github.com/SagerNet/gvisor@v0.0.0-20210707092255-7731c139d75c/pkg/sentry/platform/kvm/kvm_arm64_unsafe.go (about)

     1  // Copyright 2019 The gVisor Authors.
     2  //
     3  // Licensed under the Apache License, Version 2.0 (the "License");
     4  // you may not use this file except in compliance with the License.
     5  // You may obtain a copy of the License at
     6  //
     7  //     http://www.apache.org/licenses/LICENSE-2.0
     8  //
     9  // Unless required by applicable law or agreed to in writing, software
    10  // distributed under the License is distributed on an "AS IS" BASIS,
    11  // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    12  // See the License for the specific language governing permissions and
    13  // limitations under the License.
    14  
    15  // +build arm64
    16  
    17  package kvm
    18  
    19  import (
    20  	"fmt"
    21  
    22  	"golang.org/x/sys/unix"
    23  )
    24  
    25  var (
    26  	runDataSize  int
    27  	hasGuestPCID bool
    28  )
    29  
    30  func updateSystemValues(fd int) error {
    31  	// Extract the mmap size.
    32  	sz, _, errno := unix.RawSyscall(unix.SYS_IOCTL, uintptr(fd), _KVM_GET_VCPU_MMAP_SIZE, 0)
    33  	if errno != 0 {
    34  		return fmt.Errorf("getting VCPU mmap size: %v", errno)
    35  	}
    36  	// Save the data.
    37  	runDataSize = int(sz)
    38  	hasGuestPCID = true
    39  
    40  	// Success.
    41  	return nil
    42  }