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=-5.5 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,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 D4B41C433DF for ; Fri, 16 Oct 2020 13:19:13 +0000 (UTC) Received: from merlin.infradead.org (merlin.infradead.org [205.233.59.134]) (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 58DCC20848 for ; Fri, 16 Oct 2020 13:19:13 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="mxUpmI2W" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 58DCC20848 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=arm.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=merlin.20170209; h=Sender:Content-Type: Content-Transfer-Encoding:Cc:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:Date:Message-ID:From: References:To:Subject:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=H1ti3nLHcZMH38FQXp6xk37o/V7onOQcbZ+lG3zjFuw=; b=mxUpmI2WMm4MFDDhLHMU0fJfp c4UW/OE9sGzNHgOrWlMsbZdIdhboYYnWzSL3yWWN6rljZsLGn5STjhIrM2LHh7cXWh6ujOLR8l7Ig XpLxCrj9MAsQheDAPHk0DLFRRj/1CDz9bxsrP115Tf5nE627/hcZg92JN8Fia3hurmQ6mwPWBz5ym wSfc9ABrYK3K2a1VTBhwqj0foa9tac9NYf0PjLneN+q8IbqL7N/1tbIHJ9+joPzn4FRIHfOZ4Hw3A BW49ojNcbQPkZfVcer33ApkvVomnxXc6q7bxff8cYZz64Filp17IMnQqENvgZT+0TvDgAtGlDF84a FMjV039wA==; Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1kTPcO-0005Az-2j; Fri, 16 Oct 2020 13:18:00 +0000 Received: from foss.arm.com ([217.140.110.172]) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1kTPcL-0005AB-KC for linux-arm-kernel@lists.infradead.org; Fri, 16 Oct 2020 13:17:58 +0000 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 79AEC1FB; Fri, 16 Oct 2020 06:17:56 -0700 (PDT) Received: from [10.57.50.28] (unknown [10.57.50.28]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 87CB73F71F; Fri, 16 Oct 2020 06:17:53 -0700 (PDT) Subject: Re: [PATCH] coresight: etm4x: Add config to exclude kernel mode tracing To: Leo Yan References: <20201015124522.1876-1-saiprakash.ranjan@codeaurora.org> <20201015160257.GA1450102@xps15> <20201016072401.GC4646@leoy-ThinkPad-X240s> <20201016092450.GG4646@leoy-ThinkPad-X240s> <20201016131407.GA31839@leoy-ThinkPad-X240s> From: Suzuki Poulose Message-ID: <16b3be3a-0d2d-0d0f-24a5-020480ed980c@arm.com> Date: Fri, 16 Oct 2020 14:17:51 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.3.1 MIME-Version: 1.0 In-Reply-To: <20201016131407.GA31839@leoy-ThinkPad-X240s> Content-Language: en-GB X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20201016_091757_714978_1C0F668C X-CRM114-Status: GOOD ( 16.41 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Sai Prakash Ranjan , Denis Nikitin , Mathieu Poirier , linux-arm-msm@vger.kernel.org, coresight@lists.linaro.org, linux-kernel@vger.kernel.org, Stephen Boyd , linux-arm-kernel@lists.infradead.org, Mike Leach Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset="us-ascii"; Format="flowed" Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On 10/16/20 2:14 PM, Leo Yan wrote: > On Fri, Oct 16, 2020 at 12:38:47PM +0100, Suzuki Kuruppassery Poulose wrote: > > [...] > >>>> What happens to the sysfs mode of tracing? For that we would still >>>> need a config right to exclude kernel mode tracing completely. >>> >>> IIUC, sysfs mode and perf mode both can apply the same approach, the >>> guest OS runs a thread context for the host, so when a guest OS is >>> switched in or out, the hypervisor can save/restore the context for >>> the guest OS; thus every guest OS will have its dedicated context and >>> trace data ideally. >> >> I don't think Guest Context is something we can support as mentioned >> above, at least for systems without sysreg access for ETMs (and virtualizing >> ETRs is a different story !) > > Thanks for sharing thoughts, Suzuki. > > I missed the device virtulisation. Here should virtualize all devices > (includes CoreSight ETM/funnel/ETR/ETF)? Or only need to virtualize > ETRs? I wouldn't even think of virtualizing the components without sysreg access. So let us not worry about it :-) Cheers Suzuki _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel