/*-
 * Copyright (c) 2017 Ruslan Bukin <br@bsdpad.com>
 * All rights reserved.
 *
 * This software was developed by BAE Systems, the University of Cambridge
 * Computer Laboratory, and Memorial University under DARPA/AFRL contract
 * FA8650-15-C-7558 ("CADETS"), as part of the DARPA Transparent Computing
 * (TC) research program.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

/*
 * Design overview.
 *
 * The driver provides character device for mmap(2) and ioctl(2) system calls
 * allowing user to manage isolated compartments ("enclaves") in user VA space.
 *
 * The driver duties is EPC pages management, enclave management, user data
 * validation.
 *
 * This driver requires Intel SGX support from hardware.
 *
 * /dev/sgx:
 *    .mmap:
 *        sgx_mmap_single() allocates VM object with following pager
 *        operations:
 *              a) sgx_pg_ctor():
 *                  VM object constructor does nothing
 *              b) sgx_pg_dtor():
 *                  VM object destructor destroys the SGX enclave associated
 *                  with the object: it frees all the EPC pages allocated for
 *                  enclave and removes the enclave.
 *              c) sgx_pg_fault():
 *                  VM object fault handler does nothing
 *
 *    .ioctl:
 *        sgx_ioctl():
 *               a) SGX_IOC_ENCLAVE_CREATE
 *                   Adds Enclave SECS page: initial step of enclave creation.
 *               b) SGX_IOC_ENCLAVE_ADD_PAGE
 *                   Adds TCS, REG pages to the enclave.
 *               c) SGX_IOC_ENCLAVE_INIT
 *                   Finalizes enclave creation.
 *
 * Enclave lifecycle:
 *          .-- ECREATE  -- Add SECS page
 *   Kernel |   EADD     -- Add TCS, REG pages
 *    space |   EEXTEND  -- Measure the page (take unique hash)
 *    ENCLS |   EPA      -- Allocate version array page
 *          '-- EINIT    -- Finalize enclave creation
 *   User   .-- EENTER   -- Go to entry point of enclave
 *    space |   EEXIT    -- Exit back to main application
 *    ENCLU '-- ERESUME  -- Resume enclave execution (e.g. after exception)
 *
 * Enclave lifecycle from driver point of view:
 *  1) User calls mmap() on /dev/sgx: we allocate a VM object
 *  2) User calls ioctl SGX_IOC_ENCLAVE_CREATE: we look for the VM object
 *     associated with user process created on step 1, create SECS physical
 *     page and store it in enclave's VM object queue by special index
 *     SGX_SECS_VM_OBJECT_INDEX.
 *  3) User calls ioctl SGX_IOC_ENCLAVE_ADD_PAGE: we look for enclave created
 *     on step 2, create TCS or REG physical page and map it to specified by
 *     user address of enclave VM object.
 *  4) User finalizes enclave creation with ioctl SGX_IOC_ENCLAVE_INIT call.
 *  5) User can freely enter to and exit from enclave using ENCLU instructions
 *     from userspace: the driver does nothing here.
 *  6) User proceed munmap(2) system call (or the process with enclave dies):
 *     we destroy the enclave associated with the object.
 *
 * EPC page types and their indexes in VM object queue:
 *   - PT_SECS index is special and equals SGX_SECS_VM_OBJECT_INDEX (-1);
 *   - PT_TCS and PT_REG indexes are specified by user in addr field of ioctl
 *     request data and determined as follows:
 *       pidx = OFF_TO_IDX(addp->addr - vmh->base);
 *   - PT_VA index is special, created for PT_REG, PT_TCS and PT_SECS pages
 *     and determined by formula:
 *       va_page_idx = - SGX_VA_PAGES_OFFS - (page_idx / SGX_VA_PAGE_SLOTS);
 *     PT_VA page can hold versions of up to 512 pages, and slot for each
 *     page in PT_VA page is determined as follows:
 *       va_slot_idx = page_idx % SGX_VA_PAGE_SLOTS;
 *   - PT_TRIM is unused.
 *
 * Locking:
 *    SGX ENCLS set of instructions have limitations on concurrency:
 *    some instructions can't be executed same time on different CPUs.
 *    We use sc->mtx_encls lock around them to prevent concurrent execution.
 *    sc->mtx lock is used to manage list of created enclaves and the state of
 *    SGX driver.
 *
 * Eviction of EPC pages:
 *    Eviction support is not implemented in this driver, however the driver
 *    manages VA (version array) pages: it allocates a VA slot for each EPC
 *    page. This will be required for eviction support in future.
 *    VA pages and slots are currently unused.
 *
 * Intel® 64 and IA-32 Architectures Software Developer's Manual
 * https://software.intel.com/en-us/articles/intel-sdm
 */

