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=-2.5 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_MUTT 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 3D298C04AB5 for ; Tue, 4 Jun 2019 00:54:27 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 1711525A5C for ; Tue, 4 Jun 2019 00:54:27 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726597AbfFDAy0 (ORCPT ); Mon, 3 Jun 2019 20:54:26 -0400 Received: from mga04.intel.com ([192.55.52.120]:32636 "EHLO mga04.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726163AbfFDAyY (ORCPT ); Mon, 3 Jun 2019 20:54:24 -0400 X-Amp-Result: UNKNOWN X-Amp-Original-Verdict: FILE UNKNOWN X-Amp-File-Uploaded: False Received: from orsmga005.jf.intel.com ([10.7.209.41]) by fmsmga104.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 03 Jun 2019 17:54:23 -0700 X-ExtLoop1: 1 Received: from sjchrist-coffee.jf.intel.com (HELO linux.intel.com) ([10.54.74.36]) by orsmga005.jf.intel.com with ESMTP; 03 Jun 2019 17:54:23 -0700 Date: Mon, 3 Jun 2019 17:54:23 -0700 From: Sean Christopherson To: "Xing, Cedric" Cc: Jarkko Sakkinen , Andy Lutomirski , Stephen Smalley , James Morris , "Serge E . Hallyn" , LSM List , Paul Moore , Eric Paris , "selinux@vger.kernel.org" , Jethro Beekman , "Hansen, Dave" , Thomas Gleixner , Linus Torvalds , LKML , X86 ML , "linux-sgx@vger.kernel.org" , Andrew Morton , "nhorman@redhat.com" , "npmccallum@redhat.com" , "Ayoun, Serge" , "Katz-zamir, Shay" , "Huang, Haitao" , Andy Shevchenko , "Svahn, Kai" , Borislav Petkov , Josh Triplett , "Huang, Kai" , David Rientjes , "Roberts, William C" , "Tricca, Philip B" Subject: Re: [RFC PATCH 3/9] x86/sgx: Allow userspace to add multiple pages in single ioctl() Message-ID: <20190604005422.GA24521@linux.intel.com> References: <20190531233159.30992-1-sean.j.christopherson@intel.com> <20190531233159.30992-4-sean.j.christopherson@intel.com> <960B34DE67B9E140824F1DCDEC400C0F654ECBBD@ORSMSX116.amr.corp.intel.com> <20190603200804.GG13384@linux.intel.com> <20190603203950.GJ13384@linux.intel.com> <960B34DE67B9E140824F1DCDEC400C0F654ED478@ORSMSX116.amr.corp.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <960B34DE67B9E140824F1DCDEC400C0F654ED478@ORSMSX116.amr.corp.intel.com> User-Agent: Mutt/1.5.24 (2015-08-30) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Jun 03, 2019 at 04:45:45PM -0700, Xing, Cedric wrote: > > From: Christopherson, Sean J > > Sent: Monday, June 03, 2019 1:40 PM > > > > On Mon, Jun 03, 2019 at 01:08:04PM -0700, Sean Christopherson wrote: > > > On Sun, Jun 02, 2019 at 11:26:09PM -0700, Xing, Cedric wrote: > > > > > From: Christopherson, Sean J > > > > > Sent: Friday, May 31, 2019 4:32 PM > > > > > > > > > > +/** > > > > > + * sgx_ioc_enclave_add_pages - handler for > > > > > +%SGX_IOC_ENCLAVE_ADD_PAGES > > > > > + * > > > > > + * @filep: open file to /dev/sgx > > > > > + * @cmd: the command value > > > > > + * @arg: pointer to an &sgx_enclave_add_page instance > > > > > + * > > > > > + * Add a range of pages to an uninitialized enclave (EADD), and > > > > > +optionally > > > > > + * extend the enclave's measurement with the contents of the page > > (EEXTEND). > > > > > + * The range of pages must be virtually contiguous. The SECINFO > > > > > +and > > > > > + * measurement maskare applied to all pages, i.e. pages with > > > > > +different > > > > > + * properties must be added in separate calls. > > > > > + * > > > > > + * EADD and EEXTEND are done asynchronously via worker threads. > > > > > +A successful > > > > > + * sgx_ioc_enclave_add_page() only indicates the pages have been > > > > > +added to the > > > > > + * work queue, it does not guarantee adding the pages to the > > > > > +enclave will > > > > > + * succeed. > > > > > + * > > > > > + * Return: > > > > > + * 0 on success, > > > > > + * -errno otherwise > > > > > + */ > > > > > +static long sgx_ioc_enclave_add_pages(struct file *filep, > > unsigned int cmd, > > > > > + unsigned long arg) > > > > > +{ > > > > > + struct sgx_enclave_add_pages *addp = (void *)arg; > > > > > + struct sgx_encl *encl = filep->private_data; > > > > > + struct sgx_secinfo secinfo; > > > > > + unsigned int i; > > > > > + int ret; > > > > > + > > > > > + if (copy_from_user(&secinfo, (void __user *)addp->secinfo, > > > > > + sizeof(secinfo))) > > > > > + return -EFAULT; > > > > > + > > > > > + for (i = 0, ret = 0; i < addp->nr_pages && !ret; i++) { > > > > > + if (signal_pending(current)) > > > > > + return -ERESTARTSYS; > > > > > > > > If interrupted, how would user mode code know how many pages have > > been EADD'ed? > > > > > > Hmm, updating nr_pages would be fairly simple and shouldn't confuse > > > userspace, e.g. as opposed to overloading the return value. > > > > Or maybe update @addr and @src as well? That would allow userspace to > > re-invoke the ioctl() without having to modify the struct. > > How about returning the number of pages (or bytes) EADD'ed, similar to > write() syscall? I thought about that as well, but I think it'd be useful to update the offset on any failure, not just -ERESTARTSYS.