From nobody Tue Feb 10 15:29:43 2026 Delivered-To: importer@patchew.org Authentication-Results: mx.zohomail.com; dkim=pass; spf=pass (zohomail.com: domain of groups.io designates 66.175.222.108 as permitted sender) smtp.mailfrom=bounce+27952+82370+1787277+3901457@groups.io; arc=fail (BodyHash is different from the expected one); dmarc=pass(p=none dis=none) header.from=groups.io Received: from mail02.groups.io (mail02.groups.io [66.175.222.108]) by mx.zohomail.com with SMTPS id 163467241145930.64584437635915; Tue, 19 Oct 2021 12:40:11 -0700 (PDT) Return-Path: X-Received: by 127.0.0.2 with SMTP id ZZLtYY1788612xzKuHrZL6mp; Tue, 19 Oct 2021 12:40:11 -0700 X-Received: from NAM11-DM6-obe.outbound.protection.outlook.com (NAM11-DM6-obe.outbound.protection.outlook.com [40.107.223.51]) by mx.groups.io with SMTP id smtpd.web09.15160.1634672409159982748 for ; Tue, 19 Oct 2021 12:40:09 -0700 ARC-Seal: i=1; a=rsa-sha256; s=arcselector9901; d=microsoft.com; cv=none; b=ZNjH4sA5dV4bfpQdKwDBA8i7eZHoNuTa+04pal7Cd8haYkT6QymluaPL8KkxIouzPO1Z3zajkVDGkq0UcliHihxf4wJbMK4Dhmux4zHPcKHGxQabIhrDvxcf7nalgntvqYKXQUIMPWrBA759qZWEjaDKt6PLF1SAz962VnmM9vmOg/TTv89sWXwT/VX+8U9DAuQdY12/bt53LtYC2WuOXB8Mcd5WmIXMO6WMng2eFj8obCUArwYjjBpJMRLMsuYxHgsHZftku6OqRdkpv+D6kwTPdrsWH+j/o/XvPCRklRSw36zrv/kWSljHsZAI/4X74hweoSYISv/J1vSlV0O7ow== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=microsoft.com; s=arcselector9901; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-AntiSpam-MessageData-ChunkCount:X-MS-Exchange-AntiSpam-MessageData-0:X-MS-Exchange-AntiSpam-MessageData-1; bh=19UpFsAojMNItsCb+HCNBgIG05cw1PHsY58EmIKvSfI=; b=n06EOmcGnsz9q5xNTZfjobFFNbqxKCl5m9mOQcVqT9drBMvv45fyAPmiKQVlcW+qLuridGMQV+UG4Lvdter0GjuXiep4qdHMQP0UW4NuKqi6SjeL10+caASJtK3NmM82V7AyFEBSQiMAWqAi54kxSWUO1M58MzsTevO7tF/DrqPg0ZORFoLBdTrHfx2GP/sIVP4ZG6MWiqJeda6PNMaS9pb56PlWvUBmDy/tPWQRoI+0A7Xo8IZ7dLcEO55gx2VbNjboLBYOvdvHXCH3HqIl5HjzeXEaLNMILdSHRXqWH7hSgVeq6Slnnnqvt5i3I0lEJf6sAA4qj5yMTrnXNj54Ig== ARC-Authentication-Results: i=1; mx.microsoft.com 1; spf=pass (sender ip is 165.204.84.17) smtp.rcpttodomain=edk2.groups.io smtp.mailfrom=amd.com; dmarc=pass (p=quarantine sp=quarantine pct=100) action=none header.from=amd.com; dkim=none (message not signed); arc=none X-Received: from MWHPR02CA0012.namprd02.prod.outlook.com (2603:10b6:300:4b::22) by BYAPR12MB3269.namprd12.prod.outlook.com (2603:10b6:a03:12f::27) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.4608.16; Tue, 19 Oct 2021 19:40:05 +0000 X-Received: from CO1NAM11FT054.eop-nam11.prod.protection.outlook.com (2603:10b6:300:4b:cafe::60) by MWHPR02CA0012.outlook.office365.com (2603:10b6:300:4b::22) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.4628.15 via Frontend Transport; Tue, 