// SPDX-License-Identifier: GPL-2.0
/*
 * Copyright 2020-2021 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 long ne_ioctl(struct file *file, unsigned int cmd, unsigned long arg);

static const struct file_operations ne_fops = {
        .owner          = THIS_MODULE,
        .llseek         = noop_llseek,
        .unlocked_ioctl = ne_ioctl,
};

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 int ne_set_kernel_param(const char *val, const struct kernel_param *kp);

static const struct kernel_param_ops ne_cpu_pool_ops = {
        .get    = param_get_string,
        .set    = ne_set_kernel_param,
};

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;

/**
 * ne_check_enclaves_created() - Verify if at least one enclave has been created.
 * @void:       No parameters provided.
 *
 * Context: Process context.
 * Return:
 * * True if at least one enclave is created.
 * * False otherwise.
 */
static bool ne_check_enclaves_created(void)
{
        struct ne_pci_dev *ne_pci_dev = ne_devs.ne_pci_dev;
        bool ret = false;

        if (!ne_pci_dev)
                return ret;

        mutex_lock(&ne_pci_dev->enclaves_list_mutex);

        if (!list_empty(&ne_pci_dev->enclaves_list))
                ret = true;

        mutex_unlock(&ne_pci_dev->enclaves_list_mutex);

        return ret;
}

/**
 * ne_setup_cpu_pool() - Set the NE CPU pool after handling sanity checks such
 *                       as not sharing CPU cores with the primary / parent VM
 *                       or not using CPU 0, which should remain available for
 *                       the primary / parent VM. Offline the CPUs from the
 *                       pool after the checks passed.
 * @ne_cpu_list:        The CPU list used for setting NE CPU pool.
 *
 * Context: Process context.
 * Return:
 * * 0 on success.
 * * Negative return value on failure.
 */
static int ne_setup_cpu_pool(const char *ne_cpu_list)
{
        int core_id = -1;
        unsigned int cpu = 0;
        cpumask_var_t cpu_pool;
        unsigned int cpu_sibling = 0;
        unsigned int i = 0;
        int numa_node = -1;
        int rc = -EINVAL;

        if (!zalloc_cpumask_var(&cpu_pool, GFP_KERNEL))
                return -ENOMEM;

        mutex_lock(&ne_cpu_pool.mutex);

        rc = cpulist_parse(ne_cpu_list, cpu_pool);
        if (rc < 0) {
                pr_err("%s: Error in cpulist parse [rc=%d]\n", ne_misc_dev.name, rc);

                goto free_pool_cpumask;
        }

        cpu = cpumask_any(cpu_pool);
        if (cpu >= nr_cpu_ids) {
                pr_err("%s: No CPUs available in CPU pool\n", ne_misc_dev.name);

                rc = -EINVAL;

                goto free_pool_cpumask;
        }

        /*
         * Check if the CPUs are online, to further get info about them
         * e.g. numa node, core id, siblings.
         */
        for_each_cpu(cpu, cpu_pool)
                if (cpu_is_offline(cpu)) {
                        pr_err("%s: CPU %d is offline, has to be online to get its metadata\n",
                               ne_misc_dev.name, cpu);

                        rc = -EINVAL;

                        goto free_pool_cpumask;
                }

        /*
         * Check if the CPUs from the NE CPU pool are from the same NUMA node.
         */
        for_each_cpu(cpu, cpu_pool)
                if (numa_node < 0) {
                        numa_node = cpu_to_node(cpu);
                        if (numa_node < 0) {
                                pr_err("%s: Invalid NUMA node %d\n",
                                       ne_misc_dev.name, numa_node);

                                rc = -EINVAL;

                                goto free_pool_cpumask;
                        }
                } else {
                        if (numa_node != cpu_to_node(cpu)) {
                                pr_err("%s: CPUs with different NUMA nodes\n",
                                       ne_misc_dev.name);

                                rc = -EINVAL;

                                goto free_pool_cpumask;
                        }
                }

        /*
         * Check if CPU 0 and its siblings are included in the provided CPU pool
         * They should remain available for the primary / parent VM.
         */
        if (cpumask_test_cpu(0, cpu_pool)) {
                pr_err("%s: CPU 0 has to remain available\n", ne_misc_dev.name);

                rc = -EINVAL;

                goto free_pool_cpumask;
        }

        for_each_cpu(cpu_sibling, topology_sibling_cpumask(0)) {
                if (cpumask_test_cpu(cpu_sibling, cpu_pool)) {
                        pr_err("%s: CPU sibling %d for CPU 0 is in CPU pool\n",
                               ne_misc_dev.name, cpu_sibling);

                        rc = -EINVAL;

                        goto free_pool_cpumask;
                }
        }

        /*
         * Check if CPU siblings are included in the provided CPU pool. The
         * expectation is that full CPU cores are made available in the CPU pool
         * for enclaves.
         */
        for_each_cpu(cpu, cpu_pool) {
                for_each_cpu(cpu_sibling, topology_sibling_cpumask(cpu)) {
                        if (!cpumask_test_cpu(cpu_sibling, cpu_pool)) {
                                pr_err("%s: CPU %d is not in CPU pool\n",
                                       ne_misc_dev.name, cpu_sibling);

                                rc = -EINVAL;

                                goto free_pool_cpumask;
                        }
                }
        }

        /* Calculate the number of threads from a full CPU core. */
        cpu = cpumask_any(cpu_pool);
        for_each_cpu(cpu_sibling, topology_sibling_cpumask(cpu))
                ne_cpu_pool.nr_threads_per_core++;

        ne_cpu_pool.nr_parent_vm_cores = nr_cpu_ids / ne_cpu_pool.nr_threads_per_core;

        ne_cpu_pool.avail_threads_per_core = kcalloc(ne_cpu_pool.nr_parent_vm_cores,
                                                     sizeof(*ne_cpu_pool.avail_threads_per_core),
                                                     GFP_KERNEL);
        if (!ne_cpu_pool.avail_threads_per_core) {
                rc = -ENOMEM;

                goto free_pool_cpumask;
        }

        for (i = 0; i < ne_cpu_pool.nr_parent_vm_cores; i++)
                if (!zalloc_cpumask_var(&ne_cpu_pool.avail_threads_per_core[i], GFP_KERNEL)) {
                        rc = -ENOMEM;

                        goto free_cores_cpumask;
                }

        /*
         * Split the NE CPU pool in threads per core to keep the CPU topology
         * after offlining the CPUs.
         */
        for_each_cpu(cpu, cpu_pool) {
                core_id = topology_core_id(cpu);
                if (core_id < 0 || core_id >= ne_cpu_pool.nr_parent_vm_cores) {
                        pr_err("%s: Invalid core id  %d for CPU %d\n",
                               ne_misc_dev.name, core_id, cpu);

                        rc = -EINVAL;