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/ioccom.h>
#include <sys/malloc.h>
#include <sys/kernel.h>
#include <sys/lock.h>
#include <sys/mutex.h>
#include <sys/rwlock.h>
#include <sys/conf.h>
#include <sys/module.h>
#include <sys/proc.h>
#include <sys/vmem.h>
#include <sys/vmmeter.h>

#include <vm/vm.h>
#include <vm/vm_param.h>
#include <vm/vm_extern.h>
#include <vm/vm_kern.h>
#include <vm/vm_page.h>
#include <vm/vm_map.h>
#include <vm/vm_object.h>
#include <vm/vm_pager.h>
#include <vm/vm_phys.h>
#include <vm/vm_radix.h>
#include <vm/pmap.h>

#include <machine/md_var.h>
#include <machine/specialreg.h>
#include <machine/cpufunc.h>
#include <machine/sgx.h>
#include <machine/sgxreg.h>

#include <amd64/sgx/sgxvar.h>

#define SGX_DEBUG
#undef  SGX_DEBUG

#ifdef  SGX_DEBUG
#define dprintf(fmt, ...)       printf(fmt, ##__VA_ARGS__)
#else
#define dprintf(fmt, ...)
#endif

static struct cdev_pager_ops sgx_pg_ops;
struct sgx_softc sgx_sc;

static int
sgx_get_epc_page(struct sgx_softc *sc, struct epc_page **epc)
{
        vmem_addr_t addr;
        int i;

        if (vmem_alloc(sc->vmem_epc, PAGE_SIZE, M_FIRSTFIT | M_NOWAIT,
            &addr) == 0) {
                i = (addr - sc->epc_base) / PAGE_SIZE;
                *epc = &sc->epc_pages[i];
                return (0);
        }

        return (ENOMEM);
}

static void
sgx_put_epc_page(struct sgx_softc *sc, struct epc_page *epc)
{
        vmem_addr_t addr;

        if (epc == NULL)
                return;

        addr = (epc->index * PAGE_SIZE) + sc->epc_base;
        vmem_free(sc->vmem_epc, addr, PAGE_SIZE);
}

static void
sgx_insert_epc_page_by_index(vm_page_t page, vm_object_t object,
    vm_pindex_t pidx, struct pctrie_iter *pages)
{

        VM_OBJECT_ASSERT_WLOCKED(object);

        page->valid = VM_PAGE_BITS_ALL;
        vm_page_iter_insert(page, object, pidx, pages);
}

static int
sgx_va_slot_init_by_index(struct sgx_softc *sc, vm_object_t object,
    uint64_t idx, struct pctrie_iter *pages)
{
        struct epc_page *epc;
        vm_page_t page;
        vm_page_t p;
        int ret;

        VM_OBJECT_ASSERT_WLOCKED(object);

        p = vm_radix_iter_lookup(pages, idx);
        if (p == NULL) {
                ret = sgx_get_epc_page(sc, &epc);
                if (ret) {
                        dprintf("%s: No free EPC pages available.\n",
                            __func__);
                        return (ret);
                }

                mtx_lock(&sc->mtx_encls);
                sgx_epa((void *)epc->base);
                mtx_unlock(&sc->mtx_encls);

                page = PHYS_TO_VM_PAGE(epc->phys);
                sgx_insert_epc_page_by_index(page, object, idx, pages);
        }

        return (0);
}

static int
sgx_va_slot_init(struct sgx_softc *sc, struct sgx_enclave *enclave,
    vm_pindex_t pidx, struct pctrie_iter *pages)
{
        uint64_t va_page_idx;
        uint64_t idx;
        vm_object_t object;
        int ret;

        object = enclave->object;

        VM_OBJECT_ASSERT_WLOCKED(object);

        va_page_idx = pidx / SGX_VA_PAGE_SLOTS;
        idx = - SGX_VA_PAGES_OFFS - va_page_idx;

        ret = sgx_va_slot_init_by_index(sc, object, idx, pages);

        return (ret);
}

static int
sgx_mem_find(struct sgx_softc *sc, uint64_t addr,
    vm_map_entry_t *entry0, vm_object_t *object0)
{
        vm_map_t map;
        vm_map_entry_t entry;
        vm_object_t object;

        map = &curproc->p_vmspace->vm_map;

        vm_map_lock_read(map);
        if (!vm_map_lookup_entry(map, addr, &entry)) {
                vm_map_unlock_read(map);
                dprintf("%s: Can't find enclave.\n", __func__);
                return (EINVAL);
        }

        object = entry->object.vm_object;
        if (object == NULL || object->handle == NULL) {
                vm_map_unlock_read(map);
                return (EINVAL);
        }

        if (object->type != OBJT_MGTDEVICE ||
            object->un_pager.devp.ops != &sgx_pg_ops) {
                vm_map_unlock_read(map);
                return (EINVAL);
        }

        vm_object_reference(object);

