Re: [PATCH v8 12/46] KVM: guest_memfd: Only prepare folios for private pages

[Binbin Wu]

On 6/19/2026 8:31 AM, Ackerley Tng via B4 Relay wrote:
> From: Ackerley Tng <ackerleytng@xxxxxxxxxx>
> 
> All-shared guest_memfd used to be only supported for non-CoCo VMs where
> preparation doesn't apply. INIT_SHARED is about to be supported for CoCo
> VMs in a later patch in this series.
> 
> In addition, KVM_SET_MEMORY_ATTRIBUTES2 is about to be supported in
> guest_memfd in a later patch in this series.
> 
> This means that the kvm fault handler may now call kvm_gmem_get_pfn() on a
> shared folio for a CoCo VM where preparation applies.
> 
> Add a check to make sure that preparation is only performed for private
> folios.
> 
> Preparation will be undone on freeing (see kvm_gmem_free_folio()) and on
> conversion to shared.
> 
> Suggested-by: Michael Roth <michael.roth@xxxxxxx>
> Reviewed-by: Fuad Tabba <tabba@xxxxxxxxxx>
> Signed-off-by: Ackerley Tng <ackerleytng@xxxxxxxxxx>

Reviewed-by: Binbin Wu <binbin.wu@xxxxxxxxxxxxxxx>