/*
 * Copyright 2017 The Chromium OS Authors. All rights reserved.
 * Use of this source code is governed by a BSD-style license that can be
 * found in the LICENSE file.
 */

#include <errno.h>
#include <fcntl.h>
#include <linux/memfd.h>
#include <pthread.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/mman.h>
#include <sys/syscall.h>
#include <time.h>
#include <unistd.h>

#include "crosvm.h"

#ifndef F_LINUX_SPECIFIC_BASE
#define F_LINUX_SPECIFIC_BASE 1024
#endif

#ifndef F_ADD_SEALS
#define F_ADD_SEALS (F_LINUX_SPECIFIC_BASE + 9)
#endif

#ifndef F_SEAL_SHRINK
#define F_SEAL_SHRINK 0x0002
#endif

#define LOAD_ADDRESS 0x1000
#define DATAMATCH_VAL 0x88
#define KILL_ADDRESS 0x4000

int g_kill_evt;

void *vcpu_thread(void *arg) {
    struct crosvm_vcpu *vcpu = arg;
    struct crosvm_vcpu_event evt;
    int i = 0;
    while (crosvm_vcpu_wait(vcpu, &evt) == 0) {
        if (evt.kind == CROSVM_VCPU_EVENT_KIND_INIT) {
            struct kvm_sregs sregs;
            crosvm_vcpu_get_sregs(vcpu, &sregs);
            sregs.cs.base = 0;
            sregs.cs.selector = 0;
            sregs.es.base = KILL_ADDRESS;
            sregs.es.selector = 0;
            crosvm_vcpu_set_sregs(vcpu, &sregs);

            struct kvm_regs regs;
            crosvm_vcpu_get_regs(vcpu, &regs);
            regs.rflags = 2;
            regs.rip = LOAD_ADDRESS;
            regs.rax = DATAMATCH_VAL;
            regs.rbx = DATAMATCH_VAL - 1;
            crosvm_vcpu_set_regs(vcpu, &regs);
        }

        if (evt.kind == CROSVM_VCPU_EVENT_KIND_IO_ACCESS &&
            evt.io_access.address_space == CROSVM_ADDRESS_SPACE_MMIO &&
            evt.io_access.address == KILL_ADDRESS &&
            evt.io_access.is_write &&
            evt.io_access.length == 1 &&
            evt.io_access.data[0] == 1)
        {
            uint64_t dummy = 1;
            write(g_kill_evt, &dummy, sizeof(dummy));
            return NULL;
        }

        crosvm_vcpu_resume(vcpu);
    }

    return NULL;
}

int main(int argc, char** argv) {
    const uint8_t code[] = {
    /*
    0000  BAF803        mov dx,0x3f8
    0003  88C3          mov bl,al
    0005  EE            out dx,al
    0006  B000          mov al,0x0
    0008  EE            out dx,al
    0009  88D8          mov al,bl
    000B  EE            out dx,al
    0014  26C606000001  mov byte [es:0x0],0x1
    000C  F4            hlt
    */
        0xba, 0xf8, 0x03,
        0x88, 0xc3,
        0xee,
        0xb0, 0x00,
        0xee,
        0x88, 0xd8,
        0xee,
        0x26, 0xc6, 0x06, 0x00, 0x00, 0x01,
        0xf4,
    };

    struct crosvm *crosvm;
    int ret = crosvm_connect(&crosvm);
    if (ret) {
        fprintf(stderr, "failed to connect to crosvm: %d\n", ret);
        return 1;
    }

    g_kill_evt = crosvm_get_shutdown_eventfd(crosvm);
    if (g_kill_evt < 0) {
        fprintf(stderr, "failed to get kill eventfd: %d\n", g_kill_evt);
        return 1;
    }

    ret = crosvm_reserve_range(crosvm, CROSVM_ADDRESS_SPACE_MMIO, KILL_ADDRESS, 1);
    if (ret) {
        fprintf(stderr, "failed to reserve mmio range: %d\n", ret);
        return 1;
    }

    uint8_t datamatch = DATAMATCH_VAL;
    struct crosvm_io *io;
    ret = crosvm_create_io_event(crosvm, CROSVM_ADDRESS_SPACE_IOPORT, 0x3f8, 1, &datamatch, &io);
    if (ret) {
        fprintf(stderr, "failed to create ioevent: %d\n", ret);
        return 1;
    }

    int ioeventfd = crosvm_io_event_fd(io);

    int mem_size = 0x4000;
    int mem_fd = syscall(SYS_memfd_create, "guest_mem", MFD_CLOEXEC | MFD_ALLOW_SEALING);
    if (mem_fd < 0) {
        fprintf(stderr, "failed to create guest memfd: %d\n", errno);
        return 1;
    }
    ret = ftruncate(mem_fd, mem_size);
    if (ret) {
        fprintf(stderr, "failed to set size of guest memory: %d\n", errno);
        return 1;
    }
    uint8_t *mem = mmap(NULL, mem_size, PROT_READ | PROT_WRITE, MAP_SHARED, mem_fd, 0);
    if (mem == MAP_FAILED) {
        fprintf(stderr, "failed to mmap guest memory: %d\n", errno);
        return 1;
    }
    fcntl(mem_fd, F_ADD_SEALS, F_SEAL_SHRINK);
    memcpy(mem + LOAD_ADDRESS, code, sizeof(code));

    struct crosvm_memory *mem_obj;
    ret = crosvm_create_memory(crosvm, mem_fd, 0, mem_size, 0, false, false, &mem_obj);
    if (ret) {
        fprintf(stderr, "failed to create memory in crosvm: %d\n", ret);
        return 1;
    }

    /* get and creat a thread for each vcpu */
    struct crosvm_vcpu *vcpus[32];
    pthread_t vcpu_threads[32];
    uint32_t vcpu_count;
    for (vcpu_count = 0; vcpu_count < 32; vcpu_count++) {
        ret = crosvm_get_vcpu(crosvm, vcpu_count, &vcpus[vcpu_count]);
        if (ret == -ENOENT)
            break;

        if (ret) {
            fprintf(stderr, "error while getting all vcpus: %d\n", ret);
            return 1;
        }
        pthread_create(&vcpu_threads[vcpu_count], NULL, vcpu_thread, vcpus[vcpu_count]);
    }

    ret = crosvm_start(crosvm);
    if (ret) {
        fprintf(stderr, "failed to tell crosvm to start: %d\n", ret);
        return 1;
    }

    uint64_t dummy;
    read(g_kill_evt, &dummy, 8);

    ret = read(ioeventfd, &dummy, sizeof(dummy));
    if (ret == -1) {
        fprintf(stderr, "failed to read ioeventfd: %d\n", errno);
        return 1;
    }

    if (dummy != 2) {
        fprintf(stderr, "ioeventfd was not triggered the expected number of times: %d\n", dummy);
        return 1;
    }

    return 0;
}