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=-0.6 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS 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 15001C54FCB for ; Mon, 27 Apr 2020 16:01:24 +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 D23F0206D4 for ; Mon, 27 Apr 2020 16:01:23 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=citrix.com header.i=@citrix.com header.b="B3LB7gh2" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org D23F0206D4 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=citrix.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=xen-devel-bounces@lists.xenproject.org Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1jT6Bo-0001ka-QW; Mon, 27 Apr 2020 16:01:00 +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 1jT6Bn-0001kV-VQ for xen-devel@lists.xenproject.org; Mon, 27 Apr 2020 16:01:00 +0000 X-Inumbo-ID: 48418e64-88a0-11ea-97b3-12813bfff9fa Received: from esa2.hc3370-68.iphmx.com (unknown [216.71.145.153]) by us1-amaz-eas2.inumbo.com (Halon) with ESMTPS id 48418e64-88a0-11ea-97b3-12813bfff9fa; Mon, 27 Apr 2020 16:00:58 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=citrix.com; s=securemail; t=1588003258; h=date:from:to:cc:subject:message-id:references: mime-version:content-transfer-encoding:in-reply-to; bh=YG0ApSthlCMFZiia2oF76yi2aWS/H+oIXsuYehyDp/E=; b=B3LB7gh2Po5JYW689f3IguOWfny6NbPgIBqURIvL8E2XrLXogDHu0E5X Guajp8DPlav5xvVNZNzpqhmmVH4FhBH7D+UeNT596NmLs0Yc/tnAjOZc9 vbS7Muy/lBwrWIJf91Ism3guLfbJELrsfZlhbpKlZDBTtqborRl75xVFD k=; Authentication-Results: esa2.hc3370-68.iphmx.com; dkim=none (message not signed) header.i=none; spf=None smtp.pra=roger.pau@citrix.com; spf=Pass smtp.mailfrom=roger.pau@citrix.com; spf=None smtp.helo=postmaster@mail.citrix.com Received-SPF: None (esa2.hc3370-68.iphmx.com: no sender authenticity information available from domain of roger.pau@citrix.com) identity=pra; client-ip=162.221.158.21; receiver=esa2.hc3370-68.iphmx.com; envelope-from="roger.pau@citrix.com"; x-sender="roger.pau@citrix.com"; x-conformance=sidf_compatible Received-SPF: Pass (esa2.hc3370-68.iphmx.com: domain of roger.pau@citrix.com designates 162.221.158.21 as permitted sender) identity=mailfrom; client-ip=162.221.158.21; receiver=esa2.hc3370-68.iphmx.com; envelope-from="roger.pau@citrix.com"; x-sender="roger.pau@citrix.com"; x-conformance=sidf_compatible; x-record-type="v=spf1"; x-record-text="v=spf1 ip4:209.167.231.154 ip4:178.63.86.133 ip4:195.66.111.40/30 ip4:85.115.9.32/28 ip4:199.102.83.4 ip4:192.28.146.160 ip4:192.28.146.107 ip4:216.52.6.88 ip4:216.52.6.188 ip4:162.221.158.21 ip4:162.221.156.83 ip4:168.245.78.127 ~all" Received-SPF: None (esa2.hc3370-68.iphmx.com: no sender authenticity information available from domain of postmaster@mail.citrix.com) identity=helo; client-ip=162.221.158.21; receiver=esa2.hc3370-68.iphmx.com; envelope-from="roger.pau@citrix.com"; x-sender="postmaster@mail.citrix.com"; x-conformance=sidf_compatible IronPort-SDR: 9zur46vGKK/qFZaEWsAB61CxK9BcPgkJHG8PxvRWcHxXyOKSdlqE9U/w88jxMJX5ISSPUV1tKP CyKni0UoSmh/15RkwgeLg4mT9yAgYnsmwwbh23qmkJGm3L+PZQPEHX4BBHcleHJ/zy5LOxd34J 0s1GkCHhKXxtj0WwqpAu5O9xQDqkA5/w7102dg+JiADTuy3eJawSRr++gYdK3LXhR8Am5V0h58 kqdcj/ViuT9A548h3gbPQbTHwbMleJV3lucZLObsxcvcYaEAn6qv0lIzVvXOPeIosHNBbc6PQg ggw= X-SBRS: 2.7 X-MesageID: 16328224 X-Ironport-Server: esa2.hc3370-68.iphmx.com X-Remote-IP: 162.221.158.21 X-Policy: $RELAYED X-IronPort-AV: E=Sophos;i="5.73,324,1583211600"; d="scan'208";a="16328224" Date: Mon, 27 Apr 2020 18:00:48 +0200 From: Roger Pau =?utf-8?B?TW9ubsOp?= To: Jan Beulich Subject: Re: [PATCH] x86: refine guest_mode() Message-ID: <20200427160048.GQ28601@Air-de-Roger> References: <7b62d06c-1369-2857-81c0-45e2434357f4@suse.com> <20200427095913.GN28601@Air-de-Roger> <40d5c1b8-b68e-1aa8-b17e-77ba9afc6529@suse.com> MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <40d5c1b8-b68e-1aa8-b17e-77ba9afc6529@suse.com> X-ClientProxiedBy: AMSPEX02CAS01.citrite.net (10.69.22.112) To AMSPEX02CL02.citrite.net (10.69.22.126) X-BeenThere: xen-devel@lists.xenproject.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Cc: "xen-devel@lists.xenproject.org" , Wei Liu , Andrew Cooper Errors-To: xen-devel-bounces@lists.xenproject.org Sender: "Xen-devel" On Mon, Apr 27, 2020 at 04:08:59PM +0200, Jan Beulich wrote: > On 27.04.2020 11:59, Roger Pau Monné wrote: > > On Mon, Apr 27, 2020 at 10:03:05AM +0200, Jan Beulich wrote: > >> --- a/xen/include/asm-x86/regs.h > >> +++ b/xen/include/asm-x86/regs.h > >> @@ -10,9 +10,10 @@ > >> /* Frame pointer must point into current CPU stack. */ \ > >> ASSERT(diff < STACK_SIZE); \ > >> /* If not a guest frame, it must be a hypervisor frame. */ \ > >> - ASSERT((diff == 0) || (r->cs == __HYPERVISOR_CS)); \ > >> + if ( diff < PRIMARY_STACK_SIZE ) \ > >> + ASSERT(!diff || ((r)->cs == __HYPERVISOR_CS)); \ > > > > Why not use: > > > > ASSERT(diff >= PRIMARY_STACK_SIZE || !diff || ((r)->cs == __HYPERVISOR_CS)); > > Except for the longer (without being helpful imo) string reported if > the assertion triggers, I see not difference. Wanted to avoid the empty if on non-debug builds, but I assume the compiler will already optimize it out. > > I'm not sure I fully understand this layout, is it possible that you > > also need to account for the size of cpu_info? > > Depends on how paranoid we want the checking here to be, but in going > further I wouldn't want this to become sub-page fine-grained if we > aren't first doing e.g. what I'm mentioning in the post-commit-message > remark. Right, leaving it as-is is fine, just wanted to be sure I fully understand the layout. Thanks, Roger.