                        goto clear_cpumask;
                }

                cpumask_set_cpu(cpu, ne_cpu_pool.avail_threads_per_core[core_id]);
        }

        /*
         * CPUs that are given to enclave(s) should not be considered online
         * by Linux anymore, as the hypervisor will degrade them to floating.
         * The physical CPUs (full cores) are carved out of the primary / parent
         * VM and given to the enclave VM. The same number of vCPUs would run
         * on less pCPUs for the primary / parent VM.
         *
         * We offline them here, to not degrade performance and expose correct
         * topology to Linux and user space.
         */
        for_each_cpu(cpu, cpu_pool) {
                rc = remove_cpu(cpu);
                if (rc != 0) {
                        pr_err("%s: CPU %d is not offlined [rc=%d]\n",
                               ne_misc_dev.name, cpu, rc);

                        goto online_cpus;
                }
        }

        free_cpumask_var(cpu_pool);

        ne_cpu_pool.numa_node = numa_node;

        mutex_unlock(&ne_cpu_pool.mutex);

        return 0;

online_cpus:
        for_each_cpu(cpu, cpu_pool)
                add_cpu(cpu);
clear_cpumask:
        for (i = 0; i < ne_cpu_pool.nr_parent_vm_cores; i++)
                cpumask_clear(ne_cpu_pool.avail_threads_per_core[i]);
free_cores_cpumask:
        for (i = 0; i < ne_cpu_pool.nr_parent_vm_cores; i++)
                free_cpumask_var(ne_cpu_pool.avail_threads_per_core[i]);
        kfree(ne_cpu_pool.avail_threads_per_core);
free_pool_cpumask:
        free_cpumask_var(cpu_pool);
        ne_cpu_pool.nr_parent_vm_cores = 0;
        ne_cpu_pool.nr_threads_per_core = 0;
        ne_cpu_pool.numa_node = -1;
        mutex_unlock(&ne_cpu_pool.mutex);

        return rc;
}

/**
 * ne_teardown_cpu_pool() - Online the CPUs from the NE CPU pool and cleanup the
 *                          CPU pool.
 * @void:       No parameters provided.
 *
 * Context: Process context.
 */
static void ne_teardown_cpu_pool(void)
{
        unsigned int cpu = 0;
        unsigned int i = 0;
        int rc = -EINVAL;

        mutex_lock(&ne_cpu_pool.mutex);

        if (!ne_cpu_pool.nr_parent_vm_cores) {
                mutex_unlock(&ne_cpu_pool.mutex);

                return;
        }

        for (i = 0; i < ne_cpu_pool.nr_parent_vm_cores; i++) {
                for_each_cpu(cpu, ne_cpu_pool.avail_threads_per_core[i]) {
                        rc = add_cpu(cpu);
                        if (rc != 0)
                                pr_err("%s: CPU %d is not onlined [rc=%d]\n",
                                       ne_misc_dev.name, cpu, rc);
                }

                cpumask_clear(ne_cpu_pool.avail_threads_per_core[i]);

                free_cpumask_var(ne_cpu_pool.avail_threads_per_core[i]);
        }

        kfree(ne_cpu_pool.avail_threads_per_core);
        ne_cpu_pool.nr_parent_vm_cores = 0;
        ne_cpu_pool.nr_threads_per_core = 0;
        ne_cpu_pool.numa_node = -1;

        mutex_unlock(&ne_cpu_pool.mutex);
}

/**
 * ne_set_kernel_param() - Set the NE CPU pool value via the NE kernel parameter.
 * @val:        NE CPU pool string value.
 * @kp :        NE kernel parameter associated with the NE CPU pool.
 *
 * Context: Process context.
 * Return:
 * * 0 on success.
 * * Negative return value on failure.
 */
static int ne_set_kernel_param(const char *val, const struct kernel_param *kp)
{
        char error_val[] = "";
        int rc = -EINVAL;

        if (!capable(CAP_SYS_ADMIN))
                return -EPERM;

        if (ne_check_enclaves_created()) {
                pr_err("%s: The CPU pool is used by enclave(s)\n", ne_misc_dev.name);

                return -EPERM;
        }

        ne_teardown_cpu_pool();

        rc = ne_setup_cpu_pool(val);
        if (rc < 0) {
                pr_err("%s: Error in setup CPU pool [rc=%d]\n", ne_misc_dev.name, rc);

                param_set_copystring(error_val, kp);

                return rc;
        }

        rc = param_set_copystring(val, kp);
        if (rc < 0) {
                pr_err("%s: Error in param set copystring [rc=%d]\n", ne_misc_dev.name, rc);

                ne_teardown_cpu_pool();

                param_set_copystring(error_val, kp);

                return rc;
        }

        return 0;
}

/**
 * ne_donated_cpu() - Check if the provided CPU is already used by the enclave.
 * @ne_enclave :        Private data associated with the current enclave.
 * @cpu:                CPU to check if already used.
 *
 * Context: Process context. This function is called with the ne_enclave mutex held.
 * Return:
 * * True if the provided CPU is already used by the enclave.
 * * False otherwise.
 */
static bool ne_donated_cpu(struct ne_enclave *ne_enclave, unsigned int cpu)
{
        if (cpumask_test_cpu(cpu, ne_enclave->vcpu_ids))
                return true;

        return false;
}

/**
 * ne_get_unused_core_from_cpu_pool() - Get the id of a full core from the
 *                                      NE CPU pool.
 * @void:       No parameters provided.
 *
 * Context: Process context. This function is called with the ne_enclave and
 *          ne_cpu_pool mutexes held.
 * Return:
 * * Core id.
 * * -1 if no CPU core available in the pool.
 */
static int ne_get_unused_core_from_cpu_pool(void)
{
        int core_id = -1;
        unsigned int i = 0;

        for (i = 0; i < ne_cpu_pool.nr_parent_vm_cores; i++)
                if (!cpumask_empty(ne_cpu_pool.avail_threads_per_core[i])) {
                        core_id = i;

                        break;
                }

        return core_id;
}

/**
 * ne_set_enclave_threads_per_core() - Set the threads of the provided core in
 *                                     the enclave data structure.
 * @ne_enclave :        Private data associated with the current enclave.
 * @core_id:            Core id to get its threads from the NE CPU pool.
 * @vcpu_id:            vCPU id part of the provided core.
 *
 * Context: Process context. This function is called with the ne_enclave and
 *          ne_cpu_pool mutexes held.
 * Return:
 * * 0 on success.
 * * Negative return value on failure.
 */
static int ne_set_enclave_threads_per_core(struct ne_enclave *ne_enclave,
                                           int core_id, u32 vcpu_id)
{
        unsigned int cpu = 0;

        if (core_id < 0 && vcpu_id == 0) {
                dev_err_ratelimited(ne_misc_dev.this_device,
                                    "No CPUs available in NE CPU pool\n");

                return -NE_ERR_NO_CPUS_AVAIL_IN_POOL;
        }

        if (core_id < 0) {
                dev_err_ratelimited(ne_misc_dev.this_device,
                                    "CPU %d is not in NE CPU pool\n", vcpu_id);

