nitro_enclaves: Add ioctl interface definition

The Nitro Enclaves driver handles the enclave lifetime management. This
includes enclave creation, termination and setting up its resources such
as memory and CPU.

An enclave runs alongside the VM that spawned it. It is abstracted as a
process running in the VM that launched it. The process interacts with
the NE driver, that exposes an ioctl interface for creating an enclave
and setting up its resources.

Changelog

v9 -> v10

* Update commit message to include the changelog before the SoB tag(s).

v8 -> v9

* No changes.

v7 -> v8

* Add NE custom error codes for user space memory regions not backed by
  pages multiple of 2 MiB, invalid flags and enclave CID.
* Add max flag value for enclave image load info.

v6 -> v7

* Clarify in the ioctls documentation that the return value is -1 and
  errno is set on failure.
* Update the error code value for NE_ERR_INVALID_MEM_REGION_SIZE as it
  gets in user space as value 25 (ENOTTY) instead of 515. Update the
  NE custom error codes values range to not be the same as the ones
  defined in include/linux/errno.h, although these are not propagated
  to user space.

v5 -> v6

* Fix typo in the description about the NE CPU pool.
* Update documentation to kernel-doc format.
* Remove the ioctl to query API version.

v4 -> v5

* Add more details about the ioctl calls usage e.g. error codes, file
  descriptors used.
* Update the ioctl to set an enclave vCPU to not return a file
  descriptor.
* Add specific NE error codes.

v3 -> v4

* Decouple NE ioctl interface from KVM API.
* Add NE API version and the corresponding ioctl call.
* Add enclave / image load flags options.

v2 -> v3

* Remove the GPL additional wording as SPDX-License-Identifier is
  already in place.

v1 -> v2

* Add ioctl for getting enclave image load metadata.
* Update NE_ENCLAVE_START ioctl name to NE_START_ENCLAVE.
* Add entry in Documentation/userspace-api/ioctl/ioctl-number.rst for NE
  ioctls.
* Update NE ioctls definition based on the updated ioctl range for major
  and minor.

Reviewed-by: Alexander Graf <graf@amazon.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Alexandru Vasile <lexnv@amazon.com>
Signed-off-by: Andra Paraschiv <andraprs@amazon.com>
Link: https://lore.kernel.org/r/20200921121732.44291-2-andraprs@amazon.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

