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 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 733BAC433F5 for ; Tue, 2 Nov 2021 15:53:47 +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 3DADB61050 for ; Tue, 2 Nov 2021 15:53:47 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org 3DADB61050 Authentication-Results: mail.kernel.org; dmarc=pass (p=none dis=none) header.from=xenproject.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=lists.xenproject.org Received: from list by lists.xenproject.org with outflank-mailman.220380.381638 (Exim 4.92) (envelope-from ) id 1mhw6L-0004fg-7y; Tue, 02 Nov 2021 15:53:29 +0000 X-Outflank-Mailman: Message body and most headers restored to incoming version Received: by outflank-mailman (output) from mailman id 220380.381638; Tue, 02 Nov 2021 15:53:29 +0000 Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1mhw6L-0004fZ-54; Tue, 02 Nov 2021 15:53:29 +0000 Received: by outflank-mailman (input) for mailman id 220380; Tue, 02 Nov 2021 15:53:27 +0000 Received: from mail.xenproject.org ([104.130.215.37]) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1mhw6J-0004fT-9C for xen-devel@lists.xenproject.org; Tue, 02 Nov 2021 15:53:27 +0000 Received: from xenbits.xenproject.org ([104.239.192.120]) by mail.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1mhw6J-0008Uo-6f for xen-devel@lists.xenproject.org; Tue, 02 Nov 2021 15:53:27 +0000 Received: from iwj (helo=mariner.uk.xensource.com) by xenbits.xenproject.org with local-bsmtp (Exim 4.92) (envelope-from ) id 1mhw6J-0002hm-5p for xen-devel@lists.xenproject.org; Tue, 02 Nov 2021 15:53:27 +0000 Received: from iwj by mariner.uk.xensource.com with local (Exim 4.89) (envelope-from ) id 1mhw6A-0001UZ-Am; Tue, 02 Nov 2021 15:53:18 +0000 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" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=xenproject.org; s=20200302mail; h=References:In-Reply-To:Subject:Cc:To:Date :Message-ID:Content-Transfer-Encoding:Content-Type:MIME-Version:From; bh=DxLq0cVfeU0Tm/MxmwSBOutW+q/oNYXWgPlqeJtAvd8=; b=ZGBqZWX4rKQkfLpfcCPkLtcClw xr1doif9CohFIOl6LYTrgMNhOq4x3cj1nTQW0nlZeUTaNrudW4YP+Zw3N4gcweRImqgWwWwfvaWp7 k08zJcia9mm7a3ikKMMl0o+2KJZ6c3Xp9LZFvl3bCIvbDZl9X84KFyM7KX0rQXXM2Nss=; From: Ian Jackson MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Message-ID: <24961.24301.445326.724439@mariner.uk.xensource.com> Date: Tue, 2 Nov 2021 15:53:17 +0000 To: Jan Beulich Cc: Andrew Cooper , Roger Pau =?iso-8859-1?Q?Monn=E9?= , Wei Liu , Xen-devel Subject: Re: [PATCH for-4.16] x86/shstk: Fix use of shadow stacks with XPTI active Newsgroups: chiark.mail.xen.devel In-Reply-To: <29c59040-a2bc-69d3-db02-1345b5aa2b8b@suse.com> References: <20211102143935.17473-1-andrew.cooper3@citrix.com> <29c59040-a2bc-69d3-db02-1345b5aa2b8b@suse.com> X-Mailer: VM 8.2.0b under 24.5.1 (i686-pc-linux-gnu) Jan Beulich writes ("Re: [PATCH for-4.16] x86/shstk: Fix use of shadow stacks with XPTI active"): > On 02.11.2021 15:39, Andrew Cooper wrote: > > The call to setup_cpu_root_pgt(0) in smp_prepare_cpus() is too early. It > > clones the BSP's stack while the .data mapping is still in use, causing all > > mappings to be fully read read/write (and with no guard pages either). This > > ultimately causes #DF when trying to enter the dom0 kernel for the first time. > > > > Defer setting up BSPs XPTI pagetable until reinit_bsp_stack() after we've set > > up proper shadow stack permissions. > > > > Fixes: 60016604739b ("x86/shstk: Rework the stack layout to support shadow stacks") > > Fixes: b60ab42db2f0 ("x86/shstk: Activate Supervisor Shadow Stacks") > > Signed-off-by: Andrew Cooper > > Reviewed-by: Jan Beulich Release-Acked-by: Ian Jackson