path: root/x86_64/src/lib.rs

// 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.

extern crate byteorder;
extern crate data_model;
extern crate devices;
extern crate device_manager;
extern crate kvm;
extern crate kvm_sys;
extern crate libc;
extern crate sys_util;
extern crate kernel_cmdline;
extern crate kernel_loader;

#[allow(dead_code)]
#[allow(non_upper_case_globals)]
#[allow(non_camel_case_types)]
#[allow(non_snake_case)]
mod bootparam;
// Bindgen didn't implement copy for boot_params because edid_info contains an array with len > 32.
impl Copy for bootparam::edid_info {}
impl Clone for bootparam::edid_info {
    fn clone(&self) -> Self {
        *self
    }
}
impl Copy for bootparam::boot_params {}
impl Clone for bootparam::boot_params {
    fn clone(&self) -> Self {
        *self
    }
}
// boot_params is just a series of ints, it is safe to initialize it.
unsafe impl data_model::DataInit for bootparam::boot_params {}

#[allow(dead_code)]
#[allow(non_upper_case_globals)]
mod msr_index;

#[allow(dead_code)]
#[allow(non_upper_case_globals)]
#[allow(non_camel_case_types)]
mod mpspec;
// These mpspec types are only data, reading them from data is a safe initialization.
unsafe impl data_model::DataInit for mpspec::mpc_bus {}
unsafe impl data_model::DataInit for mpspec::mpc_cpu {}
unsafe impl data_model::DataInit for mpspec::mpc_intsrc {}
unsafe impl data_model::DataInit for mpspec::mpc_ioapic {}
unsafe impl data_model::DataInit for mpspec::mpc_table {}
unsafe impl data_model::DataInit for mpspec::mpc_lintsrc {}
unsafe impl data_model::DataInit for mpspec::mpf_intel {}

mod cpuid;
mod gdt;
mod interrupts;
mod mptable;
mod regs;

use std::mem;
use std::result;
use std::error::{self, Error as X86Error};
use std::fmt::{self, Display};
use std::fs::File;
use std::ffi::CStr;
use std::sync::{Arc, Mutex};
use std::io::stdout;

use bootparam::boot_params;
use bootparam::E820_RAM;
use sys_util::{EventFd, GuestAddress, GuestMemory};
use kvm::*;

pub use regs::Error as RegError;
pub use interrupts::Error as IntError;
pub use mptable::Error as MpTableError;

#[derive(Debug)]
pub enum Error {
    /// Error configuring the system
    ConfigureSystem,
    /// Error configuring the VCPU.
    CpuSetup(cpuid::Error),
    /// Unable to clone an EventFd
    CloneEventFd(sys_util::Error),
    /// Unable to make an EventFd
    CreateEventFd(sys_util::Error),
    /// The kernel extends past the end of RAM
    KernelOffsetPastEnd,
    /// Error configuring the VCPU registers.
    RegisterConfiguration(RegError),
    /// Error configuring the VCPU floating point registers.
    FpuRegisterConfiguration(RegError),
    /// Error registering an IrqFd
    RegisterIrqfd(sys_util::Error),
    /// Error configuring the VCPU segment registers.
    SegmentRegisterConfiguration(RegError),
    LoadCmdline(kernel_loader::Error),
    LoadKernel(kernel_loader::Error),
    /// Error configuring the VCPU local interrupt.
    LocalIntConfiguration(IntError),
    /// Error writing MP table to memory.
    MpTableSetup(MpTableError),
    /// Error writing the zero page of guest memory.
    ZeroPageSetup,
    /// The zero page extends past the end of guest_mem.
    ZeroPagePastRamEnd,
    /// Invalid e820 setup params.
    E820Configuration,
}

