Re: [GIT PULL] KVM changes for Linux 6.9 merge window

[Linus Torvalds]

On Fri, 15 Mar 2024 at 10:49, Paolo Bonzini <pbonzini@xxxxxxxxxx> 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