linux-kernel - Re: [PATCH] KVM: x86: User mutex guards to eliminate __kvm_x86_vendor

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Date:   Mon, 11 Dec 2023 18:21:40 -0800
From:   Sean Christopherson <seanjc@...gle.com>
To:     Nikolay Borisov <nik.borisov@...e.com>
Cc:     pbonzini@...hat.com, x86@...nel.org, kvm@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH] KVM: x86: User mutex guards to eliminate __kvm_x86_vendor_init()

On Sat, Dec 09, 2023, Nikolay Borisov wrote:
> 
> 
> On 30.10.23 г. 18:07 ч., Sean Christopherson wrote:
> > On Mon, Oct 30, 2023, Nikolay Borisov wrote:
> > > Current separation between (__){0,1}kvm_x86_vendor_init() is
> > > superfluos as
> > 
> > superfluous
> > 
> > But this intro is actively misleading.  The double-underscore variant
> > most definitely
> > isn't superfluous, e.g. it eliminates the need for gotos reduces the
> > probability
> > of incorrect error codes, bugs in the error handling, etc.  It _becomes_
> > superflous
> > after switching to guard(mutex).
> > 
> > IMO, this is one of the instances where the then solution problem
> > appoach is
> > counter-productive.  If there are no objections, I'll massage the change
> > log to
> > the below when applying (for 6.8, in a few weeks).
> > 
> >   Use the recently introduced guard(mutex) infrastructure acquire and
> >   automatically release vendor_module_lock when the guard goes out of
> > scope.
> >   Drop the inner __kvm_x86_vendor_init(), its sole purpose was to simplify
> >   releasing vendor_module_lock in error paths.
> > 
> >   No functional change intended.
> > 
> > > the the underscore version doesn't have any other callers.
> > > 
> 
> 
> Has this fallen through the cracks as I don't see it in 6.7?

As above, I have this tagged for inclusion in 6.8, not 6.7.  Though admittedly,
this one did actually fall through the cracks as I moved it to the wrong mailbox
when Paolo usurped the thread for unrelated guest_memfd stuff.  Anyways, I do
plan on grabbing this for 6.8, I'm just buried in non-upstream stuff right now.