From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [216.205.24.124]) by mx.groups.io with SMTP id smtpd.web08.12758.1609958795606610171 for ; Wed, 06 Jan 2021 10:46:35 -0800 Authentication-Results: mx.groups.io; dkim=pass header.i=@redhat.com header.s=mimecast20190719 header.b=ibYWHlbp; spf=pass (domain: redhat.com, ip: 216.205.24.124, mailfrom: lersek@redhat.com) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1609958794; h=from:from:reply-to:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=K5rty6MK5F9lCX1vQ9CB4xsfy91Eedn20cjs+iUV4FE=; b=ibYWHlbpcqNZePWtXmy82TzEU0bWDnJCw2JNMM5KgiFXmoSWCIG4GK3P3TKG0GyBo4EVwm TBKrV8eX+EVhkX4y7PUpte3Gac/c3wSWtQqQoYB8azpmUMo8a9DPEPdMCb7yExuWLsl2uV gvo5k8BTvXw+ufWaT3jVaZES/OB33dA= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-293-AUNOuqCqOYCunfium2N2FA-1; Wed, 06 Jan 2021 13:46:31 -0500 X-MC-Unique: AUNOuqCqOYCunfium2N2FA-1 Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.11]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 4A03C800D55; Wed, 6 Jan 2021 18:46:30 +0000 (UTC) Received: from lacos-laptop-7.usersys.redhat.com (ovpn-113-198.ams2.redhat.com [10.36.113.198]) by smtp.corp.redhat.com (Postfix) with ESMTP id 1907B18AD4; Wed, 6 Jan 2021 18:46:28 +0000 (UTC) Subject: Re: [edk2-devel] [PATCH V2] UefiCpuPkg PiSmmCpuDxeSmm: Reduce SMRAM consumption in CpuS3.c From: "Laszlo Ersek" To: devel@edk2.groups.io, star.zeng@intel.com Cc: Ray Ni , Eric Dong Reply-To: devel@edk2.groups.io, lersek@redhat.com References: <20210106064825.18984-1-star.zeng@intel.com> Message-ID: <4bfa073a-4ddb-7fd7-a4c3-ef20b3807f50@redhat.com> Date: Wed, 6 Jan 2021 19:46:28 +0100 MIME-Version: 1.0 In-Reply-To: X-Scanned-By: MIMEDefang 2.79 on 10.5.11.11 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=lersek@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit On 01/06/21 18:56, Laszlo Ersek wrote: > On 01/06/21 07:48, Zeng, Star wrote: >> This patch makes two refinements to reduce SMRAM consumption in CpuS3.c. >> 1. Only do CopyRegisterTable() when register table is not empty, >> IsRegisterTableEmpty() is created to check whether the register table >> is empty or not. >> >> Take empty PreSmmInitRegisterTable as example, about 24K SMRAM consumption >> could be reduced when mAcpiCpuData.NumberOfCpus=1024. >> sizeof (CPU_REGISTER_TABLE) = 24 >> mAcpiCpuData.NumberOfCpus = 1024 = 1K >> mAcpiCpuData.NumberOfCpus * sizeof (CPU_REGISTER_TABLE) = 24K >> >> 2. Only copy table entries buffer instead of whole buffer. >> AllocatedSize in SourceRegisterTableList is the whole buffer size. >> Actually, only the table entries buffer needs to be copied, and the size >> is TableLength * sizeof (CPU_REGISTER_TABLE_ENTRY). >> >> Take AllocatedSize=0x1000=4096, TableLength=100 and NumberOfCpus=1024 as example, >> about 1696K SMRAM consumption could be reduced. >> sizeof (CPU_REGISTER_TABLE_ENTRY) = 24 >> TableLength = 100 >> TableLength * sizeof (CPU_REGISTER_TABLE_ENTRY) = 2400 >> AllocatedSize = 0x1000 = 4096 >> AllocatedSize - TableLength * sizeof (CPU_REGISTER_TABLE_ENTRY) = 4096 - 2400 = 1696 >> NumberOfCpus = 1024 = 1K >> NumberOfCpus * (AllocatedSize - TableLength * sizeof (CPU_REGISTER_TABLE_ENTRY)) = 1696K >> >> This patch also corrects the CopyRegisterTable() function description. >> >> Signed-off-by: Star Zeng >> Cc: Ray Ni >> Cc: Eric Dong >> Cc: Laszlo Ersek >> --- >> UefiCpuPkg/PiSmmCpuDxeSmm/CpuS3.c | 71 +++++++++++++++++++++++-------- >> 1 file changed, 54 insertions(+), 17 deletions(-) >> >> diff --git a/UefiCpuPkg/PiSmmCpuDxeSmm/CpuS3.c b/UefiCpuPkg/PiSmmCpuDxeSmm/CpuS3.c >> index 9592430636ec..9b1f952c8a74 100644 >> --- a/UefiCpuPkg/PiSmmCpuDxeSmm/CpuS3.c >> +++ b/UefiCpuPkg/PiSmmCpuDxeSmm/CpuS3.c >> @@ -1,7 +1,7 @@ >> /** @file >> Code for Processor S3 restoration >> >> -Copyright (c) 2006 - 2020, Intel Corporation. All rights reserved.