                return -NE_ERR_VCPU_NOT_IN_CPU_POOL;
        }

        if (core_id >= ne_enclave->nr_parent_vm_cores) {
                dev_err_ratelimited(ne_misc_dev.this_device,
                                    "Invalid core id %d - ne_enclave\n", core_id);

                return -NE_ERR_VCPU_INVALID_CPU_CORE;
        }

        for_each_cpu(cpu, ne_cpu_pool.avail_threads_per_core[core_id])
                cpumask_set_cpu(cpu, ne_enclave->threads_per_core[core_id]);

        cpumask_clear(ne_cpu_pool.avail_threads_per_core[core_id]);

        return 0;
}

/**
 * ne_get_cpu_from_cpu_pool() - Get a CPU from the NE CPU pool, either from the
 *                              remaining sibling(s) of a CPU core or the first
 *                              sibling of a new CPU core.
 * @ne_enclave :        Private data associated with the current enclave.
 * @vcpu_id:            vCPU to get from the NE CPU pool.
 *
 * Context: Process context. This function is called with the ne_enclave mutex held.
 * Return:
 * * 0 on success.
 * * Negative return value on failure.
 */
static int ne_get_cpu_from_cpu_pool(struct ne_enclave *ne_enclave, u32 *vcpu_id)
{
        int core_id = -1;
        unsigned int cpu = 0;
        unsigned int i = 0;
        int rc = -EINVAL;

        /*
         * If previously allocated a thread of a core to this enclave, first
         * check remaining sibling(s) for new CPU allocations, so that full
         * CPU cores are used for the enclave.
         */
        for (i = 0; i < ne_enclave->nr_parent_vm_cores; i++)
                for_each_cpu(cpu, ne_enclave->threads_per_core[i])
                        if (!ne_donated_cpu(ne_enclave, cpu)) {
                                *vcpu_id = cpu;

                                return 0;
                        }

        mutex_lock(&ne_cpu_pool.mutex);

        /*
         * If no remaining siblings, get a core from the NE CPU pool and keep
         * track of all the threads in the enclave threads per core data structure.
         */
        core_id = ne_get_unused_core_from_cpu_pool();

        rc = ne_set_enclave_threads_per_core(ne_enclave, core_id, *vcpu_id);
        if (rc < 0)
                goto unlock_mutex;

        *vcpu_id = cpumask_any(ne_enclave->threads_per_core[core_id]);

        rc = 0;

unlock_mutex:
        mutex_unlock(&ne_cpu_pool.mutex);

        return rc;
}

/**
 * ne_get_vcpu_core_from_cpu_pool() - Get from the NE CPU pool the id of the
 *                                    core associated with the provided vCPU.
 * @vcpu_id:    Provided vCPU id to get its associated core id.
 *
 * Context: Process context. This function is called with the ne_enclave and
 *          ne_cpu_pool mutexes held.
 * Return:
 * * Core id.
 * * -1 if the provided vCPU is not in the pool.
 */
static int ne_get_vcpu_core_from_cpu_pool(u32 vcpu_id)
{
        int core_id = -1;
        unsigned int i = 0;

        for (i = 0; i < ne_cpu_pool.nr_parent_vm_cores; i++)
                if (cpumask_test_cpu(vcpu_id, ne_cpu_pool.avail_threads_per_core[i])) {
                        core_id = i;

                        break;
        }

        return core_id;
}

/**
 * ne_check_cpu_in_cpu_pool() - Check if the given vCPU is in the available CPUs
 *                              from the pool.
 * @ne_enclave :        Private data associated with the current enclave.
 * @vcpu_id:            ID of the vCPU to check if available in the NE CPU pool.
 *
 * Context: Process context. This function is called with the ne_enclave mutex held.
 * Return:
 * * 0 on success.
 * * Negative return value on failure.
 */
static int ne_check_cpu_in_cpu_pool(struct ne_enclave *ne_enclave, u32 vcpu_id)
{
        int core_id = -1;
        unsigned int i = 0;
        int rc = -EINVAL;

        if (ne_donated_cpu(ne_enclave, vcpu_id)) {
                dev_err_ratelimited(ne_misc_dev.this_device,
                                    "CPU %d already used\n", vcpu_id);

                return -NE_ERR_VCPU_ALREADY_USED;
        }

        /*
         * If previously allocated a thread of a core to this enclave, but not
         * the full core, first check remaining sibling(s).
         */
        for (i = 0; i < ne_enclave->nr_parent_vm_cores; i++)
                if (cpumask_test_cpu(vcpu_id, ne_enclave->threads_per_core[i]))
                        return 0;

        mutex_lock(&ne_cpu_pool.mutex);

        /*
         * If no remaining siblings, get from the NE CPU pool the core
         * associated with the vCPU and keep track of all the threads in the
         * enclave threads per core data structure.
         */
        core_id = ne_get_vcpu_core_from_cpu_pool(vcpu_id);

        rc = ne_set_enclave_threads_per_core(ne_enclave, core_id, vcpu_id);
        if (rc < 0)
                goto unlock_mutex;

        rc = 0;

unlock_mutex:
        mutex_unlock(&ne_cpu_pool.mutex);

        return rc;
}

/**
 * ne_add_vcpu_ioctl() - Add a vCPU to the slot associated with the current
 *                       enclave.
 * @ne_enclave :        Private data associated with the current enclave.
 * @vcpu_id:            ID of the CPU to be associated with the given slot,
 *                      apic id on x86.
 *
 * Context: Process context. This function is called with the ne_enclave mutex held.
 * Return:
 * * 0 on success.
 * * Negative return value on failure.
 */
static int ne_add_vcpu_ioctl(struct ne_enclave *ne_enclave, u32 vcpu_id)
{
        struct ne_pci_dev_cmd_reply cmd_reply = {};
        struct pci_dev *pdev = ne_devs.ne_pci_dev->pdev;
        int rc = -EINVAL;
        struct slot_add_vcpu_req slot_add_vcpu_req = {};

        if (ne_enclave->mm != current->mm)
                return -EIO;

        slot_add_vcpu_req.slot_uid = ne_enclave->slot_uid;
        slot_add_vcpu_req.vcpu_id = vcpu_id;

        rc = ne_do_request(pdev, SLOT_ADD_VCPU,
                           &slot_add_vcpu_req, sizeof(slot_add_vcpu_req),
                           &cmd_reply, sizeof(cmd_reply));
        if (rc < 0) {
                dev_err_ratelimited(ne_misc_dev.this_device,
                                    "Error in slot add vCPU [rc=%d]\n", rc);

                return rc;
        }

        cpumask_set_cpu(vcpu_id, ne_enclave->vcpu_ids);

        ne_enclave->nr_vcpus++;

        return 0;
}

/**
 * ne_sanity_check_user_mem_region() - Sanity check the user space memory
 *                                     region received during the set user
 *                                     memory region ioctl call.
 * @ne_enclave :        Private data associated with the current enclave.
 * @mem_region :        User space memory region to be sanity checked.
 *
 * Context: Process context. This function is called with the ne_enclave mutex held.
 * Return:
 * * 0 on success.
 * * Negative return value on failure.
 */
static int ne_sanity_check_user_mem_region(struct ne_enclave *ne_enclave,
                                           struct ne_user_memory_region mem_region)
{
        struct ne_mem_region *ne_mem_region = NULL;

