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// Copyright 2018 The gVisor Authors.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
//go:build amd64
// +build amd64
package kvm
import (
"fmt"
"unsafe"
"golang.org/x/sys/unix"
)
var (
runDataSize int
hasGuestPCID bool
cpuidSupported = cpuidEntries{nr: _KVM_NR_CPUID_ENTRIES}
)
func updateSystemValues(fd int) error {
// Extract the mmap size.
sz, _, errno := unix.RawSyscall(unix.SYS_IOCTL, uintptr(fd), _KVM_GET_VCPU_MMAP_SIZE, 0)
if errno != 0 {
return fmt.Errorf("getting VCPU mmap size: %v", errno)
}
// Save the data.
runDataSize = int(sz)
// Must do the dance to figure out the number of entries.
_, _, errno = unix.RawSyscall(
unix.SYS_IOCTL,
uintptr(fd),
_KVM_GET_SUPPORTED_CPUID,
uintptr(unsafe.Pointer(&cpuidSupported)))
if errno != 0 && errno != unix.ENOMEM {
// Some other error occurred.
return fmt.Errorf("getting supported CPUID: %v", errno)
}
// The number should now be correct.
_, _, errno = unix.RawSyscall(
unix.SYS_IOCTL,
uintptr(fd),
_KVM_GET_SUPPORTED_CPUID,
uintptr(unsafe.Pointer(&cpuidSupported)))
if errno != 0 {
// Didn't work with the right number.
return fmt.Errorf("getting supported CPUID (2nd attempt): %v", errno)
}
// Success.
return nil
}
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