From patchwork Fri May 31 04:30:33 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Nikunj A. Dadhania" X-Patchwork-Id: 13681127 Received: from NAM10-DM6-obe.outbound.protection.outlook.com (mail-dm6nam10on2073.outbound.protection.outlook.com [40.107.93.73]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id EB18582D75; Fri, 31 May 2024 04:34:47 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=fail smtp.client-ip=40.107.93.73 ARC-Seal: i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1717130089; cv=fail; b=YV5Iwss8GazGMnd5xCF8p6DQ+pIAA0MhU2Du1zV3tbKsbEShvJ5RP1iy8AgRdja2xWmFmZu1gCTNpkDtrmGpQ8zpLB14Z/Vjw/7T04NOKdzwSlzs4n0AtyP5SSjn5GZIZhKu6wAW4WAyzWO9wkZi11aBXkJQ1m1O9lJ7+R3KkHo= ARC-Message-Signature: i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1717130089; c=relaxed/simple; bh=KsIMJLJ6CQpyeDM/RXcWA6TadtVbGCuait48LQRKyZ4=; h=From:To:CC:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=m6Tff/XcbWWFxrDOOMfVHD00dwEF1YJfiam49sfwRGkbTO0+RQUb3P6AtFJavfZyfJqYTwQnzt7YUkz54kzpPjg+oJX+8Om++JjYwBW02dGkPowoy9x4D+CZK26+HrYuALk6+/Nt+KACbqtx2QVbaVN1dQ8fUatG+kdFTFXj4mI= ARC-Authentication-Results: i=2; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=amd.com; spf=fail smtp.mailfrom=amd.com; dkim=pass (1024-bit key) header.d=amd.com header.i=@amd.com header.b=RSci858z; arc=fail smtp.client-ip=40.107.93.73 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=amd.com Authentication-Results: smtp.subspace.kernel.org; spf=fail smtp.mailfrom=amd.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=amd.com header.i=@amd.com header.b="RSci858z" ARC-Seal: i=1; a=rsa-sha256; s=arcselector9901; d=microsoft.com; cv=none; b=ikIfu/R/IcMYO5A6qlHcZteYUq63yxendsAROh4u4xyg1IZYnrf7LtOzNQ58+7aO7Nj5GzaP9u5AaMPD4yKngZqkOX3BAO1RZ2w8kpqrl6k0XYfwOcvCJ+7/AhSCLOPYzq8S7cqdJXn0zi0+IdHtqzCIly42VGxOXaXWSYUGitpzsK7O4qc0eqZsVbYhh/uXZPg3YfC6wwTfV0ax+AWzgju035MMqFou9WFYGBK/ecF7204Mk2NWqH8ZgI3yRb/ZpFr6CIE6nq4cqIN3vau3KdLBhhgEax8piY3tKGr7qhLpz/NMD8vr7H6A+ibMkiEsNpp2wWN4o+jbyQJkZQHLZw== 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=DUqWOlsFxSY/Iq1jJTOUQHjey9t23YQnLfGpxy2azLQ=; b=OT3ofulVWMOO0ECB9/At+VdFp2n3MdVh736Nm/f/voUpFsFqFKgk+ectV5USoNQ0bnbEYPQwkGJtvc/US2VS/ye+8jM+R4evBXVfE0rtMJrIV3QErt+OFsRzjXpGm8sDNPDYe0VCA9ykfsiDM3v4bA29Jjox0rw/9Blfn4yTQru1B5oPD5NQZlgL2Oq2fx26W4bSyud0KABaqz3D39d7fRQz8x8uxP6VtXgF1JoqHyDNXW+GvARt1Enl9JP6zb2jbvWyNGaX+HAmRYyVnyHz38mHJlaNZEy35BAIt4S4UeFJPT7/ks2z2jL142HcwDHXPYexyEgAMk0l7HjNDy+z7A== ARC-Authentication-Results: i=1; mx.microsoft.com 1; spf=pass (sender ip is 165.204.84.17) smtp.rcpttodomain=vger.kernel.org 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 (0) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=amd.com; s=selector1; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-SenderADCheck; bh=DUqWOlsFxSY/Iq1jJTOUQHjey9t23YQnLfGpxy2azLQ=; b=RSci858zlSeqrhs6UBu0qdjckzMqrsbM4ny2+EES0JQTiFxtx6m9TTFOjMNtH1q5a/2BMtSDeHlm4Mw2hI/5uVmbI8MYxP/SmUMAr9mKn7/Mbk4eRBnCTnt9HkXolNX98Kc/l2UBWYeBy9fxGq88ls9aesgz2IUKG6fJOH5bbVI= Received: from DM6PR17CA0036.namprd17.prod.outlook.com (2603:10b6:5:1b3::49) by SJ0PR12MB7035.namprd12.prod.outlook.com (2603:10b6:a03:47c::14) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.7611.22; Fri, 31 May 2024 04:34:43 +0000 Received: from DS3PEPF000099D6.namprd04.prod.outlook.com (2603:10b6:5:1b3:cafe::c0) by DM6PR17CA0036.outlook.office365.com (2603:10b6:5:1b3::49) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.7633.22 via Frontend Transport; Fri, 31 May 2024 04:34:43 +0000 X-MS-Exchange-Authentication-Results: spf=pass (sender IP is 165.204.84.17) smtp.mailfrom=amd.com; dkim=none (message not signed) header.d=none;dmarc=pass action=none header.from=amd.com; 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; pr=C Received: from SATLEXMB04.amd.com (165.204.84.17) by DS3PEPF000099D6.mail.protection.outlook.com (10.167.17.7) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.20.7633.15 via Frontend Transport; Fri, 31 May 2024 04:34:43 +0000 Received: from gomati.