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=-8.3 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 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 1CD7BC3A59D for ; Thu, 22 Aug 2019 04:00:48 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id DEAD02173E for ; Thu, 22 Aug 2019 04:00:47 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1725783AbfHVEAr (ORCPT ); Thu, 22 Aug 2019 00:00:47 -0400 Received: from mga11.intel.com ([192.55.52.93]:10597 "EHLO mga11.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725770AbfHVEAr (ORCPT ); Thu, 22 Aug 2019 00:00:47 -0400 X-Amp-Result: UNKNOWN X-Amp-Original-Verdict: FILE UNKNOWN X-Amp-File-Uploaded: False Received: from fmsmga001.fm.intel.com ([10.253.24.23]) by fmsmga102.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 21 Aug 2019 21:00:46 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.64,415,1559545200"; d="scan'208";a="196143336" Received: from sjchrist-coffee.jf.intel.com (HELO linux.intel.com) ([10.54.74.41]) by fmsmga001.fm.intel.com with ESMTP; 21 Aug 2019 21:00:46 -0700 Date: Wed, 21 Aug 2019 21:00:46 -0700 From: Sean Christopherson To: Jarkko Sakkinen Cc: linux-sgx@vger.kernel.org, Sean Christopherson , Shay Katz-zamir , Serge Ayoun Subject: Re: [PATCH 5/5] x86/sgx: Rename vm_prot_bits as max_vm_flags Message-ID: <20190822040046.GW29345@linux.intel.com> References: <20190819152544.7296-1-jarkko.sakkinen@linux.intel.com> <20190819152544.7296-6-jarkko.sakkinen@linux.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190819152544.7296-6-jarkko.sakkinen@linux.intel.com> User-Agent: Mutt/1.5.24 (2015-08-30) Sender: linux-sgx-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-sgx@vger.kernel.org On Mon, Aug 19, 2019 at 06:25:44PM +0300, Jarkko Sakkinen wrote: > vm_prot_bits is very bad and misleading name for the field in struct > sgx_encl_page. What the field contains exactly is not @prot of > mprotect() but the *maximum* VM flags for the VMA that contains the > given enclave page. > > Thus, the only viable name for the field is max_vm_flags. In functions > that also pass VM flags the parameter name is renamed from vm_prot_bits > to vm_flags. Why not max_vm_prot_bits? 'vm_flags' implies the field contains all manner of VM_FLAGS. The 'vm_prot_bits' name was derived from calc_vm_prot_bits() to provide this differentiation, especially since there's also a calc_vm_flag_bits(), > To summarize, this commit makes two improvements to clarify the > permission handling: > > 1. Changes the name to match better the contents. > 2. Uses naming to differentiate the field inside the struct and > the parameter passed to functions. > > Cc: Sean Christopherson > Cc: Shay Katz-zamir > Cc: Serge Ayoun > Signed-off-by: Jarkko Sakkinen > --- > arch/x86/kernel/cpu/sgx/driver/ioctl.c | 2 +- > arch/x86/kernel/cpu/sgx/encl.c | 14 +++++++------- > arch/x86/kernel/cpu/sgx/encl.h | 4 ++-- > 3 files changed, 10 insertions(+), 10 deletions(-) > > diff --git a/arch/x86/kernel/cpu/sgx/driver/ioctl.c b/arch/x86/kernel/cpu/sgx/driver/ioctl.c > index 2415dcb20a6e..b61e06daad6e 100644 > --- a/arch/x86/kernel/cpu/sgx/driver/ioctl.c > +++ b/arch/x86/kernel/cpu/sgx/driver/ioctl.c > @@ -261,7 +261,7 @@ static struct sgx_encl_page *sgx_encl_page_alloc(struct sgx_encl *encl, > encl_page->encl = encl; > > /* Calculate maximum of the VM flags for the page. */ > - encl_page->vm_prot_bits = calc_vm_prot_bits(prot, 0); > + encl_page->max_vm_flags = calc_vm_prot_bits(prot, 0); > > ret = radix_tree_insert(&encl->page_tree, PFN_DOWN(encl_page->desc), > encl_page); > diff --git a/arch/x86/kernel/cpu/sgx/encl.c b/arch/x86/kernel/cpu/sgx/encl.c > index a20d498e9dcd..890eacb45a80 100644 > --- a/arch/x86/kernel/cpu/sgx/encl.c > +++ b/arch/x86/kernel/cpu/sgx/encl.c > @@ -292,25 +292,25 @@ static unsigned int sgx_vma_fault(struct vm_fault *vmf) > * @encl: an enclave > * @start: lower bound of the address range, inclusive > * @end: upper bound of the address range, exclusive > - * @vm_prot_bits: requested protections of the address range > + * @vm_flags: requested VM flags for the address range > * > * Iterate through the enclave pages contained within [@start, @end) to verify > - * the permissions requested by @vm_prot_bits do not exceed that of any enclave > - * page to be mapped. Page addresses that do not have an associated enclave > - * page are interpreted to zero permissions. > + * the the VM flags do not exceed that of any enclave page to be mapped. Page > + * addresses that do not have an associated enclave page are interpreted to zero > + * permissions. > * > * Return: > * 0 on success, > * -EACCES if VMA permissions exceed enclave page permissions > */ > int sgx_encl_may_map(struct sgx_encl *encl, unsigned long start, > - unsigned long end, unsigned long vm_prot_bits) > + unsigned long end, unsigned long vm_flags) If 'vm_prot_bits' is distasteful, 'prot' would be preferrable as its used throughout the kernel for variable that hold only the prot bits. > { > unsigned long idx, idx_start, idx_end; > struct sgx_encl_page *page; > > /* PROT_NONE always succeeds. */ > - if (!vm_prot_bits) > + if (!vm_flags) > return 0; > > idx_start = PFN_DOWN(start); > @@ -321,7 +321,7 @@ int sgx_encl_may_map(struct sgx_encl *encl, unsigned long start, > page = radix_tree_lookup(&encl->page_tree, idx); > mutex_unlock(&encl->lock); > > - if (!page || (~page->vm_prot_bits & vm_prot_bits)) > + if (!page || (~page->max_vm_flags & vm_flags)) > return -EACCES; > } > > diff --git a/arch/x86/kernel/cpu/sgx/encl.h b/arch/x86/kernel/cpu/sgx/encl.h > index d3a1687ed84c..0e28b784a8c5 100644 > --- a/arch/x86/kernel/cpu/sgx/encl.h > +++ b/arch/x86/kernel/cpu/sgx/encl.h > @@ -44,7 +44,7 @@ enum sgx_encl_page_desc { > > struct sgx_encl_page { > unsigned long desc; > - unsigned long vm_prot_bits; > + unsigned long max_vm_flags; > struct sgx_epc_page *epc_page; > struct sgx_va_page *va_page; > struct sgx_encl *encl; > @@ -134,6 +134,6 @@ void sgx_free_va_slot(struct sgx_va_page *va_page, unsigned int offset); > bool sgx_va_page_full(struct sgx_va_page *va_page); > > int sgx_encl_may_map(struct sgx_encl *encl, unsigned long start, > - unsigned long end, unsigned long vm_prot_bits); > + unsigned long end, unsigned long vm_flags); > > #endif /* _X86_ENCL_H */ > -- > 2.20.1 >