, did we miss this little fix ?
> > > 
> > > No, I have it earmarked, it's just not a priority because it doesn't truly fix
> > > anything.  Though I suppose it probably makes to apply it for 6.8, waiting one
> > > more day to send PULL requests to Paolo isn't a problem.
> > 
> > Heh, when I tried to apply this I got reminded of why I held it for later.  I
> > want to apply it to kvm-x86/misc, but that's based on ~6.6-rc2 (plus a few KVM
> > patches), i.e. doesn't have the "buggy" commit.  I don't want to rebase "misc",
> > nor do I want to create a branch and PULL request for a single trivial commit.
> > 
> > So for logistical reasons, I'm not going apply this right away, but I will make
> > sure it gets into v6.7.
> 
> Thanks, and a similar pattern occurs with these functions:
> 
>  'write_register_operand'
>  'account_shadowed'
>  'unaccount_shadowed'
>  'mtrr_lookup_fixed_next'
>  'pre_svm_run'
>  'svm_vcpu_deliver_sipi_vector'
> 
> Although the compiler will do the right thing, use 'return void' expression
> deliberately without grounds for exemption may annoy some CI pipelines.
> 
> If you need more cleanup or a new version to cover all these cases above,
> just let me know.

I'd rather update the CI pipelines to turn off -Wpedantic.  There is zero chance
that -Wpedantic will ever get enabled for kernel builds, the kernel is deliberately
not ISO C compliant.  I have no objection to cleaning up kvm_vcpu_ioctl_x86_get_xsave()
because it's an obvious goof and a recent change, but like checkpatch warnings,
I don't want to go around "fixing" warnings unless they are actively problematic
for humans.