From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:40621) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1bUDFY-0001ae-28 for qemu-devel@nongnu.org; Mon, 01 Aug 2016 09:27:24 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1bUDFS-0000bk-0x for qemu-devel@nongnu.org; Mon, 01 Aug 2016 09:27:19 -0400 Message-ID: <1470058019.3971.13.camel@redhat.com> From: Andrea Bolognani Date: Mon, 01 Aug 2016 15:26:59 +0200 In-Reply-To: <20160801130808.2igpsx52opi7ogvk@kamzik.localdomain> References: <1469723896-28049-1-git-send-email-wei@redhat.com> <20160729065453.qq44y2hxohizk3yw@hawk.localdomain> <1470053099.3971.11.camel@redhat.com> <20160801130808.2igpsx52opi7ogvk@kamzik.localdomain> Content-Type: text/plain; charset="UTF-8" Mime-Version: 1.0 Content-Transfer-Encoding: quoted-printable Subject: Re: [Qemu-devel] [PATCH RFC 1/1] arm64: add an option to turn on/off vpmu support List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Andrew Jones Cc: Wei Huang , qemu-arm@nongnu.org, qemu-devel@nongnu.org, peter.maydell@linaro.org, shannon.zhao@linaro.org On Mon, 2016-08-01 at 15:08 +0200, Andrew Jones wrote: > > I'm not sure a warning is enough: if I start a guest and > > explicitly ask for a PMU, I expect it to be there, or for > > the guest not to start at all. How does x86 behave in this > > regard? >=C2=A0 > Peter had a good suggestion for this. We need to wrap the property > addition in an arm_feature check like the has_el3 property. That will > remove it from all cpu types that don't support it. Wouldn't that mean that you'd be unable to use =C2=A0 -cpu foo,pmu=3Doff if CPU model 'foo' doesn't support a PMU? I'd expect that to work. I've played around with this a bit on x86 and it doesn't look like it necessarily behaves the way I'd expect it to, either, so maybe this is just a case of my expectations being unreasonable? :) --=C2=A0 Andrea Bolognani / Red Hat / Virtualization