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=-17.2 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,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 32150C433B4 for ; Fri, 23 Apr 2021 12:53:34 +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 C5685613F5 for ; Fri, 23 Apr 2021 12:53:33 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org C5685613F5 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.116304.221988 (Exim 4.92) (envelope-from ) id 1lZvJ8-0001OT-5j; Fri, 23 Apr 2021 12:53:18 +0000 X-Outflank-Mailman: Message body and most headers restored to incoming version Received: by outflank-mailman (output) from mailman id 116304.221988; Fri, 23 Apr 2021 12:53:18 +0000 Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1lZvJ8-0001OM-27; Fri, 23 Apr 2021 12:53:18 +0000 Received: by outflank-mailman (input) for mailman id 116304; Fri, 23 Apr 2021 12:53:17 +0000 Received: from all-amaz-eas1.inumbo.com ([34.197.232.57] helo=us1-amaz-eas2.inumbo.com) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1lZvJ7-0001OG-54 for xen-devel@lists.xenproject.org; Fri, 23 Apr 2021 12:53:17 +0000 Received: from mx2.suse.de (unknown [195.135.220.15]) by us1-amaz-eas2.inumbo.com (Halon) with ESMTPS id aba5f916-d7af-4dcb-9674-7c6fda0182d2; Fri, 23 Apr 2021 12:53:15 +0000 (UTC) Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id CC86FB1B1; Fri, 23 Apr 2021 12:53:14 +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: aba5f916-d7af-4dcb-9674-7c6fda0182d2 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=1619182394; 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=OH1ib3JmgY4rmD88rHAp/fAvcQqWqkmqvTRWo8WAEiE=; b=WZq/sSibEFlVgkk+XF4pq/IfTzj3KPe0icbBVZazaxovx2P/SXoAB062E5rCUxJeV7Z3tk fpsMK3nO98a4Gw1U9Se4zmVDdpTTfoQA8dFvO3zaBkyz9/u3ZBgMZO3CV6qSZhcpYHk0QH 0k7LPeEhNK1FI9dB65PuE73W2r0fiRA= Subject: Re: [PATCH] x86/oprofile: remove compat accessors usage from backtrace To: Roger Pau Monne Cc: Andrew Cooper , Wei Liu , xen-devel@lists.xenproject.org References: <20210423123509.9354-1-roger.pau@citrix.com> From: Jan Beulich Message-ID: <7d77cd67-5866-9d58-b2d0-b8d28b827084@suse.com> Date: Fri, 23 Apr 2021 14:53:14 +0200 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:78.0) Gecko/20100101 Thunderbird/78.10.0 MIME-Version: 1.0 In-Reply-To: <20210423123509.9354-1-roger.pau@citrix.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit On 23.04.2021 14:35, Roger Pau Monne wrote: > Remove the unneeded usage of the compat layer to copy frame pointers > from guest address space. Instead just use raw_copy_from_guest. > > Reported-by: Andrew Cooper > Signed-off-by: Roger Pau Monné > --- > Just build tested. Note sure I'm missing something, since using the > compat layer here was IMO much more complicated than just using the > raw accessors. The main reason, I suppose, was that raw_copy_*() aren't supposed to be used directly. > @@ -59,34 +56,17 @@ dump_guest_backtrace(struct vcpu *vcpu, const struct frame_head *head, > { > frame_head_t bufhead; > > -#ifdef CONFIG_COMPAT > if ( is_32bit_vcpu(vcpu) ) > { > - DEFINE_COMPAT_HANDLE(frame_head32_t); > - __compat_handle_const_frame_head32_t guest_head = > - { .c = (unsigned long)head }; You're losing the truncation to 32 bits here. > frame_head32_t bufhead32; > > - /* Also check accessibility of one struct frame_head beyond */ > - if (!compat_handle_okay(guest_head, 2)) > - return 0; If you intentionally remove this and ... > - if (__copy_from_compat(&bufhead32, guest_head, 1)) > + if (raw_copy_from_guest(&bufhead32, head, sizeof(bufhead32))) > return 0; > bufhead.ebp = (struct frame_head *)(unsigned long)bufhead32.ebp; > bufhead.ret = bufhead32.ret; > } > - else > -#endif > - { > - XEN_GUEST_HANDLE_PARAM(const_frame_head_t) guest_head = > - const_guest_handle_from_ptr(head, frame_head_t); > - > - /* Also check accessibility of one struct frame_head beyond */ > - if (!guest_handle_okay(guest_head, 2)) > - return 0; ... this, then you should justify why these aren't needed anymore (or maybe were never really needed). They've been put there for a purpose, I'm sure, even if I'm unclear about what one it was/is. Jan