Re: [edk2-devel] [Patch V2] MinPlatformPkg: Check if Acpi table is already installed.

["Nate DeSimone" <nathaniel.l.desimone@intel.com>]

Hi Ray,

Since UefiPayloadPkg is in edk2, and MinPlatformPkg is in edk2-platforms, UefiPayloadPkg should not have any dependencies on MinPlatformPkg. Therefore, I don't see how that is relevant.

Thanks,
Nate

-----Original Message-----
From: Ni, Ray <ray.ni@intel.com> 
Sent: Tuesday, December 7, 2021 10:42 PM
To: devel@edk2.groups.io; Desimone, Nathaniel L <nathaniel.l.desimone@intel.com>; Sravanthi, K KavyaX <k.kavyax.sravanthi@intel.com>
Cc: Chiu, Chasel <chasel.chiu@intel.com>; Liming Gao <gaoliming@byosoft.com.cn>; Dong, Eric <eric.dong@intel.com>; Oram, Isaac W <isaac.w.oram@intel.com>; Michael Kubacki <michael.kubacki@microsoft.com>
Subject: RE: [edk2-devel] [Patch V2] MinPlatformPkg: Check if Acpi table is already installed.

Nate,
I don't consider it as a hack. UefiPayloadPkg requires that bootloader produces all ACPI tables.
Now we are in a middle stage. So, only the MCFG and FADT are produced (as gUniversalPayloadAcpiTableGuid HOB) in PEI phase.

Thanks,
Ray


-----Original Message-----
From: devel@edk2.groups.io <devel@edk2.groups.io> On Behalf Of Nate DeSimone
Sent: Wednesday, December 8, 2021 10:06 AM
To: Sravanthi, K KavyaX <k.kavyax.sravanthi@intel.com>; devel@edk2.groups.io
Cc: Chiu, Chasel <chasel.chiu@intel.com>; Liming Gao <gaoliming@byosoft.com.cn>; Dong, Eric <eric.dong@intel.com>; Oram, Isaac W <isaac.w.oram@intel.com>; Michael Kubacki <michael.kubacki@microsoft.com>
Subject: Re: [edk2-devel] [Patch V2] MinPlatformPkg: Check if Acpi table is already installed.

This seems like a hack to me. One of the major goals of the Minimum Platform Architecture is consistency. A board override for the MinPlatform provided installation of the MCFG table runs counter to that goal. Every field in the MCFG table produced by MinPlatform's implementation is fully customizable by board code via the PciSegmentInfoLib's GetPciSegmentInfo() function. If a multi-segment MCFG table is needed, then all the board needs to do is choose a different implementation of PciSegmentInfoLib than the default one (MinPlatformPkg\Pci\Library\PciSegmentInfoLibSimple\PciSegmentInfoLibSimple.inf)

I cannot conceive of any reason why a board override of this functionality is required. Why do you need this? 

-----Original Message-----
From: Sravanthi, K KavyaX <k.kavyax.sravanthi@intel.com> 
Sent: Sunday, December 5, 2021 10:16 PM
To: devel@edk2.groups.io
Cc: Sravanthi, K KavyaX <k.kavyax.sravanthi@intel.com>; Chiu, Chasel <chasel.chiu@intel.com>; Desimone, Nathaniel L <nathaniel.l.desimone@intel.com>; Liming Gao <gaoliming@byosoft.com.cn>; Dong, Eric <eric.dong@intel.com>
Subject: [Patch V2] MinPlatformPkg: Check if Acpi table is already installed.

Check if Acpi table is already installed by locating the first ACPI table in XSDT/RSDT based on Signature

Cc: Chasel Chiu <chasel.chiu@intel.com>
Cc: Nate DeSimone <nathaniel.l.desimone@intel.com>
Cc: Liming Gao <gaoliming@byosoft.com.cn>
Cc: Eric Dong <eric.dong@intel.com>
Signed-off-by: kavya <k.kavyax.sravanthi@intel.com>
Reviewed-by: Zhiguang Liu <zhiguang.liu@intel.com>
---
 Platform/Intel/MinPlatformPkg/Acpi/AcpiTables/AcpiPlatform.c | 18 ++++++++++++++++++
 1 file changed, 18 insertions(+)

diff --git a/Platform/Intel/MinPlatformPkg/Acpi/AcpiTables/AcpiPlatform.c b/Platform/Intel/MinPlatformPkg/Acpi/AcpiTables/AcpiPlatform.c
index 785cf4c2f9..dcbb8b7c7f 100644
--- a/Platform/Intel/MinPlatformPkg/Acpi/AcpiTables/AcpiPlatform.c
+++ b/Platform/Intel/MinPlatformPkg/Acpi/AcpiTables/AcpiPlatform.c
@@ -1048,12 +1048,21 @@ InstallMcfgFromScratch (  {
   EFI_STATUS                                                                            Status;
   EFI_ACPI_MEMORY_MAPPED_CONFIGURATION_BASE_ADDRESS_TABLE_HEADER                        *McfgTable;
+  EFI_ACPI_COMMON_HEADER                                                                *Mcfg;
   EFI_ACPI_MEMORY_MAPPED_ENHANCED_CONFIGURATION_SPACE_BASE_ADDRESS_ALLOCATION_STRUCTURE *Segment;
   UINTN                                                                                 Index;
   UINTN                                                                                 SegmentCount;
   PCI_SEGMENT_INFO                                                                      *PciSegmentInfo;
   UINTN                                                                                 TableHandle;
 
+  Mcfg = (EFI_ACPI_COMMON_HEADER *) EfiLocateFirstAcpiTable (
+                                      EFI_ACPI_3_0_PCI_EXPRESS_MEMORY_MAPPED_CONFIGURATION_SPACE_BASE_ADDRESS_DESCRIPTION_TABLE_SIGNATURE
+                                      );  if (Mcfg != NULL) {
+    DEBUG ((DEBUG_INFO, "MCFG table already installed\n"));
+    return EFI_SUCCESS;
+  }
+
   PciSegmentInfo = GetPciSegmentInfo (&SegmentCount);
 
   McfgTable = AllocateZeroPool (
@@ -1365,6 +1374,7 @@ UpdateLocalTable (  {
   EFI_STATUS                    Status;
   EFI_ACPI_COMMON_HEADER        *CurrentTable;
+  EFI_ACPI_COMMON_HEADER        *Table;
   EFI_ACPI_TABLE_VERSION        Version;
   UINTN                         TableHandle;
   UINTN                         Index;
@@ -1372,6 +1382,14 @@ UpdateLocalTable (
   for (Index = 0; Index < sizeof(mLocalTable)/sizeof(mLocalTable[0]); Index++) {
     CurrentTable = mLocalTable[Index];
 
+    Table = (EFI_ACPI_COMMON_HEADER *) EfiLocateFirstAcpiTable (CurrentTable->Signature);
+    if (Table != NULL) {
+      DEBUG ((DEBUG_INFO, "Acpi table with signature=%c%c%c%c already installed\n",
+            ((CHAR8*)&CurrentTable->Signature)[0], ((CHAR8*)&CurrentTable->Signature)[1],
+            ((CHAR8*)&CurrentTable->Signature)[2], ((CHAR8*)&CurrentTable->Signature)[3]));
+      continue;
+    }
+
     PlatformUpdateTables (CurrentTable, &Version);
 
     TableHandle = 0;
--
2.16.2.windows.1