        if (ne_enclave->mm != current->mm)
                return -EIO;

        if (mem_region.memory_size & (NE_MIN_MEM_REGION_SIZE - 1)) {
                dev_err_ratelimited(ne_misc_dev.this_device,
                                    "User space memory size is not multiple of 2 MiB\n");

                return -NE_ERR_INVALID_MEM_REGION_SIZE;
        }

        if (!IS_ALIGNED(mem_region.userspace_addr, NE_MIN_MEM_REGION_SIZE)) {
                dev_err_ratelimited(ne_misc_dev.this_device,
                                    "User space address is not 2 MiB aligned\n");

                return -NE_ERR_UNALIGNED_MEM_REGION_ADDR;
        }

        if ((mem_region.userspace_addr & (NE_MIN_MEM_REGION_SIZE - 1)) ||
            !access_ok((void __user *)(unsigned long)mem_region.userspace_addr,
                       mem_region.memory_size)) {
                dev_err_ratelimited(ne_misc_dev.this_device,
                                    "Invalid user space address range\n");

                return -NE_ERR_INVALID_MEM_REGION_ADDR;
        }

        list_for_each_entry(ne_mem_region, &ne_enclave->mem_regions_list,
                            mem_region_list_entry) {
                u64 memory_size = ne_mem_region->memory_size;
                u64 userspace_addr = ne_mem_region->userspace_addr;

                if ((userspace_addr <= mem_region.userspace_addr &&
                     mem_region.userspace_addr < (userspace_addr + memory_size)) ||
                    (mem_region.userspace_addr <= userspace_addr &&
                    (mem_region.userspace_addr + mem_region.memory_size) > userspace_addr)) {
                        dev_err_ratelimited(ne_misc_dev.this_device,
                                            "User space memory region already used\n");

                        return -NE_ERR_MEM_REGION_ALREADY_USED;
                }
        }

        return 0;
}

/**
 * ne_sanity_check_user_mem_region_page() - Sanity check a page from the user space
 *                                          memory region received during the set
 *                                          user memory region ioctl call.
 * @ne_enclave :        Private data associated with the current enclave.
 * @mem_region_page:    Page from the user space memory region to be sanity checked.
 *
 * Context: Process context. This function is called with the ne_enclave mutex held.
 * Return:
 * * 0 on success.
 * * Negative return value on failure.
 */
static int ne_sanity_check_user_mem_region_page(struct ne_enclave *ne_enclave,
                                                struct page *mem_region_page)
{
        if (!PageHuge(mem_region_page)) {
                dev_err_ratelimited(ne_misc_dev.this_device,
                                    "Not a hugetlbfs page\n");

                return -NE_ERR_MEM_NOT_HUGE_PAGE;
        }

        if (page_size(mem_region_page) & (NE_MIN_MEM_REGION_SIZE - 1)) {
                dev_err_ratelimited(ne_misc_dev.this_device,
                                    "Page size not multiple of 2 MiB\n");

                return -NE_ERR_INVALID_PAGE_SIZE;
        }

        if (ne_enclave->numa_node != page_to_nid(mem_region_page)) {
                dev_err_ratelimited(ne_misc_dev.this_device,
                                    "Page is not from NUMA node %d\n",
                                    ne_enclave->numa_node);

                return -NE_ERR_MEM_DIFFERENT_NUMA_NODE;
        }

        return 0;
}

/**
 * ne_set_user_memory_region_ioctl() - Add user space memory region to the slot
 *                                     associated with the current enclave.
 * @ne_enclave :        Private data associated with the current enclave.
 * @mem_region :        User space memory region to be associated with the given slot.
 *
 * Context: Process context. This function is called with the ne_enclave mutex held.
 * Return:
 * * 0 on success.
 * * Negative return value on failure.
 */
static int ne_set_user_memory_region_ioctl(struct ne_enclave *ne_enclave,
                                           struct ne_user_memory_region mem_region)
{
        long gup_rc = 0;
        unsigned long i = 0;
        unsigned long max_nr_pages = 0;
        unsigned long memory_size = 0;
        struct ne_mem_region *ne_mem_region = NULL;
        unsigned long nr_phys_contig_mem_regions = 0;
        struct pci_dev *pdev = ne_devs.ne_pci_dev->pdev;
        struct page **phys_contig_mem_regions = NULL;
        int rc = -EINVAL;

        rc = ne_sanity_check_user_mem_region(ne_enclave, mem_region);
        if (rc < 0)
                return rc;

        ne_mem_region = kzalloc(sizeof(*ne_mem_region), GFP_KERNEL);
        if (!ne_mem_region)
                return -ENOMEM;

        max_nr_pages = mem_region.memory_size / NE_MIN_MEM_REGION_SIZE;

        ne_mem_region->pages = kcalloc(max_nr_pages, sizeof(*ne_mem_region->pages),
                                       GFP_KERNEL);
        if (!ne_mem_region->pages) {
                rc = -ENOMEM;

                goto free_mem_region;
        }

        phys_contig_mem_regions = kcalloc(max_nr_pages, sizeof(*phys_contig_mem_regions),
                                          GFP_KERNEL);
        if (!phys_contig_mem_regions) {
                rc = -ENOMEM;

                goto free_mem_region;
        }

        do {
                i = ne_mem_region->nr_pages;

                if (i == max_nr_pages) {
                        dev_err_ratelimited(ne_misc_dev.this_device,
                                            "Reached max nr of pages in the pages data struct\n");

                        rc = -ENOMEM;

                        goto put_pages;
                }

                gup_rc = get_user_pages_unlocked(mem_region.userspace_addr + memory_size, 1,
                                                 ne_mem_region->pages + i, FOLL_GET);

                if (gup_rc < 0) {
                        rc = gup_rc;

                        dev_err_ratelimited(ne_misc_dev.this_device,
                                            "Error in get user pages [rc=%d]\n", rc);

                        goto put_pages;
                }

                rc = ne_sanity_check_user_mem_region_page(ne_enclave, ne_mem_region->pages[i]);
                if (rc < 0)
                        goto put_pages;

                /*
                 * TODO: Update once handled non-contiguous memory regions
                 * received from user space or contiguous physical memory regions
                 * larger than 2 MiB e.g. 8 MiB.
                 */
                phys_contig_mem_regions[i] = ne_mem_region->pages[i];

                memory_size += page_size(ne_mem_region->pages[i]);

                ne_mem_region->nr_pages++;
        } while (memory_size < mem_region.memory_size);

