nitro_enclaves: Init misc device providing the ioctl interface

The Nitro Enclaves driver provides an ioctl interface to the user space
for enclave lifetime management e.g. enclave creation / termination and
setting enclave resources such as memory and CPU.

This ioctl interface is mapped to a Nitro Enclaves misc device.

Changelog

v9 -> v10

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

v8 -> v9

* Use the ne_devs data structure to get the refs for the NE misc device
  in the NE PCI device driver logic.

v7 -> v8

* Add define for the CID of the primary / parent VM.
* Update the NE PCI driver shutdown logic to include misc device
  deregister.

v6 -> v7

* Set the NE PCI device the parent of the NE misc device to be able to
  use it in the ioctl logic.
* Update the naming and add more comments to make more clear the logic
  of handling full CPU cores and dedicating them to the enclave.

v5 -> v6

* Remove the ioctl to query API version.
* Update documentation to kernel-doc format.

v4 -> v5

* Update the size of the NE CPU pool string from 4096 to 512 chars.

v3 -> v4

* Use dev_err instead of custom NE log pattern.
* Remove the NE CPU pool init during kernel module loading, as the CPU
  pool is now setup at runtime, via a sysfs file for the kernel
  parameter.
* Add minimum enclave memory size definition.

v2 -> v3

* Remove the GPL additional wording as SPDX-License-Identifier is
  already in place.
* Remove the WARN_ON calls.
* Remove linux/bug and linux/kvm_host includes that are not needed.
* Remove "ratelimited" from the logs that are not in the ioctl call
  paths.
* Remove file ops that do nothing for now - open and release.

v1 -> v2

* Add log pattern for NE.
* Update goto labels to match their purpose.
* Update ne_cpu_pool data structure to include the global mutex.
* Update NE misc device mode to 0660.
* Check if the CPU siblings are included in the NE CPU pool, as full CPU
  cores are given for the enclave(s).

Reviewed-by: Alexander Graf <graf@amazon.com>
Signed-off-by: Andra Paraschiv <andraprs@amazon.com>
Link: https://lore.kernel.org/r/20200921121732.44291-8-andraprs@amazon.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/virt/nitro_enclaves/ne_misc_dev.c

