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=-7.3 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,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 CADD3C433ED for ; Tue, 13 Apr 2021 12:04:13 +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 8903361222 for ; Tue, 13 Apr 2021 12:04:13 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 8903361222 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.109718.209420 (Exim 4.92) (envelope-from ) id 1lWHlr-0002F0-60; Tue, 13 Apr 2021 12:03:55 +0000 X-Outflank-Mailman: Message body and most headers restored to incoming version Received: by outflank-mailman (output) from mailman id 109718.209420; Tue, 13 Apr 2021 12:03:55 +0000 Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1lWHlr-0002Et-2r; Tue, 13 Apr 2021 12:03:55 +0000 Received: by outflank-mailman (input) for mailman id 109718; Tue, 13 Apr 2021 12:03:53 +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 1lWHlp-0002Ek-ID for xen-devel@lists.xenproject.org; Tue, 13 Apr 2021 12:03:53 +0000 Received: from mx2.suse.de (unknown [195.135.220.15]) by us1-amaz-eas2.inumbo.com (Halon) with ESMTPS id e81b8f6b-4a85-42af-b914-64040811778f; Tue, 13 Apr 2021 12:03:52 +0000 (UTC) Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id F0513AFAB; Tue, 13 Apr 2021 12:03:51 +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: e81b8f6b-4a85-42af-b914-64040811778f 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=1618315432; 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=ATfV7p4h3W1F8WQ6C9MwBGR703K73Rquu1Z0XvzEGys=; b=qEY3jvgeEfEDRKA7VsxdJrjK4FrAE7Nm22owy6YbmuxDKeI+snz4W5H6jpTz1pJGDKfEJV QMkfrTs3OufPc7Q8dXBdKsNy1szJAXYy8EiAp8dTqPsaALLlf91pIbTN0IXoooPbjpT0Oi 2RXkq2mbib5N0KyCesf6YArF3Dg2moU= Subject: Re: [PATCH v4] VMX: use a single, global APIC access page To: =?UTF-8?Q?Roger_Pau_Monn=c3=a9?= Cc: "xen-devel@lists.xenproject.org" , Andrew Cooper , Wei Liu , George Dunlap , Kevin Tian , Jun Nakajima , Tim Deegan References: <4731a3a3-906a-98ac-11ba-6a0723903391@suse.com> <1c489e77-6e65-6121-6c28-3c4bd377223c@suse.com> From: Jan Beulich Message-ID: <4190da5f-65c2-dfee-e84e-9d5560dabf69@suse.com> Date: Tue, 13 Apr 2021 14:03:52 +0200 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:78.0) Gecko/20100101 Thunderbird/78.9.1 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit On 13.04.2021 12:18, Roger Pau Monné wrote: > On Tue, Apr 13, 2021 at 11:24:09AM +0200, Jan Beulich wrote: >> On 12.04.2021 17:31, Roger Pau Monné wrote: >>> On Mon, Apr 12, 2021 at 12:40:48PM +0200, Jan Beulich wrote: >>>> + { >>>> + const struct page_info *pg = mfn_to_page(mfn); >>>> + >>>> + if ( !page_get_owner(pg) && (pg->count_info & PGC_extra) ) >>>> + { >>>> + ASSERT(type == p2m_mmio_direct); >>>> + return 0; >>> >>> Are there any other pages that could pass this check? I don't think >>> so, but wanted to assert. >> >> "Normal" extra pages have an owner, so no, there aren't any others. >> If and when any appear, this may need further customizing, albeit >> generally I'd hope further pages matching this pattern would also >> want similar treatment. > > I wonder whether we want to add an assert here to make sure only the > APIC access page receives this special handling by the shadow code, > but maybe that's a bit too much? I think so, yes: It would require either a separate function or making the variable global. Both feel like a layering violation. Jan