[PATCH V3 7/8] OvmfPkg: Update DxeAcpiTimerLib to read HostBridgeDevId in PlatformInfoHob

["Min Xu" <min.m.xu@intel.com>]

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.

Here is the summary:
 - For boot without Pei phase, HostBridgeDevId is set in PlatformInfoHob.
 - For boot with Pei phase, HostBridgeDevId is set in
   PcdOvmfHostBridgePciDevId.

As the first stage DxeAcpiTimerLib first checks PlatformInfoHob then
the PcdOvmfHostBridgePciDevId. We will revisit here after HostBridgeDevId
is uniformly set in PlatformInfoHob.

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>
Signed-off-by: Min Xu <min.m.xu@intel.com>
---
 .../Library/AcpiTimerLib/DxeAcpiTimerLib.c    | 23 ++++++++++++++++---
 .../Library/AcpiTimerLib/DxeAcpiTimerLib.inf  |  4 ++++
 2 files changed, 24 insertions(+), 3 deletions(-)

diff --git a/OvmfPkg/Library/AcpiTimerLib/DxeAcpiTimerLib.c b/OvmfPkg/Library/AcpiTimerLib/DxeAcpiTimerLib.c
index 115846187455..71c8d75200bb 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 +42,24 @@ AcpiTimerLibConstructor (
   VOID
   )
 {
-  UINT16  HostBridgeDevId;
-  UINTN   Pmba;
+  UINT16                 HostBridgeDevId;
+  UINTN                  Pmba;
+  EFI_HOB_GUID_TYPE      *GuidHob;
+  EFI_HOB_PLATFORM_INFO  *PlatformInfo = 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 (&gUefiOvmfPkgTdxPlatformGuid);
+  if (GuidHob != NULL) {
+    PlatformInfo    = (EFI_HOB_PLATFORM_INFO *)GET_GUID_HOB_DATA (GuidHob);
+    HostBridgeDevId = PlatformInfo->HostBridgePciDevId;
+  } else {
+    HostBridgeDevId = PcdGet16 (PcdOvmfHostBridgePciDevId);
+  }
+
   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 e29872add3c7..44a4423a9ddd 100644
--- a/OvmfPkg/Library/AcpiTimerLib/DxeAcpiTimerLib.inf
+++ b/OvmfPkg/Library/AcpiTimerLib/DxeAcpiTimerLib.inf
@@ -33,3 +33,7 @@
   BaseLib
   PciLib
   IoLib
+  HobLib
+
+[Guids]
+  gUefiOvmfPkgTdxPlatformGuid                      ## CONSUMES
-- 
2.29.2.windows.2