        *object0 = object;
        *entry0 = entry;
        vm_map_unlock_read(map);

        return (0);
}

static int
sgx_enclave_find(struct sgx_softc *sc, uint64_t addr,
    struct sgx_enclave **encl)
{
        struct sgx_vm_handle *vmh;
        struct sgx_enclave *enclave;
        vm_map_entry_t entry;
        vm_object_t object;
        int ret;

        ret = sgx_mem_find(sc, addr, &entry, &object);
        if (ret)
                return (ret);

        vmh = object->handle;
        if (vmh == NULL) {
                vm_object_deallocate(object);
                return (EINVAL);
        }

        enclave = vmh->enclave;
        if (enclave == NULL || enclave->object == NULL) {
                vm_object_deallocate(object);
                return (EINVAL);
        }

        *encl = enclave;

        return (0);
}

static int
sgx_enclave_alloc(struct sgx_softc *sc, struct secs *secs,
    struct sgx_enclave **enclave0)
{
        struct sgx_enclave *enclave;

        enclave = malloc(sizeof(struct sgx_enclave),
            M_SGX, M_WAITOK | M_ZERO);

        enclave->base = secs->base;
        enclave->size = secs->size;

        *enclave0 = enclave;

        return (0);
}

static void
sgx_epc_page_remove(struct sgx_softc *sc,
    struct epc_page *epc)
{

        mtx_lock(&sc->mtx_encls);
        sgx_eremove((void *)epc->base);
        mtx_unlock(&sc->mtx_encls);
}

static void
sgx_page_remove(struct sgx_softc *sc, vm_page_t p,
    struct pctrie_iter *pages)
{
        struct epc_page *epc;
        vm_paddr_t pa;
        uint64_t offs;

        if (pages != NULL)
                (void)vm_page_iter_remove(pages, p);
        else
                (void) vm_page_remove(p);

        dprintf("%s: p->pidx %ld\n", __func__, p->pindex);

        pa = VM_PAGE_TO_PHYS(p);
        epc = &sc->epc_pages[0];
        offs = (pa - epc->phys) / PAGE_SIZE;
        epc = &sc->epc_pages[offs];

        sgx_epc_page_remove(sc, epc);
        sgx_put_epc_page(sc, epc);
}

static void
sgx_enclave_remove(struct sgx_softc *sc,
    struct sgx_enclave *enclave)
{
        struct pctrie_iter pages;
        vm_object_t object;
        vm_page_t p, p_secs;

        mtx_lock(&sc->mtx);
        TAILQ_REMOVE(&sc->enclaves, enclave, next);
        mtx_unlock(&sc->mtx);

        object = enclave->object;

        vm_page_iter_init(&pages, object);
        VM_OBJECT_WLOCK(object);

        /*
         * First remove all the pages except SECS,
         * then remove SECS page.
         */
restart:
        VM_RADIX_FOREACH(p, &pages) {
                if (p->pindex == SGX_SECS_VM_OBJECT_INDEX)
                        continue;
                if (vm_page_busy_acquire(p, VM_ALLOC_WAITFAIL) == 0) {
                        pctrie_iter_reset(&pages);
                        goto restart;
                }
                sgx_page_remove(sc, p, &pages);
        }
        p_secs = vm_page_grab(object, SGX_SECS_VM_OBJECT_INDEX,
            VM_ALLOC_NOCREAT);
        /* Now remove SECS page */
        if (p_secs != NULL)
                sgx_page_remove(sc, p_secs, NULL);

        KASSERT(object->resident_page_count == 0, ("count"));

        VM_OBJECT_WUNLOCK(object);
}

static int
sgx_measure_page(struct sgx_softc *sc, struct epc_page *secs,
    struct epc_page *epc, uint16_t mrmask)
{
        int i, j;
        int ret;

        mtx_lock(&sc->mtx_encls);

        for (i = 0, j = 1; i < PAGE_SIZE; i += 0x100, j <<= 1) {
                if (!(j & mrmask))
                        continue;

                ret = sgx_eextend((void *)secs->base,
                    (void *)(epc->base + i));
                if (ret == SGX_EFAULT) {
                        mtx_unlock(&sc->mtx_encls);
                        return (ret);
                }
        }

        mtx_unlock(&sc->mtx_encls);

        return (0);
}

static int
sgx_secs_validate(struct sgx_softc *sc, struct secs *secs)
{
        struct secs_attr *attr;
        int i;

        if (secs->size == 0)
                return (EINVAL);

        /* BASEADDR must be naturally aligned on an SECS.SIZE boundary. */
        if (secs->base & (secs->size - 1))
                return (EINVAL);

        /* SECS.SIZE must be at least 2 pages. */
        if (secs->size < 2 * PAGE_SIZE)
                return (EINVAL);

        if ((secs->size & (secs->size - 1)) != 0)
                return (EINVAL);

        attr = &secs->attributes;

        if (attr->reserved1 != 0 ||
            attr->reserved2 != 0 ||
            attr->reserved3 != 0)
                return (EINVAL);

        for (i = 0; i < SECS_ATTR_RSV4_SIZE; i++)
                if (attr->reserved4[i])
                        return (EINVAL);

