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=-13.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS 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 8BF21C433E0 for ; Wed, 13 Jan 2021 01:10:02 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 4E97E23135 for ; Wed, 13 Jan 2021 01:10:02 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726718AbhAMBKC (ORCPT ); Tue, 12 Jan 2021 20:10:02 -0500 Received: from mga06.intel.com ([134.134.136.31]:42082 "EHLO mga06.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726488AbhAMBKB (ORCPT ); Tue, 12 Jan 2021 20:10:01 -0500 IronPort-SDR: SMqF4z9G7eyX6hLwisOQl6QPj8AFvsoXklcUQKo97uq8ykUO3m/2vWFq08FeWyI6lavv0jZv0t mMItqBFeQLjQ== X-IronPort-AV: E=McAfee;i="6000,8403,9862"; a="239673392" X-IronPort-AV: E=Sophos;i="5.79,343,1602572400"; d="scan'208";a="239673392" Received: from orsmga008.jf.intel.com ([10.7.209.65]) by orsmga104.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 12 Jan 2021 17:09:21 -0800 IronPort-SDR: LhQHngKa4H0CjDPuaRQbC/e4N9rAt1KV0Kz/5JYqDU03UPTPsexYgQjh4z3ula3L3l635kuXUV QEQFWOgSwiZA== X-IronPort-AV: E=Sophos;i="5.79,343,1602572400"; d="scan'208";a="381647869" Received: from rjchin-mobl.amr.corp.intel.com (HELO khuang2-desk.gar.corp.intel.com) ([10.251.18.242]) by orsmga008-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 12 Jan 2021 17:09:19 -0800 Date: Wed, 13 Jan 2021 14:09:17 +1300 From: Kai Huang To: jarkko@kernel.org Cc: linux-sgx@vger.kernel.org, dave.hansen@intel.com, haitao.huang@intel.com, Thomas Gleixner , Ingo Molnar , Borislav Petkov , x86@kernel.org, "H. Peter Anvin" Subject: Re: [PATCH v2 2/2] x86/sgx: Wipe out EREMOVE from sgx_free_epc_page() Message-Id: <20210113140917.d02dd73185604bc5d2f1501e@intel.com> In-Reply-To: <20210112233351.68678-3-jarkko@kernel.org> References: <20210112233351.68678-1-jarkko@kernel.org> <20210112233351.68678-3-jarkko@kernel.org> X-Mailer: Sylpheed 3.7.0 (GTK+ 2.24.33; x86_64-redhat-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-sgx@vger.kernel.org On Wed, 13 Jan 2021 01:33:51 +0200 jarkko@kernel.org wrote: > From: "jarkko@kernel.org" > > Encapsulate the snippet in sgx_free_epc_page() concerning EREMOVE to > sgx_reset_epc_page(), which is a static helper function for > sgx_encl_release(). It's the only function existing, which deals with > initialized pages. > > Signed-off-by: jarkko@kernel.org > --- > v2: Fixed a compilation error s/page/epc_page/ change not amended > to the patches. > arch/x86/kernel/cpu/sgx/encl.c | 15 ++++++++++++++- > arch/x86/kernel/cpu/sgx/main.c | 10 ++++------ > 2 files changed, 18 insertions(+), 7 deletions(-) > > diff --git a/arch/x86/kernel/cpu/sgx/encl.c b/arch/x86/kernel/cpu/sgx/encl.c > index fe7256db6e73..511f4bc70699 100644 > --- a/arch/x86/kernel/cpu/sgx/encl.c > +++ b/arch/x86/kernel/cpu/sgx/encl.c > @@ -389,6 +389,16 @@ const struct vm_operations_struct sgx_vm_ops = { > .access = sgx_vma_access, > }; > > + > +static void sgx_reset_epc_page(struct sgx_epc_page *epc_page) > +{ > + int ret; > + > + ret = __eremove(sgx_get_epc_virt_addr(epc_page)); > + if (WARN_ONCE(ret, "EREMOVE returned %d (0x%x)", ret, ret)) > + return; > +} > + > /** > * sgx_encl_release - Destroy an enclave instance > * @kref: address of a kref inside &sgx_encl > @@ -412,6 +422,7 @@ void sgx_encl_release(struct kref *ref) > if (sgx_unmark_page_reclaimable(entry->epc_page)) > continue; > > + sgx_reset_epc_page(entry->epc_page); > sgx_free_epc_page(entry->epc_page); > encl->secs_child_cnt--; > entry->epc_page = NULL; > @@ -423,6 +434,7 @@ void sgx_encl_release(struct kref *ref) > xa_destroy(&encl->page_array); > > if (!encl->secs_child_cnt && encl->secs.epc_page) { > + sgx_reset_epc_page(encl->secs.epc_page); > sgx_free_epc_page(encl->secs.epc_page); > encl->secs.epc_page = NULL; > } > @@ -431,7 +443,8 @@ void sgx_encl_release(struct kref *ref) > va_page = list_first_entry(&encl->va_pages, struct sgx_va_page, > list); > list_del(&va_page->list); > - sgx_free_epc_page(va_page->epc_page); > + sgx_reset_epc_page(entry->epc_page); > + sgx_free_epc_page(entry->epc_page); Reply so that Sean can see, since he just subscribed to linux-sgx list. As Sean pointed out in KVM SGX virtualization thread, entry should be va_page. > kfree(va_page); > } > > diff --git a/arch/x86/kernel/cpu/sgx/main.c b/arch/x86/kernel/cpu/sgx/main.c > index b2996cb63a8a..89d52fb56d4b 100644 > --- a/arch/x86/kernel/cpu/sgx/main.c > +++ b/arch/x86/kernel/cpu/sgx/main.c > @@ -629,16 +629,14 @@ struct sgx_epc_page *sgx_alloc_epc_page(void *owner, bool reclaim) > * sgx_free_epc_page() - Free an EPC page > * @page: an EPC page > * > - * Call EREMOVE for an EPC page and insert it back to the list of free pages. > + * Put the EPC page back to the list of free pages. It's the callers > + * responsibility to make sure that the page is in uninitialized state In other > + * words, do EREMOVE, EWB or whatever operation is necessary before calling > + * this function. > */ > void sgx_free_epc_page(struct sgx_epc_page *page) > { > struct sgx_epc_section *section = &sgx_epc_sections[page->section]; > - int ret; > - > - ret = __eremove(sgx_get_epc_virt_addr(page)); > - if (WARN_ONCE(ret, "EREMOVE returned %d (0x%x)", ret, ret)) > - return; > > spin_lock(§ion->lock); > list_add_tail(&page->list, §ion->page_list); > -- > 2.29.2 >