From 66c24219ade92b85b24f3ce29b988d187a9f6517 Mon Sep 17 00:00:00 2001
From: Gerd Hoffmann <kraxel@redhat.com>
Date: Wed, 24 Apr 2024 14:00:29 +0800
Subject: [PATCH] OvmfPkg/VirtHstiDxe: do not load driver in confidential
 guests

The VirtHstiDxe does not work in confidential guests.  There also isn't
anything we can reasonably test, neither flash storage nor SMM mode will
be used in that case.  So just skip driver load when running in a
confidential guest.

Cc: Ard Biesheuvel <ardb+tianocore@kernel.org>
Cc: Jiewen Yao <jiewen.yao@intel.com>
Fixes: 506740982bba ("OvmfPkg/VirtHstiDxe: add code flash check")
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Tested-by: Srikanth Aithal <sraithal@amd.com>
Reviewed-by: Jiewen Yao <jiewen.yao@intel.com>
---
 OvmfPkg/VirtHstiDxe/VirtHstiDxe.c   | 6 ++++++
 OvmfPkg/VirtHstiDxe/VirtHstiDxe.inf | 1 +
 2 files changed, 7 insertions(+)

diff --git a/OvmfPkg/VirtHstiDxe/VirtHstiDxe.c b/OvmfPkg/VirtHstiDxe/VirtHstiDxe.c
index b6e53a1219d1..efaff0d1f3cb 100644
--- a/OvmfPkg/VirtHstiDxe/VirtHstiDxe.c
+++ b/OvmfPkg/VirtHstiDxe/VirtHstiDxe.c
@@ -17,6 +17,7 @@ SPDX-License-Identifier: BSD-2-Clause-Patent
 #include <Library/MemoryAllocationLib.h>
 #include <Library/UefiBootServicesTableLib.h>
 #include <Library/UefiLib.h>
+#include <Library/PcdLib.h>
 #include <Library/PlatformInitLib.h>
 
 #include <IndustryStandard/Hsti.h>
@@ -140,6 +141,11 @@ VirtHstiDxeEntrypoint (
   EFI_STATUS                           Status;
   EFI_EVENT                            Event;
 
+  if (PcdGet64 (PcdConfidentialComputingGuestAttr)) {
+    DEBUG ((DEBUG_INFO, "%a: confidential guest\n", __func__));
+    return EFI_UNSUPPORTED;
+  }
+
   DevId = VirtHstiGetHostBridgeDevId ();
   switch (DevId) {
     case INTEL_82441_DEVICE_ID:
diff --git a/OvmfPkg/VirtHstiDxe/VirtHstiDxe.inf b/OvmfPkg/VirtHstiDxe/VirtHstiDxe.inf
index 9514933011e8..b5c237288766 100644
--- a/OvmfPkg/VirtHstiDxe/VirtHstiDxe.inf
+++ b/OvmfPkg/VirtHstiDxe/VirtHstiDxe.inf
@@ -49,6 +49,7 @@
   gUefiOvmfPkgTokenSpaceGuid.PcdSmmSmramRequire
 
 [Pcd]
+  gEfiMdePkgTokenSpaceGuid.PcdConfidentialComputingGuestAttr
   gUefiOvmfPkgTokenSpaceGuid.PcdBfvBase
   gUefiOvmfPkgTokenSpaceGuid.PcdOvmfFlashNvStorageVariableBase