        /*
         * TODO: Update once handled non-contiguous memory regions received
         * from user space or contiguous physical memory regions larger than
         * 2 MiB e.g. 8 MiB.
         */
        nr_phys_contig_mem_regions = ne_mem_region->nr_pages;

        if ((ne_enclave->nr_mem_regions + nr_phys_contig_mem_regions) >
            ne_enclave->max_mem_regions) {
                dev_err_ratelimited(ne_misc_dev.this_device,
                                    "Reached max memory regions %lld\n",
                                    ne_enclave->max_mem_regions);

                rc = -NE_ERR_MEM_MAX_REGIONS;

                goto put_pages;
        }

        for (i = 0; i < nr_phys_contig_mem_regions; i++) {
                u64 phys_region_addr = page_to_phys(phys_contig_mem_regions[i]);
                u64 phys_region_size = page_size(phys_contig_mem_regions[i]);

                if (phys_region_size & (NE_MIN_MEM_REGION_SIZE - 1)) {
                        dev_err_ratelimited(ne_misc_dev.this_device,
                                            "Physical mem region size is not multiple of 2 MiB\n");

                        rc = -EINVAL;

                        goto put_pages;
                }

                if (!IS_ALIGNED(phys_region_addr, NE_MIN_MEM_REGION_SIZE)) {
                        dev_err_ratelimited(ne_misc_dev.this_device,
                                            "Physical mem region address is not 2 MiB aligned\n");

                        rc = -EINVAL;

                        goto put_pages;
                }
        }

        ne_mem_region->memory_size = mem_region.memory_size;
        ne_mem_region->userspace_addr = mem_region.userspace_addr;

        list_add(&ne_mem_region->mem_region_list_entry, &ne_enclave->mem_regions_list);

        for (i = 0; i < nr_phys_contig_mem_regions; i++) {
                struct ne_pci_dev_cmd_reply cmd_reply = {};
                struct slot_add_mem_req slot_add_mem_req = {};

                slot_add_mem_req.slot_uid = ne_enclave->slot_uid;
                slot_add_mem_req.paddr = page_to_phys(phys_contig_mem_regions[i]);
                slot_add_mem_req.size = page_size(phys_contig_mem_regions[i]);

                rc = ne_do_request(pdev, SLOT_ADD_MEM,
                                   &slot_add_mem_req, sizeof(slot_add_mem_req),
                                   &cmd_reply, sizeof(cmd_reply));
                if (rc < 0) {
                        dev_err_ratelimited(ne_misc_dev.this_device,
                                            "Error in slot add mem [rc=%d]\n", rc);

                        kfree(phys_contig_mem_regions);

                        /*
                         * Exit here without put pages as memory regions may
                         * already been added.
                         */
                        return rc;
                }

                ne_enclave->mem_size += slot_add_mem_req.size;
                ne_enclave->nr_mem_regions++;
        }

        kfree(phys_contig_mem_regions);

        return 0;

put_pages:
        for (i = 0; i < ne_mem_region->nr_pages; i++)
                put_page(ne_mem_region->pages[i]);
free_mem_region:
        kfree(phys_contig_mem_regions);
        kfree(ne_mem_region->pages);

        kfree(ne_mem_region);

        return rc;
}

/**
 * ne_start_enclave_ioctl() - Trigger enclave start after the enclave resources,
 *                            such as memory and CPU, have been set.
 * @ne_enclave :                Private data associated with the current enclave.
 * @enclave_start_info :        Enclave info that includes enclave cid and flags.
 *
 * Context: Process context. This function is called with the ne_enclave mutex held.
 * Return:
 * * 0 on success.
 * * Negative return value on failure.
 */
static int ne_start_enclave_ioctl(struct ne_enclave *ne_enclave,
                                  struct ne_enclave_start_info *enclave_start_info)
{
        struct ne_pci_dev_cmd_reply cmd_reply = {};
        unsigned int cpu = 0;
        struct enclave_start_req enclave_start_req = {};
        unsigned int i = 0;
        struct pci_dev *pdev = ne_devs.ne_pci_dev->pdev;
        int rc = -EINVAL;

        if (!ne_enclave->nr_mem_regions) {
                dev_err_ratelimited(ne_misc_dev.this_device,
                                    "Enclave has no mem regions\n");

                return -NE_ERR_NO_MEM_REGIONS_ADDED;
        }

        if (ne_enclave->mem_size < NE_MIN_ENCLAVE_MEM_SIZE) {
                dev_err_ratelimited(ne_misc_dev.this_device,
                                    "Enclave memory is less than %ld\n",
                                    NE_MIN_ENCLAVE_MEM_SIZE);

                return -NE_ERR_ENCLAVE_MEM_MIN_SIZE;
        }

        if (!ne_enclave->nr_vcpus) {
                dev_err_ratelimited(ne_misc_dev.this_device,
                                    "Enclave has no vCPUs\n");

                return -NE_ERR_NO_VCPUS_ADDED;
        }

        for (i = 0; i < ne_enclave->nr_parent_vm_cores; i++)
                for_each_cpu(cpu, ne_enclave->threads_per_core[i])
                        if (!cpumask_test_cpu(cpu, ne_enclave->vcpu_ids)) {
                                dev_err_ratelimited(ne_misc_dev.this_device,
                                                    "Full CPU cores not used\n");

                                return -NE_ERR_FULL_CORES_NOT_USED;
                        }

        enclave_start_req.enclave_cid = enclave_start_info->enclave_cid;
        enclave_start_req.flags = enclave_start_info->flags;
        enclave_start_req.slot_uid = ne_enclave->slot_uid;

        rc = ne_do_request(pdev, ENCLAVE_START,
                           &enclave_start_req, sizeof(enclave_start_req),
                           &cmd_reply, sizeof(cmd_reply));
        if (rc < 0) {
                dev_err_ratelimited(ne_misc_dev.this_device,
                                    "Error in enclave start [rc=%d]\n", rc);

                return rc;
        }

        ne_enclave->state = NE_STATE_RUNNING;

        enclave_start_info->enclave_cid = cmd_reply.enclave_cid;

        return 0;
}

/**
 * ne_enclave_ioctl() - Ioctl function provided by the enclave file.
 * @file:       File associated with this ioctl function.
 * @cmd:        The command that is set for the ioctl call.
 * @arg:        The argument that is provided for the ioctl call.
 *
 * Context: Process context.
 * Return:
 * * 0 on success.
 * * Negative return value on failure.
 */
static long ne_enclave_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
{
        struct ne_enclave *ne_enclave = file->private_data;

        switch (cmd) {
        case NE_ADD_VCPU: {
                int rc = -EINVAL;
                u32 vcpu_id = 0;

                if (copy_from_user(&vcpu_id, (void __user *)arg, sizeof(vcpu_id)))
                        return -EFAULT;

                mutex_lock(&ne_enclave->enclave_info_mutex);

                if (ne_enclave->state != NE_STATE_INIT) {
                        dev_err_ratelimited(ne_misc_dev.this_device,
                                            "Enclave is not in init state\n");

                        mutex_unlock(&ne_enclave->enclave_info_mutex);

                        return -NE_ERR_NOT_IN_INIT_STATE;
                }

                if (vcpu_id >= (ne_enclave->nr_parent_vm_cores *
                    ne_enclave->nr_threads_per_core)) {
                        dev_err_ratelimited(ne_misc_dev.this_device,
                                            "vCPU id higher than max CPU id\n");

