AMD SEV and SEV-ES support measured direct boot with
kernel/initrd/cmdline hashes injected by QEMU and verified by OVMF
during boot.

To enable the same approach for AMD SEV-SNP we make sure the page in
which QEMU inserts the hashes of kernel/initrd/cmdline is not already
pre-validated, as SNP doesn't allow validating a page twice.

The first patch rearranges the pages in AmdSevX64's MEMFD so they are in
the same order both as in the main target (OvmfPkgX64), with the
exception of the SEV Launch Secret page which isn't defined in
OvmfPkgX64.

The second patch modifies the SNP metadata structure such that on
AmdSev target the SEV Launch Secret page is not included in the ranges
that are pre-validated (zero pages) by the VMM; instead the VMM will
insert content into this page, or mark it explicitly as a zero page if
no hashes are added.

A corresponding RFC patch to QEMU will be published soon.

Cc: Ard Biesheuvel <ardb+tianocore@...>
Cc: Jiewen Yao <jiewen.yao@...>
Cc: Jordan Justen <jordan.l.justen@...>
Cc: Gerd Hoffmann <kraxel@...>
Cc: Brijesh Singh <brijesh.singh@...>
Cc: Erdem Aktas <erdemaktas@...>
Cc: James Bottomley <jejb@...>
Cc: Jiewen Yao <jiewen.yao@...>
Cc: Min Xu <min.m.xu@...>
Cc: Tom Lendacky <thomas.lendacky@...>
Cc: Tobin Feldman-Fitzthum <tobin@...>

Dov Murik (2):
OvmfPkg/AmdSev: Reorder MEMFD pages to match the order in
OvmfPkgX64.fdf
OvmfPkg/ResetVector: Exclude SEV launch secrets page from
pre-validation

OvmfPkg/AmdSev/AmdSevX64.fdf | 18 +++++++++---------
OvmfPkg/ResetVector/ResetVector.nasmb | 15 ++++++++++++++-
2 files changed, 23 insertions(+), 10 deletions(-)

--
2.20.1