From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pg1-f199.google.com (mail-pg1-f199.google.com [209.85.215.199]) by kanga.kvack.org (Postfix) with ESMTP id 7CD006B0006 for ; Wed, 18 Jul 2018 13:38:31 -0400 (EDT) Received: by mail-pg1-f199.google.com with SMTP id u4-v6so2325388pgr.2 for ; Wed, 18 Jul 2018 10:38:31 -0700 (PDT) Received: from mga11.intel.com (mga11.intel.com. [192.55.52.93]) by mx.google.com with ESMTPS id 62-v6si3904477pfg.224.2018.07.18.10.38.30 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 18 Jul 2018 10:38:30 -0700 (PDT) Subject: Re: [PATCHv5 03/19] mm/ksm: Do not merge pages with different KeyIDs References: <20180717112029.42378-1-kirill.shutemov@linux.intel.com> <20180717112029.42378-4-kirill.shutemov@linux.intel.com> From: Dave Hansen Message-ID: Date: Wed, 18 Jul 2018 10:38:27 -0700 MIME-Version: 1.0 In-Reply-To: <20180717112029.42378-4-kirill.shutemov@linux.intel.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit Sender: owner-linux-mm@kvack.org List-ID: To: "Kirill A. Shutemov" , Ingo Molnar , x86@kernel.org, Thomas Gleixner , "H. Peter Anvin" , Tom Lendacky Cc: Kai Huang , Jacob Pan , linux-kernel@vger.kernel.org, linux-mm@kvack.org On 07/17/2018 04:20 AM, Kirill A. Shutemov wrote: > Pages encrypted with different encryption keys are not allowed to be > merged by KSM. Otherwise it would cross security boundary. Let's say I'm using plain AES (not AES-XTS). I use the same key in two keyid slots. I map a page with the first keyid and another with the other keyid. Won't they have the same cipertext? Why shouldn't we KSM them?