3 files changed, 374 insertions, 1 deletions

diff --git a/Documentation/userspace-api/ioctl/ioctl-number.rst b/Documentation/userspace-api/ioctl/ioctl-number.rst
index 2a198838fca9..5f7ff00f394e 100644
--- a/Documentation/userspace-api/ioctl/ioctl-number.rst
+++ b/Documentation/userspace-api/ioctl/ioctl-number.rst
@@ -328,8 +328,11 @@ Code  Seq#    Include File                                           Comments
 0xAC  00-1F  linux/raw.h
 0xAD  00                                                             Netfilter device in development:
                                                                      <mailto:rusty@rustcorp.com.au>
-0xAE  all    linux/kvm.h                                             Kernel-based Virtual Machine
+0xAE  00-1F  linux/kvm.h                                             Kernel-based Virtual Machine
                                                                      <mailto:kvm@vger.kernel.org>
+0xAE  40-FF  linux/kvm.h                                             Kernel-based Virtual Machine
+                                                                     <mailto:kvm@vger.kernel.org>
+0xAE  20-3F  linux/nitro_enclaves.h                                  Nitro Enclaves
 0xAF  00-1F  linux/fsl_hypervisor.h                                  Freescale hypervisor
 0xB0  all                                                            RATIO devices in development:
                                                                      <mailto:vgo@ratio.de>
diff --git a/include/linux/nitro_enclaves.h b/include/linux/nitro_enclaves.h
new file mode 100644
index 000000000000..d91ef2bfdf47
--- /dev/null
+++ b/include/linux/nitro_enclaves.h
@@ -0,0 +1,11 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright 2020 Amazon.com, Inc. or its affiliates. All Rights Reserved.
+ */
+
+#ifndef _LINUX_NITRO_ENCLAVES_H_
+#define _LINUX_NITRO_ENCLAVES_H_
+
+#include <uapi/linux/nitro_enclaves.h>
+
+#endif /* _LINUX_NITRO_ENCLAVES_H_ */
diff --git a/include/uapi/linux/nitro_enclaves.h b/include/uapi/linux/nitro_enclaves.h
new file mode 100644
index 000000000000..b945073fe544
--- /dev/null
+++ b/include/uapi/linux/nitro_enclaves.h
@@ -0,0 +1,359 @@
+/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
+/*
+ * Copyright 2020 Amazon.com, Inc. or its affiliates. All Rights Reserved.
+ */
+
+#ifndef _UAPI_LINUX_NITRO_ENCLAVES_H_
+#define _UAPI_LINUX_NITRO_ENCLAVES_H_
+
+#include <linux/types.h>
+
+/**
+ * DOC: Nitro Enclaves (NE) Kernel Driver Interface
+ */
+
+/**
+ * NE_CREATE_VM - The command is used to create a slot that is associated with
+ *		  an enclave VM.
+ *		  The generated unique slot id is an output parameter.
+ *		  The ioctl can be invoked on the /dev/nitro_enclaves fd, before
+ *		  setting any resources, such as memory and vCPUs, for an
+ *		  enclave. Memory and vCPUs are set for the slot mapped to an enclave.
+ *		  A NE CPU pool has to be set before calling this function. The
+ *		  pool can be set after the NE driver load, using
+ *		  /sys/module/nitro_enclaves/parameters/ne_cpus.
+ *		  Its format is the detailed in the cpu-lists section:
+ *		  https://www.kernel.org/doc/html/latest/admin-guide/kernel-parameters.html
+ *		  CPU 0 and its siblings have to remain available for the
+ *		  primary / parent VM, so they cannot be set for enclaves. Full
+ *		  CPU core(s), from the same NUMA node, need(s) to be included
+ *		  in the CPU pool.
+ *
+ * Context: Process context.
+ * Return:
+ * * Enclave file descriptor		- Enclave file descriptor used with
+ *					  ioctl calls to set vCPUs and memory
+ *					  regions, then start the enclave.
+ * *  -1				- There was a failure in the ioctl logic.
+ * On failure, errno is set to:
+ * * EFAULT				- copy_to_user() failure.
+ * * ENOMEM				- Memory allocation failure for internal
+ *					  bookkeeping variables.
+ * * NE_ERR_NO_CPUS_AVAIL_IN_POOL	- No NE CPU pool set / no CPUs available
