From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from fhigh7-smtp.messagingengine.com (fhigh7-smtp.messagingengine.com [103.168.172.158]) (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 CFBD613212F; Thu, 4 Jul 2024 19:44:51 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=103.168.172.158 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1720122293; cv=none; b=FewdVID05QhYghdJel9KnPrGSF4h+iVkHc8MTJ2CGMekPZUm1Uu/CV03kqf2/abgo1x3rjIsIsWLbwUx3WQQvwfjGb2zr0hsEtFyfdx+rCgkbe6IvArmci138mOfD103a8rUrJxiFQxEcjUaYyKOGoFU1kvizqtE5On86QT/Ul4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1720122293; c=relaxed/simple; bh=SmcieX8hv9tdN+Usq0BGXgoTSAC4OEz9ArFb+VdWXhI=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=sFLkywC1hmaFq6A3Yxydauw/69GvlJmIKZ8IS21C29WKch+vBjZTO9NqP30F76sk0S3xdSa5yiX6Uzb2ioeWOtnaeQoTyiryPFi+7saoF62pJp/FHxu7lVk1HEl5k9EUU8BBpfkbv7ZgK+mjUmyHl/prOg8xssRcC6Em95Sn1pE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=flygoat.com; spf=pass smtp.mailfrom=flygoat.com; dkim=pass (2048-bit key) header.d=flygoat.com header.i=@flygoat.com header.b=WDIOgqFF; dkim=pass (2048-bit key) header.d=messagingengine.com header.i=@messagingengine.com header.b=Sr7RX3Tf; arc=none smtp.client-ip=103.168.172.158 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=flygoat.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=flygoat.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=flygoat.com header.i=@flygoat.com header.b="WDIOgqFF"; dkim=pass (2048-bit key) header.d=messagingengine.com header.i=@messagingengine.com header.b="Sr7RX3Tf" Received: from compute4.internal (compute4.nyi.internal [10.202.2.44]) by mailfhigh.nyi.internal (Postfix) with ESMTP id EB04D114022D; Thu, 4 Jul 2024 15:44:50 -0400 (EDT) Received: from mailfrontend1 ([10.202.2.162]) by compute4.internal (MEProxy); Thu, 04 Jul 2024 15:44:50 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=flygoat.com; h= cc:cc:content-transfer-encoding:content-type:content-type:date :date:from:from:in-reply-to:in-reply-to:message-id:mime-version :references:reply-to:subject:subject:to:to; s=fm3; t=1720122290; x=1720208690; bh=Oov9piig11BcDOtLEPIu5MW4Xorms/bDxdNG3mKNI9Q=; b= WDIOgqFFHQmiy59uK1IVrEI9Le+Hi8fs8U1wqx4vhZzfPCiHZqi9u5gFc/7p9Bfe WsQqj+0nii/n7dnUcGr8M6YN3eErEcpqO6UT/GzpdRH67OCO65K+mgJRpg0VO1C5 CP3X6e2kAKUsBDm2eCGJwNz0bAi0n7+iNO98lkmf1rgvoaxS/7GHnPXnFpcxlu74 SafWYQvkruQsjwGB/vHPREo/sGGGKwvFRPDwlb0x00Rx5/p4qQ2bbvXynHocUpbI I6BG/z8G5LHWLK6tzEYYrLWdKSzjFyq3scyWycSZEeRKeJXhqDNxd0/3XhK85JoY HhIh/OuyjuW5EoVh4U7lxA== DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d= messagingengine.com; h=cc:cc:content-transfer-encoding :content-type:content-type:date:date:feedback-id:feedback-id :from:from:in-reply-to:in-reply-to:message-id:mime-version :references:reply-to:subject:subject:to:to:x-me-proxy:x-me-proxy :x-me-sender:x-me-sender:x-sasl-enc; s=fm2; t=1720122290; x= 1720208690; bh=Oov9piig11BcDOtLEPIu5MW4Xorms/bDxdNG3mKNI9Q=; b=S r7RX3TfTtJ4t8Hy9P9UavQOtiP0Wd2rxCfu9K2QZEeXWvzYJ67IqkV/w+BUgqU1w 4tNfBGYGBaLvMhMpVWs3d2yqlEROkszbeXdyVW+F3uvUottg/U5aXCYLdnG+xtDN HTl3Po7A8zwBIgVIV4MYBWSjjwUHBPykcLtDEUraiIescEVBTsCpr2DSHzG6ATNz JBCBZ0OHIYOOnHL9C7j7hSuHYZj8Hv0OtP/Or9uK1y5lES8KsXGXcvcXFoZS6fJp