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 15.1.2507.35; Thu, 30 May 2024 23:34:39 -0500 From: Nikunj A Dadhania To: , , , , CC: , , , , , , Subject: [PATCH v9 19/24] x86/sev: Change TSC MSR behavior for Secure TSC enabled guests Date: Fri, 31 May 2024 10:00:33 +0530 Message-ID: <20240531043038.3370793-20-nikunj@amd.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20240531043038.3370793-1-nikunj@amd.com> References: <20240531043038.3370793-1-nikunj@amd.com> Precedence: bulk X-Mailing-List: kvm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 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-TrafficTypeDiagnostic: DS3PEPF000099D6:EE_|SJ0PR12MB7035:EE_ X-MS-Office365-Filtering-Correlation-Id: 8609ff7f-fb54-45fb-bb36-08dc812afe65 X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230031|376005|7416005|1800799015|36860700004|82310400017; X-Microsoft-Antispam-Message-Info: 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 X-Forefront-Antispam-Report: CIP:165.204.84.17;CTRY:US;LANG:en;SCL:1;SRV:;IPV:CAL;SFV:NSPM;H:SATLEXMB04.amd.com;PTR:InfoDomainNonexistent;CAT:NONE;SFS:(13230031)(376005)(7416005)(1800799015)(36860700004)(82310400017);DIR:OUT;SFP:1101; X-OriginatorOrg: amd.com X-MS-Exchange-CrossTenant-OriginalArrivalTime: 31 May 2024 04:34:43.5519 (UTC) X-MS-Exchange-CrossTenant-Network-Message-Id: 8609ff7f-fb54-45fb-bb36-08dc812afe65 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: DS3PEPF000099D6.namprd04.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Anonymous X-MS-Exchange-CrossTenant-FromEntityHeader: HybridOnPrem X-MS-Exchange-Transport-CrossTenantHeadersStamped: SJ0PR12MB7035 Secure TSC enabled guests should not write MSR_IA32_TSC(10H) register as the subsequent TSC value reads are undefined. MSR_IA32_TSC related accesses should not exit to the hypervisor for such guests. Accesses to MSR_IA32_TSC needs special handling in the #VC handler for the guests with Secure TSC enabled. Writes to MSR_IA32_TSC should be ignored, and reads of MSR_IA32_TSC should return the result of the RDTSC instruction. Signed-off-by: Nikunj A Dadhania Reviewed-by: Tom Lendacky Tested-by: Peter Gonda --- arch/x86/kernel/sev.c | 24 ++++++++++++++++++++++++ 1 file changed, 24 insertions(+) diff --git a/arch/x86/kernel/sev.c b/arch/x86/kernel/sev.c index b4458af92a73..1f6a8d85c816 100644 --- a/arch/x86/kernel/sev.c +++ b/arch/x86/kernel/sev.c @@ -1191,6 +1191,30 @@ static enum es_result vc_handle_msr(struct ghcb *ghcb, struct es_em_ctxt *ctxt) /* Is it a WRMSR? */ exit_info_1 = (ctxt->insn.opcode.bytes[1] == 0x30) ? 1 : 0; + /* + * TSC related accesses should not exit to the hypervisor when a + * guest is executing with SecureTSC enabled, so special handling + * is required for accesses of MSR_IA32_TSC: + * + * Writes: Writing to MSR_IA32_TSC can cause subsequent reads + * of the TSC to return undefined values, so ignore all + * writes. + * Reads: Reads of MSR_IA32_TSC should return the current TSC + * value, use the value returned by RDTSC. + */ + if (regs->cx == MSR_IA32_TSC && cc_platform_has(CC_ATTR_GUEST_SECURE_TSC)) { + u64 tsc; + + if (exit_info_1) + return ES_OK; + + tsc = rdtsc(); + regs->ax = UINT_MAX & tsc; + regs->dx = UINT_MAX & (tsc >> 32); + + return ES_OK; + } + ghcb_set_rcx(ghcb, regs->cx); if (exit_info_1) { ghcb_set_rax(ghcb, regs->ax);