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=-3.9 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS autolearn=no 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 5A3B8C4727E for ; Sun, 4 Oct 2020 22:28:04 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 11E3A20796 for ; Sun, 4 Oct 2020 22:28:04 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="Nx2xxKJ4" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1725831AbgJDW17 (ORCPT ); Sun, 4 Oct 2020 18:27:59 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:60716 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725828AbgJDW17 (ORCPT ); Sun, 4 Oct 2020 18:27:59 -0400 Received: from casper.infradead.org (casper.infradead.org [IPv6:2001:8b0:10b:1236::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 1B1CCC0613CE; Sun, 4 Oct 2020 15:27:59 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=f3LoEmiicIptti0tU7n5VZZ6rnPI7Ovsk8EdYqaxzlA=; b=Nx2xxKJ4AQxDT0QwzHgb9DrrY9 nqYxZVdMKZXln955bYkzFZBZ7BriQLzXGI9keTbK1JvglUx3ANoGMeMWI8huHQKHF3sQfxOWexMCo 0aZ/YV7D8Fe5KlwcQ687pbE5x169Uz89Dd0PtCjQFyyfenlAVXRPtUCSrmbdSnoaXPfUqZYlJfj+r MX6x+g7kkRLDeBkDLSM/kTgOKNKLmGUUXyCwdSOtT2ZcaVOyDFfRmNDroZowJiTI2H9UM3LhYQSSI bInQlK/hkD8mUkBsf23QpbEvvLdaBwuvS+5Ps+DMwtksvmHSXTEKUg+JKhJtjhaJBPj7AGcdzwmjU 0pI7nmMw==; Received: from willy by casper.infradead.org with local (Exim 4.92.3 #3 (Red Hat Linux)) id 1kPCTu-0001J4-6l; Sun, 04 Oct 2020 22:27:50 +0000 Date: Sun, 4 Oct 2020 23:27:50 +0100 From: Matthew Wilcox To: Jarkko Sakkinen Cc: x86@kernel.org, linux-sgx@vger.kernel.org, linux-kernel@vger.kernel.org, linux-security-module@vger.kernel.org, linux-mm@kvack.org, Andrew Morton , Jethro Beekman , Haitao Huang , Chunyang Hui , Jordan Hand , Nathaniel McCallum , Seth Moore , Darren Kenny , Sean Christopherson , Suresh Siddha , andriy.shevchenko@linux.intel.com, asapek@google.com, bp@alien8.de, cedric.xing@intel.com, chenalexchen@google.com, conradparker@google.com, cyhanish@google.com, dave.hansen@intel.com, haitao.huang@intel.com, kai.huang@intel.com, kai.svahn@intel.com, kmoy@google.com, ludloff@google.com, luto@kernel.org, nhorman@redhat.com, puiterwijk@redhat.com, rientjes@google.com, tglx@linutronix.de, yaozhangx@google.com, mikko.ylinen@intel.com Subject: Re: [PATCH v39 11/24] x86/sgx: Add SGX enclave driver Message-ID: <20201004222750.GI20115@casper.infradead.org> References: <20201003045059.665934-1-jarkko.sakkinen@linux.intel.com> <20201003045059.665934-12-jarkko.sakkinen@linux.intel.com> <20201003195440.GD20115@casper.infradead.org> <20201004215049.GA43926@linux.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20201004215049.GA43926@linux.intel.com> Precedence: bulk List-ID: X-Mailing-List: linux-sgx@vger.kernel.org On Mon, Oct 05, 2020 at 12:50:49AM +0300, Jarkko Sakkinen wrote: > What is shoukd take is encl->lock. > > The loop was pre-v36 like: > > idx_start = PFN_DOWN(start); > idx_end = PFN_DOWN(end - 1); > > for (idx = idx_start; idx <= idx_end; ++idx) { > mutex_lock(&encl->lock); > page = radix_tree_lookup(&encl->page_tree, idx); > mutex_unlock(&encl->lock); > > if (!page || (~page->vm_max_prot_bits & vm_prot_bits)) > return -EACCES; > } > > Looking at xarray.h and filemap.c, I'm thinking something along the > lines of: > > for (idx = idx_start; idx <= idx_end; ++idx) { > mutex_lock(&encl->lock); > page = xas_find(&xas, idx + 1); > mutex_unlock(&encl->lock); > > if (!page || (~page->vm_max_prot_bits & vm_prot_bits)) > return -EACCES; > } > > Does this look about right? Not really ... int ret = 0; mutex_lock(&encl->lock); rcu_read_lock(); while (xas.index < idx_end) { page = xas_next(&xas); if (!page || (~page->vm_max_prot_bits & vm_prot_bits)) ret = -EACCESS; break; } } rcu_read_unlock(); mutex_unlock(&encl->lock); return ret; ... or you could rework to use the xa_lock instead of encl->lock. I don't know how feasible that is for you.