        /*
         * Intel® Software Guard Extensions Programming Reference
         * 6.7.2 Relevant Fields in Various Data Structures
         * 6.7.2.1 SECS.ATTRIBUTES.XFRM
         * XFRM[1:0] must be set to 0x3.
         */
        if ((attr->xfrm & 0x3) != 0x3)
                return (EINVAL);

        if (!attr->mode64bit)
                return (EINVAL);

        if (secs->size > sc->enclave_size_max)
                return (EINVAL);

        for (i = 0; i < SECS_RSV1_SIZE; i++)
                if (secs->reserved1[i])
                        return (EINVAL);

        for (i = 0; i < SECS_RSV2_SIZE; i++)
                if (secs->reserved2[i])
                        return (EINVAL);

        for (i = 0; i < SECS_RSV3_SIZE; i++)
                if (secs->reserved3[i])
                        return (EINVAL);

        for (i = 0; i < SECS_RSV4_SIZE; i++)
                if (secs->reserved4[i])
                        return (EINVAL);

        return (0);
}

static int
sgx_tcs_validate(struct tcs *tcs)
{
        int i;

        if ((tcs->flags) ||
            (tcs->ossa & (PAGE_SIZE - 1)) ||
            (tcs->ofsbasgx & (PAGE_SIZE - 1)) ||
            (tcs->ogsbasgx & (PAGE_SIZE - 1)) ||
            ((tcs->fslimit & 0xfff) != 0xfff) ||
            ((tcs->gslimit & 0xfff) != 0xfff))
                return (EINVAL);

        for (i = 0; i < nitems(tcs->reserved3); i++)
                if (tcs->reserved3[i])
                        return (EINVAL);

        return (0);
}

static void
sgx_tcs_dump(struct sgx_softc *sc, struct tcs *t)
{

        dprintf("t->flags %lx\n", t->flags);
        dprintf("t->ossa %lx\n", t->ossa);
        dprintf("t->cssa %x\n", t->cssa);
        dprintf("t->nssa %x\n", t->nssa);
        dprintf("t->oentry %lx\n", t->oentry);
        dprintf("t->ofsbasgx %lx\n", t->ofsbasgx);
        dprintf("t->ogsbasgx %lx\n", t->ogsbasgx);
        dprintf("t->fslimit %x\n", t->fslimit);
        dprintf("t->gslimit %x\n", t->gslimit);
}

static int
sgx_pg_ctor(void *handle, vm_ooffset_t size, vm_prot_t prot,
    vm_ooffset_t foff, struct ucred *cred, u_short *color)
{
        struct sgx_vm_handle *vmh;

        vmh = handle;
        if (vmh == NULL) {
                dprintf("%s: vmh not found.\n", __func__);
                return (0);
        }

        dprintf("%s: vmh->base %lx foff 0x%lx size 0x%lx\n",
            __func__, vmh->base, foff, size);

        return (0);
}

static void
sgx_pg_dtor(void *handle)
{
        struct sgx_vm_handle *vmh;
        struct sgx_softc *sc;

        vmh = handle;
        if (vmh == NULL) {
                dprintf("%s: vmh not found.\n", __func__);
                return;
        }

        sc = vmh->sc;
        if (sc == NULL) {
                dprintf("%s: sc is NULL\n", __func__);
                return;
        }

        if (vmh->enclave == NULL) {
                dprintf("%s: Enclave not found.\n", __func__);
                return;
        }

        sgx_enclave_remove(sc, vmh->enclave);

        free(vmh->enclave, M_SGX);
        free(vmh, M_SGX);
}

static int
sgx_pg_fault(vm_object_t object, vm_ooffset_t offset,
    int prot, vm_page_t *mres)
{

        /*
         * The purpose of this trivial handler is to handle the race
         * when user tries to access mmaped region before or during
         * enclave creation ioctl calls.
         */

        dprintf("%s: offset 0x%lx\n", __func__, offset);

        return (VM_PAGER_FAIL);
}

static void
sgx_pg_path(void *handle, char *path, size_t len)
{
        strlcpy(path, "sgx", len);
}

static struct cdev_pager_ops sgx_pg_ops = {
        .cdev_pg_ctor = sgx_pg_ctor,
        .cdev_pg_dtor = sgx_pg_dtor,
        .cdev_pg_fault = sgx_pg_fault,
        .cdev_pg_path = sgx_pg_path,
};

static void
sgx_insert_epc_page(struct sgx_enclave *enclave, struct epc_page *epc,
    uint64_t addr, struct pctrie_iter *pages)
{
        vm_pindex_t pidx;
        vm_page_t page;

