Re: [PATCH 07/12] KVM: guest_memfd: make kvm_gmem_prepare_folio() operate on a single struct kvm

Michael Roth
2024-07-17T21:54:22Z

On Thu, Jul 11, 2024 at 06:27:50PM -0400, Paolo Bonzini wrote:
> This is now possible because preparation is done by kvm_gmem_get_pfn()
> instead of fallocate(). In practice this is not a limitation, because
> even though guest_memfd can be bound to multiple struct kvm, for
> hardware implementations of confidential computing only one guest
> (identified by an ASID on SEV-SNP, or an HKID on TDX) will be able
> to access it.
>
> In the case of intra-host migration (not implemented yet for SEV-SNP,
> but we can use SEV-ES as an idea of how it will work), the new struct
> kvm inherits the same ASID and preparation need not be repeated.
>
> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

Reviewed-by: Michael Roth <michael.roth@amd.com>