From mboxrd@z Thu Jan 1 00:00:00 1970 From: Sean Christopherson Subject: Re: [PATCH v16 18/22] platform/x86: Intel SGX driver Date: Tue, 06 Nov 2018 08:40:00 -0800 Message-ID: <1541522400.7839.48.camel@intel.com> References: <20181106134758.10572-1-jarkko.sakkinen@linux.intel.com> <20181106134758.10572-19-jarkko.sakkinen@linux.intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 8bit Return-path: In-Reply-To: <20181106134758.10572-19-jarkko.sakkinen@linux.intel.com> Sender: linux-kernel-owner@vger.kernel.org To: Jarkko Sakkinen , x86@kernel.org, platform-driver-x86@vger.kernel.org, linux-sgx@vger.kernel.org Cc: dave.hansen@intel.com, nhorman@redhat.com, npmccallum@redhat.com, serge.ayoun@intel.com, shay.katz-zamir@intel.com, haitao.huang@intel.com, andriy.shevchenko@linux.intel.com, tglx@linutronix.de, kai.svahn@intel.com, Suresh Siddha , Ingo Molnar , Borislav Petkov , "H. Peter Anvin" , Darren Hart , Andy Shevchenko , "open list:X86 ARCHITECTURE (32-BIT AND 64-BIT)" List-Id: platform-driver-x86.vger.kernel.org On Tue, 2018-11-06 at 15:45 +0200, Jarkko Sakkinen wrote: > Intel Software Guard eXtensions (SGX) is a set of CPU instructions that > can be used by applications to set aside private regions of code and > data. The code outside the enclave is disallowed to access the memory > inside the enclave by the CPU access control. >  > SGX driver provides a ioctl API for loading and initializing enclaves. > Address range for enclaves is reserved with mmap() and they are > destroyed with munmap(). Enclave construction, measurement and > initialization is done with the provided the ioctl API. ... > +struct sgx_encl { > + unsigned int flags; > + uint64_t attributes; > + uint64_t xfrm; > + unsigned int page_cnt; > + unsigned int secs_child_cnt; > + struct mutex lock; > + struct mm_struct *mm; > + struct file *backing; Is there any particular reason why the kernel manages the backing for the enclave and the PCMDs?  Could we have userspace provide the backing either through the ECREATE ioctl() or maybe a completely new ioctl(), e.g. to give userspace the option to back the enclave with a NVDIMM instead of RAM?  A separate ioctl() with control flags might give us some flexibility in the future, e.g. maybe there are use cases where userspace would prefer to kill enclaves rather than swap EPC. > + struct kref refcount; > + unsigned long base; > + unsigned long size; > + unsigned long ssaframesize; > + struct radix_tree_root page_tree; > + struct list_head add_page_reqs; > + struct work_struct add_page_work; > + struct sgx_encl_page secs; > + struct pid *tgid; > + struct mmu_notifier mmu_notifier; > + struct notifier_block pm_notifier; > +};