impl error::Error for Error {
    fn description(&self) -> &str {
        match self {
            &Error::ConfigureSystem => "Error configuring the system",
            &Error::CpuSetup(_) => "Error configuring the VCPU",
            &Error::CloneEventFd(_) => "Unable to clone an EventFd",
            &Error::CreateEventFd(_) => "Unable to make an EventFd",
            &Error::KernelOffsetPastEnd =>
                "The kernel extends past the end of RAM",
            &Error::RegisterConfiguration(_) =>
                "Error configuring the VCPU registers",
            &Error::FpuRegisterConfiguration(_) =>
                "Error configuring the VCPU floating point registers",
            &Error::RegisterIrqfd(_) => "Error registering an IrqFd",
            &Error::SegmentRegisterConfiguration(_) =>
                "Error configuring the VCPU segment registers",
            &Error::LoadCmdline(_) => "Error Loading command line",
            &Error::LoadKernel(_) => "Error Loading Kernel",
            &Error::LocalIntConfiguration(_) =>
                "Error configuring the VCPU local interrupt",
            &Error::MpTableSetup(_) =>
                "Error writing MP table to memory",
            &Error::ZeroPageSetup =>
                "Error writing the zero page of guest memory",
            &Error::ZeroPagePastRamEnd =>
                "The zero page extends past the end of guest_mem",
            &Error::E820Configuration => "Invalid e820 setup params",
        }
    }
}

impl Display for Error {
    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
        write!(f, "X86 Arch Error: {}", Error::description(self))
    }
}

pub type Result<T> = result::Result<T, Error>;

const BOOT_STACK_POINTER: u64 = 0x8000;
const MEM_32BIT_GAP_SIZE: u64 = (768 << 20);
const FIRST_ADDR_PAST_32BITS: u64 = (1 << 32);
const KERNEL_64BIT_ENTRY_OFFSET: u64 = 0x200;
const ZERO_PAGE_OFFSET: u64 = 0x7000;

const KERNEL_START_OFFSET: u64 = 0x200000;
const CMDLINE_OFFSET: u64 = 0x20000;
const CMDLINE_MAX_SIZE: u64 = KERNEL_START_OFFSET - CMDLINE_OFFSET;

/// Loads the kernel from an open file.
///
/// # Arguments
///
/// * `mem` - The memory to be used by the guest.
/// * `kernel_image` - the File object for the specified kernel.
pub fn load_kernel(mem: &GuestMemory, mut kernel_image: File) -> Result<()> {
    kernel_loader::load_kernel(mem, GuestAddress(KERNEL_START_OFFSET), &mut kernel_image)
        .map_err(|e| Error::LoadKernel(e))?;
    Ok(())
}

/// Configures the system memory space should be called once per vm before
/// starting vcpu threads.
///
/// # Arguments
///
/// * `mem` - The memory to be used by the guest.
/// * `vcpu_count` - Number of virtual CPUs the guest will have.
/// * `cmdline` - the kernel commandline
pub fn setup_system_memory(mem: &GuestMemory, vcpu_count: u32, cmdline: &CStr) -> Result<()> {
    kernel_loader::load_cmdline(mem, GuestAddress(CMDLINE_OFFSET), cmdline)
        .map_err(|e| Error::LoadCmdline(e))?;
    configure_system(mem, GuestAddress(KERNEL_START_OFFSET), GuestAddress(CMDLINE_OFFSET),
                     cmdline.to_bytes().len() + 1, vcpu_count as u8)
        .map_err(|_| Error::ConfigureSystem)?;
    Ok(())
}

/// Creates a new VM object and initializes architecture specific devices
///
/// # Arguments
///
/// * `kvm` - The opened /dev/kvm object.
/// * `mem` - The memory to be used by the guest.
pub fn create_vm(kvm: &Kvm, mem: GuestMemory) -> result::Result<Vm, sys_util::Error> {
    let vm = Vm::new(&kvm, mem)?;
    let tss_addr = GuestAddress(0xfffbd000);
    vm.set_tss_addr(tss_addr).expect("set tss addr failed");
    vm.create_pit().expect("create pit failed");
    vm.create_irq_chip()?;
    Ok(vm)
}

