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 lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id D4ED2E68956 for ; Thu, 31 Oct 2024 07:02:41 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1t6PCM-0001ej-CE; Thu, 31 Oct 2024 03:02:26 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1t6PCI-0001eF-Si for qemu-devel@nongnu.org; Thu, 31 Oct 2024 03:02:22 -0400 Received: from mgamail.intel.com ([198.175.65.10]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1t6PCG-00072A-Ht for qemu-devel@nongnu.org; Thu, 31 Oct 2024 03:02:22 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1730358141; x=1761894141; h=date:from:to:cc:subject:message-id:references: mime-version:in-reply-to; bh=1uLbxR5aLR6yFMicCtuhn4ntzlEHWQ0jaJkDQayEaIw=; b=Qfk6kQlJut/wKbrDYgMjiIJfKdgfr+tCpe6C19ZutUp9MBcLvgJrdNpp pBcE6XD7POFGtHyiyyXUTcNS0QDTb6IBDOTq76UWDf0lCUXB5s0voxxEV 55+SSjepHGvCXbkJlQX4HkeDZf3uTZJHYkbXQpd9tTtMlolxmROEp7EuS OMJzAlTfMS0jqFs0mWtlZolCQcfgDQmU9PGOCpQxBU9N5Cf1pVk23dY3K 3naNWNqxoA6VQyDWhBjuekKqmER7AAHx3Z6UREWQ6ttdfEp3doRRhf02A +Q4QBax7812iqYdfdU4v+gpCOBejfURLNLUGDtPMnC9GcmYhD4hJoLmsu w==; X-CSE-ConnectionGUID: xAAoldaJSMeZr99vfrEXQQ== X-CSE-MsgGUID: wKaHjDhVSYavDiSEpMI1jw== X-IronPort-AV: E=McAfee;i="6700,10204,11222"; a="47540913" X-IronPort-AV: E=Sophos;i="6.11,199,1725346800"; d="scan'208";a="47540913" Received: from fmviesa004.fm.intel.com ([10.60.135.144]) by orvoesa102.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 31 Oct 2024 00:02:19 -0700 X-CSE-ConnectionGUID: Q3ET6XQQRQSP08iL/Hhc+w== X-CSE-MsgGUID: jxlgvlKCSTeQ88Hw/BhoAA== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.11,247,1725346800"; d="scan'208";a="87135339" Received: from liuzhao-optiplex-7080.sh.intel.com (HELO localhost) ([10.239.160.36]) by fmviesa004.fm.intel.com with ESMTP; 31 Oct 2024 00:02:17 -0700 Date: Thu, 31 Oct 2024 15:18:37 +0800 From: Zhao Liu To: Tao Su Cc: Paolo Bonzini , qemu-devel@nongnu.org, xiaoyao.li@intel.com Subject: Re: [PATCH 4/8] target/i386: add AVX10 feature and AVX10 version property Message-ID: References: <20241029151858.550269-1-pbonzini@redhat.com> <20241029151858.550269-5-pbonzini@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Received-SPF: pass client-ip=198.175.65.10; envelope-from=zhao1.liu@intel.com; helo=mgamail.intel.com X-Spam_score_int: -47 X-Spam_score: -4.8 X-Spam_bar: ---- X-Spam_report: (-4.8 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.366, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_MED=-2.3, RCVD_IN_VALIDITY_CERTIFIED_BLOCKED=0.001, RCVD_IN_VALIDITY_RPBL_BLOCKED=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org > > > > > > @@ -7674,13 +7682,21 @@ static bool x86_cpu_filter_features(X86CPU *cpu, bool verbose) > > > > > > &eax_0, &ebx_0, &ecx_0, &edx_0); > > > > > > uint8_t version = ebx_0 & 0xff; > > > > > > > > > > > > - if (version < env->avx10_version) { > > > > > > + if (!env->avx10_version) { > > > > > > + env->avx10_version = version; > > > > > > > > > > x86_cpu_filter_features() is not a good place to assign avx10_version, I > > > > > still tend to set it in max_x86_cpu_realize(). > > > > > > > > It's not proper to get the host's version when AVX10 cannot be enabled, > > > > even maybe host doesn't support AVX10. > > > > > > > > As you found out earlier, max_x86_cpu_realize doesn't know if AVX10 can > > > > be enabled or not. > > > > > > > > > > How about moving to x86_cpu_expand_features()? We can set when checking > > > cpu->max_features. > > > > The feature bit set in x86_cpu_expand_features() is unstable since it > > may be masked later in x86_cpu_filter_features(). :) > > > > A lot of feature bits are set in x86_cpu_expand_features() with reported > value, so I think avx10_version can also be set to reported value there. > > I mainly want to let avx10_version be assigned only when -cpu host or max, > so that it can be distinguished from the cpu model. This should also be > Paolo's original intention in v2. OK. In this case, extend avx10-version is also consistent with the semantics of this function. Even if host doesn't support avx10, then in principle it's ok to read unimplemented avx10-version as 0. Pls go ahead. :) Thanks, Zhao