        VM_OBJECT_ASSERT_WLOCKED(enclave->object);

        pidx = OFF_TO_IDX(addr);
        page = PHYS_TO_VM_PAGE(epc->phys);

        sgx_insert_epc_page_by_index(page, enclave->object, pidx, pages);
}

static int
sgx_ioctl_create(struct sgx_softc *sc, struct sgx_enclave_create *param)
{
        struct pctrie_iter pages;
        struct sgx_vm_handle *vmh;
        vm_map_entry_t entry;
        vm_page_t p;
        struct page_info pginfo;
        struct secinfo secinfo;
        struct sgx_enclave *enclave;
        struct epc_page *epc;
        struct secs *secs;
        vm_object_t object;
        vm_page_t page;
        int ret;

        epc = NULL;
        secs = NULL;
        enclave = NULL;
        object = NULL;

        /* SGX Enclave Control Structure (SECS) */
        secs = malloc(PAGE_SIZE, M_SGX, M_WAITOK | M_ZERO);
        ret = copyin((void *)param->src, secs, sizeof(struct secs));
        if (ret) {
                dprintf("%s: Can't copy SECS.\n", __func__);
                goto error;
        }

        ret = sgx_secs_validate(sc, secs);
        if (ret) {
                dprintf("%s: SECS validation failed.\n", __func__);
                goto error;
        }

        ret = sgx_mem_find(sc, secs->base, &entry, &object);
        if (ret) {
                dprintf("%s: Can't find vm_map.\n", __func__);
                goto error;
        }

        vmh = object->handle;
        if (!vmh) {
                dprintf("%s: Can't find vmh.\n", __func__);
                ret = ENXIO;
                goto error;
        }

        dprintf("%s: entry start %lx offset %lx\n",
            __func__, entry->start, entry->offset);
        vmh->base = (entry->start - entry->offset);

        ret = sgx_enclave_alloc(sc, secs, &enclave);
        if (ret) {
                dprintf("%s: Can't alloc enclave.\n", __func__);
                goto error;
        }
        enclave->object = object;
        enclave->vmh = vmh;

        memset(&secinfo, 0, sizeof(struct secinfo));
        memset(&pginfo, 0, sizeof(struct page_info));
        pginfo.linaddr = 0;
        pginfo.srcpge = (uint64_t)secs;
        pginfo.secinfo = &secinfo;
        pginfo.secs = 0;

        ret = sgx_get_epc_page(sc, &epc);
        if (ret) {
                dprintf("%s: Failed to get free epc page.\n", __func__);
                goto error;
        }
        enclave->secs_epc_page = epc;

        vm_page_iter_init(&pages, object);
        VM_OBJECT_WLOCK(object);
        p = vm_radix_iter_lookup(&pages, SGX_SECS_VM_OBJECT_INDEX);
        if (p) {
                VM_OBJECT_WUNLOCK(object);
                /* SECS page already added. */
                ret = ENXIO;
                goto error;
        }

        ret = sgx_va_slot_init_by_index(sc, object,
            - SGX_VA_PAGES_OFFS - SGX_SECS_VM_OBJECT_INDEX, &pages);
        if (ret) {
                VM_OBJECT_WUNLOCK(object);
                dprintf("%s: Can't init va slot.\n", __func__);
                goto error;
        }

        mtx_lock(&sc->mtx);
        if ((sc->state & SGX_STATE_RUNNING) == 0) {
                mtx_unlock(&sc->mtx);
                /* Remove VA page that was just created for SECS page. */
                p = vm_page_grab(enclave->object,
                    - SGX_VA_PAGES_OFFS - SGX_SECS_VM_OBJECT_INDEX,
                    VM_ALLOC_NOCREAT);
                sgx_page_remove(sc, p, NULL);
                VM_OBJECT_WUNLOCK(object);
                goto error;
        }
        mtx_lock(&sc->mtx_encls);
        ret = sgx_ecreate(&pginfo, (void *)epc->base);
        mtx_unlock(&sc->mtx_encls);
        if (ret == SGX_EFAULT) {
                dprintf("%s: gp fault\n", __func__);
                mtx_unlock(&sc->mtx);
                /* Remove VA page that was just created for SECS page. */
                p = vm_page_grab(enclave->object,
                    - SGX_VA_PAGES_OFFS - SGX_SECS_VM_OBJECT_INDEX,
                    VM_ALLOC_NOCREAT);
                sgx_page_remove(sc, p, NULL);
                VM_OBJECT_WUNLOCK(object);
                goto error;
        }

        TAILQ_INSERT_TAIL(&sc->enclaves, enclave, next);
        mtx_unlock(&sc->mtx);

        vmh->enclave = enclave;

        page = PHYS_TO_VM_PAGE(epc->phys);
        sgx_insert_epc_page_by_index(page, enclave->object,
            SGX_SECS_VM_OBJECT_INDEX, &pages);

        VM_OBJECT_WUNLOCK(object);

