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=-2.3 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,USER_AGENT_MUTT autolearn=ham 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 34396ECE566 for ; Thu, 20 Sep 2018 15:31:59 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id DC8E721529 for ; Thu, 20 Sep 2018 15:31:58 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org DC8E721529 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linux.intel.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732963AbeITVP6 (ORCPT ); Thu, 20 Sep 2018 17:15:58 -0400 Received: from mga05.intel.com ([192.55.52.43]:54579 "EHLO mga05.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728444AbeITVP6 (ORCPT ); Thu, 20 Sep 2018 17:15:58 -0400 X-Amp-Result: UNKNOWN X-Amp-Original-Verdict: FILE UNKNOWN X-Amp-File-Uploaded: False Received: from fmsmga007.fm.intel.com ([10.253.24.52]) by fmsmga105.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 20 Sep 2018 08:31:53 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.53,398,1531810800"; d="scan'208";a="71571741" Received: from tassilo.jf.intel.com (HELO tassilo.localdomain) ([10.7.201.126]) by fmsmga007.fm.intel.com with ESMTP; 20 Sep 2018 08:30:35 -0700 Received: by tassilo.localdomain (Postfix, from userid 1000) id 455C7301A71; Thu, 20 Sep 2018 08:30:35 -0700 (PDT) Date: Thu, 20 Sep 2018 08:30:35 -0700 From: Andi Kleen To: Wei Wang Cc: linux-kernel@vger.kernel.org, kvm@vger.kernel.org, pbonzini@redhat.com, kan.liang@intel.com, peterz@infradead.org, mingo@redhat.com, rkrcmar@redhat.com, like.xu@intel.com, jannh@google.com, arei.gonglei@huawei.com Subject: Re: [PATCH v3 4/5] KVM/x86/vPMU: Add APIs to support host save/restore the guest lbr stack Message-ID: <20180920153035.GB10360@tassilo.jf.intel.com> References: <1537437959-8751-1-git-send-email-wei.w.wang@intel.com> <1537437959-8751-5-git-send-email-wei.w.wang@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1537437959-8751-5-git-send-email-wei.w.wang@intel.com> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org > +int intel_pmu_enable_save_guest_lbr(struct kvm_vcpu *vcpu) > +{ > + struct kvm_pmu *pmu = vcpu_to_pmu(vcpu); > + struct perf_event *event; > + struct perf_event_attr attr = { > + .type = PERF_TYPE_RAW, > + .size = sizeof(attr), > + .pinned = true, > + .exclude_host = true, > + .sample_type = PERF_SAMPLE_BRANCH_STACK, > + .branch_sample_type = PERF_SAMPLE_BRANCH_CALL_STACK | > + PERF_SAMPLE_BRANCH_USER | > + PERF_SAMPLE_BRANCH_KERNEL, I think that will allocate an extra perfmon counter, right? So if the guest wants to use all perfmon counters we would start to multiplex, which would be bad Would need to fix perf core to not allocate a perfmon counter in this case, if no period and no event count is requested. -Andi