19 Oct 2021 19:40:05 +0000 X-MS-Exchange-Authentication-Results: spf=pass (sender IP is 165.204.84.17) smtp.mailfrom=amd.com; edk2.groups.io; dkim=none (message not signed) header.d=none;edk2.groups.io; dmarc=pass action=none header.from=amd.com; Received-SPF: pass (zohomail.com: domain of groups.io designates 66.175.222.108 as permitted sender) client-ip=66.175.222.108; envelope-from=bounce+27952+82370+1787277+3901457@groups.io; helo=mail02.groups.io; Received-SPF: Pass (protection.outlook.com: domain of amd.com designates 165.204.84.17 as permitted sender) receiver=protection.outlook.com; client-ip=165.204.84.17; helo=SATLEXMB04.amd.com; X-Received: from SATLEXMB04.amd.com (165.204.84.17) by CO1NAM11FT054.mail.protection.outlook.com (10.13.174.70) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.20.4608.15 via Frontend Transport; Tue, 19 Oct 2021 19:40:04 +0000 X-Received: from sbrijesh-desktop.amd.com (10.180.168.240) by SATLEXMB04.amd.com (10.181.40.145) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2308.15; Tue, 19 Oct 2021 14:39:56 -0500 From: "Brijesh Singh via groups.io" To: CC: James Bottomley , Min Xu , "Jiewen Yao" , Tom Lendacky , "Jordan Justen" , Ard Biesheuvel , Erdem Aktas , "Michael Roth" , Gerd Hoffmann , Michael Roth , Jiewen Yao , Brijesh Singh Subject: [edk2-devel] [PATCH v10 08/32] OvmfPkg/ResetVector: use SEV-SNP-validated CPUID values Date: Tue, 19 Oct 2021 14:39:10 -0500 Message-ID: <20211019193934.1052465-9-brijesh.singh@amd.com> In-Reply-To: <20211019193934.1052465-1-brijesh.singh@amd.com> References: <20211019193934.1052465-1-brijesh.singh@amd.com> MIME-Version: 1.0 X-Originating-IP: [10.180.168.240] X-ClientProxiedBy: SATLEXMB04.amd.com (10.181.40.145) To SATLEXMB04.amd.com (10.181.40.145) X-EOPAttributedMessage: 0 X-MS-PublicTrafficType: Email X-MS-Office365-Filtering-Correlation-Id: eebb83f0-f445-4c3f-2b1c-08d993383fef X-MS-TrafficTypeDiagnostic: BYAPR12MB3269: X-Microsoft-Antispam-PRVS: X-MS-Oob-TLC-OOBClassifiers: OLM:8273; X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam-Message-Info: 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 X-OriginatorOrg: amd.com X-MS-Exchange-CrossTenant-OriginalArrivalTime: 19 Oct 2021 19:40:04.8197 (UTC) X-MS-Exchange-CrossTenant-Network-Message-Id: eebb83f0-f445-4c3f-2b1c-08d993383fef X-MS-Exchange-CrossTenant-Id: 3dd8961f-e488-4e60-8e11-a82d994e183d X-MS-Exchange-CrossTenant-OriginalAttributedTenantConnectingIp: TenantId=3dd8961f-e488-4e60-8e11-a82d994e183d;Ip=[165.204.84.17];Helo=[SATLEXMB04.amd.com] X-MS-Exchange-CrossTenant-AuthSource: CO1NAM11FT054.eop-nam11.prod.protection.