Re: [PATCH v28 11/22] x86/sgx: Linux Enclave Driver

[Sean Christopherson <sean.j.christopherson@intel.com>]

On Wed, Mar 04, 2020 at 01:35:58AM +0200, Jarkko Sakkinen wrote:
> diff --git a/arch/x86/include/uapi/asm/sgx.h b/arch/x86/include/uapi/asm/sgx.h
> new file mode 100644
> index 000000000000..5edb08ab8fd0
> --- /dev/null
> +++ b/arch/x86/include/uapi/asm/sgx.h
> @@ -0,0 +1,66 @@
> +/* SPDX-License-Identifier: (GPL-2.0 OR BSD-3-Clause) WITH Linux-syscall-note */
> +/*
> + * Copyright(c) 2016-19 Intel Corporation.
> + */
> +#ifndef _UAPI_ASM_X86_SGX_H
> +#define _UAPI_ASM_X86_SGX_H
> +
> +#include <linux/types.h>
> +#include <linux/ioctl.h>
> +
> +/**
> + * enum sgx_epage_flags - page control flags
> + * %SGX_PAGE_MEASURE:	Measure the page contents with a sequence of
> + *			ENCLS[EEXTEND] operations.
> + */
> +enum sgx_page_flags {
> +	SGX_PAGE_MEASURE	= 0x01,
> +};
> +
> +#define SGX_MAGIC 0xA4
> +
> +#define SGX_IOC_ENCLAVE_CREATE \
> +	_IOW(SGX_MAGIC, 0x00, struct sgx_enclave_create)
> +#define SGX_IOC_ENCLAVE_ADD_PAGES \
> +	_IOWR(SGX_MAGIC, 0x01, struct sgx_enclave_add_pages)
> +#define SGX_IOC_ENCLAVE_INIT \
> +	_IOW(SGX_MAGIC, 0x02, struct sgx_enclave_init)
> +
> +/**
> + * struct sgx_enclave_create - parameter structure for the
> + *                             %SGX_IOC_ENCLAVE_CREATE ioctl
> + * @src:	address for the SECS page data
> + */
> +struct sgx_enclave_create  {
> +	__u64	src;

Would it make sense to add reserved fields to the structs so that new
features can be added in a backwards compatible way?  E.g. if we want to
allow userspace to control the backing store by passing in a file
descriptor ENCLAVE_CREATE.

> +};
> +
> +/**
> + * struct sgx_enclave_add_pages - parameter structure for the
> + *                                %SGX_IOC_ENCLAVE_ADD_PAGE ioctl
> + * @src:	start address for the page data
> + * @offset:	starting page offset
> + * @length:	length of the data (multiple of the page size)
> + * @secinfo:	address for the SECINFO data
> + * @flags:	page control flags
> + * @count:	number of bytes added (multiple of the page size)
> + */
> +struct sgx_enclave_add_pages {
> +	__u64	src;
> +	__u64	offset;
> +	__u64	length;
> +	__u64	secinfo;
> +	__u64	flags;
> +	__u64	count;
> +};
> +
> +/**
> + * struct sgx_enclave_init - parameter structure for the
> + *                           %SGX_IOC_ENCLAVE_INIT ioctl
> + * @sigstruct:	address for the SIGSTRUCT data
> + */
> +struct sgx_enclave_init {
> +	__u64 sigstruct;
> +};