From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 0C228C433F5 for ; Mon, 23 May 2022 15:30:35 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S237888AbiEWPad (ORCPT ); Mon, 23 May 2022 11:30:33 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:44026 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S237879AbiEWPac (ORCPT ); Mon, 23 May 2022 11:30:32 -0400 Received: from mga17.intel.com (mga17.intel.com [192.55.52.151]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 209FA5FF36 for ; Mon, 23 May 2022 08:30:31 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1653319831; x=1684855831; h=message-id:date:mime-version:subject:to:cc:references: from:in-reply-to:content-transfer-encoding; bh=7OenGLB7dGpptwRRzjJaPmhu5ShRYU9QhFSj1l1mbT8=; b=Uhn4xmGhvhMd7pzLfDbGBc9gviUz74WJ5ZLNB1PrEdZt7YAdziXNHL9A kBwAFR/GtcYJnB78JaGXAxTOz3SsoiV0oslfoo7z2Sgn30P/SQOuorx8s zk4v9ZBjtFnj048aL/f7BGNOgWTigMAlsN2r93MAcXQpgJ+IKtdfK3aPJ sXjta4PUjGFH1s/7UrCzsrmL30CKYIBNyA/Rxcy0jW7WZbmOYEqM38f05 EYkaJiVWEmN0mEGCJAxJNIlE2EfSLkFaRa93t/E5q3Lli+I7hNOuoME/Y 417mhm7siFAfxm/ZD/MpamKnZNQHiY+TYLTrj2yEQjBQSHZ0FwLPNTKo/ Q==; X-IronPort-AV: E=McAfee;i="6400,9594,10356"; a="253758187" X-IronPort-AV: E=Sophos;i="5.91,246,1647327600"; d="scan'208";a="253758187" Received: from orsmga008.jf.intel.com ([10.7.209.65]) by fmsmga107.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 23 May 2022 08:30:30 -0700 X-IronPort-AV: E=Sophos;i="5.91,246,1647327600"; d="scan'208";a="600706775" Received: from xiaoyaol-hp-g830.ccr.corp.intel.com (HELO [10.249.171.127]) ([10.249.171.127]) by orsmga008-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 23 May 2022 08:30:24 -0700 Message-ID: Date: Mon, 23 May 2022 23:30:21 +0800 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:91.0) Gecko/20100101 Firefox/91.0 Thunderbird/91.9.0 Subject: Re: [RFC PATCH v4 06/36] i386/tdx: Get tdx_capabilities via KVM_TDX_CAPABILITIES Content-Language: en-US To: Gerd Hoffmann Cc: Paolo Bonzini , Isaku Yamahata , isaku.yamahata@intel.com, =?UTF-8?Q?Daniel_P=2e_Berrang=c3=a9?= , =?UTF-8?Q?Philippe_Mathieu-Daud=c3=a9?= , Richard Henderson , "Michael S . Tsirkin" , Marcel Apfelbaum , Cornelia Huck , Marcelo Tosatti , Laszlo Ersek , Eric Blake , Connor Kuehl , erdemaktas@google.com, kvm@vger.kernel.org, qemu-devel@nongnu.org, seanjc@google.com References: <20220512031803.3315890-1-xiaoyao.li@intel.com> <20220512031803.3315890-7-xiaoyao.li@intel.com> <20220523084530.baedwpbwldc7cbnz@sirius.home.kraxel.org> From: Xiaoyao Li In-Reply-To: <20220523084530.baedwpbwldc7cbnz@sirius.home.kraxel.org> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org On 5/23/2022 4:45 PM, Gerd Hoffmann wrote: > Hi, > >> + do { >> + size = sizeof(struct kvm_tdx_capabilities) + >> + max_ent * sizeof(struct kvm_tdx_cpuid_config); >> + caps = g_malloc0(size); >> + caps->nr_cpuid_configs = max_ent; >> + >> + r = tdx_platform_ioctl(KVM_TDX_CAPABILITIES, 0, caps); >> + if (r == -E2BIG) { >> + g_free(caps); >> + max_ent *= 2; >> + } else if (r < 0) { >> + error_report("KVM_TDX_CAPABILITIES failed: %s\n", strerror(-r)); >> + exit(1); >> + } >> + } >> + while (r == -E2BIG); > > This should have a limit for the number of loop runs. Actually, this logic is copied from get_supported_cpuid(). Anyway, I can put a maximum limit as 256 (it should be large enough) or maybe re-use KVM_MAX_CPUID_ENTRIES. When it gets hit, we know we need to update QEMU to fit with TDX on new platform. > take care, > Gerd >