linux-kernel - Re: [PATCH 4/9] KVM: x86/mmu: Rename MMU_WARN_ON() to KVM_MMU_WARN

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Message-ID: <CALzav=cNJSqhbYhoNLTXJ4Kc=ZmgRPOo9U5bqqFTxhdSatnUag@mail.gmail.com>
Date:   Fri, 12 May 2023 16:35:42 -0700
From:   David Matlack <dmatlack@...gle.com>
To:     Sean Christopherson <seanjc@...gle.com>
Cc:     Paolo Bonzini <pbonzini@...hat.com>, kvm@...r.kernel.org,
        linux-kernel@...r.kernel.org, Mingwei Zhang <mizhang@...gle.com>,
        Jim Mattson <jmattson@...gle.com>
Subject: Re: [PATCH 4/9] KVM: x86/mmu: Rename MMU_WARN_ON() to KVM_MMU_WARN_ON()

On Fri, May 12, 2023 at 4:30 PM Sean Christopherson <seanjc@...gle.com> wrote:
>
> On Fri, May 12, 2023, David Matlack wrote:
> > On Thu, May 11, 2023 at 04:59:12PM -0700, Sean Christopherson wrote:
> > > Rename MMU_WARN_ON() to make it super obvious that the assertions are
> > > all about KVM's MMU, not the primary MMU.
> >
> > I think adding KVM is a step in the right direction but I have 2
> > remaining problems with KVM_MMU_WARN_ON():
> >
> >  - Reminds me of VM_WARN_ON(), which toggles between WARN_ON() and
> >    BUG_ON(), whereas KVM_MMU_WARN_ON() toggles between no-op and
> >    WARN_ON().
>
> No, VM_WARN_ON() bounces between WARN_ON() and nop, just like KVM_MMU_WARN_ON().
> There's an extra bit of magic that adds a static assert that the code is valid
> (which I can/should/will add), but the runtime behavior is a nop.

Ah, you're right, I misread VM_WARN_ON().