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

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Message-ID: <ZT_ppBmxdd6917cl@google.com>
Date:   Mon, 30 Oct 2023 10:36:36 -0700
From:   Sean Christopherson <seanjc@...gle.com>
To:     Paolo Bonzini <pbonzini@...hat.com>
Cc:     Nikolay Borisov <nik.borisov@...e.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 Mon, Oct 30, 2023, Paolo Bonzini wrote:
> On 10/30/23 17:07, 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).
> 
> I think this is a "Speak Now or Forever Rest in Peace" situation.  I'm going
> to wait a couple days more for reviews to come in, post a v14 myself, and
> apply the series to kvm/next as soon as Linus merges the 6.7 changes.  The
> series will be based on the 6.7 tags/for-linus, and when 6.7-rc1 comes up,
> I'll do this to straighten the history:

Heh, I'm pretty sure you meant to respond to the guest_memfd series.

> 	git checkout kvm/next
> 	git tag -s -f kvm-gmem HEAD
> 	git reset --hard v6.7-rc1
> 	git merge tags/kvm-gmem
> 	# fix conflict with Christian Brauner's VFS series
> 	git commit
> 	git push kvm
> 
> 6.8 is not going to be out for four months, and I'm pretty sure that
> anything discovered within "a few weeks" can be applied on top, and the
> heaviness of a 35-patch series will outweigh any imperfections by a long
> margin).
> 
> (Full disclosure: this is _also_ because I want to apply this series to the
> RHEL kernel, and Red Hat has a high level of disdain for non-upstream
> patches.  But it's mostly because I want all dependencies to be able to move
> on and be developed on top of stock kvm/next).