                        mutex_unlock(&ne_enclave->enclave_info_mutex);

                        return -NE_ERR_INVALID_VCPU;
                }

                if (!vcpu_id) {
                        /* Use the CPU pool for choosing a CPU for the enclave. */
                        rc = ne_get_cpu_from_cpu_pool(ne_enclave, &vcpu_id);
                        if (rc < 0) {
                                dev_err_ratelimited(ne_misc_dev.this_device,
                                                    "Error in get CPU from pool [rc=%d]\n",
                                                    rc);

                                mutex_unlock(&ne_enclave->enclave_info_mutex);

                                return rc;
                        }
                } else {
                        /* Check if the provided vCPU is available in the NE CPU pool. */
                        rc = ne_check_cpu_in_cpu_pool(ne_enclave, vcpu_id);
                        if (rc < 0) {
                                dev_err_ratelimited(ne_misc_dev.this_device,
                                                    "Error in check CPU %d in pool [rc=%d]\n",
                                                    vcpu_id, rc);

                                mutex_unlock(&ne_enclave->enclave_info_mutex);

                                return rc;
                        }
                }

                rc = ne_add_vcpu_ioctl(ne_enclave, vcpu_id);
                if (rc < 0) {
                        mutex_unlock(&ne_enclave->enclave_info_mutex);

                        return rc;
                }

                mutex_unlock(&ne_enclave->enclave_info_mutex);

                if (copy_to_user((void __user *)arg, &vcpu_id, sizeof(vcpu_id)))
                        return -EFAULT;

                return 0;
        }

        case NE_GET_IMAGE_LOAD_INFO: {
                struct ne_image_load_info image_load_info = {};

                if (copy_from_user(&image_load_info, (void __user *)arg, sizeof(image_load_info)))
                        return -EFAULT;

                mutex_lock(&ne_enclave->enclave_info_mutex);

                if (ne_enclave->state != NE_STATE_INIT) {
                        dev_err_ratelimited(ne_misc_dev.this_device,
                                            "Enclave is not in init state\n");

                        mutex_unlock(&ne_enclave->enclave_info_mutex);

                        return -NE_ERR_NOT_IN_INIT_STATE;
                }

                mutex_unlock(&ne_enclave->enclave_info_mutex);

                if (!image_load_info.flags ||
                    image_load_info.flags >= NE_IMAGE_LOAD_MAX_FLAG_VAL) {
                        dev_err_ratelimited(ne_misc_dev.this_device,
                                            "Incorrect flag in enclave image load info\n");

                        return -NE_ERR_INVALID_FLAG_VALUE;
                }

                if (image_load_info.flags == NE_EIF_IMAGE)
                        image_load_info.memory_offset = NE_EIF_LOAD_OFFSET;

                if (copy_to_user((void __user *)arg, &image_load_info, sizeof(image_load_info)))
                        return -EFAULT;

                return 0;
        }

        case NE_SET_USER_MEMORY_REGION: {
                struct ne_user_memory_region mem_region = {};
                int rc = -EINVAL;

                if (copy_from_user(&mem_region, (void __user *)arg, sizeof(mem_region)))
                        return -EFAULT;

                if (mem_region.flags >= NE_MEMORY_REGION_MAX_FLAG_VAL) {
                        dev_err_ratelimited(ne_misc_dev.this_device,
                                            "Incorrect flag for user memory region\n");

                        return -NE_ERR_INVALID_FLAG_VALUE;
                }

                mutex_lock(&ne_enclave->enclave_info_mutex);

                if (ne_enclave->state != NE_STATE_INIT) {
                        dev_err_ratelimited(ne_misc_dev.this_device,
                                            "Enclave is not in init state\n");

                        mutex_unlock(&ne_enclave->enclave_info_mutex);

                        return -NE_ERR_NOT_IN_INIT_STATE;
                }

                rc = ne_set_user_memory_region_ioctl(ne_enclave, mem_region);
                if (rc < 0) {
                        mutex_unlock(&ne_enclave->enclave_info_mutex);

                        return rc;
                }

                mutex_unlock(&ne_enclave->enclave_info_mutex);

                return 0;
        }

        case NE_START_ENCLAVE: {
                struct ne_enclave_start_info enclave_start_info = {};
                int rc = -EINVAL;

                if (copy_from_user(&enclave_start_info, (void __user *)arg,
                                   sizeof(enclave_start_info)))
                        return -EFAULT;

                if (enclave_start_info.flags >= NE_ENCLAVE_START_MAX_FLAG_VAL) {
                        dev_err_ratelimited(ne_misc_dev.this_device,
                                            "Incorrect flag in enclave start info\n");

                        return -NE_ERR_INVALID_FLAG_VALUE;
                }

                /*
                 * Do not use well-known CIDs - 0, 1, 2 - for enclaves.
                 * VMADDR_CID_ANY = -1U
                 * VMADDR_CID_HYPERVISOR = 0
                 * VMADDR_CID_LOCAL = 1
                 * VMADDR_CID_HOST = 2
                 * Note: 0 is used as a placeholder to auto-generate an enclave CID.
                 * http://man7.org/linux/man-pages/man7/vsock.7.html
                 */
                if (enclave_start_info.enclave_cid > 0 &&
                    enclave_start_info.enclave_cid <= VMADDR_CID_HOST) {
                        dev_err_ratelimited(ne_misc_dev.this_device,
                                            "Well-known CID value, not to be used for enclaves\n");

                        return -NE_ERR_INVALID_ENCLAVE_CID;
                }

                if (enclave_start_info.enclave_cid == U32_MAX) {
                        dev_err_ratelimited(ne_misc_dev.this_device,
                                            "Well-known CID value, not to be used for enclaves\n");

                        return -NE_ERR_INVALID_ENCLAVE_CID;
                }

                /*
                 * Do not use the CID of the primary / parent VM for enclaves.
                 */
                if (enclave_start_info.enclave_cid == NE_PARENT_VM_CID) {
                        dev_err_ratelimited(ne_misc_dev.this_device,
                                            "CID of the parent VM, not to be used for enclaves\n");

                        return -NE_ERR_INVALID_ENCLAVE_CID;
                }

                /* 64-bit CIDs are not yet supported for the vsock device. */
                if (enclave_start_info.enclave_cid > U32_MAX) {
                        dev_err_ratelimited(ne_misc_dev.this_device,
                                            "64-bit CIDs not yet supported for the vsock device\n");

                        return -NE_ERR_INVALID_ENCLAVE_CID;
                }

                mutex_lock(&ne_enclave->enclave_info_mutex);

                if (ne_enclave->state != NE_STATE_INIT) {
                        dev_err_ratelimited(ne_misc_dev.this_device,
                                            "Enclave is not in init state\n");

                        mutex_unlock(&ne_enclave->enclave_info_mutex);

                        return -NE_ERR_NOT_IN_INIT_STATE;
                }

                rc = ne_start_enclave_ioctl(ne_enclave, &enclave_start_info);
                if (rc < 0) {
                        mutex_unlock(&ne_enclave->enclave_info_mutex);