+ *					  in the pool.
+ * * Error codes from get_unused_fd_flags() and anon_inode_getfile().
+ * * Error codes from the NE PCI device request.
+ */
+#define NE_CREATE_VM			_IOR(0xAE, 0x20, __u64)
+
+/**
+ * NE_ADD_VCPU - The command is used to set a vCPU for an enclave. The vCPU can
+ *		 be auto-chosen from the NE CPU pool or it can be set by the
+ *		 caller, with the note that it needs to be available in the NE
+ *		 CPU pool. Full CPU core(s), from the same NUMA node, need(s) to
+ *		 be associated with an enclave.
+ *		 The vCPU id is an input / output parameter. If its value is 0,
+ *		 then a CPU is chosen from the enclave CPU pool and returned via
+ *		 this parameter.
+ *		 The ioctl can be invoked on the enclave fd, before an enclave
+ *		 is started.
+ *
+ * Context: Process context.
+ * Return:
+ * * 0					- Logic succesfully completed.
+ * *  -1				- There was a failure in the ioctl logic.
+ * On failure, errno is set to:
+ * * EFAULT				- copy_from_user() / copy_to_user() failure.
+ * * ENOMEM				- Memory allocation failure for internal
+ *					  bookkeeping variables.
+ * * EIO				- Current task mm is not the same as the one
+ *					  that created the enclave.
+ * * NE_ERR_NO_CPUS_AVAIL_IN_POOL	- No CPUs available in the NE CPU pool.
+ * * NE_ERR_VCPU_ALREADY_USED		- The provided vCPU is already used.
+ * * NE_ERR_VCPU_NOT_IN_CPU_POOL	- The provided vCPU is not available in the
+ *					  NE CPU pool.
+ * * NE_ERR_VCPU_INVALID_CPU_CORE	- The core id of the provided vCPU is invalid
+ *					  or out of range.
+ * * NE_ERR_NOT_IN_INIT_STATE		- The enclave is not in init state
+ *					  (init = before being started).
+ * * NE_ERR_INVALID_VCPU		- The provided vCPU is not in the available
+ *					  CPUs range.
+ * * Error codes from the NE PCI device request.
+ */
+#define NE_ADD_VCPU			_IOWR(0xAE, 0x21, __u32)
+
+/**
+ * NE_GET_IMAGE_LOAD_INFO - The command is used to get information needed for
+ *			    in-memory enclave image loading e.g. offset in
+ *			    enclave memory to start placing the enclave image.
+ *			    The image load info is an input / output parameter.
+ *			    It includes info provided by the caller - flags -
+ *			    and returns the offset in enclave memory where to
+ *			    start placing the enclave image.
+ *			    The ioctl can be invoked on the enclave fd, before
+ *			    an enclave is started.
+ *
+ * Context: Process context.
+ * Return:
+ * * 0				- Logic succesfully completed.
+ * *  -1			- There was a failure in the ioctl logic.
+ * On failure, errno is set to:
+ * * EFAULT			- copy_from_user() / copy_to_user() failure.
+ * * NE_ERR_NOT_IN_INIT_STATE	- The enclave is not in init state (init =
+ *				  before being started).
+ * * NE_ERR_INVALID_FLAG_VALUE	- The value of the provided flag is invalid.
+ */
+#define NE_GET_IMAGE_LOAD_INFO		_IOWR(0xAE, 0x22, struct ne_image_load_info)
+
+/**
+ * NE_SET_USER_MEMORY_REGION - The command is used to set a memory region for an
+ *			       enclave, given the allocated memory from the
+ *			       userspace. Enclave memory needs to be from the
+ *			       same NUMA node as the enclave CPUs.
+ *			       The user memory region is an input parameter. It
+ *			       includes info provided by the caller - flags,
+ *			       memory size and userspace address.
+ *			       The ioctl can be invoked on the enclave fd,
+ *			       before an enclave is started.
+ *
+ * Context: Process context.
+ * Return:
+ * * 0					- Logic succesfully completed.
+ * *  -1				- There was a failure in the ioctl logic.
+ * On failure, errno is set to:
+ * * EFAULT				- copy_from_user() failure.
+ * * EINVAL				- Invalid physical memory region(s) e.g.
+ *					  unaligned address.
+ * * EIO				- Current task mm is not the same as
+ *					  the one that created the enclave.
+ * * ENOMEM				- Memory allocation failure for internal
+ *					  bookkeeping variables.
+ * * NE_ERR_NOT_IN_INIT_STATE		- The enclave is not in init state