@@ -0,0 +1,139 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright 2020 Amazon.com, Inc. or its affiliates. All Rights Reserved.
+ */
+
+/**
+ * DOC: Enclave lifetime management driver for Nitro Enclaves (NE).
+ * Nitro is a hypervisor that has been developed by Amazon.
+ */
+
+#include <linux/anon_inodes.h>
+#include <linux/capability.h>
+#include <linux/cpu.h>
+#include <linux/device.h>
+#include <linux/file.h>
+#include <linux/hugetlb.h>
+#include <linux/limits.h>
+#include <linux/list.h>
+#include <linux/miscdevice.h>
+#include <linux/mm.h>
+#include <linux/mman.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/nitro_enclaves.h>
+#include <linux/pci.h>
+#include <linux/poll.h>
+#include <linux/slab.h>
+#include <linux/types.h>
+#include <uapi/linux/vm_sockets.h>
+
+#include "ne_misc_dev.h"
+#include "ne_pci_dev.h"
+
+/**
+ * NE_CPUS_SIZE - Size for max 128 CPUs, for now, in a cpu-list string, comma
+ *		  separated. The NE CPU pool includes CPUs from a single NUMA
+ *		  node.
+ */
+#define NE_CPUS_SIZE		(512)
+
+/**
+ * NE_EIF_LOAD_OFFSET - The offset where to copy the Enclave Image Format (EIF)
+ *			image in enclave memory.
+ */
+#define NE_EIF_LOAD_OFFSET	(8 * 1024UL * 1024UL)
+
+/**
+ * NE_MIN_ENCLAVE_MEM_SIZE - The minimum memory size an enclave can be launched
+ *			     with.
+ */
+#define NE_MIN_ENCLAVE_MEM_SIZE	(64 * 1024UL * 1024UL)
+
+/**
+ * NE_MIN_MEM_REGION_SIZE - The minimum size of an enclave memory region.
+ */
+#define NE_MIN_MEM_REGION_SIZE	(2 * 1024UL * 1024UL)
+
+/**
+ * NE_PARENT_VM_CID - The CID for the vsock device of the primary / parent VM.
+ */
+#define NE_PARENT_VM_CID	(3)
+
+static const struct file_operations ne_fops = {
+	.owner		= THIS_MODULE,
+	.llseek		= noop_llseek,
+};
+
+static struct miscdevice ne_misc_dev = {
+	.minor	= MISC_DYNAMIC_MINOR,
+	.name	= "nitro_enclaves",
+	.fops	= &ne_fops,
+	.mode	= 0660,
+};
+
+struct ne_devs ne_devs = {
+	.ne_misc_dev	= &ne_misc_dev,
+};
+
+/*
+ * TODO: Update logic to create new sysfs entries instead of using
+ * a kernel parameter e.g. if multiple sysfs files needed.
+ */
+static const struct kernel_param_ops ne_cpu_pool_ops = {
+	.get	= param_get_string,
+};
+
+static char ne_cpus[NE_CPUS_SIZE];
+static struct kparam_string ne_cpus_arg = {
+	.maxlen	= sizeof(ne_cpus),
+	.string	= ne_cpus,
+};
+
+module_param_cb(ne_cpus, &ne_cpu_pool_ops, &ne_cpus_arg, 0644);
+/* https://www.kernel.org/doc/html/latest/admin-guide/kernel-parameters.html#cpu-lists */
+MODULE_PARM_DESC(ne_cpus, "<cpu-list> - CPU pool used for Nitro Enclaves");
+
+/**
+ * struct ne_cpu_pool - CPU pool used for Nitro Enclaves.
+ * @avail_threads_per_core:	Available full CPU cores to be dedicated to
+ *				enclave(s). The cpumasks from the array, indexed
+ *				by core id, contain all the threads from the
+ *				available cores, that are not set for created
+ *				enclave(s). The full CPU cores are part of the
+ *				NE CPU pool.
+ * @mutex:			Mutex for the access to the NE CPU pool.
+ * @nr_parent_vm_cores :	The size of the available threads per core array.
+ *				The total number of CPU cores available on the
+ *				primary / parent VM.
+ * @nr_threads_per_core:	The number of threads that a full CPU core has.
+ * @numa_node:			NUMA node of the CPUs in the pool.
+ */
+struct ne_cpu_pool {
+	cpumask_var_t	*avail_threads_per_core;
+	struct mutex	mutex;
+	unsigned int	nr_parent_vm_cores;
+	unsigned int	nr_threads_per_core;
+	int		numa_node;
+};
+
+static struct ne_cpu_pool ne_cpu_pool;
+
+static int __init ne_init(void)
+{
+	mutex_init(&ne_cpu_pool.mutex);
+
+	return pci_register_driver(&ne_pci_driver);
+}
+
+static void __exit ne_exit(void)
+{
+	pci_unregister_driver(&ne_pci_driver);
+}
+
+module_init(ne_init);
+module_exit(ne_exit);
+
+MODULE_AUTHOR("Amazon.com, Inc. or its affiliates");
+MODULE_DESCRIPTION("Nitro Enclaves Driver");
+MODULE_LICENSE("GPL v2");

drivers/virt/nitro_enclaves/ne_pci_dev.c

@@ -523,8 +523,18 @@ static int ne_pci_probe(struct pci_dev *pdev, const struct pci_device_id *id)
 
 	ne_devs.ne_pci_dev = ne_pci_dev;
 
+	rc = misc_register(ne_devs.ne_misc_dev);
+	if (rc < 0) {
+		dev_err(&pdev->dev, "Error in misc dev register [rc=%d]\n", rc);
+
+		goto disable_ne_pci_dev;
+	}
+
 	return 0;
 
+disable_ne_pci_dev:
+	ne_devs.ne_pci_dev = NULL;
+	ne_pci_dev_disable(pdev);
 teardown_msix:
 	ne_teardown_msix(pdev);
 iounmap_pci_bar:
@@ -550,6 +560,8 @@ static void ne_pci_remove(struct pci_dev *pdev)
 {
 	struct ne_pci_dev *ne_pci_dev = pci_get_drvdata(pdev);
 
+	misc_deregister(ne_devs.ne_misc_dev);
+
 	ne_devs.ne_pci_dev = NULL;
 
 	ne_pci_dev_disable(pdev);
@@ -580,6 +592,8 @@ static void ne_pci_shutdown(struct pci_dev *pdev)
 	if (!ne_pci_dev)
 		return;
 
+	misc_deregister(ne_devs.ne_misc_dev);
+
 	ne_devs.ne_pci_dev = NULL;
 
 	ne_pci_dev_disable(pdev);