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// 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.
use std::arch::x86_64::{__cpuid, __cpuid_count};
use std::fmt::{self, Display};
use std::result;
use kvm;
use sys_util;
#[derive(Debug, PartialEq)]
pub enum Error {
GetSupportedCpusFailed(sys_util::Error),
SetSupportedCpusFailed(sys_util::Error),
}
pub type Result<T> = result::Result<T, Error>;
impl std::error::Error for Error {}
impl Display for Error {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
use self::Error::*;
match self {
GetSupportedCpusFailed(e) => write!(f, "GetSupportedCpus ioctl failed: {}", e),
SetSupportedCpusFailed(e) => write!(f, "SetSupportedCpus ioctl failed: {}", e),
}
}
}
// CPUID bits in ebx, ecx, and edx.
const EBX_CLFLUSH_CACHELINE: u32 = 8; // Flush a cache line size.
const EBX_CLFLUSH_SIZE_SHIFT: u32 = 8; // Bytes flushed when executing CLFLUSH.
const EBX_CPU_COUNT_SHIFT: u32 = 16; // Index of this CPU.
const EBX_CPUID_SHIFT: u32 = 24; // Index of this CPU.
const ECX_EPB_SHIFT: u32 = 3; // "Energy Performance Bias" bit.
const ECX_TSC_DEADLINE_TIMER_SHIFT: u32 = 24; // TSC deadline mode of APIC timer
const ECX_HYPERVISOR_SHIFT: u32 = 31; // Flag to be set when the cpu is running on a hypervisor.
const EDX_HTT_SHIFT: u32 = 28; // Hyper Threading Enabled.
fn filter_cpuid(
cpu_id: u64,
cpu_count: u64,
kvm_cpuid: &mut kvm::CpuId,
kvm: &kvm::Kvm,
) -> Result<()> {
let entries = kvm_cpuid.mut_entries_slice();
for entry in entries {
match entry.function {
1 => {
// X86 hypervisor feature
if entry.index == 0 {
entry.ecx |= 1 << ECX_HYPERVISOR_SHIFT;
}
if kvm.check_extension(kvm::Cap::TscDeadlineTimer) {
entry.ecx |= 1 << ECX_TSC_DEADLINE_TIMER_SHIFT;
}
entry.ebx = (cpu_id << EBX_CPUID_SHIFT) as u32
| (EBX_CLFLUSH_CACHELINE << EBX_CLFLUSH_SIZE_SHIFT);
if cpu_count > 1 {
entry.ebx |= (cpu_count as u32) << EBX_CPU_COUNT_SHIFT;
entry.edx |= 1 << EDX_HTT_SHIFT;
}
}
2 | 0x80000005 | 0x80000006 => unsafe {
let result = __cpuid(entry.function);
entry.eax = result.eax;
entry.ebx = result.ebx;
entry.ecx = result.ecx;
entry.edx = result.edx;
},
4 => {
unsafe {
let result = __cpuid_count(entry.function, entry.index);
entry.eax = result.eax;
entry.ebx = result.ebx;
entry.ecx = result.ecx;
entry.edx = result.edx;
}
entry.eax &= !0xFC000000;
}
6 => {
// Clear X86 EPB feature. No frequency selection in the hypervisor.
entry.ecx &= !(1 << ECX_EPB_SHIFT);
}
_ => (),
}
}
Ok(())
}
/// Sets up the cpuid entries for the given vcpu. Can fail if there are too many CPUs specified or
/// if an ioctl returns an error.
///
/// # Arguments
///
/// * `kvm` - `Kvm` structure created with KVM_CREATE_VM ioctl.
/// * `vcpu` - `Vcpu` for setting CPU ID.
/// * `cpu_id` - The index of the CPU `vcpu` is for.
/// * `nrcpus` - The number of vcpus being used by this VM.
pub fn setup_cpuid(kvm: &kvm::Kvm, vcpu: &kvm::Vcpu, cpu_id: u64, nrcpus: u64) -> Result<()> {
let mut kvm_cpuid = kvm
.get_supported_cpuid()
.map_err(Error::GetSupportedCpusFailed)?;
filter_cpuid(cpu_id, nrcpus, &mut kvm_cpuid, kvm)?;
vcpu.set_cpuid2(&kvm_cpuid)
.map_err(Error::SetSupportedCpusFailed)
}
/// get host cpu max physical address bits
pub fn phy_max_address_bits() -> u32 {
let mut phys_bits: u32 = 36;
let highest_ext_function = unsafe { __cpuid(0x80000000) };
if highest_ext_function.eax >= 0x80000008 {
let addr_size = unsafe { __cpuid(0x80000008) };
phys_bits = addr_size.eax & 0xff;
}
phys_bits
}
#[cfg(test)]
mod tests {
use super::*;
#[test]
fn feature_and_vendor_name() {
let mut cpuid = kvm::CpuId::new(2);
let kvm = kvm::Kvm::new().unwrap();
let entries = cpuid.mut_entries_slice();
entries[0].function = 0;
entries[1].function = 1;
entries[1].ecx = 0x10;
entries[1].edx = 0;
assert_eq!(Ok(()), filter_cpuid(1, 2, &mut cpuid, &kvm));
let entries = cpuid.mut_entries_slice();
assert_eq!(entries[0].function, 0);
assert_eq!(1, (entries[1].ebx >> EBX_CPUID_SHIFT) & 0x000000ff);
assert_eq!(2, (entries[1].ebx >> EBX_CPU_COUNT_SHIFT) & 0x000000ff);
assert_eq!(
EBX_CLFLUSH_CACHELINE,
(entries[1].ebx >> EBX_CLFLUSH_SIZE_SHIFT) & 0x000000ff
);
assert_ne!(0, entries[1].ecx & (1 << ECX_HYPERVISOR_SHIFT));
assert_ne!(0, entries[1].edx & (1 << EDX_HTT_SHIFT));
}
}
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