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=-0.6 required=3.0 tests=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 DC599C432C0 for ; Tue, 19 Nov 2019 09:23:45 +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 A72D220721 for ; Tue, 19 Nov 2019 09:23:45 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=linaro.org header.i=@linaro.org header.b="VsfHeuE3" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org A72D220721 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linaro.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:43084 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1iWzjc-00079j-SV for qemu-devel@archiver.kernel.org; Tue, 19 Nov 2019 04:23:44 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]:58740) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1iWziq-0006Ra-DK for qemu-devel@nongnu.org; Tue, 19 Nov 2019 04:22:57 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1iWzip-0000U9-7N for qemu-devel@nongnu.org; Tue, 19 Nov 2019 04:22:56 -0500 Received: from mail-oi1-x243.google.com ([2607:f8b0:4864:20::243]:38814) by eggs.gnu.org with esmtps (TLS1.0:RSA_AES_128_CBC_SHA1:16) (Exim 4.71) (envelope-from ) id 1iWzip-0000Sh-1P for qemu-devel@nongnu.org; Tue, 19 Nov 2019 04:22:55 -0500 Received: by mail-oi1-x243.google.com with SMTP id a14so18253906oid.5 for ; Tue, 19 Nov 2019 01:22:54 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=INYAegvOpUBaRi4FPo8ZjEkeL6wUMxLwNO+KgbJ3gXI=; b=VsfHeuE31igtz93uXRDmrvmMnS71H+vpMVh8IK0xyWmTnznO6kkulBxLVAoN7g5Nqt DqVdjIrJbtDiVKxcU78RAdsRH5eJXPBk/bCvPuqzKt0oAFl35BvIQF8DtTvgkefBfpR5 ytpmOxCGPbqGWY2Vko/zgKGYlOUI/Jgmq57R+/vOVHYgW+/It1jH69aVHzd9RhNdCs9w 2ombuNddE0U0SbGdDHw8x/By69YowzZvOmVA/QVF270+On+PvB4Hs6bStgpKFBRWXftx qJ74YyoBq2dWFByPTsKdvNriJBrvvhkKaElKFjlkARpeIJXkHfk8j829D6EJ95N9yTe3 d7MQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=INYAegvOpUBaRi4FPo8ZjEkeL6wUMxLwNO+KgbJ3gXI=; b=DFR6iOYqsS8L9RTKdOfu0qvU7d9WYdoS8r9HRHmtSKVq+cvkts+GD0v3JP0LtSsLnA SBjB/K0dwgIXq8Afw3RA8ysGRinwtm9nzY+u46ls66PJrPjQRv2lFpEBljyp3YwH7yCV Gk/CXFSFqPAJ+Ji0N0YfXPAIuMwCfx/bl1vVfH2hZVtHq1YLLeBlH/NmN7lQhfiNpuaE VnorwbCzFC+3uFoa4nzwVSzP9WJyc9UFSGtdnqjjVAGteJXLIskLo6XqVQK/4v5xLDnf MQWhY1zs56h5ELcs6dOPDWKfwKRubIgomsjxDsrtsEITMCFpqtxPoNno3DylbAXTyJfW 7K3w== X-Gm-Message-State: APjAAAW/zz+7f8Y/G+yPCAVQKVv6BAYSAt03q7moJOlrGvJrWSgmM5Mu ONb1SAaMHq/cpEB/TE58NRopYz+vqwFgXr+ZAVMsaQ== X-Google-Smtp-Source: APXvYqzHBQQ6NtVrgBUqRoknC4LDQfFlsz2kVDCS8PP/yzobSSG44vqgR5pUZL2rAvyFafIVKnEqqHEFjXbBVWZgbb4= X-Received: by 2002:aca:cf12:: with SMTP id f18mr3076287oig.48.1574155373787; Tue, 19 Nov 2019 01:22:53 -0800 (PST) MIME-Version: 1.0 References: <5dd613c0-6d9e-b943-b64d-7ba1791cbefe@redhat.com> <20191108191057.GZ3812@habkost.net> <66c64c6d-b7c0-2cb1-2b29-4fdd9b369714@redhat.com> <3aa1d025-20a3-e813-2fe6-35518efedf2f@redhat.com> <20191118184906.GB3812@habkost.net> <20191118220417.GF3812@habkost.net> In-Reply-To: <20191118220417.GF3812@habkost.net> From: Peter Maydell Date: Tue, 19 Nov 2019 09:22:42 +0000 Message-ID: Subject: Re: [PATCH v1 0/2] s390x/cpumodel: Introduce "best" model variants To: Eduardo Habkost Content-Type: text/plain; charset="UTF-8" X-detected-operating-system: by eggs.gnu.org: Genre and OS details not recognized. X-Received-From: 2607:f8b0:4864:20::243 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: Thomas Huth , =?UTF-8?Q?Daniel_P_=2E_Berrang=C3=A9?= , Janosch Frank , David Hildenbrand , Cornelia Huck , Richard Henderson , QEMU Developers , Markus Armbruster , Halil Pasic , Christian Borntraeger , qemu-s390x , Michael Mueller , Jiri Denemark Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On Mon, 18 Nov 2019 at 22:04, Eduardo Habkost wrote: > > On Mon, Nov 18, 2019 at 09:19:55PM +0000, Peter Maydell wrote: > > Why should it matter whether a feature is enabled > > or disabled by default in the CPU type? It ought to be probeable > > by QMP either way (ie there is a difference between > > "this CPU has this feature switch and it is on by default", > > "this CPU has this feature switch and it is off by default" > > and "this CPU does not have this feature switch at all", > > and presumably libvirt needs to distinguish them). > > Its use case is neither "this CPU has this feature switch" or for > "it is on|off by default". We use it to probe for "this feature > can be enabled in this host hardware+kernel+QEMU combination". OK. Well, the answer to that depends on the name of the CPU, in general. So you can't use a fake CPU name to try to answer the question. > In other words, in x86 and s390x "max" is just a reserved name > for the query-cpu-model-expansion command arguments in s390x and > x86. The fact that it is visible to users can be considered a > bug, and we can fix that. I think 'max' is useful to users, and we've provided it to users, so removing it again would be a compatibility break. I'm not entirely sure where we go from here... > If you still don't like how query-cpu-model-expansion works, we > can also discuss that. But I'm not sure it would be a good use > of our (and libvirt developers') time. I don't hugely care about query-cpu-model-expansion. I just don't want it to have bad effects on the semantics of user-facing stuff like x- properties. thanks -- PMM