>> +Copyright (c) 2006 - 2021, Intel Corporation. All rights reserved.
>> SPDX-License-Identifier: BSD-2-Clause-Patent >> >> **/ >> @@ -487,6 +487,9 @@ SetRegister ( >> } else { >> RegisterTables = (CPU_REGISTER_TABLE *)(UINTN)mAcpiCpuData.RegisterTable; >> } >> + if (RegisterTables == NULL) { >> + return; >> + } >> >> InitApicId = GetInitialApicId (); >> RegisterTable = NULL; >> @@ -948,7 +951,7 @@ InitSmmS3ResumeState ( >> } >> >> /** >> - Copy register table from ACPI NVS memory into SMRAM. >> + Copy register table from non-SMRAM into SMRAM. >> >> @param[in] DestinationRegisterTableList Points to destination register table. >> @param[in] SourceRegisterTableList Points to source register table. >> @@ -967,7 +970,8 @@ CopyRegisterTable ( >> >> CopyMem (DestinationRegisterTableList, SourceRegisterTableList, NumberOfCpus * sizeof (CPU_REGISTER_TABLE)); >> for (Index = 0; Index < NumberOfCpus; Index++) { >> - if (DestinationRegisterTableList[Index].AllocatedSize != 0) { >> + if (DestinationRegisterTableList[Index].TableLength != 0) { >> + DestinationRegisterTableList[Index].AllocatedSize = DestinationRegisterTableList[Index].TableLength * sizeof (CPU_REGISTER_TABLE_ENTRY); >> RegisterTableEntry = AllocateCopyPool ( >> DestinationRegisterTableList[Index].AllocatedSize, >> (VOID *)(UINTN)SourceRegisterTableList[Index].RegisterTableEntry >> @@ -978,6 +982,31 @@ CopyRegisterTable ( >> } >> } >> >> +/** >> + Check whether the register table is empty or not. >> + >> + @param[in] RegisterTable Point to the register table. >> + >> + @retval TRUE The register table is empty. >> + @retval FALSE The register table is not empty. >> +**/ >> +BOOLEAN >> +IsRegisterTableEmpty ( >> + IN CPU_REGISTER_TABLE *RegisterTable, >> + IN UINT32 NumberOfCpus >> + ) >> +{ >> + UINTN Index; >> + >> + for (Index = 0; Index < NumberOfCpus; Index++) { >> + if (RegisterTable[Index].TableLength != 0) { >> + return FALSE; >> + } >> + } >> + >> + return TRUE; >> +} >> + >> /** >> Get ACPI CPU data. >> >> @@ -1032,23 +1061,31 @@ GetAcpiCpuData ( >> >> CopyMem ((VOID *)(UINTN)mAcpiCpuData.IdtrProfile, (VOID *)(UINTN)AcpiCpuData->IdtrProfile, sizeof (IA32_DESCRIPTOR)); >> >> - mAcpiCpuData.PreSmmInitRegisterTable = (EFI_PHYSICAL_ADDRESS)(UINTN)AllocatePool (mAcpiCpuData.NumberOfCpus * sizeof (CPU_REGISTER_TABLE)); >> - ASSERT (mAcpiCpuData.PreSmmInitRegisterTable != 0); >> + if (!IsRegisterTableEmpty ((CPU_REGISTER_TABLE *)(UINTN)AcpiCpuData->PreSmmInitRegisterTable, mAcpiCpuData.NumberOfCpus)) { >> + mAcpiCpuData.PreSmmInitRegisterTable = (EFI_PHYSICAL_ADDRESS)(UINTN)AllocatePool (mAcpiCpuData.NumberOfCpus * sizeof (CPU_REGISTER_TABLE)); >> + ASSERT (mAcpiCpuData.PreSmmInitRegisterTable != 