        /* Release the reference. */
        vm_object_deallocate(object);

        free(secs, M_SGX);

        return (0);

error:
        free(secs, M_SGX);
        sgx_put_epc_page(sc, epc);
        free(enclave, M_SGX);
        vm_object_deallocate(object);

        return (ret);
}

static int
sgx_ioctl_add_page(struct sgx_softc *sc,
    struct sgx_enclave_add_page *addp)
{
        struct pctrie_iter pages;
        struct epc_page *secs_epc_page;
        struct sgx_enclave *enclave;
        struct sgx_vm_handle *vmh;
        struct epc_page *epc;
        struct page_info pginfo;
        struct secinfo secinfo;
        vm_object_t object;
        void *tmp_vaddr;
        uint64_t page_type;
        struct tcs *t;
        uint64_t addr;
        uint64_t pidx;
        vm_page_t p;
        int ret;

        tmp_vaddr = NULL;
        epc = NULL;
        object = NULL;

        /* Find and get reference to VM object. */
        ret = sgx_enclave_find(sc, addp->addr, &enclave);
        if (ret) {
                dprintf("%s: Failed to find enclave.\n", __func__);
                goto error;
        }

        object = enclave->object;
        KASSERT(object != NULL, ("vm object is NULL\n"));
        vmh = object->handle;

        ret = sgx_get_epc_page(sc, &epc);
        if (ret) {
                dprintf("%s: Failed to get free epc page.\n", __func__);
                goto error;
        }

        memset(&secinfo, 0, sizeof(struct secinfo));
        ret = copyin((void *)addp->secinfo, &secinfo,
            sizeof(struct secinfo));
        if (ret) {
                dprintf("%s: Failed to copy secinfo.\n", __func__);
                goto error;
        }

        tmp_vaddr = malloc(PAGE_SIZE, M_SGX, M_WAITOK | M_ZERO);
        ret = copyin((void *)addp->src, tmp_vaddr, PAGE_SIZE);
        if (ret) {
                dprintf("%s: Failed to copy page.\n", __func__);
                goto error;
        }

        page_type = (secinfo.flags & SECINFO_FLAGS_PT_M) >>
            SECINFO_FLAGS_PT_S;
        if (page_type != SGX_PT_TCS && page_type != SGX_PT_REG) {
                dprintf("%s: page can't be added.\n", __func__);
                goto error;
        }
        if (page_type == SGX_PT_TCS) {
                t = (struct tcs *)tmp_vaddr;
                ret = sgx_tcs_validate(t);
                if (ret) {
                        dprintf("%s: TCS page validation failed.\n",
                            __func__);
                        goto error;
                }
                sgx_tcs_dump(sc, t);
        }

        addr = (addp->addr - vmh->base);
        pidx = OFF_TO_IDX(addr);

        vm_page_iter_init(&pages, object);
        VM_OBJECT_WLOCK(object);
        p = vm_radix_iter_lookup(&pages, pidx);
        if (p) {
                VM_OBJECT_WUNLOCK(object);
                /* Page already added. */
                ret = ENXIO;
                goto error;
        }

        ret = sgx_va_slot_init(sc, enclave, pidx, &pages);
        if (ret) {
                VM_OBJECT_WUNLOCK(object);
                dprintf("%s: Can't init va slot.\n", __func__);
                goto error;
        }

        secs_epc_page = enclave->secs_epc_page;
        memset(&pginfo, 0, sizeof(struct page_info));
        pginfo.linaddr = (uint64_t)addp->addr;
        pginfo.srcpge = (uint64_t)tmp_vaddr;
        pginfo.secinfo = &secinfo;
        pginfo.secs = (uint64_t)secs_epc_page->base;

        mtx_lock(&sc->mtx_encls);
        ret = sgx_eadd(&pginfo, (void *)epc->base);
        if (ret == SGX_EFAULT) {
                dprintf("%s: gp fault on eadd\n", __func__);
                mtx_unlock(&sc->mtx_encls);
                VM_OBJECT_WUNLOCK(object);
                goto error;
        }
        mtx_unlock(&sc->mtx_encls);

        ret = sgx_measure_page(sc, enclave->secs_epc_page, epc, addp->mrmask);
        if (ret == SGX_EFAULT) {
                dprintf("%s: gp fault on eextend\n", __func__);
                sgx_epc_page_remove(sc, epc);
                VM_OBJECT_WUNLOCK(object);
                goto error;
        }

        sgx_insert_epc_page(enclave, epc, addr, &pages);

        VM_OBJECT_WUNLOCK(object);

        /* Release the reference. */
        vm_object_deallocate(object);

        free(tmp_vaddr, M_SGX);

        return (0);

error:
        free(tmp_vaddr, M_SGX);
        sgx_put_epc_page(sc, epc);
        vm_object_deallocate(object);

        return (ret);
}

static int
sgx_ioctl_init(struct sgx_softc *sc, struct sgx_enclave_init *initp)
{
        struct epc_page *secs_epc_page;
        struct sgx_enclave *enclave;
        struct thread *td;
        void *tmp_vaddr;
        void *einittoken;
        void *sigstruct;
        vm_object_t object;
        int retry;
        int ret;

        td = curthread;
        tmp_vaddr = NULL;
        object = NULL;

        dprintf("%s: addr %lx, sigstruct %lx, einittoken %lx\n",
            __func__, initp->addr, initp->sigstruct, initp->einittoken);

