Re: [PATCH v16 13/22] KVM: x86/mmu: Hoist guest_memfd max level/order helpers "up" in mmu.c

[Xiaoyao Li <xiaoyao.li@intel.com>]

On 7/23/2025 6:47 PM, Fuad Tabba wrote:
> From: Sean Christopherson <seanjc@google.com>
> 
> Move kvm_max_level_for_order() and kvm_max_private_mapping_level() up in
> mmu.c so that they can be used by __kvm_mmu_max_mapping_level().
> 
> Opportunistically drop the "inline" from kvm_max_level_for_order().
> 
> No functional change intended.
> 
> Signed-off-by: Sean Christopherson <seanjc@google.com>
> Signed-off-by: Fuad Tabba <tabba@google.com>

Reviewed-by: Xiaoyao Li <xiaoyao.li@intel.com>

> ---
>   arch/x86/kvm/mmu/mmu.c | 72 +++++++++++++++++++++---------------------
>   1 file changed, 36 insertions(+), 36 deletions(-)
> 
> diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
> index b735611e8fcd..20dd9f64156e 100644
> --- a/arch/x86/kvm/mmu/mmu.c
> +++ b/arch/x86/kvm/mmu/mmu.c
> @@ -3285,6 +3285,42 @@ static int host_pfn_mapping_level(struct kvm *kvm, gfn_t gfn,
>   	return level;
>   }
>   
> +static u8 kvm_max_level_for_order(int order)
> +{
> +	BUILD_BUG_ON(KVM_MAX_HUGEPAGE_LEVEL > PG_LEVEL_1G);
> +
> +	KVM_MMU_WARN_ON(order != KVM_HPAGE_GFN_SHIFT(PG_LEVEL_1G) &&
> +			order != KVM_HPAGE_GFN_SHIFT(PG_LEVEL_2M) &&
> +			order != KVM_HPAGE_GFN_SHIFT(PG_LEVEL_4K));
> +
> +	if (order >= KVM_HPAGE_GFN_SHIFT(PG_LEVEL_1G))
> +		return PG_LEVEL_1G;
> +
> +	if (order >= KVM_HPAGE_GFN_SHIFT(PG_LEVEL_2M))
> +		return PG_LEVEL_2M;
> +
> +	return PG_LEVEL_4K;
> +}
> +
> +static u8 kvm_max_private_mapping_level(struct kvm *kvm, kvm_pfn_t pfn,
> +					u8 max_level, int gmem_order)
> +{
> +	u8 req_max_level;
> +
> +	if (max_level == PG_LEVEL_4K)
> +		return PG_LEVEL_4K;
> +
> +	max_level = min(kvm_max_level_for_order(gmem_order), max_level);
> +	if (max_level == PG_LEVEL_4K)
> +		return PG_LEVEL_4K;
> +
> +	req_max_level = kvm_x86_call(gmem_max_mapping_level)(kvm, pfn);
> +	if (req_max_level)
> +		max_level = min(max_level, req_max_level);
> +
> +	return max_level;
> +}
> +
>   static int __kvm_mmu_max_mapping_level(struct kvm *kvm,
>   				       const struct kvm_memory_slot *slot,
>   				       gfn_t gfn, int max_level, bool is_private)
> @@ -4503,42 +4539,6 @@ void kvm_arch_async_page_ready(struct kvm_vcpu *vcpu, struct kvm_async_pf *work)
>   		vcpu->stat.pf_fixed++;
>   }
>   
> -static inline u8 kvm_max_level_for_order(int order)
> -{
> -	BUILD_BUG_ON(KVM_MAX_HUGEPAGE_LEVEL > PG_LEVEL_1G);
> -
> -	KVM_MMU_WARN_ON(order != KVM_HPAGE_GFN_SHIFT(PG_LEVEL_1G) &&
> -			order != KVM_HPAGE_GFN_SHIFT(PG_LEVEL_2M) &&
> -			order != KVM_HPAGE_GFN_SHIFT(PG_LEVEL_4K));
> -
> -	if (order >= KVM_HPAGE_GFN_SHIFT(PG_LEVEL_1G))
> -		return PG_LEVEL_1G;
> -
> -	if (order >= KVM_HPAGE_GFN_SHIFT(PG_LEVEL_2M))
> -		return PG_LEVEL_2M;
> -
> -	return PG_LEVEL_4K;
> -}
> -
> -static u8 kvm_max_private_mapping_level(struct kvm *kvm, kvm_pfn_t pfn,
> -					u8 max_level, int gmem_order)
> -{
> -	u8 req_max_level;
> -
> -	if (max_level == PG_LEVEL_4K)
> -		return PG_LEVEL_4K;
> -
> -	max_level = min(kvm_max_level_for_order(gmem_order), max_level);
> -	if (max_level == PG_LEVEL_4K)
> -		return PG_LEVEL_4K;
> -
> -	req_max_level = kvm_x86_call(gmem_max_mapping_level)(kvm, pfn);
> -	if (req_max_level)
> -		max_level = min(max_level, req_max_level);
> -
> -	return max_level;
> -}
> -
>   static void kvm_mmu_finish_page_fault(struct kvm_vcpu *vcpu,
>   				      struct kvm_page_fault *fault, int r)
>   {