Re: [PATCH v8 09/46] KVM: guest_memfd: Introduce function to check GFN private/shared status

[Binbin Wu]

On 6/24/2026 10:38 PM, Ackerley Tng wrote:
> Binbin Wu <binbin.wu@xxxxxxxxxxxxxxx> writes:
> 
>>
>> [...snip...]
>>
>>> +bool kvm_gmem_is_private(struct kvm *kvm, gfn_t gfn)
>>> +{
>>> +	struct kvm_memory_slot *slot = gfn_to_memslot(kvm, gfn);
>>> +	struct inode *inode;
>>> +
>>> +	/*
>>> +	 * If this gfn has no associated memslot, there's no chance of the gfn
>>> +	 * being backed by private memory, since guest_memfd must be used for
>>> +	 * private memory,
>>
>> "guest_memfd must be used for private memory" is a bit confusing to me.
>>
> 
> Hmm good point. Is the source of confusion that guest_memfd can be used
> for both shared and private memory?

Yes.

> 
> Perhaps this can be rephrased as:
> 
> guest_memfd is the only provider of private memory and guest_memfd must
> be used with a memslot, hence if there's no associated memslot, there's
> no chance of this gfn being private.

LGTM.

> 
>>> and guest_memfd must be associated with some memslot.
>>> +	 */
>>> +	if (!slot)
>>> +		return 0;
>>> +
>>>
>>> [...snip...]
>>>
>