CCJRwPZqBKXBH2FJp9d4xl/Rvu8V/VqbFgzO382vwKtsn7X3+6eYFnWy02zF8ABt bsAVercGaagCZNofrkWZA== X-ME-Sender: X-ME-Received: X-ME-Proxy-Cause: gggruggvucftvghtrhhoucdtuddrgeeftddrudelgddufeekucetufdoteggodetrfdotf fvucfrrhhofhhilhgvmecuhfgrshhtofgrihhlpdfqfgfvpdfurfetoffkrfgpnffqhgen uceurghilhhouhhtmecufedttdenucesvcftvggtihhpihgvnhhtshculddquddttddmne cujfgurhepkfffgggfuffvvehfhffpjggtgfesthekredttderjeenucfhrhhomheplfhi rgiguhhnucgjrghnghcuoehjihgrgihunhdrhigrnhhgsehflhihghhorghtrdgtohhmqe enucggtffrrghtthgvrhhnpeefkefhgeeuieevtdeuhefhhfdtuddvleehvdffjedtieev ledvieegueejleejveenucevlhhushhtvghrufhiiigvpedtnecurfgrrhgrmhepmhgrih hlfhhrohhmpehjihgrgihunhdrhigrnhhgsehflhihghhorghtrdgtohhm X-ME-Proxy: Feedback-ID: ifd894703:Fastmail Received: by mail.messagingengine.com (Postfix) with ESMTPA; Thu, 4 Jul 2024 15:44:48 -0400 (EDT) Message-ID: Date: Fri, 5 Jul 2024 03:44:44 +0800 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Betterbird (Linux) Subject: Re: [PATCH v4 2/3] LoongArch: KVM: Add LBT feature detection function To: maobibo , Huacai Chen Cc: Tianrui Zhao , WANG Xuerui , kvm@vger.kernel.org, loongarch@lists.linux.dev, linux-kernel@vger.kernel.org References: <20240626063239.3722175-1-maobibo@loongson.cn> <20240626063239.3722175-3-maobibo@loongson.cn> <79dcf093-614f-2737-bb03-698b0b3abc57@loongson.cn> <9c7d242e-660b-8d39-b69e-201fd0a4bfbf@loongson.cn> <059d66e4-dd5d-0091-01d9-11aaba9297bd@loongson.cn> <7e6a1dbc-779a-4669-4541-c5952c9bdf24@loongson.cn> <81dded06-ad03-9aed-3f07-cf19c5538723@loongson.cn> <0e28596c-3fe9-b716-b193-200b9b1d5516@loongson.cn> Content-Language: en-US From: Jiaxun Yang In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit On 2024/7/4 09:35, maobibo wrote: > In another thread I found that Jiaxun said he has a solution to make >> LBT be a vcpu feature and still works well. However, that may take >> some time and is too late for 6.11. >> >> But we have another choice now: just remove the UAPI and vm.c parts in >> this series, let the LBT main parts be upstream in 6.11, and then >> solve other problems after 6.11. Even if Jiaxun's solution isn't >> usable, we can still use this old vm feature solution then. IMO this is the best approach to make some progress. > > I am sure it is best if it is VM feature for LBT feature detection, > LSX/LASX feature detection uses CPU feature, we can improve it later. Please justify the reason, we should always be serious on UAPI design choices. I don't really understand why the approach worked so well on Arm & RISC-V is not working for you. I understand you may have some plans in your mind, please elaborate so we can smash them together. That's how community work. > > For host cpu type or migration feature detection, I have no idea now, > also I do not think it will be big issue for me, I will do it with > scheduled time. Of source, welcome Jiaxun and you to implement host > cpu type or migration feature detection. My concern is if you allow CPU features to have "auto" property you are risking create inconsistency among migration. Once you've done that it's pretty hard to get rid of it. Please check how RISC-V dealing with CPU features at QMP side. I'm not meant to hinder your development work, but we should always think ahead. Thanks - Jiaxun >