> From: Andy Lutomirski [mailto:luto@xxxxxxxxxx] > Sent: Tuesday, June 04, 2019 1:18 PM > > On Mon, Jun 3, 2019 at 1:39 PM Sean Christopherson > <sean.j.christopherson@xxxxxxxxx> wrote: > > > > On Mon, Jun 03, 2019 at 01:08:04PM -0700, Sean Christopherson wrote: > > > On Sun, Jun 02, 2019 at 11:26:09PM -0700, Xing, Cedric wrote: > > > > > From: Christopherson, Sean J > > > > > Sent: Friday, May 31, 2019 4:32 PM > > > > > > > > > > +/** > > > > > + * sgx_ioc_enclave_add_pages - handler for > > > > > +%SGX_IOC_ENCLAVE_ADD_PAGES > > > > > + * > > > > > + * @filep: open file to /dev/sgx > > > > > + * @cmd: the command value > > > > > + * @arg: pointer to an &sgx_enclave_add_page instance > > > > > + * > > > > > + * Add a range of pages to an uninitialized enclave (EADD), and > > > > > +optionally > > > > > + * extend the enclave's measurement with the contents of the > page (EEXTEND). > > > > > + * The range of pages must be virtually contiguous. The > > > > > +SECINFO and > > > > > + * measurement maskare applied to all pages, i.e. pages with > > > > > +different > > > > > + * properties must be added in separate calls. > > > > > + * > > > > > + * EADD and EEXTEND are done asynchronously via worker threads. > > > > > +A successful > > > > > + * sgx_ioc_enclave_add_page() only indicates the pages have > > > > > +been added to the > > > > > + * work queue, it does not guarantee adding the pages to the > > > > > +enclave will > > > > > + * succeed. > > > > > + * > > > > > + * Return: > > > > > + * 0 on success, > > > > > + * -errno otherwise > > > > > + */ > > > > > +static long sgx_ioc_enclave_add_pages(struct file *filep, > unsigned int cmd, > > > > > + unsigned long arg) { struct > > > > > +sgx_enclave_add_pages *addp = (void *)arg; struct sgx_encl > > > > > +*encl = filep->private_data; struct sgx_secinfo secinfo; > > > > > +unsigned int i; int ret; > > > > > + > > > > > + if (copy_from_user(&secinfo, (void __user *)addp->secinfo, > > > > > + sizeof(secinfo))) > > > > > + return -EFAULT; > > > > > + > > > > > + for (i = 0, ret = 0; i < addp->nr_pages && !ret; i++) { > > > > > + if (signal_pending(current)) > > > > > + return -ERESTARTSYS; > > > > > > > > If interrupted, how would user mode code know how many pages have > been EADD'ed? > > > > > > Hmm, updating nr_pages would be fairly simple and shouldn't confuse > > > userspace, e.g. as opposed to overloading the return value. > > > > Or maybe update @addr and @src as well? That would allow userspace to > > re-invoke the ioctl() without having to modify the struct. > > If you're going to use -ERESTARTSYS, that's the way to go. -EINTR would > be an alternative. A benefit of -ERESTARTSYS is that, with -EINTR, it > wouldn't be that surprising for user code to simply fail to handle it. -EINTR means the call was interrupted before anything could be done. Am I correct? But in this case some pages have been processed already so I guess we cannot return any error code. I think it more reasonable to return the number of pages (or bytes) processed.
