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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id E5AD3C19F2A for ; Fri, 29 Jul 2022 17:45:26 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230501AbiG2RpZ (ORCPT ); Fri, 29 Jul 2022 13:45:25 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:56196 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229700AbiG2RpY (ORCPT ); Fri, 29 Jul 2022 13:45:24 -0400 Received: from mga02.intel.com (mga02.intel.com [134.134.136.20]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 804096A49F; Fri, 29 Jul 2022 10:45:23 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1659116723; x=1690652723; h=date:from:to:cc:subject:message-id:references: mime-version:in-reply-to; bh=dg2oEUXQjesKyq4mqy/LM3/pJlZaSHEjJ/Zzh7Iz+r0=; b=TlFvqxNoOaBg0qHwOuaygQ9zoLvc7gvZsrcldOpHwQmQ7nuVNk9o4IgS Y/bHT7gEIq0e6M8qRSdNatYXEV35NPRnbaL0b9Y59t7/u75L6OZgp2Xiq WzxsIUxqWkJCpBIFMN7WJigSYCPIxR0So+vxcnHua2NuxOlHYbtBxqi+J n0E9zw2cD3mz34yUxydty9a+p+RulNA1uaOauMC2vQ+NR9TTneOrwfTOP OeSGYIjnoKER22oPwFhhGiv8Emk31vmOAh8iTRj+OYodHGETmdmhrliLB RA7QBD6gH49E2sGDIhDizzgYCuuIc0z/9XbfaYMVw3HZplTM9FEy5khFD g==; X-IronPort-AV: E=McAfee;i="6400,9594,10423"; a="275701539" X-IronPort-AV: E=Sophos;i="5.93,201,1654585200"; d="scan'208";a="275701539" Received: from orsmga003.jf.intel.com ([10.7.209.27]) by orsmga101.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 29 Jul 2022 10:45:23 -0700 X-IronPort-AV: E=Sophos;i="5.93,201,1654585200"; d="scan'208";a="551809239" Received: from aahmedsi-mobl.amr.corp.intel.com (HELO desk) ([10.209.118.55]) by orsmga003-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 29 Jul 2022 10:45:22 -0700 Date: Fri, 29 Jul 2022 10:45:21 -0700 From: 'Pawan Gupta' To: David Laight Cc: Borislav Petkov , Jonathan Corbet , Thomas Gleixner , Ingo Molnar , Dave Hansen , "x86@kernel.org" , "H. Peter Anvin" , "linux-doc@vger.kernel.org" , "linux-kernel@vger.kernel.org" , "stable@vger.kernel.org" , "tony.luck@intel.com" , "antonio.gomez.iglesias@linux.intel.com" , Daniel Sneddon , "andrew.cooper3@citrix.com" , Josh Poimboeuf Subject: Re: [RESEND RFC PATCH] x86/bugs: Add "unknown" reporting for MMIO Stale Data Message-ID: <20220729174521.kvbudqlpsoyvxzrv@desk> References: <20220729022851.mdj3wuevkztspodh@desk> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org On Fri, Jul 29, 2022 at 10:40:20AM +0000, David Laight wrote: > From: Pawan Gupta > > Sent: 29 July 2022 03:29 > > > > On Thu, Jul 28, 2022 at 02:00:13PM +0200, Borislav Petkov wrote: > > > On Thu, Jul 14, 2022 at 06:30:18PM -0700, Pawan Gupta wrote: > > > > Older CPUs beyond its Servicing period are not listed in the affected > > > > processor list for MMIO Stale Data vulnerabilities. These CPUs currently > > > > report "Not affected" in sysfs, which may not be correct. > > I looked this up.... > > The mitigations seem to rely on unprivileged code not being able > to do MMIO accesses. > That isn't true, device drivers can mmap PCIe addresses directly > into user program address space. > While unlikely, there is no reason this can't be supported for > non-root processes. Agree. Would it be fair to assume that processes that get direct hardware access are trusted?