From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jarkko Sakkinen Subject: Re: [PATCH v15 16/23] x86/sgx: Enumerate and track EPC sections Date: Mon, 5 Nov 2018 19:35:57 +0200 Message-ID: <20181105173557.GF4502@linux.intel.com> References: <20181102231320.29164-1-jarkko.sakkinen@linux.intel.com> <20181102231320.29164-17-jarkko.sakkinen@linux.intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: Sender: linux-kernel-owner@vger.kernel.org To: Andy Shevchenko Cc: "maintainer:X86 ARCHITECTURE (32-BIT AND 64-BIT)" , Platform Driver , linux-sgx@vger.kernel.org, Dave Hansen , sean.j.christopherson@intel.com, nhorman@redhat.com, npmccallum@redhat.com, serge.ayoun@intel.com, shay.katz-zamir@intel.com, haitao.huang@intel.com, mark.shanahan@intel.com, Andy Shevchenko , suresh.b.siddha@intel.com, Thomas Gleixner , Ingo Molnar , Borislav Petkov , "H. Peter Anvin" , Reinette Chatre , "Rafael J. Wysocki" , "Kirill A. Shutemov" , Linux Kernel Mailing List List-Id: platform-driver-x86.vger.kernel.org On Sat, Nov 03, 2018 at 03:22:34PM +0200, Andy Shevchenko wrote: > On Sat, Nov 3, 2018 at 1:17 AM Jarkko Sakkinen > wrote: > > > > From: Sean Christopherson > > > > Enumerate Enclave Page Cache (EPC) sections via CPUID and add the data > > structures necessary to track EPC pages so that they can be allocated, > > freed and managed. As a system may have multiple EPC sections, invoke > > CPUID on SGX sub-leafs until an invalid leaf is encountered. > > > > On NUMA systems, a node can have at most one bank. A bank can be at > > most part of two nodes. SGX supports both nodes with a single memory > > controller and also sub-cluster nodes with severals memory controllers > > on a single die. > > > > For simplicity, support a maximum of eight EPC sections. Current > > client hardware supports only a single section, while upcoming server > > hardware will support at most eight sections. Bounding the number of > > sections also allows the section ID to be embedded along with a page's > > offset in a single unsigned long, enabling easy retrieval of both the > > VA and PA for a given page. > > > + iounmap(section->va); > > > + section->va = ioremap_cache(addr, size); > > + if (!section->va) > > + return -ENOMEM; > > I forgot if it's a place in code on which we discussed ioremap() vs. > memremap() call. > And I forgot why the conclusion is to leave ioremap(). > > Sorry, if I'm mistaken. Thanks for pointing this out. It very well might I have either 1. forgotten to do the switch. 2. had some open about it that I forgot to ask. Anyway, I'll check this and at minimum document the reason to the change log if there is one to keep the ioremap(). /Jarkko