AcpiPlatform: use GUIDed HOBs for VMM-provided ACPI tables

MsvmPkg/AcpiPlatformDxe/AcpiPlatformDxe.inf

@@ -37,13 +37,17 @@
     CrashLib
     DebugLib
     DxeServicesLib
+    HobLib
     IoLib
     IsolationLib
     PcdLib
     UefiBootServicesTableLib
     UefiDriverEntryPoint
     UefiLib
 
+[Guids]
+    gAcpiReplacementTableHobGuid                      ## CONSUMES
+
 [Protocols]
     gEfiAcpiTableProtocolGuid                     ## CONSUMES
 
@@ -53,8 +57,6 @@
     gEfiMdePkgTokenSpaceGuid.PcdUartDefaultBaudRate             ## CONSUMES
     gEfiMdePkgTokenSpaceGuid.PcdUartDefaultParity               ## CONSUMES
     gEfiMdePkgTokenSpaceGuid.PcdUartDefaultStopBits             ## CONSUMES
-    gMsvmPkgTokenSpaceGuid.PcdAcpiTablePtr                      ## CONSUMES
-    gMsvmPkgTokenSpaceGuid.PcdAcpiTableSize                     ## CONSUMES
     gMsvmPkgTokenSpaceGuid.PcdBiosBaseAddress                   ## CONSUMES
     gMsvmPkgTokenSpaceGuid.PcdCom1RegisterBase                  ## CONSUMES
     gMsvmPkgTokenSpaceGuid.PcdCom1Vector                        ## CONSUMES
@@ -73,34 +75,18 @@
     gMsvmPkgTokenSpaceGuid.PcdLowPowerS0IdleEnabled             ## CONSUMES
     gMsvmPkgTokenSpaceGuid.PcdMadtPtr                           ## CONSUMES
     gMsvmPkgTokenSpaceGuid.PcdMadtSize                          ## CONSUMES
-    gMsvmPkgTokenSpaceGuid.PcdMcfgPtr                           ## CONSUMES
-    gMsvmPkgTokenSpaceGuid.PcdMcfgSize                          ## CONSUMES
-    gMsvmPkgTokenSpaceGuid.PcdSsdtPtr                           ## CONSUMES
-    gMsvmPkgTokenSpaceGuid.PcdSsdtSize                          ## CONSUMES
-    gMsvmPkgTokenSpaceGuid.PcdIortPtr                           ## CONSUMES
-    gMsvmPkgTokenSpaceGuid.PcdIortSize                          ## CONSUMES
     gMsvmPkgTokenSpaceGuid.PcdNvdimmCount                       ## CONSUMES
-    gMsvmPkgTokenSpaceGuid.PcdPpttPtr                           ## CONSUMES
-    gMsvmPkgTokenSpaceGuid.PcdPpttSize                          ## CONSUMES
     gMsvmPkgTokenSpaceGuid.PcdProcessorCount                    ## CONSUMES
     gMsvmPkgTokenSpaceGuid.PcdProcIdleEnabled                   ## CONSUMES
     gMsvmPkgTokenSpaceGuid.PcdCxlMemoryEnabled                  ## CONSUMES
     gMsvmPkgTokenSpaceGuid.PcdSerialControllersEnabled          ## CONSUMES
     gMsvmPkgTokenSpaceGuid.PcdSgxMemoryEnabled                  ## CONSUMES
-    gMsvmPkgTokenSpaceGuid.PcdSlitPtr                           ## CONSUMES
-    gMsvmPkgTokenSpaceGuid.PcdSlitSize                          ## CONSUMES
-    gMsvmPkgTokenSpaceGuid.PcdSratPtr                           ## CONSUMES
-    gMsvmPkgTokenSpaceGuid.PcdSratSize                          ## CONSUMES
-    gMsvmPkgTokenSpaceGuid.PcdHmatPtr                           ## CONSUMES
-    gMsvmPkgTokenSpaceGuid.PcdHmatSize                          ## CONSUMES
     gMsvmPkgTokenSpaceGuid.PcdTpmEnabled                        ## CONSUMES
     gMsvmPkgTokenSpaceGuid.PcdVirtualBatteryEnabled             ## CONSUMES
     gMsvmPkgTokenSpaceGuid.PcdWatchdogEnabled                   ## CONSUMES
 
 [Pcd.X64]
     gMsvmPkgTokenSpaceGuid.PcdAcpiMadtMpMailBoxAddress          ## PRODUCES
-    gMsvmPkgTokenSpaceGuid.PcdAsptPtr                           ## CONSUMES
-    gMsvmPkgTokenSpaceGuid.PcdAsptSize                          ## CONSUMES
 
