[PATCH v8 23/32] UefiCpuPkg: add PcdGhcbHypervisorFeatures

["Brijesh Singh" <brijesh.singh@amd.com>]

BZ: https://bugzilla.tianocore.org/show_bug.cgi?id=3275

Version 2 of the GHCB specification added a new VMGEXIT that the guest
could use for querying the hypervisor features. One of the immediate
users for it will be an AP creation code. When SEV-SNP is enabled, the
guest can use the newly added AP_CREATE VMGEXIT to create the APs.

The MpInitLib will check the hypervisor feature, and if AP_CREATE is
available, it will use it.

See GHCB spec version 2 for more details on the VMGEXIT.

Cc: Michael Roth <michael.roth@amd.com>
Cc: Ray Ni <ray.ni@intel.com>
Cc: Rahul Kumar <rahul1.kumar@intel.com>
Cc: Eric Dong <eric.dong@intel.com>
Cc: James Bottomley <jejb@linux.ibm.com>
Cc: Min Xu <min.m.xu@intel.com>
Cc: Jiewen Yao <jiewen.yao@intel.com>
Cc: Tom Lendacky <thomas.lendacky@amd.com>
Cc: Jordan Justen <jordan.l.justen@intel.com>
Cc: Ard Biesheuvel <ardb+tianocore@kernel.org>
Cc: Erdem Aktas <erdemaktas@google.com>
Cc: Gerd Hoffmann <kraxel@redhat.com>
Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
---
 UefiCpuPkg/UefiCpuPkg.dec | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/UefiCpuPkg/UefiCpuPkg.dec b/UefiCpuPkg/UefiCpuPkg.dec
index 9dbaa407c399..c979a0a90a0e 100644
--- a/UefiCpuPkg/UefiCpuPkg.dec
+++ b/UefiCpuPkg/UefiCpuPkg.dec
@@ -400,5 +400,10 @@ [PcdsDynamic, PcdsDynamicEx]
   # @Prompt Memory encryption attribute
   gUefiCpuPkgTokenSpaceGuid.PcdConfidentialComputingGuestAttr|0|UINT64|0x60000017
 
+  ## This dynamic PCD contains the hypervisor features value obtained through the GHCB HYPERVISOR
+  #  features VMGEXIT defined in the version 2 of GHCB spec.
+  # @Prompt GHCB Hypervisor Features
+  gUefiCpuPkgTokenSpaceGuid.PcdGhcbHypervisorFeatures|0x0|UINT64|0x60000018
+
 [UserExtensions.TianoCore."ExtraFiles"]
   UefiCpuPkgExtra.uni
-- 
2.25.1