        /* Find and get reference to VM object. */
        ret = sgx_enclave_find(sc, initp->addr, &enclave);
        if (ret) {
                dprintf("%s: Failed to find enclave.\n", __func__);
                goto error;
        }

        object = enclave->object;

        tmp_vaddr = malloc(PAGE_SIZE, M_SGX, M_WAITOK | M_ZERO);
        sigstruct = tmp_vaddr;
        einittoken = (void *)((uint64_t)sigstruct + PAGE_SIZE / 2);

        ret = copyin((void *)initp->sigstruct, sigstruct,
            SGX_SIGSTRUCT_SIZE);
        if (ret) {
                dprintf("%s: Failed to copy SIGSTRUCT page.\n", __func__);
                goto error;
        }

        ret = copyin((void *)initp->einittoken, einittoken,
            SGX_EINITTOKEN_SIZE);
        if (ret) {
                dprintf("%s: Failed to copy EINITTOKEN page.\n", __func__);
                goto error;
        }

        secs_epc_page = enclave->secs_epc_page;
        retry = 16;
        do {
                mtx_lock(&sc->mtx_encls);
                ret = sgx_einit(sigstruct, (void *)secs_epc_page->base,
                    einittoken);
                mtx_unlock(&sc->mtx_encls);
                dprintf("%s: sgx_einit returned %d\n", __func__, ret);
        } while (ret == SGX_UNMASKED_EVENT && retry--);

        if (ret) {
                dprintf("%s: Failed init enclave: %d\n", __func__, ret);
                td->td_retval[0] = ret;
                ret = 0;
        }

error:
        free(tmp_vaddr, M_SGX);

        /* Release the reference. */
        vm_object_deallocate(object);

        return (ret);
}

static int
sgx_ioctl(struct cdev *dev, u_long cmd, caddr_t addr, int flags,
    struct thread *td)
{
        struct sgx_enclave_add_page *addp;
        struct sgx_enclave_create *param;
        struct sgx_enclave_init *initp;
        struct sgx_softc *sc;
        int ret;
        int len;

        sc = &sgx_sc;

        len = IOCPARM_LEN(cmd);

        dprintf("%s: cmd %lx, addr %lx, len %d\n",
            __func__, cmd, (uint64_t)addr, len);

        if (len > SGX_IOCTL_MAX_DATA_LEN)
                return (EINVAL);

        switch (cmd) {
        case SGX_IOC_ENCLAVE_CREATE:
                param = (struct sgx_enclave_create *)addr;
                ret = sgx_ioctl_create(sc, param);
                break;
        case SGX_IOC_ENCLAVE_ADD_PAGE:
                addp = (struct sgx_enclave_add_page *)addr;
                ret = sgx_ioctl_add_page(sc, addp);
                break;
        case SGX_IOC_ENCLAVE_INIT:
                initp = (struct sgx_enclave_init *)addr;
                ret = sgx_ioctl_init(sc, initp);
                break;
        default:
                return (EINVAL);
        }

        return (ret);
}

static int
sgx_mmap_single(struct cdev *cdev, vm_ooffset_t *offset,
    vm_size_t mapsize, struct vm_object **objp, int nprot)
{
        struct sgx_vm_handle *vmh;
        struct sgx_softc *sc;

        sc = &sgx_sc;

        dprintf("%s: mapsize 0x%lx, offset %lx\n",
            __func__, mapsize, *offset);

        vmh = malloc(sizeof(struct sgx_vm_handle),
            M_SGX, M_WAITOK | M_ZERO);
        vmh->sc = sc;
        vmh->size = mapsize;
        vmh->mem = cdev_pager_allocate(vmh, OBJT_MGTDEVICE, &sgx_pg_ops,
            mapsize, nprot, *offset, NULL);
        if (vmh->mem == NULL) {
                free(vmh, M_SGX);
                return (ENOMEM);
        }

        VM_OBJECT_WLOCK(vmh->mem);
        vm_object_set_flag(vmh->mem, OBJ_PG_DTOR);
        VM_OBJECT_WUNLOCK(vmh->mem);