0); >> >> - CopyRegisterTable ( >> - (CPU_REGISTER_TABLE *)(UINTN)mAcpiCpuData.PreSmmInitRegisterTable, >> - (CPU_REGISTER_TABLE *)(UINTN)AcpiCpuData->PreSmmInitRegisterTable, >> - mAcpiCpuData.NumberOfCpus >> - ); >> + CopyRegisterTable ( >> + (CPU_REGISTER_TABLE *)(UINTN)mAcpiCpuData.PreSmmInitRegisterTable, >> + (CPU_REGISTER_TABLE *)(UINTN)AcpiCpuData->PreSmmInitRegisterTable, >> + mAcpiCpuData.NumberOfCpus >> + ); >> + } else { >> + mAcpiCpuData.PreSmmInitRegisterTable = 0; >> + } >> >> - mAcpiCpuData.RegisterTable = (EFI_PHYSICAL_ADDRESS)(UINTN)AllocatePool (mAcpiCpuData.NumberOfCpus * sizeof (CPU_REGISTER_TABLE)); >> - ASSERT (mAcpiCpuData.RegisterTable != 0); >> + if (!IsRegisterTableEmpty ((CPU_REGISTER_TABLE *)(UINTN)AcpiCpuData->RegisterTable, mAcpiCpuData.NumberOfCpus)) { >> + mAcpiCpuData.RegisterTable = (EFI_PHYSICAL_ADDRESS)(UINTN)AllocatePool (mAcpiCpuData.NumberOfCpus * sizeof (CPU_REGISTER_TABLE)); >> + ASSERT (mAcpiCpuData.RegisterTable != 0); >> >> - CopyRegisterTable ( >> - (CPU_REGISTER_TABLE *)(UINTN)mAcpiCpuData.RegisterTable, >> - (CPU_REGISTER_TABLE *)(UINTN)AcpiCpuData->RegisterTable, >> - mAcpiCpuData.NumberOfCpus >> - ); >> + CopyRegisterTable ( >> + (CPU_REGISTER_TABLE *)(UINTN)mAcpiCpuData.RegisterTable, >> + (CPU_REGISTER_TABLE *)(UINTN)AcpiCpuData->RegisterTable, >> + mAcpiCpuData.NumberOfCpus >> + ); >> + } else { >> + mAcpiCpuData.RegisterTable = 0; >> + } >> >> // >> // Copy AP's GDT, IDT and Machine Check handler into SMRAM. >> > > This patch is a step in the right direction, but, IMO, it can be improved. > > The IsRegisterTableEmpty() function should also handle the case when the > "RegisterTable" parameter is NULL. The function should then also return > TRUE. > > And then, two more patches would be nice: > > > (2) The register table allocation in > "UefiCpuPkg/CpuS3DataDxe/CpuS3Data.c" should be removed. > > Right now, the code there allocates memory just so it can set the > "TableLength" and "AllocatedSize" fields to zero, for each "InitialApicId". > > It's a waste -- the memory is allocated only for ensuring that > PiSmmCpuDxeSmm does not program any CPU registers during S3 resume. > > Setting "AcpiCpuData->RegisterTable" and > "AcpiCpuData->PreSmmInitRegisterTable" should have the same effect. ... sorry, I meant: setting "AcpiCpuData->RegisterTable" and "AcpiCpuData->PreSmmInitRegisterTable" *TO NULL* should have the same effect. Thanks, Laszlo > > > (3) The same simplification should be then mirrored to > "OvmfPkg/CpuS3DataDxe/CpuS3Data.c". > > I can write the OvmfPkg patch myself, of course, but first I'd like to > see this use case confirmed / supported. > > This patch looks OK otherwise. > > Thanks! > Laszlo > > > > > >