[PATCH v6 07/18] nitro_enclaves: Init misc device providing the ioctl interface

Andra Paraschiv
2020-08-05T09:12:51Z

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.

Signed-off-by: Andra Paraschiv <andraprs@amazon.com>
---
Changelog

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).
---
drivers/virt/nitro_enclaves/ne_misc_dev.c | 121 ++++++++++++++++++++++
drivers/virt/nitro_enclaves/ne_pci_dev.c | 11 ++
2 files changed, 132 insertions(+)
create mode 100644 drivers/virt/nitro_enclaves/ne_misc_dev.c

diff --git a/drivers/virt/nitro_enclaves/ne_misc_dev.c b/drivers/virt/nitro_enclaves/ne_misc_dev.c
new file mode 100644
index 000000000000..472850250220
--- /dev/null
+++ b/drivers/virt/nitro_enclaves/ne_misc_dev.c
@@ -0,0 +1,121 @@
+// 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/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 "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)
+
+/*
+ * 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_cores: Available CPU cores in the pool.
+ * @avail_cores_size: The size of the available cores array.
+ * @mutex: Mutex for the access to the NE CPU pool.
+ * @numa_node: NUMA node of the CPUs in the pool.
+ */
+struct ne_cpu_pool {
+ cpumask_var_t *avail_cores;
+ unsigned int avail_cores_size;
+ struct mutex mutex;
+ int numa_node;
+};
+
+static struct ne_cpu_pool ne_cpu_pool;
+
+static const struct file_operations ne_fops = {
+ .owner = THIS_MODULE,
+ .llseek = noop_llseek,
+};
+
+struct miscdevice ne_misc_dev = {
+ .minor = MISC_DYNAMIC_MINOR,
+ .name = "nitro_enclaves",
+ .fops = &ne_fops,
+ .mode = 0660,
+};
+
+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);
+}
+
+/* TODO: Handle actions such as reboot, kexec. */
+
+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");
diff --git a/drivers/virt/nitro_enclaves/ne_pci_dev.c b/drivers/virt/nitro_enclaves/ne_pci_dev.c
index a898fae066d9..1e434bf44c9d 100644
--- a/drivers/virt/nitro_enclaves/ne_pci_dev.c
+++ b/drivers/virt/nitro_enclaves/ne_pci_dev.c
@@ -527,6 +527,13 @@ static int ne_pci_probe(struct pci_dev *pdev, const struct pci_device_id *id)
goto teardown_msix;
}

+ rc = misc_register(&ne_misc_dev);
+ if (rc < 0) {
+ dev_err(&pdev->dev, "Error in misc dev register [rc=%d]\n", rc);
+
+ goto disable_ne_pci_dev;
+ }
+
atomic_set(&ne_pci_dev->cmd_reply_avail, 0);
init_waitqueue_head(&ne_pci_dev->cmd_reply_wait_q);
INIT_LIST_HEAD(&ne_pci_dev->enclaves_list);
@@ -536,6 +543,8 @@ static int ne_pci_probe(struct pci_dev *pdev, const struct pci_device_id *id)

return 0;

+disable_ne_pci_dev:
+ ne_pci_dev_disable(pdev);
teardown_msix:
ne_teardown_msix(pdev);
iounmap_pci_bar:
@@ -561,6 +570,8 @@ static void ne_pci_remove(struct pci_dev *pdev)
{
struct ne_pci_dev *ne_pci_dev = pci_get_drvdata(pdev);

+ misc_deregister(&ne_misc_dev);
+
ne_pci_dev_disable(pdev);

ne_teardown_msix(pdev);