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=-0.9 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,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 E4D25C2D0CF for ; Mon, 16 Dec 2019 09:14:25 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id BC505222D9 for ; Mon, 16 Dec 2019 09:14:25 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="dw3DA+QK" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727210AbfLPJOW (ORCPT ); Mon, 16 Dec 2019 04:14:22 -0500 Received: from us-smtp-2.mimecast.com ([205.139.110.61]:25290 "EHLO us-smtp-delivery-1.mimecast.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1727166AbfLPJOV (ORCPT ); Mon, 16 Dec 2019 04:14:21 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1576487659; 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: in-reply-to:in-reply-to:references:references; bh=zgh8B5UVVhJ0kb2aJHbZhSX9CjHmzX3Tc0hUU8X+B0k=; b=dw3DA+QKWLJv+H/d1j+osckC/ggAZvEJHMXDI6q7YzkkGlJjETWBF9d+RheFcpPjlFIn8b DyJxmW1PBHkNk1vmxV8tpobFbHvaz/CaJbWB9u9+XJ3u7FG8k2+LE7v1GrS8ix+9SZLr0o ycPUvYwaLI68TyGuRMFIPqyHLJpKSd0= Received: from mail-wr1-f71.google.com (mail-wr1-f71.google.com [209.85.221.71]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-168-MRTJvcWZOfCwwEpmZbNmSQ-1; Mon, 16 Dec 2019 04:14:18 -0500 X-MC-Unique: MRTJvcWZOfCwwEpmZbNmSQ-1 Received: by mail-wr1-f71.google.com with SMTP id f15so3463634wrr.2 for ; Mon, 16 Dec 2019 01:14:18 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:in-reply-to:references:date :message-id:mime-version; bh=zgh8B5UVVhJ0kb2aJHbZhSX9CjHmzX3Tc0hUU8X+B0k=; b=CQ3blf7YIgF8hXdC+Mx4ISsgOGEuQcLUmCuk4BxmuqEI7aeJor5v/u5jJGzjZKL5oc GsCjstmnngYSzS7yLQg7Yt9NbHPfIqfQJ2MjFogu8AeMh90WXXwh4ChhLSomzafsOVHT 0JCqiMU+K0IMjAn+f1SvQan4L4oX/9GkJWuOpamJr8EO5OAt8E9fJTuiIZehbOJneMrl uAVImC+jyhx5kx/bnimT5JspP4n5XjLQbYNP0/oE0xY7dbs40GEPka4fi9A00o8NMOFA OQUcgDSbT9lN41Cf+2Q5MmHC8ZZnZtpeKcGWaRq7A/hXFDV2ZZZce4MAL2xGvEmkM4c7 4MpQ== X-Gm-Message-State: APjAAAWpunTETiZ6ctaCRg08BLg311r/OFAdKHObkZ4Sm2ik85IZYrYp BSHVwDPPdXeb+HtGUCtKe+N8v3bS1kbPnVcUMRGuOKuivKQLbLMFGqip3M/Q1YeOsNRyx5oBkst x48EaQ3FIAaAT X-Received: by 2002:a05:600c:2549:: with SMTP id e9mr16935304wma.6.1576487657439; Mon, 16 Dec 2019 01:14:17 -0800 (PST) X-Google-Smtp-Source: APXvYqxXoQiyltOeC7M9BlpXK4XdsqqaREp6LjN+cHXuu5VqMmNwvD7OlJzLsprEYJzn+O3p3AgavQ== X-Received: by 2002:a05:600c:2549:: with SMTP id e9mr16935286wma.6.1576487657225; Mon, 16 Dec 2019 01:14:17 -0800 (PST) Received: from vitty.brq.redhat.com ([95.82.135.38]) by smtp.gmail.com with ESMTPSA id k4sm20814513wmk.26.2019.12.16.01.14.16 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 16 Dec 2019 01:14:16 -0800 (PST) From: Vitaly Kuznetsov To: Gavin Shan Cc: kvm@vger.kernel.org, pbonzini@redhat.com, rkrcmar@redhat.com, paulus@ozlabs.org, jhogan@kernel.org, drjones@redhat.com, Marc Zyngier Subject: Re: [PATCH 3/3] kvm/arm: Standardize kvm exit reason field In-Reply-To: References: <20191212024512.39930-4-gshan@redhat.com> <2e960d77afc7ac75f1be73a56a9aca66@www.loen.fr> <30c0da369a898143246106205cb3af59@www.loen.fr> Date: Mon, 16 Dec 2019 10:14:16 +0100 Message-ID: <87r214aazb.fsf@vitty.brq.redhat.com> MIME-Version: 1.0 Content-Type: text/plain Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org Gavin Shan writes: > On 12/13/19 8:47 PM, Marc Zyngier wrote: >> On 2019-12-13 00:50, Gavin Shan wrote: >>> >>> Yeah, I think it is ABI change unfortunately, but I'm not sure how >>> many applications are using this filter. >> >> Nobody can tell. The problem is that someone will write a script that >> parses this trace point based on an older kernel release (such as >> what the distros are shipping today), and two years from now will >> shout at you (and me) for having broken their toy. >> > > Well, I would like to receive Vitaly's comments here. Vitaly, it seems it's > more realistic to fix the issue from kvm_stat side according to the comments > given by Marc? > Sure, if we decide to treat tracepoints as ABI then fixing users is likely the way to go. Personally, I think that we should have certain freedom with them and consider only tools which live in linux.git when making changes (and changing the tool to match in the same patch series is OK from this PoV, no need to support all possible versions of the tool). Also, we can be a bit more conservative and in this particular case instead of renaming fields just add 'exit_reason' to all architectures where it's missing. For ARM, 'esr_ec' will then stay with what it is and 'exit_reason' may contain something different (like the information why the guest exited actually). But I don't know much about ARM specifics and I'm not sure how feasible the suggestion would be. -- Vitaly