From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mga09.intel.com (mga09.intel.com [134.134.136.24]) (using TLSv1 with cipher CAMELLIA256-SHA (256/256 bits)) (No client certificate requested) by ml01.01.org (Postfix) with ESMTPS id 3D5701A1E21 for ; Tue, 23 Aug 2016 19:39:37 -0700 (PDT) Received: from fmsmga002.fm.intel.com ([10.253.24.26]) by orsmga102.jf.intel.com with ESMTP; 23 Aug 2016 19:39:36 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.28,568,1464678000"; d="scan'208";a="1046231544" Received: from shzintpr02.sh.intel.com (HELO [10.253.24.26]) ([10.239.4.160]) by fmsmga002.fm.intel.com with ESMTP; 23 Aug 2016 19:39:35 -0700 To: Laszlo Ersek , "Fan, Jeff" , "edk2-devel@ml01.01.org" References: <1470128388-17960-1-git-send-email-jeff.fan@intel.com> <1470128388-17960-49-git-send-email-jeff.fan@intel.com> <4f61b2b4-eeb4-8435-412f-20848347c88e@redhat.com> <542CF652F8836A4AB8DBFAAD40ED192A143D9CFD@shsmsx102.ccr.corp.intel.com> <795dd4fe-cd16-c0f1-7f04-f78601e2c7a8@redhat.com> <82c6b5c9-dcab-f3c1-5ffe-20fb27ddb1af@intel.com> <6cd44902-8c07-8f76-1204-d79c85559ae5@intel.com> Cc: "Kinney, Michael D" , "Tian, Feng" From: "Zeng, Star" Message-ID: <7d39ce29-88ce-c5f2-af61-7fd964acb5c0@intel.com> Date: Wed, 24 Aug 2016 10:39:04 +0800 User-Agent: Mozilla/5.0 (Windows NT 6.3; WOW64; rv:45.0) Gecko/20100101 Thunderbird/45.2.0 MIME-Version: 1.0 In-Reply-To: Subject: Re: [Patch v5 48/48] UefiCpuPkg/PiSmmCpuDxeSmm: Add gEfiVariableArchProtocolGuid dependency X-BeenThere: edk2-devel@lists.01.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: EDK II Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 24 Aug 2016 02:39:37 -0000 Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit On 2016/8/23 23:33, Laszlo Ersek wrote: > On 08/18/16 22:57, Zeng, Star wrote: >> On 2016/8/19 10:45, Zeng, Star wrote: >>> On 2016/8/19 10:26, Laszlo Ersek wrote: >>>> On 08/19/16 04:00, Fan, Jeff wrote: >>>>> Laszlo, >>>>> >>>>> I could revert this patch firstly. >>>> >>>> Thank you, that would be very kind. >>>> >>>>> Could you please dig out the OVMF to address the potential issue, >>>>> then I could re-commit it for those platforms required this patch. >>>> >>>> The problem is that this week (what remains of it) and the next week >>>> I won't really have time for this -- tomorrow I'm hoping to finish >>>> up something else in a mortal hurry. It was actually in preparation >>>> for rebasing / pushing that work that I pulled "master", and found >>>> out about the regression. >>>> >>>> Can we perhaps get help from the variable stack maintainers? What's >>>> the design of the (lack of) depexes on those drivers? >>> >>> Variable driver consumes >>> PcdFlashNvStorageVariableBase(64)/PcdFlashNvStorageVariableSize to >>> produce *gEfiVariableArchProtocolGuid* protocol. Variable driver >>> registers (SMM)FTW protocol notification function >>> SmmFtwNotificationEvent() or FtwNotificationEvent() to produce >>> *gEfiVariableWriteArchProtocolGuid* protocol. (SMM)FTW driver has >>> dependency on gEfiSmmFirmwareVolumeBlockProtocolGuid or >>> gEfiFirmwareVolumeBlockProtocolGuid. >>> >>> I am not so sure what you said about the (lack of) depexes on those >>> drivers. >>> >>> Did you see variable driver loaded and started when ASSERT appeared >>> on OVMF? >> >> >> You may could compare the serial logs to get if there is some driver >> execution flow differences for the images built without and with this >> patch. > > The only difference is that in the working case, PiSmmCpuDxeSmm.efi is > dispatched immediately before FvbServicesSmm.efi, while in the broken > case, PiSmmCpuDxeSmm.efi is not dispatched (it is delayed due to the new > depex) and FvbServicesSmm.efi is dispatched without PiSmmCpuDxeSmm.efi > being present, and it breaks. > > I