Re: [PATCH 5.10.y 13/17] KVM: x86/mmu: pull call to drop_large_spte() into __link_shadow_page()

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [Low] The newly added `cache` parameter in `__link_shadow_page()` is never used.
--

commit 58832cb7365080324e7906cc11df0e03073304a5
Author: Paolo Bonzini <pbonzini@redhat.com>

KVM: x86/mmu: pull call to drop_large_spte() into __link_shadow_page()

This commit moves the dropping of large SPTEs from the callers into
__link_shadow_page() to happen just before the shadow page is installed.
It also modifies kvm_mmu_get_child_sp() to return an error pointer if the
shadow page already exists, preventing duplicate links.

> diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
> index 5df1cd5bff1b9..47c5c3613b682 100644
> --- a/arch/x86/kvm/mmu/mmu.c
> +++ b/arch/x86/kvm/mmu/mmu.c

[ ... ]

> @@ -2208,13 +2201,21 @@ static void shadow_walk_next(struct kvm_shadow_walk_iterator *iterator)
>  	__shadow_walk_next(iterator, *iterator->sptep);
>  }
>  
> -static void link_shadow_page(struct kvm_vcpu *vcpu, u64 *sptep,
> -			     struct kvm_mmu_page *sp)
> +static void __link_shadow_page(struct kvm_vcpu *vcpu,
> +			       struct kvm_mmu_memory_cache *cache, u64 *sptep,

[Severity: Low]
This isn't a bug, but is the new cache parameter intended to be used?

Looking at the rest of this function, the cache argument is never referenced.
Instead, nested operations like mmu_page_add_parent_pte() continue to
implicitly use vcpu->arch.mmu_pte_list_desc_cache from the vcpu struct.

> +			       struct kvm_mmu_page *sp)
>  {
>  	u64 spte;
>  
>  	BUILD_BUG_ON(VMX_EPT_WRITABLE_MASK != PT_WRITABLE_MASK);

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Sashiko AI review · https://sashiko.dev/#/patchset/20260626112634.1778506-1-pbonzini@redhat.com?part=13