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:

quoted

quoted

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.