 [Depex]
     gEfiAcpiTableProtocolGuid

MsvmPkg/Include/AcpiReplacementTable.h

@@ -0,0 +1,95 @@
+/** @file
+  Shared definitions for VMM-provided ACPI table replacements passed via HOBs.
+
+  Copyright (c) Microsoft Corporation.
+  SPDX-License-Identifier: BSD-2-Clause-Patent
+
+**/
+
+#pragma once
+
+#include <Uefi.h>
+#include <Library/HobLib.h>
+#include <IndustryStandard/Acpi.h>
+
+//
+// GUID used to identify ACPI replacement table HOBs.
+// Each HOB with this GUID contains an ACPI_REPLACEMENT_TABLE_HOB_DATA
+// structure that points to a complete ACPI table (starting with
+// EFI_ACPI_DESCRIPTION_HEADER) in persistent memory. When an ACPI table from
+// the firmware volume has the same signature as a replacement table HOB, the
+// FV table is suppressed and the HOB-referenced table is installed instead.
+//
+#define ACPI_REPLACEMENT_TABLE_HOB_GUID \
+  { 0xa24aef4c, 0xa824, 0x48e9, { 0xb5, 0xb8, 0xbc, 0xd9, 0x6a, 0x59, 0x71, 0xaf } }
+
+extern EFI_GUID gAcpiReplacementTableHobGuid;
+
+//
+// HOB payload: pointer to an ACPI table in persistent memory.
+//
+typedef struct {
+    EFI_ACPI_DESCRIPTION_HEADER *Table;
+} ACPI_REPLACEMENT_TABLE_HOB_DATA;
+
+//
+// Helper: get the ACPI table header from a replacement table HOB.
+// HobRaw must point to a valid GUIDed HOB with gAcpiReplacementTableHobGuid.
+//
+static inline EFI_ACPI_DESCRIPTION_HEADER *
+AcpiReplacementTableFromHob(
+    IN VOID *HobRaw
+    )
+{
+    EFI_HOB_GUID_TYPE *GuidHob = (EFI_HOB_GUID_TYPE *)HobRaw;
+    ACPI_REPLACEMENT_TABLE_HOB_DATA *Data =
+        (ACPI_REPLACEMENT_TABLE_HOB_DATA *)GET_GUID_HOB_DATA(GuidHob);
+    return Data->Table;
+}
+
+//
+// Helper: get the first replacement table HOB, returning the raw HOB pointer.
+// Returns NULL if none exist. Use with AcpiReplacementTableFromHob() and
+// GetNextAcpiReplacementTableHob() to iterate.
+//
+static inline VOID *
+GetFirstAcpiReplacementTableHob(
+    VOID
+    )
+{
+    return GetFirstGuidHob(&gAcpiReplacementTableHobGuid);
+}
+
+//
+// Helper: get the next replacement table HOB after CurrentHob.
+// Returns NULL if no more exist.
+//
+static inline VOID *
+GetNextAcpiReplacementTableHob(
+    IN VOID *CurrentHob
+    )
+{
+    return GetNextGuidHob(&gAcpiReplacementTableHobGuid, GET_NEXT_HOB(CurrentHob));
+}
+
+//
+// Helper: find the first replacement table matching a given ACPI signature.
+// Returns the table header pointer, or NULL if not found.
+//
+static inline EFI_ACPI_DESCRIPTION_HEADER *
+FindAcpiReplacementTable(
+    IN UINT32 Signature
+    )
+{
+    VOID *Hob = GetFirstAcpiReplacementTableHob();
+    while (Hob != NULL)
+    {
+        EFI_ACPI_DESCRIPTION_HEADER *Table = AcpiReplacementTableFromHob(Hob);
+        if (Table->Signature == Signature)
+        {
+            return Table;
+        }
+        Hob = GetNextAcpiReplacementTableHob(Hob);
+    }
+    return NULL;
+}

MsvmPkg/Library/PciHostBridgeLib/PciHostBridgeLib.c

@@ -1,8 +1,8 @@
 /** @file
   Platform PCI Host Bridge Library for Hyper-V Gen2 VMs.
 
-  Reads MCFG + PcieBarApertures from config blob PCDs and returns
-  a PCI_ROOT_BRIDGE array for PciHostBridgeDxe.
+  Reads MCFG from the ACPI replacement table HOB + PcieBarApertures from
+  config blob PCDs and returns a PCI_ROOT_BRIDGE array for PciHostBridgeDxe.
 
