Re: [PATCH v9 07/41] KVM: guest_memfd: Wire up core private/shared attribute interfaces

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

On 7/29/2026 8:35 AM, Ackerley Tng via B4 Relay wrote:
> diff --git a/virt/kvm/guest_memfd.c b/virt/kvm/guest_memfd.c
> index 33c9830190e2e..89cf922232920 100644
> --- a/virt/kvm/guest_memfd.c
> +++ b/virt/kvm/guest_memfd.c
> @@ -893,6 +893,27 @@ int kvm_gmem_get_pfn(struct kvm *kvm, struct kvm_memory_slot *slot,
>   EXPORT_SYMBOL_FOR_KVM_INTERNAL(kvm_gmem_get_pfn);
>   
>   #ifdef CONFIG_HAVE_KVM_ARCH_GMEM_POPULATE
> +static bool kvm_range_is_private(struct file *file, pgoff_t index,
> +				 size_t nr_pages, struct kvm *kvm, gfn_t gfn)
> +{
> +	struct inode *inode = file_inode(file);
> +	pgoff_t last = index + nr_pages - 1;
> +	struct maple_tree *mt;
> +	void *entry;
> +
> +	if (!gmem_in_place_conversion)
> +		return kvm_range_has_vm_memory_attributes(kvm, gfn, gfn + nr_pages,
> +							  KVM_MEMORY_ATTRIBUTE_PRIVATE,
> +							  KVM_MEMORY_ATTRIBUTE_PRIVATE);
> +
> +	mt = &GMEM_I(inode)->attributes;
> +	mt_for_each(mt, entry, index, last) {
> +		if (kvm_gmem_interpret_entry(inode, entry) !=
> +		    KVM_MEMORY_ATTRIBUTE_PRIVATE)
> +			return false;
> +	}
> +	return true;
> +}
>   
>   static long __kvm_gmem_populate(struct kvm *kvm, struct kvm_memory_slot *slot,
>   				struct file *file, gfn_t gfn, struct page *src_page,
> @@ -913,9 +934,7 @@ static long __kvm_gmem_populate(struct kvm *kvm, struct kvm_memory_slot *slot,
>   
>   	folio_unlock(folio);
>   
> -	if (!kvm_range_has_vm_memory_attributes(kvm, gfn, gfn + 1,
> -						KVM_MEMORY_ATTRIBUTE_PRIVATE,
> -						KVM_MEMORY_ATTRIBUTE_PRIVATE)) {
> +	if (!kvm_range_is_private(file, index, 1, kvm, gfn)) {

It's checking if a single gfn is private.

We can just use kvm_mem_is_private()? And it seems can be a separate patch.

>   		ret = -EINVAL;
>   		goto out_put_folio;
>   	}