/// This creates a GuestMemory object for this VM
///
/// * `mem_size` - Desired physical memory size for this VM
pub fn setup_memory(mem_size: usize) -> result::Result<sys_util::GuestMemory, sys_util::GuestMemoryError> {
    let arch_mem_regions = arch_memory_regions(mem_size as u64);
    GuestMemory::new(&arch_mem_regions)
}

/// This returns the first page frame number for use by the balloon driver.
pub fn get_base_dev_pfn(mem_size: u64) -> u64 {
    // Put device memory at nearest 2MB boundary after physical memory
    const MB: u64 = 1024 * 1024;
    let mem_size_round_2mb = (mem_size + 2*MB - 1) / (2*MB) * (2*MB);
    mem_size_round_2mb / sys_util::pagesize() as u64
}

/// This returns a base part of the kernel command for this architecture
pub fn get_base_linux_cmdline() -> kernel_cmdline::Cmdline {
    let mut cmdline = kernel_cmdline::Cmdline::new(CMDLINE_MAX_SIZE as usize);
    cmdline.insert_str("console=ttyS0 noacpi reboot=k panic=1 pci=off").
        unwrap();
    cmdline
}

/// This creates and returns a device_manager object for this vm.
///
/// # Arguments
///
/// * `vm` - the vm object
/// * `mem` - A copy of the GuestMemory object for this VM.
pub fn get_device_manager(vm: &mut Vm, mem: GuestMemory) -> device_manager::DeviceManager {
    const MMIO_BASE: u64 = 0xd0000000;
    const MMIO_LEN: u64 = 0x1000;
    const IRQ_BASE: u32 = 5;

    device_manager::DeviceManager::new(vm, mem, MMIO_LEN, MMIO_BASE, IRQ_BASE)
}

/// Sets up the IO bus for this platform
///
/// # Arguments
///
/// * - `vm` the vm object
/// * - `exit_evt` - the event fd object which should receive exit events
pub fn setup_io_bus(vm: &mut Vm, exit_evt: EventFd)
                    -> Result<(devices::Bus, Arc<Mutex<devices::Serial>>)> {
    struct NoDevice;
    impl devices::BusDevice for NoDevice {}

    let mut io_bus = devices::Bus::new();

    let com_evt_1_3 = EventFd::new().map_err(Error::CreateEventFd)?;
    let com_evt_2_4 = EventFd::new().map_err(Error::CreateEventFd)?;
    let stdio_serial =
        Arc::new(Mutex::new(devices::Serial::new_out(com_evt_1_3
                                                         .try_clone()
                                                         .map_err(Error::CloneEventFd)?,
                                                     Box::new(stdout()))));
    let nul_device = Arc::new(Mutex::new(NoDevice));
    io_bus.insert(stdio_serial.clone(), 0x3f8, 0x8).unwrap();
    io_bus
        .insert(Arc::new(Mutex::new(devices::Serial::new_sink(com_evt_2_4
                                                                  .try_clone()
                                                                  .map_err(Error::CloneEventFd)?))),
                0x2f8,
                0x8)
        .unwrap();
    io_bus
        .insert(Arc::new(Mutex::new(devices::Serial::new_sink(com_evt_1_3
                                                                  .try_clone()
                                                                  .map_err(Error::CloneEventFd)?))),
                0x3e8,
                0x8)
        .unwrap();
    io_bus
        .insert(Arc::new(Mutex::new(devices::Serial::new_sink(com_evt_2_4
                                                                  .try_clone()
                                                                  .map_err(Error::CloneEventFd)?))),
                0x2e8,
                0x8)
        .unwrap();
    io_bus
        .insert(Arc::new(Mutex::new(devices::Cmos::new())), 0x70, 0x2)
        .unwrap();
    io_bus
        .insert(Arc::new(Mutex::new(devices::I8042Device::new(exit_evt
                                                                  .try_clone()
                                                                  .map_err(Error::CloneEventFd)?))),
                0x061,
                0x4)
        .unwrap();
    io_bus.insert(nul_device.clone(), 0x040, 0x8).unwrap(); // ignore pit
    io_bus.insert(nul_device.clone(), 0x0ed, 0x1).unwrap(); // most likely this one does nothing
    io_bus.insert(nul_device.clone(), 0x0f0, 0x2).unwrap(); // ignore fpu
    io_bus.insert(nul_device.clone(), 0xcf8, 0x8).unwrap(); // ignore pci

