From f674fa9cde3d2d6919bb3e35b94d95c098b6696a Mon Sep 17 00:00:00 2001
From: Min Xu <min.m.xu@intel.com>
Date: Tue, 14 Dec 2021 10:54:14 +0800
Subject: [PATCH] OvmfPkg: Update DxeAcpiTimerLib to read HostBridgeDevId in
 PlatformInfoHob

RFC: https://bugzilla.tianocore.org/show_bug.cgi?id=3429

The entrypoint of DxeAcpiTimerLib checks HostBridgeDevId by reading
PcdOvmfHostBridgePciDevId. If the DevId is not set, ASSERT is
triggered. Normally this DevId is set in PlatformPei which is executed
in PEI phase.

This patch-set is introducing PEI-less boot which means PEI phase is
skipped. So there is no chance to set this DevId. Instead HostBridgeDevId
is set in PlatformInfoHob. So we can check if PlatformInfoHob exists and
if HostBridgeDevId is set in this Hob.

Cc: Michael D Kinney <michael.d.kinney@intel.com>
Cc: Brijesh Singh <brijesh.singh@amd.com>
Cc: Erdem Aktas <erdemaktas@google.com>
Cc: James Bottomley <jejb@linux.ibm.com>
Cc: Jiewen Yao <jiewen.yao@intel.com>
Cc: Tom Lendacky <thomas.lendacky@amd.com>
Cc: Gerd Hoffmann <kraxel@redhat.com>
Acked-by: Gerd Hoffmann <kraxel@redhat.com>
Reviewed-by: Jiewen Yao <jiewen.yao@intel.com>
Signed-off-by: Min Xu <min.m.xu@intel.com>
---
 .../Library/AcpiTimerLib/DxeAcpiTimerLib.c    | 25 ++++++++++++++++---
 .../Library/AcpiTimerLib/DxeAcpiTimerLib.inf  |  7 +++---
 2 files changed, 26 insertions(+), 6 deletions(-)

diff --git a/OvmfPkg/Library/AcpiTimerLib/DxeAcpiTimerLib.c b/OvmfPkg/Library/AcpiTimerLib/DxeAcpiTimerLib.c
index 1158461874..01a41a6a45 100644
--- a/OvmfPkg/Library/AcpiTimerLib/DxeAcpiTimerLib.c
+++ b/OvmfPkg/Library/AcpiTimerLib/DxeAcpiTimerLib.c
@@ -6,10 +6,16 @@
   SPDX-License-Identifier: BSD-2-Clause-Patent
 **/
 
+#include <Uefi/UefiBaseType.h>
+#include <Uefi/UefiMultiPhase.h>
+#include <Pi/PiBootMode.h>
+#include <Pi/PiHob.h>
+#include <Library/HobLib.h>
 #include <Library/DebugLib.h>
 #include <Library/IoLib.h>
 #include <Library/PcdLib.h>
 #include <Library/PciLib.h>
+#include <Library/PlatformInitLib.h>
 #include <OvmfPlatforms.h>
 
 //
@@ -36,13 +42,26 @@ AcpiTimerLibConstructor (
   VOID
   )
 {
-  UINT16  HostBridgeDevId;
-  UINTN   Pmba;
+  UINT16                 HostBridgeDevId;
+  UINTN                  Pmba;
+  EFI_HOB_GUID_TYPE      *GuidHob;
+  EFI_HOB_PLATFORM_INFO  *PlatformInfoHob = NULL;
 
   //
   // Query Host Bridge DID to determine platform type
+  // Tdx guest stores the HostBridgePciDevId in a GuidHob.
+  // So we first check if this HOB exists
   //
-  HostBridgeDevId = PcdGet16 (PcdOvmfHostBridgePciDevId);
+  GuidHob = GetFirstGuidHob (&gUefiOvmfPkgPlatformInfoGuid);
+  if (GuidHob != NULL) {
+    PlatformInfoHob = (EFI_HOB_PLATFORM_INFO *)GET_GUID_HOB_DATA (GuidHob);
+    HostBridgeDevId = PlatformInfoHob->HostBridgeDevId;
+  } else {
+    DEBUG ((DEBUG_ERROR, "PlatformInfoHob is not found.\n"));
+    ASSERT (FALSE);
+    return RETURN_UNSUPPORTED;
+  }
+
   switch (HostBridgeDevId) {
     case INTEL_82441_DEVICE_ID:
       Pmba = POWER_MGMT_REGISTER_PIIX4 (PIIX4_PMBA);
diff --git a/OvmfPkg/Library/AcpiTimerLib/DxeAcpiTimerLib.inf b/OvmfPkg/Library/AcpiTimerLib/DxeAcpiTimerLib.inf
index e29872add3..9c364be886 100644
--- a/OvmfPkg/Library/AcpiTimerLib/DxeAcpiTimerLib.inf
+++ b/OvmfPkg/Library/AcpiTimerLib/DxeAcpiTimerLib.inf
@@ -26,10 +26,11 @@
   MdePkg/MdePkg.dec
   OvmfPkg/OvmfPkg.dec
 
-[Pcd]
-  gUefiOvmfPkgTokenSpaceGuid.PcdOvmfHostBridgePciDevId
-
 [LibraryClasses]
   BaseLib
   PciLib
   IoLib
+  HobLib
+
+[Guids]
+  gUefiOvmfPkgPlatformInfoGuid                      ## CONSUMES
-- 
2.39.5