Laszlo: > -----Original Message----- > From: devel@edk2.groups.io [mailto:devel@edk2.groups.io] On Behalf Of Laszlo > Ersek > Sent: Friday, August 16, 2019 11:18 PM > To: Gao, Liming <liming....@intel.com>; devel@edk2.groups.io; Kinney, Michael > D <michael.d.kin...@intel.com> > Cc: Mike Turner <mike...@microsoft.com>; Wang, Jian J > <jian.j.w...@intel.com>; Wu, Hao A <hao.a...@intel.com>; Bi, Dandan > <dandan...@intel.com> > Subject: Re: [edk2-devel] [Patch] MdeModulePkg DxeCore: Fix for missing MAT > update > > On 08/14/19 17:55, Gao, Liming wrote: > > > If Platform PEIM doesn't build HOB, DxeIpl will not build HOB, > > My reading of the code is the opposite. If the platform PEIM does not build > the HOB, then the DXE IPL PEIM will attempt to build the HOB, > from the UEFI variable. > > At commit caa7d3a896f6, in file "MdeModulePkg/Core/DxeIplPeim/DxeLoad.c", > function DxeLoadCore(), we have: > > 363 if (GetFirstGuidHob ((CONST EFI_GUID > *)&gEfiMemoryTypeInformationGuid) == NULL) { > 364 // > 365 // Don't build GuidHob if GuidHob has been installed. > 366 // > 367 Status = PeiServicesLocatePpi ( > 368 &gEfiPeiReadOnlyVariable2PpiGuid, > 369 0, > 370 NULL, > 371 (VOID **)&Variable > 372 ); > 373 if (!EFI_ERROR (Status)) { > 374 DataSize = sizeof (MemoryData); > 375 Status = Variable->GetVariable ( > 376 Variable, > 377 EFI_MEMORY_TYPE_INFORMATION_VARIABLE_NAME, > 378 &gEfiMemoryTypeInformationGuid, > 379 NULL, > 380 &DataSize, > 381 &MemoryData > 382 ); > 383 if (!EFI_ERROR (Status) && > ValidateMemoryTypeInfoVariable(MemoryData, DataSize)) {
Only when this variable exists, Hob will be built. But, if no PEIM builds Hob, BDS will not set the variable. So, there is still no HOB. Thanks Liming > 384 // > 385 // Build the GUID'd HOB for DXE > 386 // > 387 BuildGuidDataHob ( > 388 &gEfiMemoryTypeInformationGuid, > 389 MemoryData, > 390 DataSize > 391 ); > 392 } > 393 } > 394 } > > Thanks > Laszlo > > -=-=-=-=-=-=-=-=-=-=-=- Groups.io Links: You receive all messages sent to this group. View/Reply Online (#45821): https://edk2.groups.io/g/devel/message/45821 Mute This Topic: https://groups.io/mt/32821535/21656 Group Owner: devel+ow...@edk2.groups.io Unsubscribe: https://edk2.groups.io/g/devel/unsub [arch...@mail-archive.com] -=-=-=-=-=-=-=-=-=-=-=-
