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=-12.5 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, 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 59538C433E6 for ; Fri, 22 Jan 2021 16:31:14 +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 192ED23A7D for ; Fri, 22 Jan 2021 16:31:14 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 192ED23A7D 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.72967.131549 (Exim 4.92) (envelope-from ) id 1l2zKz-00026Z-KJ; Fri, 22 Jan 2021 16:31:05 +0000 X-Outflank-Mailman: Message body and most headers restored to incoming version Received: by outflank-mailman (output) from mailman id 72967.131549; Fri, 22 Jan 2021 16:31:05 +0000 Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1l2zKz-00026R-HC; Fri, 22 Jan 2021 16:31:05 +0000 Received: by outflank-mailman (input) for mailman id 72967; Fri, 22 Jan 2021 16:31:04 +0000 Received: from us1-rack-iad1.inumbo.com ([172.99.69.81]) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1l2zKy-00026L-5V for xen-devel@lists.xenproject.org; Fri, 22 Jan 2021 16:31:04 +0000 Received: from mx2.suse.de (unknown [195.135.220.15]) by us1-rack-iad1.inumbo.com (Halon) with ESMTPS id a1302fc1-3d5f-4578-a6b8-bc9bfcd3b932; Fri, 22 Jan 2021 16:31:03 +0000 (UTC) Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id 8C820AF55; Fri, 22 Jan 2021 16:31:02 +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: a1302fc1-3d5f-4578-a6b8-bc9bfcd3b932 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=1611333062; 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=O7a/Zyytzg3YUE+x0QCxzMkbKbeUK2iNB/hBGFCQJho=; b=ILk8MoaDQoWHIoSFbTbcb2sH+qmntK5iAJavlfDovnSo/0rQ3k4R/qiv43hX5/Gy3UR+hj YvrRBhYlkkrxVeOIszBaTH+3EL5kZjFIs234RaNSiTeAh+5yeb+lnOj7XEt7XStuF5JxD+ GdSAmQjEeZHO2mpjjZh5vpOsc6rAYok= Subject: Re: [PATCH 15/17] x86/shadow: drop SH_type_l2h_pae_shadow To: Tim Deegan Cc: "xen-devel@lists.xenproject.org" , Andrew Cooper , Wei Liu , =?UTF-8?Q?Roger_Pau_Monn=c3=a9?= , George Dunlap References: <4f1975a9-bdd9-f556-9db5-eb6c428f258f@suse.com> From: Jan Beulich Message-ID: Date: Fri, 22 Jan 2021 17:31:02 +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: Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit On 22.01.2021 14:11, Tim Deegan wrote: > At 16:10 +0100 on 14 Jan (1610640627), Jan Beulich wrote: >> This is a remnant from 32-bit days, having no place anymore where a >> shadow of this type would be created. >> >> Signed-off-by: Jan Beulich >> --- >> hash_{domain,vcpu}_foreach() have a use each of literal 15. It's not >> clear to me what the proper replacement constant would be, as it >> doesn't look as if SH_type_monitor_table was meant. > > Good spot. I think the '<= 15' should be replaced with '< SH_type_unused'. > It originally matched the callback arrays all being coded as > "static hash_callback_t callbacks[16]". So are you saying this was off by one then prior to this patch (when SH_type_unused was still 17), albeit in apparently a benign way? And the comments in sh_remove_write_access(), sh_remove_all_mappings(), sh_remove_shadows(), and sh_reset_l3_up_pointers() are then wrong as well, and would instead better be like in shadow_audit_tables()? Because of this having been benign (due to none of the callback tables specifying non-NULL entries there), wouldn't it make sense to dimension the tables by SH_type_max_shadow + 1 only? Or would you consider this too risky? In any event I guess I'll make the patch addressing this (one way or the other) a prereq to everything here. Jan