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=-7.0 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 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 D6C28C433DF for ; Fri, 7 Aug 2020 06:24:36 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id AA0D022D00 for ; Fri, 7 Aug 2020 06:24:36 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726448AbgHGGYf (ORCPT ); Fri, 7 Aug 2020 02:24:35 -0400 Received: from mga03.intel.com ([134.134.136.65]:57393 "EHLO mga03.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725379AbgHGGYf (ORCPT ); Fri, 7 Aug 2020 02:24:35 -0400 IronPort-SDR: 31i3ylkGB3hKMkCLwwl7zL4105EViOSCJOPAGVmGXTbED3wketAtP3/+n35i8pkOSYRC0tm99W YHs8/CRWN3vA== X-IronPort-AV: E=McAfee;i="6000,8403,9705"; a="152977193" X-IronPort-AV: E=Sophos;i="5.75,444,1589266800"; d="scan'208";a="152977193" X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga008.jf.intel.com ([10.7.209.65]) by orsmga103.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 06 Aug 2020 23:24:34 -0700 IronPort-SDR: huJd/lVVwUtCWnSKGLh7ckeH+x+Y58COZcTNohZIkopRpa4YH9GaJO5+Rc0wia8Ylek+jqD4N9 dDzDp97VQBsA== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.75,444,1589266800"; d="scan'208";a="323671588" Received: from yjin15-mobl1.ccr.corp.intel.com (HELO [10.238.5.239]) ([10.238.5.239]) by orsmga008.jf.intel.com with ESMTP; 06 Aug 2020 23:24:31 -0700 Subject: Re: [PATCH v1 2/2] perf/core: Fake regs for leaked kernel samples To: peterz@infradead.org Cc: mingo@redhat.com, oleg@redhat.com, acme@kernel.org, jolsa@kernel.org, Linux-kernel@vger.kernel.org, ak@linux.intel.com, kan.liang@intel.com, yao.jin@intel.com, alexander.shishkin@linux.intel.com, mark.rutland@arm.com References: <20200731025617.16243-1-yao.jin@linux.intel.com> <20200731025617.16243-2-yao.jin@linux.intel.com> <20200804114900.GI2657@hirez.programming.kicks-ass.net> <4c958d61-11a7-9f3e-9e7d-d733270144a1@linux.intel.com> <20200805124454.GP2657@hirez.programming.kicks-ass.net> <797aa4de-c618-f340-ad7b-cef38c96b035@linux.intel.com> <20200806091827.GY2674@hirez.programming.kicks-ass.net> <20200806110046.GF35926@hirez.programming.kicks-ass.net> From: "Jin, Yao" Message-ID: <1d03d443-b187-bc1f-2601-a54037a64eff@linux.intel.com> Date: Fri, 7 Aug 2020 14:24:30 +0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:68.0) Gecko/20100101 Thunderbird/68.11.0 MIME-Version: 1.0 In-Reply-To: <20200806110046.GF35926@hirez.programming.kicks-ass.net> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Peter, On 8/6/2020 7:00 PM, peterz@infradead.org wrote: > On Thu, Aug 06, 2020 at 11:18:27AM +0200, peterz@infradead.org wrote: > >> Suppose we have nested virt: >> >> L0-hv >> | >> G0/L1-hv >> | >> G1 >> >> And we're running in G0, then: >> >> - 'exclude_hv' would exclude L0 events >> - 'exclude_host' would ... exclude L1-hv events? >> - 'exclude_guest' would ... exclude G1 events? > > So in arch/x86/events/intel/core.c we have: > > static inline void intel_set_masks(struct perf_event *event, int idx) > { > struct cpu_hw_events *cpuc = this_cpu_ptr(&cpu_hw_events); > > if (event->attr.exclude_host) > __set_bit(idx, (unsigned long *)&cpuc->intel_ctrl_guest_mask); > if (event->attr.exclude_guest) > __set_bit(idx, (unsigned long *)&cpuc->intel_ctrl_host_mask); > if (event_is_checkpointed(event)) > __set_bit(idx, (unsigned long *)&cpuc->intel_cp_status); > } > exclude_host is now set by guest (pmc_reprogram_counter, arch/x86/kvm/pmu.c). When enabling the event, we can check exclude_host to know if it's a guest. Otherwise we may need more flags in event->attr to indicate the status. > which is, afaict, just plain wrong. Should that not be something like: > > if (!event->attr.exclude_host) > __set_bit(idx, (unsigned long *)&cpuc->intel_ctrl_host_mask); > if (!event->attr.exclude_guest) > __set_bit(idx, (unsigned long *)&cpuc->intel_ctrl_guest_mask); > > How can we know it's guest or host even if exclude_host is set in guest? Thanks Jin Yao > Also, ARM64 seems to also implement this stuff, Mark, do you have any > insight on how all this is 'supposed' to work? >