        *objp = vmh->mem;

        return (0);
}

static struct cdevsw sgx_cdevsw = {
        .d_version =            D_VERSION,
        .d_ioctl =              sgx_ioctl,
        .d_mmap_single =        sgx_mmap_single,
        .d_name =               "Intel SGX",
};

static int
sgx_get_epc_area(struct sgx_softc *sc)
{
        vm_offset_t epc_base_vaddr;
        u_int cp[4];
        int error;
        int i;

        cpuid_count(SGX_CPUID, 0x2, cp);

        sc->epc_base = ((uint64_t)(cp[1] & 0xfffff) << 32) +
            (cp[0] & 0xfffff000);
        sc->epc_size = ((uint64_t)(cp[3] & 0xfffff) << 32) +
            (cp[2] & 0xfffff000);
        sc->npages = sc->epc_size / SGX_PAGE_SIZE;

        if (sc->epc_size == 0 || sc->epc_base == 0) {
                printf("%s: Incorrect EPC data: EPC base %lx, size %lu\n",
                    __func__, sc->epc_base, sc->epc_size);
                return (EINVAL);
        }

        if (cp[3] & 0xffff)
                sc->enclave_size_max = (1 << ((cp[3] >> 8) & 0xff));
        else
                sc->enclave_size_max = SGX_ENCL_SIZE_MAX_DEF;

        epc_base_vaddr = (vm_offset_t)pmap_mapdev_attr(sc->epc_base,
            sc->epc_size, VM_MEMATTR_DEFAULT);

        sc->epc_pages = malloc(sizeof(struct epc_page) * sc->npages,
            M_DEVBUF, M_WAITOK | M_ZERO);

        for (i = 0; i < sc->npages; i++) {
                sc->epc_pages[i].base = epc_base_vaddr + SGX_PAGE_SIZE * i;
                sc->epc_pages[i].phys = sc->epc_base + SGX_PAGE_SIZE * i;
                sc->epc_pages[i].index = i;
        }

        sc->vmem_epc = vmem_create("SGX EPC", sc->epc_base, sc->epc_size,
            PAGE_SIZE, PAGE_SIZE, M_FIRSTFIT | M_WAITOK);
        if (sc->vmem_epc == NULL) {
                printf("%s: Can't create vmem arena.\n", __func__);
                free(sc->epc_pages, M_SGX);
                return (EINVAL);
        }

        error = vm_phys_fictitious_reg_range(sc->epc_base,
            sc->epc_base + sc->epc_size, VM_MEMATTR_DEFAULT);
        if (error) {
                printf("%s: Can't register fictitious space.\n", __func__);
                free(sc->epc_pages, M_SGX);
                return (EINVAL);
        }

        return (0);
}

static void
sgx_put_epc_area(struct sgx_softc *sc)
{

        vm_phys_fictitious_unreg_range(sc->epc_base,
            sc->epc_base + sc->epc_size);

        free(sc->epc_pages, M_SGX);
}

static int
sgx_load(void)
{
        struct sgx_softc *sc;
        int error;

        sc = &sgx_sc;

        if ((cpu_stdext_feature & CPUID_STDEXT_SGX) == 0)
                return (ENXIO);

        error = sgx_get_epc_area(sc);
        if (error) {
                printf("%s: Failed to get Processor Reserved Memory area.\n",
                    __func__);
                return (ENXIO);
        }

        mtx_init(&sc->mtx_encls, "SGX ENCLS", NULL, MTX_DEF);
        mtx_init(&sc->mtx, "SGX driver", NULL, MTX_DEF);

        TAILQ_INIT(&sc->enclaves);

        sc->sgx_cdev = make_dev(&sgx_cdevsw, 0, UID_ROOT, GID_WHEEL,
            0600, "isgx");

        sc->state |= SGX_STATE_RUNNING;

        printf("SGX initialized: EPC base 0x%lx size %ld (%d pages)\n",
            sc->epc_base, sc->epc_size, sc->npages);

        return (0);
}

static int
sgx_unload(void)
{
        struct sgx_softc *sc;

        sc = &sgx_sc;

        if ((sc->state & SGX_STATE_RUNNING) == 0)
                return (0);

        mtx_lock(&sc->mtx);
        if (!TAILQ_EMPTY(&sc->enclaves)) {
                mtx_unlock(&sc->mtx);
                return (EBUSY);
        }
        sc->state &= ~SGX_STATE_RUNNING;
        mtx_unlock(&sc->mtx);

        destroy_dev(sc->sgx_cdev);

        vmem_destroy(sc->vmem_epc);
        sgx_put_epc_area(sc);

        mtx_destroy(&sc->mtx_encls);
        mtx_destroy(&sc->mtx);

        return (0);
}

static int
sgx_handler(module_t mod, int what, void *arg)
{
        int error;

        switch (what) {
        case MOD_LOAD:
                error = sgx_load();
                break;
        case MOD_UNLOAD:
                error = sgx_unload();
                break;
        default:
                error = 0;
                break;
        }

        return (error);
}

static moduledata_t sgx_kmod = {
        "sgx",
        sgx_handler,
        NULL
};

DECLARE_MODULE(sgx, sgx_kmod, SI_SUB_LAST, SI_ORDER_ANY);
MODULE_VERSION(sgx, 1);