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Anonymous X-MS-Exchange-CrossTenant-FromEntityHeader: HybridOnPrem X-MS-Exchange-Transport-CrossTenantHeadersStamped: BYAPR12MB3269 Precedence: Bulk List-Unsubscribe: List-Subscribe: List-Help: Sender: devel@edk2.groups.io List-Id: Mailing-List: list devel@edk2.groups.io; contact devel+owner@edk2.groups.io Reply-To: devel@edk2.groups.io,brijesh.singh@amd.com X-Gm-Message-State: MN7jAePaICz71i5jS5DnJQMQx1787277AA= Content-Transfer-Encoding: quoted-printable DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=groups.io; q=dns/txt; s=20140610; t=1634672411; bh=gLcl40WPvN0AkXt5bTcYrtckX1lM8mY9XlcCDJtUq9k=; h=CC:Content-Type:Date:From:Reply-To:Subject:To; b=wEBAsB3yRzTNt8909c4KOo/IZ12lIISiRdZuMyoxrQkeHZSXR5FVYZa2PtVvln2Gv0y TC7a0odDQ6PpJMZlDkJjCXnQSPQo6Pmv/3M2isunx9WESYW5jPfe2cgMiFyVS1AIhJ+sG sk6Ipk5mWH9itsAJCBgk3bksbJAVPSdxsd0= X-ZohoMail-DKIM: pass (identity @groups.io) X-ZM-MESSAGEID: 1634672415702100003 Content-Type: text/plain; charset="utf-8" From: Michael Roth CPUID instructions are issued during early boot to do things like probe for SEV support. Currently these are handled by a minimal #VC handler that uses the MSR-based GHCB protocol to fetch the CPUID values from the hypervisor. When SEV-SNP is enabled, use the firmware-validated CPUID values from the CPUID page instead [1]. [1]: SEV SNP Firmware ABI Specification, Rev. 0.8, 8.13.2.6 Cc: Michael Roth Cc: James Bottomley Cc: Min Xu Cc: Jiewen Yao Cc: Tom Lendacky Cc: Jordan Justen Cc: Ard Biesheuvel Cc: Erdem Aktas Cc: Gerd Hoffmann Acked-by: Jiewen Yao Acked-by: Gerd Hoffmann Signed-off-by: Michael Roth Signed-off-by: Brijesh Singh --- OvmfPkg/ResetVector/Ia32/AmdSev.asm | 80 +++++++++++++++++++++++++++-- 1 file changed, 75 insertions(+), 5 deletions(-) diff --git a/OvmfPkg/ResetVector/Ia32/AmdSev.asm b/OvmfPkg/ResetVector/Ia32= /AmdSev.asm index 48d9178168b0..1f827da3b929 100644 --- a/OvmfPkg/ResetVector/Ia32/AmdSev.asm +++ b/OvmfPkg/ResetVector/Ia32/AmdSev.asm @@ -34,6 +34,18 @@ BITS 32 %define GHCB_CPUID_REGISTER_SHIFT 30 %define CPUID_INSN_LEN 2 =20 +; #VC handler offsets/sizes for accessing SNP CPUID page +; +%define SNP_CPUID_ENTRY_SZ 48 +%define SNP_CPUID_COUNT 0 +%define SNP_CPUID_ENTRY 16 +%define SNP_CPUID_ENTRY_EAX_IN 0 +%define SNP_CPUID_ENTRY_ECX_IN 4 +%define SNP_CPUID_ENTRY_EAX 24 +%define SNP_CPUID_ENTRY_EBX 28 +%define SNP_CPUID_ENTRY_ECX 32 +%define SNP_CPUID_ENTRY_EDX 36 + =20 %define SEV_GHCB_MSR 0xc0010130 %define SEV_STATUS_MSR 0xc0010131 @@ -335,11 +347,61 @@ SevEsIdtNotCpuid: TerminateVmgExit TERM_VC_NOT_CPUID iret =20 - ; - ; Total stack usage for the #VC handler is 44 bytes: - ; - 12 bytes for the exception IRET (after popping error code) - ; - 32 bytes for the local variables. - ; +; Use the SNP CPUID page to handle the