+ *					  (init = before being started).
+ * * NE_ERR_INVALID_MEM_REGION_SIZE	- The memory size of the region is not
+ *					  multiple of 2 MiB.
+ * * NE_ERR_INVALID_MEM_REGION_ADDR	- Invalid user space address given.
+ * * NE_ERR_UNALIGNED_MEM_REGION_ADDR	- Unaligned user space address given.
+ * * NE_ERR_MEM_REGION_ALREADY_USED	- The memory region is already used.
+ * * NE_ERR_MEM_NOT_HUGE_PAGE		- The memory region is not backed by
+ *					  huge pages.
+ * * NE_ERR_MEM_DIFFERENT_NUMA_NODE	- The memory region is not from the same
+ *					  NUMA node as the CPUs.
+ * * NE_ERR_MEM_MAX_REGIONS		- The number of memory regions set for
+ *					  the enclave reached maximum.
+ * * NE_ERR_INVALID_PAGE_SIZE		- The memory region is not backed by
+ *					  pages multiple of 2 MiB.
+ * * NE_ERR_INVALID_FLAG_VALUE		- The value of the provided flag is invalid.
+ * * Error codes from get_user_pages().
+ * * Error codes from the NE PCI device request.
+ */
+#define NE_SET_USER_MEMORY_REGION	_IOW(0xAE, 0x23, struct ne_user_memory_region)
+
+/**
+ * NE_START_ENCLAVE - The command is used to trigger enclave start after the
+ *		      enclave resources, such as memory and CPU, have been set.
+ *		      The enclave start info is an input / output parameter. It
+ *		      includes info provided by the caller - enclave cid and
+ *		      flags - and returns the cid (if input cid is 0).
+ *		      The ioctl can be invoked on the enclave fd, after an
+ *		      enclave slot is created and resources, such as memory and
+ *		      vCPUs are set for an enclave.
+ *
+ * Context: Process context.
+ * Return:
+ * * 0					- Logic succesfully completed.
+ * *  -1				- There was a failure in the ioctl logic.
+ * On failure, errno is set to:
+ * * EFAULT				- copy_from_user() / copy_to_user() failure.
+ * * NE_ERR_NOT_IN_INIT_STATE		- The enclave is not in init state
+ *					  (init = before being started).
+ * * NE_ERR_NO_MEM_REGIONS_ADDED	- No memory regions are set.
+ * * NE_ERR_NO_VCPUS_ADDED		- No vCPUs are set.
+ * *  NE_ERR_FULL_CORES_NOT_USED	- Full core(s) not set for the enclave.
+ * * NE_ERR_ENCLAVE_MEM_MIN_SIZE	- Enclave memory is less than minimum
+ *					  memory size (64 MiB).
+ * * NE_ERR_INVALID_FLAG_VALUE		- The value of the provided flag is invalid.
+ * *  NE_ERR_INVALID_ENCLAVE_CID	- The provided enclave CID is invalid.
+ * * Error codes from the NE PCI device request.
+ */
+#define NE_START_ENCLAVE		_IOWR(0xAE, 0x24, struct ne_enclave_start_info)
+
+/**
+ * DOC: NE specific error codes
+ */
+
+/**
+ * NE_ERR_VCPU_ALREADY_USED - The provided vCPU is already used.
+ */
+#define NE_ERR_VCPU_ALREADY_USED		(256)
+/**
+ * NE_ERR_VCPU_NOT_IN_CPU_POOL - The provided vCPU is not available in the
+ *				 NE CPU pool.
+ */
+#define NE_ERR_VCPU_NOT_IN_CPU_POOL		(257)
+/**
+ * NE_ERR_VCPU_INVALID_CPU_CORE - The core id of the provided vCPU is invalid
+ *				  or out of range of the NE CPU pool.
+ */
+#define NE_ERR_VCPU_INVALID_CPU_CORE		(258)
+/**
+ * NE_ERR_INVALID_MEM_REGION_SIZE - The user space memory region size is not
+ *				    multiple of 2 MiB.
+ */
+#define NE_ERR_INVALID_MEM_REGION_SIZE		(259)
+/**
+ * NE_ERR_INVALID_MEM_REGION_ADDR - The user space memory region address range
+ *				    is invalid.
+ */
+#define NE_ERR_INVALID_MEM_REGION_ADDR		(260)
+/**
+ * NE_ERR_UNALIGNED_MEM_REGION_ADDR - The user space memory region address is
+ *				      not aligned.
+ */
+#define NE_ERR_UNALIGNED_MEM_REGION_ADDR	(261)
+/**
+ * NE_ERR_MEM_REGION_ALREADY_USED - The user space memory region is already used.
+ */
+#define NE_ERR_MEM_REGION_ALREADY_USED		(262)
+/**
+ * NE_ERR_MEM_NOT_HUGE_PAGE - The user space memory region is not backed by
+ *			      contiguous physical huge page(s).
+ */
+#define NE_ERR_MEM_NOT_HUGE_PAGE		(263)
+/**
+ * NE_ERR_MEM_DIFFERENT_NUMA_NODE - The user space memory region is backed by
+ *				    pages from different NUMA nodes than the CPUs.
