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=-0.8 required=3.0 tests=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 576A9C433DF for ; Wed, 3 Jun 2020 15:01:18 +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 271E520679 for ; Wed, 3 Jun 2020 15:01:18 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 271E520679 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=huawei.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:47238 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1jgUtJ-0006nb-AY for qemu-devel@archiver.kernel.org; Wed, 03 Jun 2020 11:01:17 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:35810) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1jgUlk-0008PH-OT; Wed, 03 Jun 2020 10:53:28 -0400 Received: from lhrrgout.huawei.com ([185.176.76.210]:2106 helo=huawei.com) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1jgUlj-0000Z9-1B; Wed, 03 Jun 2020 10:53:28 -0400 Received: from lhreml701-chm.china.huawei.com (unknown [172.18.7.108]) by Forcepoint Email with ESMTP id 123029BDA1E0E550BEA2; Wed, 3 Jun 2020 15:53:22 +0100 (IST) Received: from lhreml703-chm.china.huawei.com (10.201.108.52) by lhreml701-chm.china.huawei.com (10.201.108.50) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256_P256) id 15.1.1913.5; Wed, 3 Jun 2020 15:53:21 +0100 Received: from lhreml703-chm.china.huawei.com ([10.201.68.198]) by lhreml703-chm.china.huawei.com ([10.201.68.198]) with mapi id 15.01.1913.007; Wed, 3 Jun 2020 15:53:21 +0100 From: Salil Mehta To: Andrew Jones Subject: RE: [Question] Regarding PMU initialization within the QEMU for ARM VCPUs Thread-Topic: [Question] Regarding PMU initialization within the QEMU for ARM VCPUs Thread-Index: AdY3+/mIYt1+TQdDQmymnxAa7PkUWwBhkdKAAAS79tAAAMvMAAAC6ahgAAIBWIAAAj9tUA== Date: Wed, 3 Jun 2020 14:53:21 +0000 Message-ID: <70ab2e21085844999f5f8615b32dde1d@huawei.com> References: <20200603093745.dwfb55ny34az7rez@kamzik.brq.redhat.com> <6bacdd359e504ed8924e67ed125bf15d@huawei.com> <20200603121606.bj3mjlqsstzbu7py@kamzik.brq.redhat.com> <5cb329f13566411eadfeca7c9a1b4bf5@huawei.com> <20200603143655.vk3uqw5lvgv6sm5p@kamzik.brq.redhat.com> In-Reply-To: <20200603143655.vk3uqw5lvgv6sm5p@kamzik.brq.redhat.com> Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-originating-ip: [10.47.30.55] Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 X-CFilter-Loop: Reflected Received-SPF: pass client-ip=185.176.76.210; envelope-from=salil.mehta@huawei.com; helo=huawei.com X-detected-operating-system: by eggs.gnu.org: First seen = 2020/06/03 07:45:22 X-ACL-Warn: Detected OS = Linux 3.11 and newer [fuzzy] X-Spam_score_int: -41 X-Spam_score: -4.2 X-Spam_bar: ---- X-Spam_report: (-4.2 / 5.0 requ) BAYES_00=-1.9, RCVD_IN_DNSWL_MED=-2.3, RCVD_IN_MSPIKE_H3=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_HELO_PASS=-0.001, SPF_PASS=-0.001, URIBL_BLOCKED=0.001 autolearn=_AUTOLEARN 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: Peter Maydell , "gshan@redhat.com" , "mst@redhat.com" , "qemu-devel@nongnu.org" , "eric.auger@redhat.com" , "qemu-arm@nongnu.org" , Igor Mammedov Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" > From: Qemu-arm [mailto:qemu-arm-bounces+salil.mehta=3Dhuawei.com@nongnu.o= rg] > On Behalf Of Andrew Jones > Sent: Wednesday, June 3, 2020 3:37 PM > To: Salil Mehta > Cc: Peter Maydell ; mst@redhat.com; > qemu-devel@nongnu.org; eric.auger@redhat.com; qemu-arm@nongnu.org; Igor > Mammedov > Subject: Re: [Question] Regarding PMU initialization within the QEMU for = ARM > VCPUs >=20 > On Wed, Jun 03, 2020 at 01:48:10PM +0000, Salil Mehta wrote: > > (Maybe I should float the ARM VCPU Hotplug patches and let this > > discussion be held over there?) > > >=20 > Yes, I think that would be best. Keep in mind that the 'pmu' CPU property > is just one CPU property that we require all CPUs to have, if any have it= . > 'aarch64' and 'sve' are two other examples. And, likely any CPU feature > that comes down the line that we want to use with KVM will fit that > pattern. I think the hotplug patch series will need to handle those > features in some way other than to push them all into machine properties. Sure, I do have realization about that. I have for now used a per virt machine flag for PMU to do a workaround of the problem I discussed. Maybe once I float the patches further comments on the ways to improve the design would be very helpful. So for now I will keep the flag and use this approach and invite everyone for open discussion about this and we could evolve the design as we discuss there. Many thanks Salil.