cpuid lookup +; +; Modified: EAX, EBX, ECX, EDX +; +; Relies on the stack setup/usage in #VC handler: +; +; On entry, +; [esp + VC_CPUID_FUNCTION] contains EAX input to cpuid instruction +; +; On return, stores corresponding results of CPUID lookup in: +; [esp + VC_CPUID_RESULT_EAX] +; [esp + VC_CPUID_RESULT_EBX] +; [esp + VC_CPUID_RESULT_ECX] +; [esp + VC_CPUID_RESULT_EDX] +; +SnpCpuidLookup: + mov eax, [esp + VC_CPUID_FUNCTION] + mov ebx, [CPUID_BASE + SNP_CPUID_COUNT] + mov ecx, CPUID_BASE + SNP_CPUID_ENTRY + ; Zero these out now so we can simply return if lookup fails + mov dword[esp + VC_CPUID_RESULT_EAX], 0 + mov dword[esp + VC_CPUID_RESULT_EBX], 0 + mov dword[esp + VC_CPUID_RESULT_ECX], 0 + mov dword[esp + VC_CPUID_RESULT_EDX], 0 + +SnpCpuidCheckEntry: + cmp ebx, 0 + je VmmDoneSnpCpuid + cmp dword[ecx + SNP_CPUID_ENTRY_EAX_IN], eax + jne SnpCpuidCheckEntryNext + ; As with SEV-ES handler we assume requested CPUID sub-leaf/index is 0 + cmp dword[ecx + SNP_CPUID_ENTRY_ECX_IN], 0 + je SnpCpuidEntryFound + +SnpCpuidCheckEntryNext: + dec ebx + add ecx, SNP_CPUID_ENTRY_SZ + jmp SnpCpuidCheckEntry + +SnpCpuidEntryFound: + mov eax, [ecx + SNP_CPUID_ENTRY_EAX] + mov [esp + VC_CPUID_RESULT_EAX], eax + mov eax, [ecx + SNP_CPUID_ENTRY_EBX] + mov [esp + VC_CPUID_RESULT_EBX], eax + mov eax, [ecx + SNP_CPUID_ENTRY_EDX] + mov [esp + VC_CPUID_RESULT_ECX], eax + mov eax, [ecx + SNP_CPUID_ENTRY_ECX] + mov [esp + VC_CPUID_RESULT_EDX], eax + jmp VmmDoneSnpCpuid + +; +; Total stack usage for the #VC handler is 44 bytes: +; - 12 bytes for the exception IRET (after popping error code) +; - 32 bytes for the local variables. +; SevEsIdtVmmComm: ; ; If we're here, then we are an SEV-ES guest and this @@ -367,6 +429,13 @@ SevEsIdtVmmComm: ; Save the CPUID function being requested mov [esp + VC_CPUID_FUNCTION], eax =20 + ; If SEV-SNP is enabled, use the CPUID page to handle the CPUID + ; instruction. + mov ecx, SEV_STATUS_MSR + rdmsr + bt eax, 2 + jc SnpCpuidLookup + ; The GHCB CPUID protocol uses the following mapping to request ; a specific register: ; 0 =3D> EAX, 1 =3D> EBX, 2 =3D> ECX, 3 =3D> EDX @@ -424,6 +493,7 @@ VmmDone: mov ecx, SEV_GHCB_MSR wrmsr =20 +VmmDoneSnpCpuid: mov eax, [esp + VC_CPUID_RESULT_EAX] mov ebx, [esp + VC_CPUID_RESULT_EBX] mov ecx, [esp + VC_CPUID_RESULT_ECX] --=20 2.25.1 -=3D-=3D-=3D-=3D-=3D-=3D-=3D-=3D-=3D-=3D-=3D- Groups.io Links: You receive all messages sent to this group. View/Reply Online (#82370): https://edk2.groups.io/g/devel/message/82370 Mute This Topic: https://groups.io/mt/86448805/1787277 Group Owner: devel+owner@edk2.groups.io Unsubscribe: https://edk2.groups.io/g/devel/unsub [importer@patchew.org] -=3D-=3D-=3D-=3D-=3D-=3D-=3D-=3D-=3D-=3D-=3D-