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=-12.3 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 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 0B608C433DB for ; Tue, 26 Jan 2021 14:27:22 +0000 (UTC) Received: from lists.xenproject.org (lists.xenproject.org [192.237.175.120]) (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 BFCE7206CA for ; Tue, 26 Jan 2021 14:27:21 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org BFCE7206CA Authentication-Results: mail.kernel.org; dmarc=fail (p=quarantine dis=none) header.from=suse.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=xen-devel-bounces@lists.xenproject.org Received: from list by lists.xenproject.org with outflank-mailman.75124.135186 (Exim 4.92) (envelope-from ) id 1l4PJI-0007bd-II; Tue, 26 Jan 2021 14:27:12 +0000 X-Outflank-Mailman: Message body and most headers restored to incoming version Received: by outflank-mailman (output) from mailman id 75124.135186; Tue, 26 Jan 2021 14:27:12 +0000 Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1l4PJI-0007bW-EL; Tue, 26 Jan 2021 14:27:12 +0000 Received: by outflank-mailman (input) for mailman id 75124; Tue, 26 Jan 2021 14:27:10 +0000 Received: from us1-rack-iad1.inumbo.com ([172.99.69.81]) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1l4PJG-0007bR-IW for xen-devel@lists.xenproject.org; Tue, 26 Jan 2021 14:27:10 +0000 Received: from mx2.suse.de (unknown [195.135.220.15]) by us1-rack-iad1.inumbo.com (Halon) with ESMTPS id 43ae0976-76d6-4985-973a-7ce48dcb6ddb; Tue, 26 Jan 2021 14:27:09 +0000 (UTC) Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id 04D69AB9F; Tue, 26 Jan 2021 14:27:09 +0000 (UTC) X-BeenThere: xen-devel@lists.xenproject.org List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Errors-To: xen-devel-bounces@lists.xenproject.org Precedence: list Sender: "Xen-devel" X-Inumbo-ID: 43ae0976-76d6-4985-973a-7ce48dcb6ddb X-Virus-Scanned: by amavisd-new at test-mx.suse.de DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=susede1; t=1611671229; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=DP9o7AG7KhKYrjHHwEksfK3xiNirkEzXYfFpkJrVL1k=; b=fuFWScGOq2W8pA/n74dDk8npeuyDxzml8J2lore6dvcy/52f7TVUSPJItrNSxIYl1wuNnE 8f3bX2bt3nxmp911YzgI5dnJR6owJnV/TH7LZhofjoRzxHBlRucoyO/MZpyYgR5d7LIkcH Ug7L3Lhp0oxH/ZJIj9taEXYpufyo0C8= Subject: Re: [PATCH v7 10/10] x86/vm_event: Carry Processor Trace buffer offset in vm_event To: Andrew Cooper Cc: Tamas K Lengyel , =?UTF-8?Q?Roger_Pau_Monn=c3=a9?= , Wei Liu , Jun Nakajima , Kevin Tian , =?UTF-8?Q?Micha=c5=82_Leszczy=c5=84ski?= , Tamas K Lengyel , Xen-devel References: <20210121212718.2441-1-andrew.cooper3@citrix.com> <20210121212718.2441-11-andrew.cooper3@citrix.com> From: Jan Beulich Message-ID: Date: Tue, 26 Jan 2021 15:27:09 +0100 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:78.0) Gecko/20100101 Thunderbird/78.6.1 MIME-Version: 1.0 In-Reply-To: <20210121212718.2441-11-andrew.cooper3@citrix.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit On 21.01.2021 22:27, Andrew Cooper wrote: > --- a/xen/arch/x86/vm_event.c > +++ b/xen/arch/x86/vm_event.c > @@ -251,6 +251,9 @@ void vm_event_fill_regs(vm_event_request_t *req) > > req->data.regs.x86.shadow_gs = ctxt.shadow_gs; > req->data.regs.x86.dr6 = ctxt.dr6; > + > + if ( hvm_vmtrace_output_position(curr, &req->data.regs.x86.pt_offset) != 1 ) > + req->data.regs.x86.pt_offset = ~0; Ah. (Regarding my earlier question about this returning -errno or boolean). > --- a/xen/include/public/vm_event.h > +++ b/xen/include/public/vm_event.h > @@ -223,6 +223,12 @@ struct vm_event_regs_x86 { > */ > uint64_t npt_base; > > + /* > + * Current offset in the Processor Trace buffer. For Intel Processor Trace > + * this is MSR_RTIT_OUTPUT_MASK. Set to ~0 if no Processor Trace is active. > + */ > + uint64_t pt_offset; According to vmtrace_output_position() the value is only one half of what the named MSR contains. Perhaps "... this is from MSR_..."? Not sure whether, despite this, there still is a reason to have this 64-bit wide. Jan