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=-6.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,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 2B2ABC31E44 for ; Mon, 17 Jun 2019 08:39:50 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 049452080A for ; Mon, 17 Jun 2019 08:39:50 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727823AbfFQIjs (ORCPT ); Mon, 17 Jun 2019 04:39:48 -0400 Received: from mga04.intel.com ([192.55.52.120]:3979 "EHLO mga04.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725837AbfFQIjs (ORCPT ); Mon, 17 Jun 2019 04:39:48 -0400 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga005.fm.intel.com ([10.253.24.32]) by fmsmga104.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 17 Jun 2019 01:39:47 -0700 X-ExtLoop1: 1 Received: from khuang2-desk.gar.corp.intel.com ([10.255.91.82]) by fmsmga005.fm.intel.com with ESMTP; 17 Jun 2019 01:39:44 -0700 Message-ID: <1560760783.5187.10.camel@linux.intel.com> Subject: Re: [PATCH, RFC 49/62] mm, x86: export several MKTME variables From: Kai Huang To: Peter Zijlstra Cc: "Kirill A. Shutemov" , Andrew Morton , x86@kernel.org, Thomas Gleixner , Ingo Molnar , "H. Peter Anvin" , Borislav Petkov , Andy Lutomirski , David Howells , Kees Cook , Dave Hansen , Jacob Pan , Alison Schofield , linux-mm@kvack.org, kvm@vger.kernel.org, keyrings@vger.kernel.org, linux-kernel@vger.kernel.org Date: Mon, 17 Jun 2019 20:39:43 +1200 In-Reply-To: <20190617074643.GW3436@hirez.programming.kicks-ass.net> References: <20190508144422.13171-1-kirill.shutemov@linux.intel.com> <20190508144422.13171-50-kirill.shutemov@linux.intel.com> <20190614115647.GI3436@hirez.programming.kicks-ass.net> <1560741269.5187.7.camel@linux.intel.com> <20190617074643.GW3436@hirez.programming.kicks-ass.net> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.24.6 (3.24.6-1.fc26) Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 2019-06-17 at 09:46 +0200, Peter Zijlstra wrote: > On Mon, Jun 17, 2019 at 03:14:29PM +1200, Kai Huang wrote: > > On Fri, 2019-06-14 at 13:56 +0200, Peter Zijlstra wrote: > > > On Wed, May 08, 2019 at 05:44:09PM +0300, Kirill A. Shutemov wrote: > > > > From: Kai Huang > > > > > > > > KVM needs those variables to get/set memory encryption mask. > > > > > > > > Signed-off-by: Kai Huang > > > > Signed-off-by: Kirill A. Shutemov > > > > --- > > > > arch/x86/mm/mktme.c | 3 +++ > > > > 1 file changed, 3 insertions(+) > > > > > > > > diff --git a/arch/x86/mm/mktme.c b/arch/x86/mm/mktme.c > > > > index df70651816a1..12f4266cf7ea 100644 > > > > --- a/arch/x86/mm/mktme.c > > > > +++ b/arch/x86/mm/mktme.c > > > > @@ -7,13 +7,16 @@ > > > > > > > > /* Mask to extract KeyID from physical address. */ > > > > phys_addr_t mktme_keyid_mask; > > > > +EXPORT_SYMBOL_GPL(mktme_keyid_mask); > > > > /* > > > > * Number of KeyIDs available for MKTME. > > > > * Excludes KeyID-0 which used by TME. MKTME KeyIDs start from 1. > > > > */ > > > > int mktme_nr_keyids; > > > > +EXPORT_SYMBOL_GPL(mktme_nr_keyids); > > > > /* Shift of KeyID within physical address. */ > > > > int mktme_keyid_shift; > > > > +EXPORT_SYMBOL_GPL(mktme_keyid_shift); > > > > > > > > DEFINE_STATIC_KEY_FALSE(mktme_enabled_key); > > > > EXPORT_SYMBOL_GPL(mktme_enabled_key); > > > > > > NAK, don't export variables. Who owns the values, who enforces this? > > > > > > > Both KVM and IOMMU driver need page_keyid() and mktme_keyid_shift to set page's keyID to the > > right > > place in the PTE (of KVM EPT and VT-d DMA page table). > > > > MKTME key type code need to know mktme_nr_keyids in order to alloc/free keyID. > > > > Maybe better to introduce functions instead of exposing variables directly? > > > > Or instead of introducing page_keyid(), we use page_encrypt_mask(), which essentially holds > > "page_keyid() << mktme_keyid_shift"? > > Yes, that's much better, because that strictly limits the access to R/O. > Thanks. I think Kirill will be the one to handle your suggestion. :) Kirill? Thanks, -Kai