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 6961CC433F5 for ; Thu, 17 Mar 2022 04:54:47 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229525AbiCQE4B (ORCPT ); Thu, 17 Mar 2022 00:56:01 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:36142 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229495AbiCQEzx (ORCPT ); Thu, 17 Mar 2022 00:55:53 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 52B0314032; Wed, 16 Mar 2022 21:37:22 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 20D6D60F0A; Thu, 17 Mar 2022 04:29:34 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 7A975C340E9; Thu, 17 Mar 2022 04:29:32 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1647491373; bh=Neci+Gx7EQANLBllG8qEVqee6Rk06O2hKQ7VcxDD5SA=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=rFLzPGJitUQLpWpLvTLS6Pd9Jo9WbMANCy0sdJZCliVpMsCuoWElqZck021vKBfC2 X1IA5SndaNeP11C/Oo90JsRhM0Kuu8o4A9wZ1s2DveLwpmoorBwH3DE+Rmw5oyX3Iz 3OVLbMNIWRMBBj28wgNSAzh+9Fm5XuDQLJUC7oQwDpdF1Kk2auKjEtEDcyHsrGRU0Z CoR4JkjZJFXB6OIvKsvidB15RkIvMLdetr/GR59XqZdLCu0IPch5lgmCci1ZYuHo8S U+TEDBU4G6d64B+WK+YLs7jTwdWoL3ysvoLBXot9FnuRNq4HP6ia6cHObSQecE8ZB7 PEQpKhDtyc0pw== Date: Thu, 17 Mar 2022 06:30:29 +0200 From: Jarkko Sakkinen To: Reinette Chatre Cc: Haitao Huang , "Dhanraj, Vijay" , "dave.hansen@linux.intel.com" , "tglx@linutronix.de" , "bp@alien8.de" , "Lutomirski, Andy" , "mingo@redhat.com" , "linux-sgx@vger.kernel.org" , "x86@kernel.org" , "Christopherson,, Sean" , "Huang, Kai" , "Zhang, Cathy" , "Xing, Cedric" , "Huang, Haitao" , "Shanahan, Mark" , "hpa@zytor.com" , "linux-kernel@vger.kernel.org" Subject: Re: [PATCH V2 16/32] x86/sgx: Support restricting of enclave page permissions Message-ID: References: <97565fed-dc67-bab1-28d4-c40201c9f055@intel.com> <7ff5e217-4042-764b-3d32-49314f00ff54@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <7ff5e217-4042-764b-3d32-49314f00ff54@intel.com> Precedence: bulk List-ID: X-Mailing-List: linux-sgx@vger.kernel.org On Mon, Mar 14, 2022 at 08:32:28AM -0700, Reinette Chatre wrote: > Hi Jarkko, > > On 3/13/2022 8:42 PM, Jarkko Sakkinen wrote: > > On Fri, Mar 11, 2022 at 11:28:27AM -0800, Reinette Chatre wrote: > >> Supporting permission restriction in an ioctl() enables the runtime to manage > >> the enclave memory without needing to map it. > > > > Which is opposite what you do in EAUG. You can also augment pages without > > needing the map them. Sure you get that capability, but it is quite useless > > in practice. > > > >> I have considered the idea of supporting the permission restriction with > >> mprotect() but as you can see in this response I did not find it to be > >> practical. > > > > Where is it practical? What is your application? How is it practical to > > delegate the concurrency management of a split mprotect() to user space? > > How do we get rid off a useless up-call to the host? > > > > The email you responded to contained many obstacles against using mprotect() > but you chose to ignore them and snipped them all from your response. Could > you please address the issues instead of dismissing them? I did read the whole email but did not see anything that would make a case for fully exposed EMODPR, or having asymmetrical towards how EAUG works. I had the same discussion with Haitao about PROT_NONE earlier, and am fully aware that PROT_READ is required. BR, Jarkko