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,DKIMWL_WL_HIGH, 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 3B349C4167B for ; Fri, 11 Dec 2020 13:57:12 +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 0193223ECD for ; Fri, 11 Dec 2020 13:57:11 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 0193223ECD Authentication-Results: mail.kernel.org; dmarc=fail (p=reject dis=none) header.from=citrix.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.50624.89325 (Exim 4.92) (envelope-from ) id 1kniui-0005P8-Cb; Fri, 11 Dec 2020 13:56:52 +0000 X-Outflank-Mailman: Message body and most headers restored to incoming version Received: by outflank-mailman (output) from mailman id 50624.89325; Fri, 11 Dec 2020 13:56:52 +0000 Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1kniui-0005P1-8i; Fri, 11 Dec 2020 13:56:52 +0000 Received: by outflank-mailman (input) for mailman id 50624; Fri, 11 Dec 2020 13:56:51 +0000 Received: from us1-rack-iad1.inumbo.com ([172.99.69.81]) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1kniug-0005Ow-V8 for xen-devel@lists.xenproject.org; Fri, 11 Dec 2020 13:56:50 +0000 Received: from esa2.hc3370-68.iphmx.com (unknown [216.71.145.153]) by us1-rack-iad1.inumbo.com (Halon) with ESMTPS id b62ecfc1-3390-4ead-827b-32d980ad6ff0; Fri, 11 Dec 2020 13:56:49 +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: b62ecfc1-3390-4ead-827b-32d980ad6ff0 DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=citrix.com; s=securemail; t=1607695009; h=subject:to:cc:references:from:message-id:date: mime-version:in-reply-to:content-transfer-encoding; bh=Y9q/K51kNVP1X62NUU7bPzV0ysaWRI9CTxHOwDYR8cg=; b=ZQUc9v3ko9tDvDGkzK9cp994xESiwy+8bIvmg5Ph0uHygWBPwVxr84BP qDgHx2R1G2LP7jA2iYEhJmdpKZB7mCnp99IpurqNlZtEmS7F5Nyst49ai cWBmyt2k1pMDDuG+llAvfA9W8nfFkmxjrKu/rmtCwHZ02fKi07PFKj/Hu U=; Authentication-Results: esa2.hc3370-68.iphmx.com; dkim=none (message not signed) header.i=none IronPort-SDR: 2AX/flIBpSAkFKmEn8A5EmZ9AIVTEcTNs7qkHBgYHDsWdg45+5R3AocvWAzhEaCGSKNuNP2gOG /a7gyjz0uzos6JvXet4SEk+piKEzpQn9S79yv32wf+Rjyw/AMdBK4Nfm35doFVerF6fapLop9R peLqKXVyfKdm9WUO04iTrqfkJLwl58aL6PFaaTnAFa9UfiEehaKrHZFYBFgLNdYd/oWvou60M3 tKt5eTZX80rJ5+Y87E8vjLy6cwKFW+AbUexJzC0oP7RflPEQJLVkJ6qDPJyFjj83XtFzV7ma3r 4Jk= X-SBRS: 5.2 X-MesageID: 33051843 X-Ironport-Server: esa2.hc3370-68.iphmx.com X-Remote-IP: 162.221.158.21 X-Policy: $RELAYED X-IronPort-AV: E=Sophos;i="5.78,411,1599537600"; d="scan'208";a="33051843" Subject: Re: dom0 PV looping on search_pre_exception_table() To: Manuel Bouyer , Jan Beulich CC: References: <20201209135908.GA4269@antioche.eu.org> <20201209154431.GA4913@antioche.eu.org> <52e1b10d-75d4-63ac-f91e-cb8f0dcca493@citrix.com> <20201209163049.GA6158@antioche.eu.org> <30a71c9d-3eff-3727-9c61-e387b5bccc95@citrix.com> <20201209185714.GS1469@antioche.eu.org> <6c06abf1-7efe-f02c-536a-337a2704e265@citrix.com> <20201210095139.GA455@antioche.eu.org> <2c345ef9-1f05-f883-d294-7ac1b3851f08@suse.com> <20201211111546.GE1423@antioche.eu.org> From: Andrew Cooper Message-ID: Date: Fri, 11 Dec 2020 13:56:43 +0000 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0 MIME-Version: 1.0 In-Reply-To: <20201211111546.GE1423@antioche.eu.org> Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 8bit Content-Language: en-GB X-ClientProxiedBy: AMSPEX02CAS01.citrite.net (10.69.22.112) To FTLPEX02CL03.citrite.net (10.13.108.165) On 11/12/2020 11:15, Manuel Bouyer wrote: > On Fri, Dec 11, 2020 at 09:58:54AM +0100, Jan Beulich wrote: >> Could you please revert 9ff970564764 ("x86/mm: drop guest_get_eff_l1e()")? >> I think there was a thinko there in that the change can't be split from >> the bigger one which was part of the originally planned set for XSA-286. >> We mustn't avoid the switching of page tables as long as >> guest_get_eff{,_kern}_l1e() makes use of the linear page tables. > Yes, reverting this commit also makes the dom0 boot. > This was going to be my next area of investigation.  Thanks for confirming. In hindsight, the bug is very obvious... ~Andrew