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 X-Spam-Level: X-Spam-Status: No, score=-3.6 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id E0B25C433E0 for ; Wed, 20 Jan 2021 10:00:16 +0000 (UTC) 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 mail.kernel.org (Postfix) with ESMTPS id 4C8002332A for ; Wed, 20 Jan 2021 10:00:16 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 4C8002332A Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:37748 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1l2AHf-0005tq-B4 for qemu-devel@archiver.kernel.org; Wed, 20 Jan 2021 05:00:15 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]:57264) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1l2AH3-0005UL-2m for qemu-devel@nongnu.org; Wed, 20 Jan 2021 04:59:37 -0500 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]:34622) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA1:256) (Exim 4.90_1) (envelope-from ) id 1l2AH1-0007ZC-IM for qemu-devel@nongnu.org; Wed, 20 Jan 2021 04:59:36 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1611136774; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=KjTPR/DfQlG40nP6llGhEKB0T34Hf6G82Lf9PCIHxQY=; b=AVyd14FkQHLmLQuQRhSvYYBh3Xc+IVYkU9u7cygWO1/9EYZwzUsoKqTTIWwpQfEpuc/c9c hJYdzIPgd0yi7KRWS7AgNXf7X32iGRf4jrJzJeWOYDo9zJmxTuEnr59mUaSVXmLUSgS+gA II3yGFXETh4+LnLklXQ2IW899yni96A= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-18-aY-iat-MO_aTQJJtYRaaWA-1; Wed, 20 Jan 2021 04:59:33 -0500 X-MC-Unique: aY-iat-MO_aTQJJtYRaaWA-1 Received: from smtp.corp.redhat.com (int-mx05.intmail.prod.int.phx2.redhat.com [10.5.11.15]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 030D359; Wed, 20 Jan 2021 09:59:32 +0000 (UTC) Received: from localhost (unknown [10.40.208.9]) by smtp.corp.redhat.com (Postfix) with ESMTP id 2FC1369321; Wed, 20 Jan 2021 09:59:26 +0000 (UTC) Date: Wed, 20 Jan 2021 10:59:24 +0100 From: Igor Mammedov To: Eduardo Habkost Subject: Re: [External] : Re: [RFC PATCH 1/2] hw/i386: -cpu model,-feature,+feature should enable feature Message-ID: <20210120105924.3ffd1723@redhat.com> In-Reply-To: <20210119163052.GG1227584@habkost.net> References: <20210119142207.3443123-1-david.edmondson@oracle.com> <20210119142207.3443123-2-david.edmondson@oracle.com> <20210119152056.GE1227584@habkost.net> <20210119163052.GG1227584@habkost.net> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.15 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=imammedo@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Received-SPF: pass client-ip=170.10.133.124; envelope-from=imammedo@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -22 X-Spam_score: -2.3 X-Spam_bar: -- X-Spam_report: (-2.3 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.195, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, 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: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Laurent Vivier , Thomas Huth , "Michael S. Tsirkin" , David Edmondson , Richard Henderson , qemu-devel@nongnu.org, Paolo Bonzini Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On Tue, 19 Jan 2021 11:30:52 -0500 Eduardo Habkost wrote: > On Tue, Jan 19, 2021 at 04:27:56PM +0000, David Edmondson wrote: > > On Tuesday, 2021-01-19 at 10:20:56 -05, Eduardo Habkost wrote: > > > > > Hi, > > > > > > Thanks for the patch. Getting rid of special -feature/+feature > > > behavior was in our TODO list for a long time. > > > > > > On Tue, Jan 19, 2021 at 02:22:06PM +0000, David Edmondson wrote: > > >> "Minus" features are applied after "plus" features, so ensure that a > > >> later "plus" feature causes an earlier "minus" feature to be removed. > > >> > > >> This has no effect on the existing "-feature,feature=on" backward > > >> compatibility code (which warns and turns the feature off). > > > > > > If we are changing behavior, why not change behavior of > > > "-feature,feature=on" at the same time? This would allow us to > > > get rid of plus_features/minus_features completely and just make > > > +feature/-feature synonyms to feature=on/feature=off. > > > > Okay, I'll do that. > > > > Given that there have been warnings associated with > > "-feature,feature=on" for a while, changing that behaviour seems > > acceptable. > > > > Would the same be true for changing "-feature,+feature"? (i.e. what this > > patch does) Really: can this just be changed, or does there have to be > > some period where the behaviour stays the same with a warning? > > I actually expected warnings to be triggered when using > "-feature,+feature" as well. If we were not generating warnings > for that case, it will need more careful evaluation, just to be > sure it's safe. Igor, do you remember the details here? As part of preparation to define/create machines via QMP, I plan to post patch(s) to deprecate +-features in 6.0 (including special casing for -feat behavior (affects x86/sparc only)) and drop support for +-feat in 2 releases. So we should end up with canonical property behavior only like all other CPUs and devices.