From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753655AbeCFOJx (ORCPT ); Tue, 6 Mar 2018 09:09:53 -0500 Received: from mail-wm0-f66.google.com ([74.125.82.66]:33319 "EHLO mail-wm0-f66.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753069AbeCFOJu (ORCPT ); Tue, 6 Mar 2018 09:09:50 -0500 X-Google-Smtp-Source: AG47ELuq6ouYBF8mAUEDWY7xy189TRMzv1amxT8hQaShwx1dloDnYqc6F1qOrLnUESnpM772JP2urA== Date: Tue, 6 Mar 2018 17:09:32 +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 , linux-kernel@vger.kernel.org, linux-mm@kvack.org Subject: Re: [RFC, PATCH 19/22] x86/mm: Implement free_encrypt_page() Message-ID: <20180306140932.bdll5vh6qzyydqg4@node.shutemov.name> References: <20180305162610.37510-1-kirill.shutemov@linux.intel.com> <20180305162610.37510-20-kirill.shutemov@linux.intel.com> <20180306085412.vkgheeya24dze53t@node.shutemov.name> <64d11e65-76b7-4e70-553c-009263b50a1c@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <64d11e65-76b7-4e70-553c-009263b50a1c@intel.com> User-Agent: NeoMutt/20180223 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Mar 06, 2018 at 05:52:44AM -0800, Dave Hansen wrote: > On 03/06/2018 12:54 AM, Kirill A. Shutemov wrote: > >> Have you measured how slow this is? > > No, I have not. > > It would be handy to do this. I *think* you can do it on normal > hardware, even if it does not have "real" support for memory encryption. > Just don't set the encryption bits in the PTEs but go through all the > motions of cache flushing. Yes, allocation/freeing and KeyID interfaces can be tested with MKTME support in hardware. I did most of my testing this way. > I think that will help tell us whether this is a really specialized > thing a la hugetlbfs or whether it's something we really want to support > as a first-class citizen in the VM. I will benchmark this. But not right now. -- Kirill A. Shutemov