    vm.register_irqfd(&com_evt_1_3, 4)
        .map_err(Error::RegisterIrqfd)?;
    vm.register_irqfd(&com_evt_2_4, 3)
        .map_err(Error::RegisterIrqfd)?;

    Ok((io_bus, stdio_serial))
}

/// Returns a Vec of the valid memory addresses.
/// These should be used to configure the GuestMemory structure for the platfrom.
/// For x86_64 all addresses are valid from the start of the kenel except a
/// carve out at the end of 32bit address space.
fn arch_memory_regions(size: u64) -> Vec<(GuestAddress, u64)> {
    let mem_end = GuestAddress(size);
    let first_addr_past_32bits = GuestAddress(FIRST_ADDR_PAST_32BITS);
    let end_32bit_gap_start = GuestAddress(FIRST_ADDR_PAST_32BITS - MEM_32BIT_GAP_SIZE);

    let mut regions = Vec::new();
    if mem_end < end_32bit_gap_start {
        regions.push((GuestAddress(0), size));
    } else {
        regions.push((GuestAddress(0), end_32bit_gap_start.offset()));
        if mem_end > first_addr_past_32bits {
            regions.push((first_addr_past_32bits, mem_end.offset_from(first_addr_past_32bits)));
        }
    }

    regions
}

/// Configures the vcpu and should be called once per vcpu from the vcpu's thread.
///
/// # Arguments
///
/// * `guest_mem` - The memory to be used by the guest.
/// * `kernel_load_offset` - Offset from `guest_mem` at which the kernel starts.
/// * `kvm` - The /dev/kvm object that created vcpu.
/// * `vcpu` - The VCPU object to configure.
/// * `cpu_id` - The id of the given `vcpu`.
/// * `num_cpus` - Number of virtual CPUs the guest will have.
pub fn configure_vcpu(guest_mem: &GuestMemory,
                      kvm: &kvm::Kvm,
                      vcpu: &kvm::Vcpu,
                      cpu_id: u64,
                      num_cpus: u64)
                      -> Result<()> {
    let kernel_load_addr = GuestAddress(KERNEL_START_OFFSET);
    cpuid::setup_cpuid(kvm, vcpu, cpu_id, num_cpus).map_err(Error::CpuSetup)?;
    regs::setup_msrs(vcpu).map_err(Error::RegisterConfiguration)?;
    let kernel_end = guest_mem.checked_offset(kernel_load_addr, KERNEL_64BIT_ENTRY_OFFSET)
        .ok_or(Error::KernelOffsetPastEnd)?;
    regs::setup_regs(vcpu,
                     (kernel_end).offset() as u64,
                     BOOT_STACK_POINTER as u64,
                     ZERO_PAGE_OFFSET as u64).map_err(Error::RegisterConfiguration)?;
    regs::setup_fpu(vcpu).map_err(Error::FpuRegisterConfiguration)?;
    regs::setup_sregs(guest_mem, vcpu).map_err(Error::SegmentRegisterConfiguration)?;
    interrupts::set_lint(vcpu).map_err(Error::LocalIntConfiguration)?;
    Ok(())
}

