Re: [PATCH 5.15.y v2 5/8] 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 `cache` parameter added to `__link_shadow_page` is unused.
--

commit ed55c138ec7737d6fb972fc8e93a6a6549ebcdf9
Author: Paolo Bonzini <pbonzini@redhat.com>

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

This commit moves the drop_large_spte() call out of individual callers
and directly into __link_shadow_page() before the shadow page is installed.
It also updates kvm_mmu_get_child_sp() to return an error pointer when a
shadow page already exists.

> diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
> index dbc18d4cc572c..d58be2e698f79 100644
> --- a/arch/x86/kvm/mmu/mmu.c
> +++ b/arch/x86/kvm/mmu/mmu.c
[ ... ]
> @@ -2264,13 +2257,21 @@ 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 cache parameter used anywhere inside
__link_shadow_page()?

Looking at the full function body, it seems to rely on
mmu_page_add_parent_pte(vcpu, sp, sptep), which implicitly uses
vcpu->arch.mmu_pte_list_desc_cache rather than this new parameter.

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

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260626174620.1819772-1-pbonzini@redhat.com?part=5