see that PiSmmCpuDxeSmm.efi installs: > - gEfiSmmConfigurationProtocolGuid, > - EfiSmmCpuProtocol, > - EfiSmmCpuServiceProtocol, > > so it might not be hard to add a depex on one of those (DXE/SMM) > protocols to FvbServicesSmm.efi. In particular, the PI 1.4a spec says in > Volume 4, "1.6.1 SMM Drivers": > > the dependency expression in the file section EFI_SECTION_SMM_DEPEX > [...] can refer to both UEFI and SMM protocols > > so we could easily make FvbServicesSmm.efi dependent on either of those > protocols, I think. > > However, is that the official way to delay the entry point function of a > DXE_SMM_DRIVER module until the code would actually run in SMM? Section > "1.7 SMM Driver Initialization" says: > > An SMM Driver's initialization phase begins when the driver has been > loaded into SMRAM and its entry point is called. An SMM Driver's > initialization phase ends when the entry point returns. > > During SMM Driver initialization, SMM Drivers have access to two > sets of protocols: UEFI and SMM. UEFI protocols are those which are > installed and discovered using the UEFI Boot Services. UEFI > protocols can be located and used by SMM drivers only during SMM > Initialization. SMM protocols are those which are installed and > discovered using the System Management Services Table (SMST). SMM > protocols can be discovered by SMM drivers during initialization > time and accessed while inside of SMM. > > These paragraphs seem to imply that the processor will execute the entry > point function of a DXE_SMM_DRIVER module from SMRAM, without the > processor necessarily being in SMM just yet. (Which further implies that > SMRAM will not have been closed and locked at that point, but that's a > side remark only.) > > This seems reasonable to me, but in the entry point of OVMF's > FvbServicesSmm.efi, we specifically need to test a write access to the > pflash chip, to make sure that the QEMU configuration is suitable and > secure. For this, FvbServicesSmm.efi must be dispatched in SMM. And, > apparently, in the current tree, when PiSmmCpuDxe launches first, > FvbServicesSmm *is* dispatched in SMM. > > I find it quite non-intuitive that a DXE_SMM_DRIVER's entry point may or > may not be executed in SMM, but more importantly, what's the best way to > delay the driver dispatch until after PiSmmCpuDxe has been dispatched? > > The PiSmmIpl driver (a DXE_RUNTIME_DRIVER) produces the > EFI_SMM_BASE2_PROTOCOL, which has a member function called InSmm(). > However: > > - according to the documentation, it doesn't test for SMM, it tests for > being executed from SMRAM (which are two different things!), and it > only really makes sense for SMM/DXE combined drivers, > > - in fact I don't need a query-like function here, for the code, but > likely a new depex for FvbServicesSmm that delays its dispatch until > after PiSmmCpuDxe. > > Actually, I think the simplest way to solve this in OVMF is to add a > depex on EFI_SMM_CPU_PROTOCOL to FvbServicesSmm. From the spec: > > Provides access to CPU-related information while in SMM. > > [...] > > This protocol allows SMM drivers to access architecture-standard > registers from any of the CPU save state areas. [...] > > I think a DXE_SMM_DRIVER might perfectly want to use this protocol in > its entry point function (in the general case, for whatever reason), so > it seems very suitable for delaying FvbServicesSmm. > > For example, in > "QuarkPlatformPkg/Acpi/DxeSmm/SmmPowerManagement/SmmPowerManagement.inf", > I think we see the same pattern: > - MODULE_TYPE = DXE_SMM_DRIVER > - Depex on gEfiSmmCpuProtocolGuid > > .... Okay, I tried to test this patch (in combination with re-adding the > gEfiVariableArchProtocolGuid dependency to PiSmmCpuDxeSmm): > >> diff --git