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=-2.8 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS,T_DKIMWL_WL_MED, USER_AGENT_NEOMUTT autolearn=ham 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 8D20AC468C6 for ; Thu, 19 Jul 2018 07:22:37 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 3C1A120693 for ; Thu, 19 Jul 2018 07:22:37 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=shutemov-name.20150623.gappssmtp.com header.i=@shutemov-name.20150623.gappssmtp.com header.b="0SLvjTn9" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 3C1A120693 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=shutemov.name Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730432AbeGSIEP (ORCPT ); Thu, 19 Jul 2018 04:04:15 -0400 Received: from mail-pl0-f53.google.com ([209.85.160.53]:46686 "EHLO mail-pl0-f53.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727451AbeGSIEO (ORCPT ); Thu, 19 Jul 2018 04:04:14 -0400 Received: by mail-pl0-f53.google.com with SMTP id t17-v6so667047ply.13 for ; Thu, 19 Jul 2018 00:22:33 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=shutemov-name.20150623.gappssmtp.com; s=20150623; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to:user-agent; bh=CQnIrC/UF3jw2Pp17aC6lk4RP7cOOWSL/mYL4siOjeM=; b=0SLvjTn9qryo7iJhVB424QYE0aaGBCFoxvaRHPY0Ds5DwKxp68+HwFWONLVSnXDTE8 P/0H8/5JuhUed55jB01NhnADn3n4/Tt0obJfldtsLtDc7zFyGbaHKQjsPXve++25WAnF oIOkQgsOMMO74CakxyyRS3hZvi7wkHAxQvHfac3/tvt9pijrNHoTl/0QCSSWQYCNK8cT hyItoOVdWa9Q7600lmG8rI4YU/diCKs5kxcFrenqYWiUBdAhJ4QQGSU4+wFLaQamSTZc hfFHT+JoaFM1AUdrgG+81gc0EbYE0u9Rl6l/MaVjqAEbPBrPT8R6AgfB8i/JoIwFmrX4 NH7w== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to:user-agent; bh=CQnIrC/UF3jw2Pp17aC6lk4RP7cOOWSL/mYL4siOjeM=; b=iw69u29+0M1AMk6O15QEXmbGMzpVBff/K80EDLu/IpTe5rwn5Vu3s7v/rzeYU+5Ur1 11CLKlT+N27CzWeGCCN2JEQR5cl07FnNqHXmd1JkFfOCmYnB3SU9kWdhnbkfSZT5ncqs 7JRX48Bot8xEehUhwj+ocSadIK5rk/VhClJqvUU+QIo0E9TDfUNN2khdwMsUbGbQFG7X bwoxmI3KcjmRIvEHteKqRAFchcHBQ05t8ZNymk6aP+Tbcqe5J/t/n5zsxw0Uox7R4V4t 3tOHVsGGKTZVMMUYOSZa/si5i8Qawnfk8pc5syTGgV+R3+/2EW446/O5F7AWBRabnCKQ Wd7g== X-Gm-Message-State: AOUpUlEY3tOogxfUjmh8xQkdSorm9ZfB4ENKVoUVeSH0TsS0Eis/Ajnk K3tYl/Rk1ckDHDpJaa5AugyA5w== X-Google-Smtp-Source: AAOMgpfe97877ID/Q5v+0GF/KPzPbbNIlGQ0B5i45MoaRFuaMjVYW3Kl7h+dotpxC140dDbVehXW/w== X-Received: by 2002:a17:902:981:: with SMTP id 1-v6mr9108153pln.11.1531984953178; Thu, 19 Jul 2018 00:22:33 -0700 (PDT) Received: from kshutemo-mobl1.localdomain ([134.134.139.83]) by smtp.gmail.com with ESMTPSA id p62-v6sm8289481pfb.58.2018.07.19.00.22.32 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 19 Jul 2018 00:22:32 -0700 (PDT) Received: by kshutemo-mobl1.localdomain (Postfix, from userid 1000) id BE0913001F8; Thu, 19 Jul 2018 10:16:06 +0300 (+03) Date: Thu, 19 Jul 2018 10:16:06 +0300 From: "Kirill A. Shutemov" To: Dave Hansen Cc: "Kirill A. Shutemov" , Ingo Molnar , x86@kernel.org, Thomas Gleixner , "H. Peter Anvin" , Tom Lendacky , Kai Huang , Jacob Pan , linux-kernel@vger.kernel.org, linux-mm@kvack.org Subject: Re: [PATCHv5 02/19] mm: Do not use zero page in encrypted pages Message-ID: <20180719071606.dkeq5btz5wlzk4oq@kshutemo-mobl1> References: <20180717112029.42378-1-kirill.shutemov@linux.intel.com> <20180717112029.42378-3-kirill.shutemov@linux.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: NeoMutt/20180622 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Jul 18, 2018 at 10:36:24AM -0700, Dave Hansen wrote: > On 07/17/2018 04:20 AM, Kirill A. Shutemov wrote: > > Zero page is not encrypted and putting it into encrypted VMA produces > > garbage. > > > > We can map zero page with KeyID-0 into an encrypted VMA, but this would > > be violation security boundary between encryption domains. > > Why? How is it a violation? > > It only matters if they write secrets. They can't write secrets to the > zero page. I believe usage of zero page is wrong here. It would indirectly reveal content of supposedly encrypted memory region. I can see argument why it should be okay and I don't have very strong opinion on this. If folks see it's okay to use zero page in encrypted VMAs I can certainly make it work. > Is this only because you accidentally inherited ->vm_page_prot on the > zero page PTE? Yes, in previous patchset I mapped zero page with wrong KeyID. This is one of possible fixes for this. -- Kirill A. Shutemov