   Copyright (c) Microsoft Corporation.
   SPDX-License-Identifier: BSD-2-Clause-Patent
@@ -12,13 +12,15 @@
 #include <Library/BaseMemoryLib.h>
 #include <Library/DebugLib.h>
 #include <Library/DevicePathLib.h>
+#include <Library/HobLib.h>
 #include <Library/MemoryAllocationLib.h>
 #include <Library/PcdLib.h>
 #include <Library/PciHostBridgeLib.h>
 #include <Protocol/PciRootBridgeIo.h>
 #include <Protocol/PciHostBridgeResourceAllocation.h>
 #include <IndustryStandard/Acpi.h>
 #include <IndustryStandard/MemoryMappedConfigurationSpaceAccessTable.h>
+#include <AcpiReplacementTable.h>
 #include <BiosInterface.h>
 #include <PciConstants.h>
 
@@ -62,9 +64,6 @@ PciHostBridgeGetRootBridges (
     OUT UINTN  *Count
     )
 {
-    UINT64                       McfgPtr;
-    UINT32                       McfgSize;
-    MCFG_TABLE_HEADER            *McfgHdr;
     UINT32                       McfgDataLen;
     UINT32                       McfgEntryCount;
     MCFG_ALLOCATION_ENTRY        *McfgEntries;
@@ -80,27 +79,18 @@ PciHostBridgeGetRootBridges (
     *Count = 0;
 
     //
-    // Read MCFG from PCD.
+    // Find MCFG table from HOB list.
     //
-    McfgPtr  = PcdGet64 (PcdMcfgPtr);
-    McfgSize = PcdGet32 (PcdMcfgSize);
+    MCFG_TABLE_HEADER *McfgHdr = (MCFG_TABLE_HEADER *)FindAcpiReplacementTable(
+        EFI_ACPI_6_2_PCI_EXPRESS_MEMORY_MAPPED_CONFIGURATION_SPACE_BASE_ADDRESS_DESCRIPTION_TABLE_SIGNATURE);
 
-    DEBUG ((DEBUG_VERBOSE, "PCIe: PciHostBridgeLib McfgPtr=0x%lx McfgSize=%u\n", McfgPtr, McfgSize));
+    DEBUG ((DEBUG_VERBOSE, "PCIe: PciHostBridgeLib McfgHdr=%p\n", McfgHdr));
 
-    if (McfgPtr == 0 || McfgSize < sizeof (MCFG_TABLE_HEADER)) {
+    if (McfgHdr == NULL || McfgHdr->Header.Length < sizeof(MCFG_TABLE_HEADER)) {
         DEBUG ((DEBUG_INFO, "PCIe: No MCFG table, no root bridges\n"));
         return NULL;
     }
 
-    McfgHdr = (MCFG_TABLE_HEADER *)(UINTN)McfgPtr;
-
-    if (McfgHdr->Header.Length < sizeof (MCFG_TABLE_HEADER) ||
-        McfgHdr->Header.Length > McfgSize) {
-        DEBUG ((DEBUG_ERROR, "PCIe: Invalid MCFG Length %u (PCD size %u)\n",
-                McfgHdr->Header.Length, McfgSize));
-        return NULL;
-    }
-
     McfgDataLen = McfgHdr->Header.Length - sizeof (MCFG_TABLE_HEADER);
     McfgEntryCount = McfgDataLen / sizeof (MCFG_ALLOCATION_ENTRY);
 

MsvmPkg/Library/PciHostBridgeLib/PciHostBridgeLib.inf

@@ -25,12 +25,14 @@
 [LibraryClasses]
   BaseMemoryLib
   DebugLib
+  HobLib
   PcdLib
   MemoryAllocationLib
   DevicePathLib
 
 [Pcd]
-  gMsvmPkgTokenSpaceGuid.PcdMcfgPtr
-  gMsvmPkgTokenSpaceGuid.PcdMcfgSize
   gMsvmPkgTokenSpaceGuid.PcdPcieBarAperturesPtr
   gMsvmPkgTokenSpaceGuid.PcdPcieBarAperturesSize
+
+[Guids]
+  gAcpiReplacementTableHobGuid

MsvmPkg/Library/PciSegmentInfoLib/PciSegmentInfoLib.c

@@ -1,7 +1,7 @@
 /** @file
   Platform PCI Segment Info Library for Hyper-V Gen2 VMs.
 