fn configure_system(guest_mem: &GuestMemory,
                    kernel_addr: GuestAddress,
                    cmdline_addr: GuestAddress,
                    cmdline_size: usize,
                    num_cpus: u8)
                    -> Result<()> {
    const EBDA_START: u64 = 0x0009fc00;
    const KERNEL_BOOT_FLAG_MAGIC: u16 = 0xaa55;
    const KERNEL_HDR_MAGIC: u32 = 0x53726448;
    const KERNEL_LOADER_OTHER: u8 = 0xff;
    const KERNEL_MIN_ALIGNMENT_BYTES: u32 = 0x1000000; // Must be non-zero.
    let first_addr_past_32bits = GuestAddress(FIRST_ADDR_PAST_32BITS);
    let end_32bit_gap_start = GuestAddress(FIRST_ADDR_PAST_32BITS - MEM_32BIT_GAP_SIZE);

    // Note that this puts the mptable at 0x0 in guest physical memory.
    mptable::setup_mptable(guest_mem, num_cpus).map_err(Error::MpTableSetup)?;

    let mut params: boot_params = Default::default();

    params.hdr.type_of_loader = KERNEL_LOADER_OTHER;
    params.hdr.boot_flag = KERNEL_BOOT_FLAG_MAGIC;
    params.hdr.header = KERNEL_HDR_MAGIC;
    params.hdr.cmd_line_ptr = cmdline_addr.offset() as u32;
    params.hdr.cmdline_size = cmdline_size as u32;
    params.hdr.kernel_alignment = KERNEL_MIN_ALIGNMENT_BYTES;

    add_e820_entry(&mut params, 0, EBDA_START, E820_RAM)?;

    let mem_end = guest_mem.end_addr();
    if mem_end < end_32bit_gap_start {
        add_e820_entry(&mut params,
                       kernel_addr.offset() as u64,
                       mem_end.offset_from(kernel_addr) as u64,
                       E820_RAM)?;
    } else {
        add_e820_entry(&mut params,
                       kernel_addr.offset() as u64,
                       end_32bit_gap_start.offset_from(kernel_addr) as u64,
                       E820_RAM)?;
        if mem_end > first_addr_past_32bits {
            add_e820_entry(&mut params,
                           first_addr_past_32bits.offset() as u64,
                           mem_end.offset_from(first_addr_past_32bits) as u64,
                           E820_RAM)?;
        }
    }

    let zero_page_addr = GuestAddress(ZERO_PAGE_OFFSET);
    guest_mem.checked_offset(zero_page_addr, mem::size_of::<boot_params>() as u64)
        .ok_or(Error::ZeroPagePastRamEnd)?;
    guest_mem.write_obj_at_addr(params, zero_page_addr)
        .map_err(|_| Error::ZeroPageSetup)?;

    Ok(())
}

/// Add an e820 region to the e820 map.
/// Returns Ok(()) if successful, or an error if there is no space left in the map.
fn add_e820_entry(params: &mut boot_params, addr: u64, size: u64, mem_type: u32) -> Result<()> {
    if params.e820_entries >= params.e820_map.len() as u8 {
        return Err(Error::E820Configuration);
    }

    params.e820_map[params.e820_entries as usize].addr = addr;
    params.e820_map[params.e820_entries as usize].size = size;
    params.e820_map[params.e820_entries as usize].type_ = mem_type;
    params.e820_entries += 1;

    Ok(())
}

#[cfg(test)]
mod tests {
    use super::*;

    #[test]
    fn regions_lt_4gb() {
        let regions = arch_memory_regions(1u64 << 29);
        assert_eq!(1, regions.len());
        assert_eq!(GuestAddress(0), regions[0].0);
        assert_eq!(1u64 << 29, regions[0].1);
    }

    #[test]
    fn regions_gt_4gb() {
        let regions = arch_memory_regions((1u64 << 32) + 0x8000);
        assert_eq!(2, regions.len());
        assert_eq!(GuestAddress(0), regions[0].0);
        assert_eq!(GuestAddress(1u64 << 32), regions[1].0);
    }
}