                        return rc;
                }

                mutex_unlock(&ne_enclave->enclave_info_mutex);

                if (copy_to_user((void __user *)arg, &enclave_start_info,
                                 sizeof(enclave_start_info)))
                        return -EFAULT;

                return 0;
        }

        default:
                return -ENOTTY;
        }

        return 0;
}

/**
 * ne_enclave_remove_all_mem_region_entries() - Remove all memory region entries
 *                                              from the enclave data structure.
 * @ne_enclave :        Private data associated with the current enclave.
 *
 * Context: Process context. This function is called with the ne_enclave mutex held.
 */
static void ne_enclave_remove_all_mem_region_entries(struct ne_enclave *ne_enclave)
{
        unsigned long i = 0;
        struct ne_mem_region *ne_mem_region = NULL;
        struct ne_mem_region *ne_mem_region_tmp = NULL;

        list_for_each_entry_safe(ne_mem_region, ne_mem_region_tmp,
                                 &ne_enclave->mem_regions_list,
                                 mem_region_list_entry) {
                list_del(&ne_mem_region->mem_region_list_entry);

                for (i = 0; i < ne_mem_region->nr_pages; i++)
                        put_page(ne_mem_region->pages[i]);

                kfree(ne_mem_region->pages);

                kfree(ne_mem_region);
        }
}

/**
 * ne_enclave_remove_all_vcpu_id_entries() - Remove all vCPU id entries from
 *                                           the enclave data structure.
 * @ne_enclave :        Private data associated with the current enclave.
 *
 * Context: Process context. This function is called with the ne_enclave mutex held.
 */
static void ne_enclave_remove_all_vcpu_id_entries(struct ne_enclave *ne_enclave)
{
        unsigned int cpu = 0;
        unsigned int i = 0;

        mutex_lock(&ne_cpu_pool.mutex);

        for (i = 0; i < ne_enclave->nr_parent_vm_cores; i++) {
                for_each_cpu(cpu, ne_enclave->threads_per_core[i])
                        /* Update the available NE CPU pool. */
                        cpumask_set_cpu(cpu, ne_cpu_pool.avail_threads_per_core[i]);

                free_cpumask_var(ne_enclave->threads_per_core[i]);
        }

        mutex_unlock(&ne_cpu_pool.mutex);

        kfree(ne_enclave->threads_per_core);

        free_cpumask_var(ne_enclave->vcpu_ids);
}

/**
 * ne_pci_dev_remove_enclave_entry() - Remove the enclave entry from the data
 *                                     structure that is part of the NE PCI
 *                                     device private data.
 * @ne_enclave :        Private data associated with the current enclave.
 * @ne_pci_dev :        Private data associated with the PCI device.
 *
 * Context: Process context. This function is called with the ne_pci_dev enclave
 *          mutex held.
 */
static void ne_pci_dev_remove_enclave_entry(struct ne_enclave *ne_enclave,
                                            struct ne_pci_dev *ne_pci_dev)
{
        struct ne_enclave *ne_enclave_entry = NULL;
        struct ne_enclave *ne_enclave_entry_tmp = NULL;

        list_for_each_entry_safe(ne_enclave_entry, ne_enclave_entry_tmp,
                                 &ne_pci_dev->enclaves_list, enclave_list_entry) {
                if (ne_enclave_entry->slot_uid == ne_enclave->slot_uid) {
                        list_del(&ne_enclave_entry->enclave_list_entry);

                        break;
                }
        }
}

/**
 * ne_enclave_release() - Release function provided by the enclave file.
 * @inode:      Inode associated with this file release function.
 * @file:       File associated with this release function.
 *
 * Context: Process context.
 * Return:
 * * 0 on success.
 * * Negative return value on failure.
 */
static int ne_enclave_release(struct inode *inode, struct file *file)
{
        struct ne_pci_dev_cmd_reply cmd_reply = {};
        struct enclave_stop_req enclave_stop_request = {};
        struct ne_enclave *ne_enclave = file->private_data;
        struct ne_pci_dev *ne_pci_dev = ne_devs.ne_pci_dev;
        struct pci_dev *pdev = ne_pci_dev->pdev;
        int rc = -EINVAL;
        struct slot_free_req slot_free_req = {};

        if (!ne_enclave)
                return 0;

        /*
         * Early exit in case there is an error in the enclave creation logic
         * and fput() is called on the cleanup path.
         */
        if (!ne_enclave->slot_uid)
                return 0;

        /*
         * Acquire the enclave list mutex before the enclave mutex
         * in order to avoid deadlocks with @ref ne_event_work_handler.
         */
        mutex_lock(&ne_pci_dev->enclaves_list_mutex);
        mutex_lock(&ne_enclave->enclave_info_mutex);

        if (ne_enclave->state != NE_STATE_INIT && ne_enclave->state != NE_STATE_STOPPED) {
                enclave_stop_request.slot_uid = ne_enclave->slot_uid;

                rc = ne_do_request(pdev, ENCLAVE_STOP,
                                   &enclave_stop_request, sizeof(enclave_stop_request),
                                   &cmd_reply, sizeof(cmd_reply));
                if (rc < 0) {
                        dev_err_ratelimited(ne_misc_dev.this_device,
                                            "Error in enclave stop [rc=%d]\n", rc);

                        goto unlock_mutex;
                }

                memset(&cmd_reply, 0, sizeof(cmd_reply));
        }

        slot_free_req.slot_uid = ne_enclave->slot_uid;

        rc = ne_do_request(pdev, SLOT_FREE,
                           &slot_free_req, sizeof(slot_free_req),
                           &cmd_reply, sizeof(cmd_reply));
        if (rc < 0) {
                dev_err_ratelimited(ne_misc_dev.this_device,
                                    "Error in slot free [rc=%d]\n", rc);

                goto unlock_mutex;
        }

        ne_pci_dev_remove_enclave_entry(ne_enclave, ne_pci_dev);
        ne_enclave_remove_all_mem_region_entries(ne_enclave);
        ne_enclave_remove_all_vcpu_id_entries(ne_enclave);

        mutex_unlock(&ne_enclave->enclave_info_mutex);
        mutex_unlock(&ne_pci_dev->enclaves_list_mutex);

        kfree(ne_enclave);

        return 0;

unlock_mutex:
        mutex_unlock(&ne_enclave->enclave_info_mutex);
        mutex_unlock(&ne_pci_dev->enclaves_list_mutex);

        return rc;
}

/**
 * ne_enclave_poll() - Poll functionality used for enclave out-of-band events.
 * @file:       File associated with this poll function.
 * @wait:       Poll table data structure.
 *
 * Context: Process context.
 * Return:
 * * Poll mask.
 */
static __poll_t ne_enclave_poll(struct file *file, poll_table *wait)
{
        __poll_t mask = 0;
        struct ne_enclave *ne_enclave = file->private_data;

        poll_wait(file, &ne_enclave->eventq, wait);

        if (ne_enclave->has_event)
                mask |= EPOLLHUP;

        return mask;
}

static const struct file_operations ne_enclave_fops = {
        .owner          = THIS_MODULE,
        .llseek         = noop_llseek,
        .poll           = ne_enclave_poll,
        .unlocked_ioctl = ne_enclave_ioctl,
        .release        = ne_enclave_release,
};

