Re: [PATCH v1 3/5] KVM: SEV: Provide support for SNP_EXTENDED_GUEST_REQUEST NAE event

[Tom Lendacky <thomas.lendacky@amd.com>]

On 6/21/24 08:40, Michael Roth wrote:
> Version 2 of GHCB specification added support for the SNP Extended Guest
> Request Message NAE event. This event serves a nearly identical purpose
> to the previously-added SNP_GUEST_REQUEST event, but for certain message
> types it allows the guest to supply a buffer to be used for additional
> information in some cases.
> 
> Currently the GHCB spec only defines extended handling of this sort in
> the case of attestation requests, where the additional buffer is used to
> supply a table of certificate data corresponding to the attestion
> report's signing key. Support for this extended handling will require
> additional KVM APIs to handle coordinating with userspace.
> 
> Whether or not the hypervisor opts to provide this certificate data is
> optional. However, support for processing SNP_EXTENDED_GUEST_REQUEST
> GHCB requests is required by the GHCB 2.0 specification for SNP guests,
> so for now implement a stub implementation that provides an empty
> certificate table to the guest if it supplies an additional buffer, but
> otherwise behaves identically to SNP_GUEST_REQUEST.
> 
> Signed-off-by: Michael Roth <michael.roth@amd.com>

Reviewed-by: Tom Lendacky <thomas.lendacky@amd.com>

> ---
>  arch/x86/kvm/svm/sev.c | 60 ++++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 60 insertions(+)
>