From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mgamail.intel.com (mgamail.intel.com [192.55.52.93]) (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 225A3DDA3 for ; Fri, 22 Dec 2023 08:35:08 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=intel.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=intel.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b="Grec/3T0" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1703234109; x=1734770109; h=date:from:to:cc:subject:message-id:references: mime-version:in-reply-to; bh=LoIAA0CvLDyDd2zMRzU7xGB8nmg2Wi0fDASQta4ZIUM=; b=Grec/3T0OJW2w4ihOeaat/A655ZrUJlAwRlo4p6GhJtYkHqwu0Q2uR0w JKKW4LeK2WkHrXQkNIBEGQBboprYx4R5gG3r7HZQ1aNKYceiyfbaOxEwP m7e5oqYVeeX2OtPyMHMLAVkDDQ3AQ/5Qx+KEFMnBGMaxk/KMy5+YQSPRx WcnSRtVUtIUZ7n9/H6trzA5fYFyKry5CeKgg6R0sGRV3tGy2jUswBSeX3 6uKfehltL2D330fKzk5dFHUAG9QgW9DF0IcNTGXg20fbH1ne3lP8Ny+r1 mmSuDzG18R1yZuG647sp5xbnjsIdqBLx7IU3gWtMb4qwJSADPOo6p5EF5 Q==; X-IronPort-AV: E=McAfee;i="6600,9927,10931"; a="393255159" X-IronPort-AV: E=Sophos;i="6.04,294,1695711600"; d="scan'208";a="393255159" Received: from orsmga006.jf.intel.com ([10.7.209.51]) by fmsmga102.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 22 Dec 2023 00:35:08 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=McAfee;i="6600,9927,10931"; a="753202490" X-IronPort-AV: E=Sophos;i="6.04,294,1695711600"; d="scan'208";a="753202490" Received: from liuzhao-optiplex-7080.sh.intel.com (HELO localhost) ([10.239.160.36]) by orsmga006.jf.intel.com with ESMTP; 22 Dec 2023 00:35:00 -0800 Date: Fri, 22 Dec 2023 16:47:46 +0800 From: "Liu, Zhao1" To: "Li, Xin3" Cc: "qemu-devel@nongnu.org" , "kvm@vger.kernel.org" , "richard.henderson@linaro.org" , "pbonzini@redhat.com" , "eduardo@habkost.net" , "seanjc@google.com" , "Gao, Chao" , "hpa@zytor.com" , "Li, Xiaoyao" , "Yang, Weijiang" , "Wu, Dan1" Subject: Re: [PATCH v3A 1/6] target/i386: add support for FRED in CPUID enumeration Message-ID: References: <20231222030336.38096-1-xin3.li@intel.com> Precedence: bulk X-Mailing-List: kvm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: On Fri, Dec 22, 2023 at 08:24:52AM +0000, Li, Xin3 wrote: > Date: Fri, 22 Dec 2023 08:24:52 +0000 > From: "Li, Xin3" > Subject: RE: [PATCH v3A 1/6] target/i386: add support for FRED in CPUID > enumeration > > > > > > NULL, NULL, NULL, NULL, @@ -1552,6 +1552,14 @@ static > > > > FeatureDep feature_dependencies[] = { > > > > .from = { FEAT_VMX_SECONDARY_CTLS, > > VMX_SECONDARY_EXEC_ENABLE_USER_WAIT_PAUSE }, > > > > .to = { FEAT_7_0_ECX, CPUID_7_0_ECX_WAITPKG }, > > > > }, > > > > + { > > > > + .from = { FEAT_7_1_EAX, CPUID_7_1_EAX_LKGS }, > > > > + .to = { FEAT_7_1_EAX, CPUID_7_1_EAX_FRED }, > > > > + }, > > > > + { > > > > + .from = { FEAT_7_1_EAX, CPUID_7_1_EAX_WRMSRNS }, > > > > + .to = { FEAT_7_1_EAX, CPUID_7_1_EAX_FRED }, > > > > + }, > > > > Oh, sorry, one thing that comes to mind, is this dependency required? > > Since the FRED spec (v3.0) is all about WRMSR as the example, without > > mentioning WRMSRNS, could there be other implementations that depend on > > WRMSR instead of WRMSRNS? > > This is a community ask from tglx: > https://lkml.kernel.org/kvm/87y1h81ht4.ffs@tglx/ > > Boris had the same question: > https://lore.kernel.org/lkml/20231114050201.GAZVL%2FSd%2FyLIdON9la@fat_crate.local/ > > But it needs to go through a formal approach, which takes time, to reach > the FRED public spec. > Thanks Xin! You can add a simple note in the commit message, such as FRED's dependency on WRMSRNS will be documented, to avoid confusion for later reviewers interested in FRED. Regards, Zhao