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Subject[PATCH v3 07/18] nitro_enclaves: Init misc device providing the ioctl interface
Date
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

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 | 165 ++++++++++++++++++++++
drivers/virt/nitro_enclaves/ne_pci_dev.c | 12 ++
2 files changed, 177 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..4a6f74cacdb0
--- /dev/null
+++ b/drivers/virt/nitro_enclaves/ne_misc_dev.c
@@ -0,0 +1,165 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright 2020 Amazon.com, Inc. or its affiliates. All Rights Reserved.
+ */
+
+/**
+ * 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/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"
+
+#define MIN_MEM_REGION_SIZE (2 * 1024UL * 1024UL)
+
+#define NE "nitro_enclaves: "
+
+#define NE_DEV_NAME "nitro_enclaves"
+
+#define NE_IMAGE_LOAD_OFFSET (8 * 1024UL * 1024UL)
+
+static char *ne_cpus;
+module_param(ne_cpus, charp, 0644);
+MODULE_PARM_DESC(ne_cpus, "<cpu-list> - CPU pool used for Nitro Enclaves");
+
+/* CPU pool used for Nitro Enclaves. */
+struct ne_cpu_pool {
+ /* Available CPUs in the pool. */
+ cpumask_var_t avail;
+ struct mutex mutex;
+};
+
+static struct ne_cpu_pool ne_cpu_pool;
+
+static long ne_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
+{
+ switch (cmd) {
+
+ default:
+ return -ENOTTY;
+ }
+
+ return 0;
+}
+
+static const struct file_operations ne_fops = {
+ .owner = THIS_MODULE,
+ .llseek = noop_llseek,
+ .unlocked_ioctl = ne_ioctl,
+};
+
+struct miscdevice ne_miscdevice = {
+ .minor = MISC_DYNAMIC_MINOR,
+ .name = NE_DEV_NAME,
+ .fops = &ne_fops,
+ .mode = 0660,
+};
+
+static int __init ne_init(void)
+{
+ unsigned int cpu = 0;
+ unsigned int cpu_sibling = 0;
+ int rc = -EINVAL;
+
+ if (!zalloc_cpumask_var(&ne_cpu_pool.avail, GFP_KERNEL))
+ return -ENOMEM;
+
+ mutex_init(&ne_cpu_pool.mutex);
+
+ rc = cpulist_parse(ne_cpus, ne_cpu_pool.avail);
+ if (rc < 0) {
+ pr_err(NE "Error in cpulist parse [rc=%d]\n", rc);
+
+ goto free_cpumask;
+ }
+
+ /*
+ * Check if CPU siblings are included in the provided CPU pool. The
+ * expectation is that CPU cores are made available in the CPU pool for
+ * enclaves.
+ */
+ for_each_cpu(cpu, ne_cpu_pool.avail) {
+ for_each_cpu(cpu_sibling, topology_sibling_cpumask(cpu)) {
+ if (!cpumask_test_cpu(cpu_sibling, ne_cpu_pool.avail)) {
+ pr_err(NE "CPU %d is not in the CPU pool\n",
+ cpu_sibling);
+
+ rc = -EINVAL;
+
+ goto free_cpumask;
+ }
+ }
+ }
+
+ for_each_cpu(cpu, ne_cpu_pool.avail) {
+ rc = remove_cpu(cpu);
+ if (rc != 0) {
+ pr_err(NE "CPU %d not offlined [rc=%d]\n", cpu, rc);
+
+ goto online_cpus;
+ }
+ }
+
+ rc = pci_register_driver(&ne_pci_driver);
+ if (rc < 0) {
+ pr_err(NE "Error in pci register driver [rc=%d]\n", rc);
+
+ goto online_cpus;
+ }
+
+ return 0;
+
+online_cpus:
+ for_each_cpu(cpu, ne_cpu_pool.avail)
+ add_cpu(cpu);
+free_cpumask:
+ free_cpumask_var(ne_cpu_pool.avail);
+
+ return rc;
+}
+
+static void __exit ne_exit(void)
+{
+ unsigned int cpu = 0;
+ int rc = -EINVAL;
+
+ pci_unregister_driver(&ne_pci_driver);
+
+ if (!ne_cpu_pool.avail)
+ return;
+
+ for_each_cpu(cpu, ne_cpu_pool.avail) {
+ rc = add_cpu(cpu);
+ if (rc != 0)
+ pr_err(NE "CPU %d not onlined [rc=%d]\n", cpu, rc);
+ }
+
+ free_cpumask_var(ne_cpu_pool.avail);
+}
+
+/* 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 fd796450c9eb..01213e2cfed8 100644
--- a/drivers/virt/nitro_enclaves/ne_pci_dev.c
+++ b/drivers/virt/nitro_enclaves/ne_pci_dev.c
@@ -537,6 +537,14 @@ static int ne_pci_probe(struct pci_dev *pdev, const struct pci_device_id *id)
goto teardown_msix;
}

+ rc = misc_register(&ne_miscdevice);
+ if (rc < 0) {
+ dev_err(&pdev->dev, NE "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);
@@ -545,6 +553,8 @@ 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:
@@ -567,6 +577,8 @@ static void ne_pci_remove(struct pci_dev *pdev)
if (!ne_pci_dev || !ne_pci_dev->iomem_base)
return;

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

ne_teardown_msix(pdev);
--
2.20.1 (Apple Git-117)



Amazon Development Center (Romania) S.R.L. registered office: 27A Sf. Lazar Street, UBC5, floor 2, Iasi, Iasi County, 700045, Romania. Registered in Romania. Registration number J22/2621/2005.

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