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From: Linus Torvalds <torvalds@linux-foundation.org>
Date: Fri, 15 Mar 2024 15:28:29 -0700
Message-ID: <CAHk-=whCvkhc8BbFOUf1ddOsgSGgEjwoKv77=HEY1UiVCydGqw@mail.gmail.com>
Subject: Re: [GIT PULL] KVM changes for Linux 6.9 merge window
To: Paolo Bonzini <pbonzini@redhat.com>, Marc Zyngier <maz@kernel.org>, 
	Oliver Upton <oliver.upton@linux.dev>, Catalin Marinas <catalin.marinas@arm.com>, 
	Mark Rutland <mark.rutland@arm.com>, Will Deacon <will@kernel.org>
Cc: linux-kernel@vger.kernel.org, kvm@vger.kernel.org
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On Fri, 15 Mar 2024 at 10:49, Paolo Bonzini <pbonzini@redhat.com> wrote:
>
>   https://git.kernel.org/pub/scm/virt/kvm/kvm.git tags/for-linus

Argh.

This causes my arm64 build to fail, but since I don't do that between
every pull, I didn't notice until after I had already pushed things
out.

I get a failure on arch/arm64/kvm/check-res-bits.h (line 60):

        BUILD_BUG_ON(ID_AA64DFR1_EL1_RES0       != (GENMASK_ULL(63, 0)));

and at least in my build, the generated sysreg-defs.h file has

 #define ID_AA64DFR1_EL1_RES0 (UL(0))

so yeah, it most definitely doesn't match that GENMASK_ULL(63, 0).

I did *not* go delve into how arch/arm64/tools/gen-sysreg.awk works. I
don't really do awk any more.

The immediate cause of the failure is commit b80b701d5a67 ("KVM:
arm64: Snapshot all non-zero RES0/RES1 sysreg fields for later
checking") but I hope it worked at *some* point. I can't see how.

I would guess / assume that commit cfc680bb04c5 ("arm64: sysreg: Add
layout for ID_AA64MMFR4_EL1") is also involved, but having recoiled in
horror from the awk script, I really can't even begin to guess at what
is going on.

Bringing in other people who hopefully can sort this out.

                   Linus