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 F3292C27C77 for ; Wed, 12 Jun 2024 11:05:20 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1sHLmG-0001wk-8p; Wed, 12 Jun 2024 07:04:28 -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 1sHLmE-0001wb-Qz for qemu-devel@nongnu.org; Wed, 12 Jun 2024 07:04:26 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1sHLmC-0002Wa-TL for qemu-devel@nongnu.org; Wed, 12 Jun 2024 07:04:26 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1718190263; h=from:from:reply-to:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type:in-reply-to:in-reply-to: references:references; bh=AQyVqN7iSD/pR2CqV7F/XSQBanFKWHkrFzJ5noQtfvY=; b=D1vQv12E+CCo6V47CKVfkT/Ez9L1CaufLPCu+vjBn03nDX4F3WYLGbcmrY1kbVMrR/v4cS IMP6M9gIgxnIFP3erzOBEGyiV71lVrGKy8IF6GolCNQADlwrcoj6FLDKwsJ8k0KzAKSgc/ zARzSgzsW/aiMOBHn/O1QcumkUk8hM4= Received: from mx-prod-mc-03.mail-002.prod.us-west-2.aws.redhat.com (ec2-54-186-198-63.us-west-2.compute.amazonaws.com [54.186.198.63]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-630-gjl-Xfz7MKCUOCEizMFGzg-1; Wed, 12 Jun 2024 07:04:20 -0400 X-MC-Unique: gjl-Xfz7MKCUOCEizMFGzg-1 Received: from mx-prod-int-01.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-01.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.4]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mx-prod-mc-03.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 9507419560BC; Wed, 12 Jun 2024 11:04:18 +0000 (UTC) Received: from redhat.com (unknown [10.42.28.115]) by mx-prod-int-01.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 749EC30000C4; Wed, 12 Jun 2024 11:04:15 +0000 (UTC) Date: Wed, 12 Jun 2024 12:04:11 +0100 From: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= To: Alexander Monakov Cc: qemu-devel@nongnu.org, Richard Henderson , Paolo Bonzini Subject: Re: [PATCH 0/5] Reinstate ability to use Qemu on pre-SSE4.1 x86 hosts Message-ID: References: <20240612105525.8795-1-amonakov@ispras.ru> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20240612105525.8795-1-amonakov@ispras.ru> User-Agent: Mutt/2.2.12 (2023-09-09) X-Scanned-By: MIMEDefang 3.4.1 on 10.30.177.4 Received-SPF: pass client-ip=170.10.133.124; envelope-from=berrange@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: 11 X-Spam_score: 1.1 X-Spam_bar: + X-Spam_report: (1.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.141, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H4=0.001, RCVD_IN_MSPIKE_WL=0.001, RCVD_IN_SBL_CSS=3.335, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, T_SCC_BODY_TEXT_LINE=-0.01 autolearn=no 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: , Reply-To: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org On Wed, Jun 12, 2024 at 01:55:20PM +0300, Alexander Monakov wrote: > Hello, > > I'm sending straightforward reverts to recent patches that bumped minimum > required x86 instruction set to SSE4.2. The older chips did not stop working, > and people still test and use new software on older hardware: > https://sourceware.org/bugzilla/show_bug.cgi?id=31867 > > Considering the very minor gains from the baseline raise, I'm honestly not > sure why it happened. It seems better to let distributions handle that. Indeed distros are opinionated about the x86_64 baseline they want to target. While RHEL-9 switched to a x86_64-v2 baseline, Fedora has repeatedly rejected the idea of moving to an x86_64-v2 baseline, wanting to retain full backwards compat. So this assumption in QEMU is preventing the distros from satisfying their chosen build target goals. > Alexander Monakov (5): > Revert "host/i386: assume presence of POPCNT" > Revert "host/i386: assume presence of SSSE3" > Revert "host/i386: assume presence of SSE2" > Revert "host/i386: assume presence of CMOV" > Revert "meson: assume x86-64-v2 baseline ISA" > > host/include/i386/host/cpuinfo.h | 3 +++ > meson.build | 10 +++------- > tcg/i386/tcg-target.c.inc | 15 ++++++++++++++- > tcg/i386/tcg-target.h | 5 +++-- > util/bufferiszero.c | 4 ++-- > util/cpuinfo-i386.c | 7 +++++-- > 6 files changed, 30 insertions(+), 14 deletions(-) > > -- > 2.32.0 > > With regards, Daniel -- |: https://berrange.com -o- https://www.flickr.com/photos/dberrange :| |: https://libvirt.org -o- https://fstop138.berrange.com :| |: https://entangle-photo.org -o- https://www.instagram.com/dberrange :|