Re: [PATCH 10/11] KVM: arm64: CCA: Support runtime faulting of memory

[Fuad Tabba]

Hi Suzuki,

On Mon, 09 Nov 2026 11:35:31 +0000, Suzuki K Poulose
<suzuki.poulose@xxxxxxx> wrote:
[...]
>> applies as is. Only how the expected state is computed differs: for a
>> pVM it comes from the per-page share state rather than an IPA bit.
>
> When you say, per-page, you mean per-IPA or per "backing page" ? i.e.,
> can pKVM do something like :
>
>     kvm_ipa_is_private(kvm, ipa) ?
>
> (similar to Realm) or does it need the struct page backing the "ipa" ?

Per IPA, so kvm_ipa_is_private(kvm, ipa) would work for pKVM too. A
pVM's page is private unless the guest has shared it, and that state
is in its stage-2 PTE at EL2, not in the struct page. The host kernel
doesn't have a copy today, since EL2 handles the share and unshare
hypercalls and the new state is only at EL2, so the pKVM side of the
check, a hypercall or a host-side mirror, is part of pKVM's
guest_memfd support when that lands.

Cheers,
/fuad