/**
 * ne_create_vm_ioctl() - Alloc slot to be associated with an enclave. Create
 *                        enclave file descriptor to be further used for enclave
 *                        resources handling e.g. memory regions and CPUs.
 * @ne_pci_dev :        Private data associated with the PCI device.
 * @slot_uid:           User pointer to store the generated unique slot id
 *                      associated with an enclave to.
 *
 * Context: Process context. This function is called with the ne_pci_dev enclave
 *          mutex held.
 * Return:
 * * Enclave fd on success.
 * * Negative return value on failure.
 */
static int ne_create_vm_ioctl(struct ne_pci_dev *ne_pci_dev, u64 __user *slot_uid)
{
        struct ne_pci_dev_cmd_reply cmd_reply = {};
        int enclave_fd = -1;
        struct file *enclave_file = NULL;
        unsigned int i = 0;
        struct ne_enclave *ne_enclave = NULL;
        struct pci_dev *pdev = ne_pci_dev->pdev;
        int rc = -EINVAL;
        struct slot_alloc_req slot_alloc_req = {};

        mutex_lock(&ne_cpu_pool.mutex);

        for (i = 0; i < ne_cpu_pool.nr_parent_vm_cores; i++)
                if (!cpumask_empty(ne_cpu_pool.avail_threads_per_core[i]))
                        break;

        if (i == ne_cpu_pool.nr_parent_vm_cores) {
                dev_err_ratelimited(ne_misc_dev.this_device,
                                    "No CPUs available in CPU pool\n");

                mutex_unlock(&ne_cpu_pool.mutex);

                return -NE_ERR_NO_CPUS_AVAIL_IN_POOL;
        }

        mutex_unlock(&ne_cpu_pool.mutex);

        ne_enclave = kzalloc(sizeof(*ne_enclave), GFP_KERNEL);
        if (!ne_enclave)
                return -ENOMEM;

        mutex_lock(&ne_cpu_pool.mutex);

        ne_enclave->nr_parent_vm_cores = ne_cpu_pool.nr_parent_vm_cores;
        ne_enclave->nr_threads_per_core = ne_cpu_pool.nr_threads_per_core;
        ne_enclave->numa_node = ne_cpu_pool.numa_node;

        mutex_unlock(&ne_cpu_pool.mutex);

        ne_enclave->threads_per_core = kcalloc(ne_enclave->nr_parent_vm_cores,
                                               sizeof(*ne_enclave->threads_per_core),
                                               GFP_KERNEL);
        if (!ne_enclave->threads_per_core) {
                rc = -ENOMEM;

                goto free_ne_enclave;
        }

        for (i = 0; i < ne_enclave->nr_parent_vm_cores; i++)
                if (!zalloc_cpumask_var(&ne_enclave->threads_per_core[i], GFP_KERNEL)) {
                        rc = -ENOMEM;

                        goto free_cpumask;
                }

        if (!zalloc_cpumask_var(&ne_enclave->vcpu_ids, GFP_KERNEL)) {
                rc = -ENOMEM;

                goto free_cpumask;
        }

        enclave_fd = get_unused_fd_flags(O_CLOEXEC);
        if (enclave_fd < 0) {
                rc = enclave_fd;

                dev_err_ratelimited(ne_misc_dev.this_device,
                                    "Error in getting unused fd [rc=%d]\n", rc);

                goto free_cpumask;
        }

        enclave_file = anon_inode_getfile("ne-vm", &ne_enclave_fops, ne_enclave, O_RDWR);
        if (IS_ERR(enclave_file)) {
                rc = PTR_ERR(enclave_file);

                dev_err_ratelimited(ne_misc_dev.this_device,
                                    "Error in anon inode get file [rc=%d]\n", rc);

                goto put_fd;
        }

        rc = ne_do_request(pdev, SLOT_ALLOC,
                           &slot_alloc_req, sizeof(slot_alloc_req),
                           &cmd_reply, sizeof(cmd_reply));
        if (rc < 0) {
                dev_err_ratelimited(ne_misc_dev.this_device,
                                    "Error in slot alloc [rc=%d]\n", rc);

                goto put_file;
        }

        init_waitqueue_head(&ne_enclave->eventq);
        ne_enclave->has_event = false;
        mutex_init(&ne_enclave->enclave_info_mutex);
        ne_enclave->max_mem_regions = cmd_reply.mem_regions;
        INIT_LIST_HEAD(&ne_enclave->mem_regions_list);
        ne_enclave->mm = current->mm;
        ne_enclave->slot_uid = cmd_reply.slot_uid;
        ne_enclave->state = NE_STATE_INIT;

        list_add(&ne_enclave->enclave_list_entry, &ne_pci_dev->enclaves_list);

        if (copy_to_user(slot_uid, &ne_enclave->slot_uid, sizeof(ne_enclave->slot_uid))) {
                /*
                 * As we're holding the only reference to 'enclave_file', fput()
                 * will call ne_enclave_release() which will do a proper cleanup
                 * of all so far allocated resources, leaving only the unused fd
                 * for us to free.
                 */
                fput(enclave_file);
                put_unused_fd(enclave_fd);

                return -EFAULT;
        }

        fd_install(enclave_fd, enclave_file);

        return enclave_fd;

put_file:
        fput(enclave_file);
put_fd:
        put_unused_fd(enclave_fd);
free_cpumask:
        free_cpumask_var(ne_enclave->vcpu_ids);
        for (i = 0; i < ne_enclave->nr_parent_vm_cores; i++)
                free_cpumask_var(ne_enclave->threads_per_core[i]);
        kfree(ne_enclave->threads_per_core);
free_ne_enclave:
        kfree(ne_enclave);

        return rc;
}

/**
 * ne_ioctl() - Ioctl function provided by the NE misc device.
 * @file:       File associated with this ioctl function.
 * @cmd:        The command that is set for the ioctl call.
 * @arg:        The argument that is provided for the ioctl call.
 *
 * Context: Process context.
 * Return:
 * * Ioctl result (e.g. enclave file descriptor) on success.
 * * Negative return value on failure.
 */
static long ne_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
{
        switch (cmd) {
        case NE_CREATE_VM: {
                int enclave_fd = -1;
                struct ne_pci_dev *ne_pci_dev = ne_devs.ne_pci_dev;
                u64 __user *slot_uid = (void __user *)arg;

                mutex_lock(&ne_pci_dev->enclaves_list_mutex);
                enclave_fd = ne_create_vm_ioctl(ne_pci_dev, slot_uid);
                mutex_unlock(&ne_pci_dev->enclaves_list_mutex);

                return enclave_fd;
        }

        default:
                return -ENOTTY;
        }

        return 0;
}

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);

        ne_teardown_cpu_pool();
}

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");