From patchwork Tue Feb 16 02:13:05 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Isaku Yamahata X-Patchwork-Id: 12089425 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-16.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 86691C433E0 for ; Tue, 16 Feb 2021 02:16:38 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 5D12464DE8 for ; Tue, 16 Feb 2021 02:16:38 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229662AbhBPCQ2 (ORCPT ); Mon, 15 Feb 2021 21:16:28 -0500 Received: from mga06.intel.com ([134.134.136.31]:39373 "EHLO mga06.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229497AbhBPCQD (ORCPT ); Mon, 15 Feb 2021 21:16:03 -0500 IronPort-SDR: ooO5XO7X2Tiryi/lPYb2Tjt+WUYSxRzepLabYNiyW0v6+sue2o8qu53uV8p89S5WHtbtT5fw1L BQHv7mEhc9nw== X-IronPort-AV: E=McAfee;i="6000,8403,9896"; a="244270202" X-IronPort-AV: E=Sophos;i="5.81,182,1610438400"; d="scan'208";a="244270202" Received: from fmsmga005.fm.intel.com ([10.253.24.32]) by orsmga104.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 15 Feb 2021 18:14:51 -0800 IronPort-SDR: IMUUA3bKKiJ20NH1cCwy4eaJvgH448mUZ64kz7iauktw/bpJCLxiti5q80tCZBoM3DZVVp7iKB 9PWCJJoT1mrg== X-IronPort-AV: E=Sophos;i="5.81,182,1610438400"; d="scan'208";a="591705407" Received: from ls.sc.intel.com (HELO localhost) ([143.183.96.54]) by fmsmga005-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 15 Feb 2021 18:14:51 -0800 From: Isaku Yamahata To: qemu-devel@nongnu.org, pbonzini@redhat.com, alistair@alistair23.me, ehabkost@redhat.com, marcel.apfelbaum@gmail.com, mst@redhat.com, cohuck@redhat.com, mtosatti@redhat.com, xiaoyao.li@intel.com, seanjc@google.com Cc: kvm@vger.kernel.org, isaku.yamahata@gmail.com, isaku.yamahata@intel.com Subject: [RFC PATCH 09/23] target/i386: kvm: don't synchronize guest tsc for TD guest Date: Mon, 15 Feb 2021 18:13:05 -0800 Message-Id: X-Mailer: git-send-email 2.17.1 In-Reply-To: References: In-Reply-To: References: Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org Make kvm_synchronize_all_tsc() nop for TD-guest. TDX module specification, 9.11.1 TSC Virtualization "Virtual TSC values are consistent among all the TD;s VCPUs at the level suppored by the CPU". There is no need for qemu to synchronize tsc and VMM can't access to guest TSC. Actually do_kvm_synchronize_tsc() hits assert due to failure to write to guest tsc. > qemu/target/i386/kvm.c:235: kvm_get_tsc: Assertion `ret == 1' failed. Signed-off-by: Isaku Yamahata --- target/i386/kvm/kvm.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/target/i386/kvm/kvm.c b/target/i386/kvm/kvm.c index fb94cdd370..beb768a7d3 100644 --- a/target/i386/kvm/kvm.c +++ b/target/i386/kvm/kvm.c @@ -247,7 +247,7 @@ void kvm_synchronize_all_tsc(void) { CPUState *cpu; - if (kvm_enabled()) { + if (kvm_enabled() && vm_type != KVM_X86_TDX_VM) { CPU_FOREACH(cpu) { run_on_cpu(cpu, do_kvm_synchronize_tsc, RUN_ON_CPU_NULL); }