a/OvmfPkg/QemuFlashFvbServicesRuntimeDxe/FvbServicesSmm.inf b/OvmfPkg/QemuFlashFvbServicesRuntimeDxe/FvbServicesSmm.inf >> index ba2d3679a46d..a241f7702ca2 100644 >> --- a/OvmfPkg/QemuFlashFvbServicesRuntimeDxe/FvbServicesSmm.inf >> +++ b/OvmfPkg/QemuFlashFvbServicesRuntimeDxe/FvbServicesSmm.inf >> @@ -88,4 +88,4 @@ [FeaturePcd] >> gUefiOvmfPkgTokenSpaceGuid.PcdSmmSmramRequire >> >> [Depex] >> - TRUE >> + gEfiSmmCpuProtocolGuid > > With this patch, in the build report I get: > >> Module Name: FvbServicesSmm >> Module INF Path: OvmfPkg/QemuFlashFvbServicesRuntimeDxe/FvbServicesSmm.inf >> >> [...] >> >>> ----------------------------------------------------------------------------------------------------------------------< >> Final Dependency Expression (DEPEX) Instructions >> PUSH gEfiSmmCpuProtocolGuid >> PUSH gEfiPcdProtocolGuid >> PUSH gEfiSmmBase2ProtocolGuid >> PUSH gEfiSmmAccess2ProtocolGuid >> PUSH gEfiDevicePathUtilitiesProtocolGuid >> AND >> AND >> AND >> AND >> END >> ------------------------------------------------------------------------------------------------------------------------ >> Dependency Expression (DEPEX) from INF >> (gEfiSmmCpuProtocolGuid) AND (gEfiPcdProtocolGuid) AND (gEfiSmmBase2ProtocolGuid) AND (gEfiSmmAccess2ProtocolGuid) AND >> (gEfiDevicePathUtilitiesProtocolGuid) >> ------------------------------------------------------------------------------------------------------------------------ >> From Module INF: gEfiSmmCpuProtocolGuid >> From Library INF: (gEfiPcdProtocolGuid) AND (gEfiSmmBase2ProtocolGuid) AND (gEfiSmmAccess2ProtocolGuid) AND >> (gEfiDevicePathUtilitiesProtocolGuid) >> <----------------------------------------------------------------------------------------------------------------------> > > and FvbServicesSmm *is* appropriately delayed. However, the variable > driver blows up: > >> Loading SMM driver at 0x0007FF7D000 EntryPoint=0x0007FF7D271 VariableSmm.efi >> mSmmMemLibInternalMaximumSupportAddress = 0xFFFFFFFFF >> VarCheckLibRegisterSetVariableCheckHandler - 0x7FF89334 Success >> Firmware Volume for Variable Store is corrupted >> >> ASSERT_EFI_ERROR (Status = Volume Corrupt) >> ASSERT MdeModulePkg/Universal/Variable/RuntimeDxe/VariableSmm.c(927): !EFI_ERROR (Status) > > This is the call tree that fails: > > VariableServiceInitialize() [MdeModulePkg/Universal/Variable/RuntimeDxe/VariableSmm.c] > VariableCommonInitialize() [MdeModulePkg/Universal/Variable/RuntimeDxe/Variable.c] > InitNonVolatileVariableStore() [MdeModulePkg/Universal/Variable/RuntimeDxe/Variable.c] > > However, the variable store is definitely not corrupted; this failure > reproduces with the pristine "OVMF_VARS.fd" varstore template that falls > right out of the OVMF build. I am not so clear about "the pristine "OVMF_VARS.fd" varstore template that falls right out of the OVMF build". Variable driver depends on PcdFlashNvStorageVariableBase(64) be set correctly to produce gEfiVariableArchProtocolGuid protocol. After PiSmmCpuDxeSmm adds gEfiVariableArchProtocolGuid dependency and FvbServicesSmm adds gEfiSmmCpuProtocolGuid dependency, there will be a dependency circle below. - PiSmmCpuDxeSmm depends on Variable driver to produce gEfiVariableArchProtocolGuid protocol. - FvbServicesSmm depends on PiSmmCpuDxeSmm to produce gEfiSmmCpuProtocolGuid protocol. - Variable driver depends on FvbServicesSmm to set PcdFlashNvStorageVariableBase(64) PCD. Are below approaches possible in OVMF? 1. Do InitializeVariableFvHeader () and PcdFlashNvStorageVariableBase(64) PCD set at PEI phase. 2. Do InitializeVariableFvHeader () and PcdFlashNvStorageVariableBase(64) PCD set in entrypoint with dependency = TRUE, and do other part of code in FvbInitialize() in another gEfiSmmCpuProtocolGuid notification function? Thanks, Star > > Thanks! > Laszlo > >