From mboxrd@z Thu Jan 1 00:00:00 1970 Received: by 10.25.21.156 with SMTP id 28csp1527048lfv; Mon, 15 Aug 2016 09:59:49 -0700 (PDT) X-Received: by 10.55.5.5 with SMTP id 5mr32420829qkf.24.1471280389105; Mon, 15 Aug 2016 09:59:49 -0700 (PDT) Return-Path: Received: from lists.gnu.org (lists.gnu.org. [2001:4830:134:3::11]) by mx.google.com with ESMTPS id s127si12982335qkc.40.2016.08.15.09.59.48 for (version=TLS1 cipher=AES128-SHA bits=128/128); Mon, 15 Aug 2016 09:59:49 -0700 (PDT) Received-SPF: pass (google.com: domain of qemu-arm-bounces+alex.bennee=linaro.org@nongnu.org designates 2001:4830:134:3::11 as permitted sender) client-ip=2001:4830:134:3::11; Authentication-Results: mx.google.com; spf=pass (google.com: domain of qemu-arm-bounces+alex.bennee=linaro.org@nongnu.org designates 2001:4830:134:3::11 as permitted sender) smtp.mailfrom=qemu-arm-bounces+alex.bennee=linaro.org@nongnu.org Received: from localhost ([::1]:38086 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1bZLEq-00052e-Jn for alex.bennee@linaro.org; Mon, 15 Aug 2016 12:59:48 -0400 Received: from eggs.gnu.org ([2001:4830:134:3::10]:39625) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1bZLEn-00052P-8M for qemu-arm@nongnu.org; Mon, 15 Aug 2016 12:59:46 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1bZLEh-0004RS-8m for qemu-arm@nongnu.org; Mon, 15 Aug 2016 12:59:44 -0400 Received: from mx1.redhat.com ([209.132.183.28]:58314) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1bZLEh-0004RN-39; Mon, 15 Aug 2016 12:59:39 -0400 Received: from int-mx09.intmail.prod.int.phx2.redhat.com (int-mx09.intmail.prod.int.phx2.redhat.com [10.5.11.22]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 4E76E61E54; Mon, 15 Aug 2016 16:59:38 +0000 (UTC) Received: from dhcp129-212.brq.redhat.com (dhcp129-212.brq.redhat.com [10.34.129.212]) by int-mx09.intmail.prod.int.phx2.redhat.com (8.14.4/8.14.4) with ESMTP id u7FGxZM8025311 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=NO); Mon, 15 Aug 2016 12:59:36 -0400 Message-ID: <1471280374.3003.10.camel@redhat.com> From: Andrea Bolognani To: Andrew Jones , Wei Huang Date: Mon, 15 Aug 2016 18:59:34 +0200 In-Reply-To: <20160815100938.vve6hknieytt2ys7@kamzik.localdomain> References: <1471067570-7503-1-git-send-email-wei@redhat.com> <20160815100938.vve6hknieytt2ys7@kamzik.localdomain> Content-Type: text/plain; charset="UTF-8" Mime-Version: 1.0 X-Scanned-By: MIMEDefang 2.68 on 10.5.11.22 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.39]); Mon, 15 Aug 2016 16:59:38 +0000 (UTC) Content-Transfer-Encoding: quoted-printable X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 209.132.183.28 Subject: Re: [Qemu-arm] [Qemu-devel] [PATCH V1 1/1] arm64: Add an option to turn on/off host-backed vPMU support X-BeenThere: qemu-arm@nongnu.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: peter.maydell@linaro.org, qemu-arm@nongnu.org, qemu-devel@nongnu.org, shannon.zhao@linaro.org Errors-To: qemu-arm-bounces+alex.bennee=linaro.org@nongnu.org Sender: "Qemu-arm" X-TUID: AyVEHkcUrs3m On Mon, 2016-08-15 at 12:09 +0200, Andrew Jones wrote: > Hmm... so now if the user doesn't specify pmu=3Don (off by default) the= n we > silently disable it (I think that's a 2.6 compat issue), and if they do > specify pmu=3Don, but KVM doesn't support it, then it's silently disabl= ed, > which isn't nice. I think QEMU should error out in that case, explainin= g > that the user specified incompatible options, i.e. they selected accel=3D= kvm > and pmu=3Don, but their KVM version (or cpu model) doesn't support PMU > emulation. I agree. Asking qemu to provide a feature that it can't provide should definitely result in a big fat error. --=C2=A0 Andrea Bolognani / Red Hat / Virtualization