Re: [PATCH v2 18/28] KVM: arm64: Add kvm_has_nv{2,3}() predicates

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [Medium] kvm_has_nv3() will always return false because ARM64_HAS_NV3 is never populated in the capabilities bitmap.
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--- Patch [18]: [PATCH v2 18/28] KVM: arm64: Add kvm_has_nv{2,3}() predicates ---
commit e61ff01470e9cbe730c6702e605c3c17d525ca4e
Author: Marc Zyngier <maz@kernel.org>

KVM: arm64: Add kvm_has_nv{2,3}() predicates

This commit adds a new set of predicates indicating whether a VM is capable
of NV2, NV3, and is in a nested NV3 context.

> diff --git a/arch/arm64/include/asm/kvm_emulate.h b/arch/arm64/include/asm/kvm_emulate.h
> index 9831166695186..c562d8171d5e1 100644
> --- a/arch/arm64/include/asm/kvm_emulate.h
> +++ b/arch/arm64/include/asm/kvm_emulate.h

[ ... ]

> +static inline bool kvm_has_nv3(struct kvm *kvm)
> +{
> +	return (cpus_have_final_cap(ARM64_HAS_NESTED_VIRT) &&
> +		cpus_have_final_cap(ARM64_HAS_NV3) &&

[Severity: Medium]
Will kvm_has_nv3() always return false here?

It appears the ARM64_HAS_NV3 capability was added to the cpucaps tools, but
the corresponding hardware detection entry is missing from the arm64_features
array in arch/arm64/kernel/cpufeature.c. Since it is never populated,
cpus_have_final_cap(ARM64_HAS_NV3) will unconditionally evaluate to false,
turning any code relying on this predicate into dead code.

> +		kvm_has_feat(kvm, ID_AA64MMFR4_EL1, NV_frac, NV3));
> +}

[ ... ]

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Sashiko AI review · https://sashiko.dev/#/patchset/20260714091641.1970822-1-maz@kernel.org?part=18