+ */
+#define NE_ERR_MEM_DIFFERENT_NUMA_NODE		(264)
+/**
+ * NE_ERR_MEM_MAX_REGIONS - The supported max memory regions per enclaves has
+ *			    been reached.
+ */
+#define NE_ERR_MEM_MAX_REGIONS			(265)
+/**
+ * NE_ERR_NO_MEM_REGIONS_ADDED - The command to start an enclave is triggered
+ *				 and no memory regions are added.
+ */
+#define NE_ERR_NO_MEM_REGIONS_ADDED		(266)
+/**
+ * NE_ERR_NO_VCPUS_ADDED - The command to start an enclave is triggered and no
+ *			   vCPUs are added.
+ */
+#define NE_ERR_NO_VCPUS_ADDED			(267)
+/**
+ * NE_ERR_ENCLAVE_MEM_MIN_SIZE - The enclave memory size is lower than the
+ *				 minimum supported.
+ */
+#define NE_ERR_ENCLAVE_MEM_MIN_SIZE		(268)
+/**
+ * NE_ERR_FULL_CORES_NOT_USED - The command to start an enclave is triggered and
+ *				full CPU cores are not set.
+ */
+#define NE_ERR_FULL_CORES_NOT_USED		(269)
+/**
+ * NE_ERR_NOT_IN_INIT_STATE - The enclave is not in init state when setting
+ *			      resources or triggering start.
+ */
+#define NE_ERR_NOT_IN_INIT_STATE		(270)
+/**
+ * NE_ERR_INVALID_VCPU - The provided vCPU is out of range of the available CPUs.
+ */
+#define NE_ERR_INVALID_VCPU			(271)
+/**
+ * NE_ERR_NO_CPUS_AVAIL_IN_POOL - The command to create an enclave is triggered
+ *				  and no CPUs are available in the pool.
+ */
+#define NE_ERR_NO_CPUS_AVAIL_IN_POOL		(272)
+/**
+ * NE_ERR_INVALID_PAGE_SIZE - The user space memory region is not backed by pages
+ *			      multiple of 2 MiB.
+ */
+#define NE_ERR_INVALID_PAGE_SIZE		(273)
+/**
+ * NE_ERR_INVALID_FLAG_VALUE - The provided flag value is invalid.
+ */
+#define NE_ERR_INVALID_FLAG_VALUE		(274)
+/**
+ * NE_ERR_INVALID_ENCLAVE_CID - The provided enclave CID is invalid, either
+ *				being a well-known value or the CID of the
+ *				parent / primary VM.
+ */
+#define NE_ERR_INVALID_ENCLAVE_CID		(275)
+
+/**
+ * DOC: Image load info flags
+ */
+
+/**
+ * NE_EIF_IMAGE - Enclave Image Format (EIF)
+ */
+#define NE_EIF_IMAGE			(0x01)
+
+#define NE_IMAGE_LOAD_MAX_FLAG_VAL	(0x02)
+
+/**
+ * struct ne_image_load_info - Info necessary for in-memory enclave image
+ *			       loading (in / out).
+ * @flags:		Flags to determine the enclave image type
+ *			(e.g. Enclave Image Format - EIF) (in).
+ * @memory_offset:	Offset in enclave memory where to start placing the
+ *			enclave image (out).
+ */
+struct ne_image_load_info {
+	__u64	flags;
+	__u64	memory_offset;
+};
+
+/**
+ * DOC: User memory region flags
+ */
+
+/**
+ * NE_DEFAULT_MEMORY_REGION - Memory region for enclave general usage.
+ */
+#define NE_DEFAULT_MEMORY_REGION	(0x00)
+
+#define NE_MEMORY_REGION_MAX_FLAG_VAL	(0x01)
+
+/**
+ * struct ne_user_memory_region - Memory region to be set for an enclave (in).
+ * @flags:		Flags to determine the usage for the memory region (in).
+ * @memory_size:	The size, in bytes, of the memory region to be set for
+ *			an enclave (in).
+ * @userspace_addr:	The start address of the userspace allocated memory of
+ *			the memory region to set for an enclave (in).
+ */
+struct ne_user_memory_region {
+	__u64	flags;
+	__u64	memory_size;
+	__u64	userspace_addr;
+};
+
+/**
+ * DOC: Enclave start info flags
+ */
+
+/**
+ * NE_ENCLAVE_PRODUCTION_MODE - Start enclave in production mode.
+ */
+#define NE_ENCLAVE_PRODUCTION_MODE	(0x00)
+/**
+ * NE_ENCLAVE_DEBUG_MODE - Start enclave in debug mode.
+ */
+#define NE_ENCLAVE_DEBUG_MODE		(0x01)
+
+#define NE_ENCLAVE_START_MAX_FLAG_VAL	(0x02)
+
+/**
+ * struct ne_enclave_start_info - Setup info necessary for enclave start (in / out).
+ * @flags:		Flags for the enclave to start with (e.g. debug mode) (in).
+ * @enclave_cid:	Context ID (CID) for the enclave vsock device. If 0 as
+ *			input, the CID is autogenerated by the hypervisor and
+ *			returned back as output by the driver (in / out).
+ */
+struct ne_enclave_start_info {
+	__u64	flags;
+	__u64	enclave_cid;
+};
+
+#endif /* _UAPI_LINUX_NITRO_ENCLAVES_H_ */