Re: [RFC PATCH v7 28/28] KVM: arm64: Allow the creation of a SPE enabled VM

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [Medium] The Kconfig dependency for `KVM_ARM_SPE` restricts it to 'n' when the `ARM_SPE_PMU` driver is built as a module, preventing users from enabling SPE virtualization.
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commit 9bb804f4572dd230ad3b5db909bd2001b3ee3186
Author: Alexandru Elisei <alexandru.elisei@arm.com>

KVM: arm64: Allow the creation of a SPE enabled VM

This commit introduces the Kconfig option KVM_ARM_SPE to allow userspace
to enable the Statistical Profiling Extension (SPE) for virtual machines.

[ ... ]

> diff --git a/arch/arm64/kvm/Kconfig b/arch/arm64/kvm/Kconfig
> --- a/arch/arm64/kvm/Kconfig
> +++ b/arch/arm64/kvm/Kconfig
> @@ -106,9 +106,9 @@ endif # NVHE_EL2_DEBUG
>  
>  
>  config KVM_ARM_SPE
> -	bool
> +	bool "Support SPE in guest"
>  	depends on KVM && ARM_SPE_PMU

[Severity: Medium]
Does this Kconfig dependency unintentionally disable KVM_ARM_SPE when the
host driver ARM_SPE_PMU is built as a module?

Because KVM_ARM_SPE is a boolean, if ARM_SPE_PMU is configured as a
loadable module (=m), the Kconfig dependency evaluates to m. For a boolean
config, this restricts its maximum value to n, effectively disabling the
feature in the build configuration.

Since the implementation in arch/arm64/kvm/spe.c supports being built
against a modular driver (using try_module_get()), should this dependency
be relaxed or handled differently so the feature can still be selected?

> -	default n
> +	default y
>  	help
>  	  Adds support for Statistical Profiling Extension (SPE) in virtual
>  	  machines.

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Sashiko AI review · https://sashiko.dev/#/patchset/20260903160623.315525-1-alexandru.elisei@arm.com?part=28