From patchwork Thu Jul 8 00:54:39 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Isaku Yamahata X-Patchwork-Id: 12364223 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=-13.7 required=3.0 tests=BAYES_00, DKIM_ADSP_CUSTOM_MED,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, 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 E44D9C11F68 for ; Thu, 8 Jul 2021 00:56:14 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id BC2E361CD6 for ; Thu, 8 Jul 2021 00:56:14 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230359AbhGHA6o (ORCPT ); Wed, 7 Jul 2021 20:58:44 -0400 Received: from mga18.intel.com ([134.134.136.126]:19318 "EHLO mga18.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230173AbhGHA6g (ORCPT ); Wed, 7 Jul 2021 20:58:36 -0400 X-IronPort-AV: E=McAfee;i="6200,9189,10038"; a="196696064" X-IronPort-AV: E=Sophos;i="5.84,222,1620716400"; d="scan'208";a="196696064" Received: from fmsmga007.fm.intel.com ([10.253.24.52]) by orsmga106.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 07 Jul 2021 17:55:55 -0700 X-IronPort-AV: E=Sophos;i="5.84,222,1620716400"; d="scan'208";a="423770018" Received: from ls.sc.intel.com (HELO localhost) ([143.183.96.54]) by fmsmga007-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 07 Jul 2021 17:55:54 -0700 From: isaku.yamahata@gmail.com 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, erdemaktas@google.com Cc: kvm@vger.kernel.org, isaku.yamahata@gmail.com, isaku.yamahata@intel.com Subject: [RFC PATCH v2 09/44] target/i386: kvm: don't synchronize guest tsc for TD guest Date: Wed, 7 Jul 2021 17:54:39 -0700 Message-Id: X-Mailer: git-send-email 2.25.1 In-Reply-To: References: MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org From: Isaku Yamahata 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 Reviewed-by: Connor Kuehl --- 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 c29cb420a1..ecb1714920 100644 --- a/target/i386/kvm/kvm.c +++ b/target/i386/kvm/kvm.c @@ -254,7 +254,7 @@ 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); }