Re: [PATCH 2/2] KVM: x86/mmu: Expose number of shadow MMU shadow pages as a stat

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [Low] The field `n_used_mmu_pages` was not removed from `struct kvm_arch`, leaving unused dead code.
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commit 5fa7e390c84e0ce29ce7989e7bf60ba442c4e942
Author: Sean Christopherson <seanjc@google.com>

KVM: x86/mmu: Expose number of shadow MMU shadow pages as a stat

Turn arch.n_used_mmu_pages into a stat, mmu_shadow_pages, as the number of
live shadow pages is arguably the most critical datapoint when it comes
to analyzing the shadow MMU. 

> diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
> index 3886b536c8a57..be84e4d2405e0 100644
> --- a/arch/x86/include/asm/kvm_host.h
> +++ b/arch/x86/include/asm/kvm_host.h
> @@ -1701,6 +1701,7 @@ struct kvm_vm_stat {
>  	u64 mmu_recycled;
>  	u64 mmu_cache_miss;
>  	u64 mmu_unsync;
> +	u64 mmu_shadow_pages;
>  	union {
>  		struct {
>  			atomic64_t pages_4k;

[Severity: Low]
Should n_used_mmu_pages be removed from struct kvm_arch in this file?

Since all usages of kvm->arch.n_used_mmu_pages are replaced by
kvm->stat.mmu_shadow_pages in this patch, it appears the original
declaration is left behind as unused dead code:

arch/x86/include/asm/kvm_host.h:
struct kvm_arch {
	unsigned long n_used_mmu_pages;
	...
}

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Sashiko AI review · https://sashiko.dev/#/patchset/20260605174611.2222504-1-seanjc@google.com?part=2