-  Reads MCFG from config blob PCD and provides segment-to-ECAM-base
+  Reads MCFG from the ACPI replacement table HOB and provides segment-to-ECAM-base
   mapping for BasePciSegmentLibSegmentInfo.
 
   Copyright (c) Microsoft Corporation.
@@ -11,11 +11,12 @@
 #include <PiDxe.h>
 #include <Library/BaseMemoryLib.h>
 #include <Library/DebugLib.h>
+#include <Library/HobLib.h>
 #include <Library/MemoryAllocationLib.h>
-#include <Library/PcdLib.h>
 #include <Library/PciSegmentInfoLib.h>
 #include <IndustryStandard/Acpi.h>
 #include <IndustryStandard/MemoryMappedConfigurationSpaceAccessTable.h>
+#include <AcpiReplacementTable.h>
 #include <PciConstants.h>
 
 STATIC
@@ -34,9 +35,6 @@ GetPciSegmentInfo (
     OUT UINTN  *Count
     )
 {
-    UINT64                       McfgPtr;
-    UINT32                       McfgSize;
-    MCFG_TABLE_HEADER            *McfgHdr;
     UINT32                       DataLen;
     UINT32                       EntryCount;
     MCFG_ALLOCATION_ENTRY        *Entries;
@@ -48,23 +46,13 @@ GetPciSegmentInfo (
     }
 
     //
-    // Parse MCFG table from PCD (same data PlatformPei extracted from config blob).
+    // Find MCFG table from HOB list.
     //
-    McfgPtr  = PcdGet64 (PcdMcfgPtr);
-    McfgSize = PcdGet32 (PcdMcfgSize);
+    MCFG_TABLE_HEADER *McfgHdr = (MCFG_TABLE_HEADER *)FindAcpiReplacementTable(
+        EFI_ACPI_6_2_PCI_EXPRESS_MEMORY_MAPPED_CONFIGURATION_SPACE_BASE_ADDRESS_DESCRIPTION_TABLE_SIGNATURE);
 
-    if (McfgPtr == 0 || McfgSize < sizeof (MCFG_TABLE_HEADER)) {
-        DEBUG ((DEBUG_INFO, "PCIe: PciSegmentInfoLib: No MCFG table\n"));
-        *Count = 0;
-        return NULL;
-    }
-
-    McfgHdr = (MCFG_TABLE_HEADER *)(UINTN)McfgPtr;
-
-    if (McfgHdr->Header.Length < sizeof (MCFG_TABLE_HEADER) ||
-        McfgHdr->Header.Length > McfgSize) {
-        DEBUG ((DEBUG_ERROR, "PCIe: PciSegmentInfoLib: Invalid MCFG Length %u (PCD size %u)\n",
-                McfgHdr->Header.Length, McfgSize));
+    if (McfgHdr == NULL || McfgHdr->Header.Length < sizeof(MCFG_TABLE_HEADER)) {
+        DEBUG ((DEBUG_INFO, "PCIe: PciSegmentInfoLib: No MCFG table in HOBs\n"));
         *Count = 0;
         return NULL;
     }

MsvmPkg/Library/PciSegmentInfoLib/PciSegmentInfoLib.inf

@@ -24,9 +24,8 @@
 [LibraryClasses]
   BaseMemoryLib
   DebugLib
-  PcdLib
+  HobLib
   MemoryAllocationLib
 
-[Pcd]
-  gMsvmPkgTokenSpaceGuid.PcdMcfgPtr
-  gMsvmPkgTokenSpaceGuid.PcdMcfgSize
+[Guids]
+  gAcpiReplacementTableHobGuid

MsvmPkg/MsvmPkg.dec

@@ -41,6 +41,11 @@
   gSyntheticVmbfsClassGuid        = {0xc376c1c3, 0xd276, 0x48d2, {0x90, 0xa9, 0xc0, 0x47, 0x48, 0x07, 0x2c, 0x60}}
   gSyntheticVpciClassGuid         = {0x44c4f61d, 0x4444, 0x4400, {0x9d, 0x52, 0x80, 0x2e, 0x27, 0xed, 0xe1, 0x9f}}
 
+  #
+  # HOB GUID for VMM-provided ACPI table replacements
+  #
+  gAcpiReplacementTableHobGuid    = {0xa24aef4c, 0xa824, 0x48e9, {0xb5, 0xb8, 0xbc, 0xd9, 0x6a, 0x59, 0x71, 0xaf}}
+
   #
   # MsvmPkg specific events
   #