78 lines
2.1 KiB
Go
78 lines
2.1 KiB
Go
// Copyright 2018 Google Inc.
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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// +build amd64
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package kvm
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import (
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"fmt"
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"syscall"
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"unsafe"
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)
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var (
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runDataSize int
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hasGuestPCID bool
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cpuidSupported = cpuidEntries{nr: _KVM_NR_CPUID_ENTRIES}
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)
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func updateSystemValues(fd int) error {
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// Extract the mmap size.
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sz, _, errno := syscall.RawSyscall(syscall.SYS_IOCTL, uintptr(fd), _KVM_GET_VCPU_MMAP_SIZE, 0)
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if errno != 0 {
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return fmt.Errorf("getting VCPU mmap size: %v", errno)
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}
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// Save the data.
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runDataSize = int(sz)
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// Must do the dance to figure out the number of entries.
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_, _, errno = syscall.RawSyscall(
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syscall.SYS_IOCTL,
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uintptr(fd),
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_KVM_GET_SUPPORTED_CPUID,
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uintptr(unsafe.Pointer(&cpuidSupported)))
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if errno != 0 && errno != syscall.ENOMEM {
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// Some other error occurred.
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return fmt.Errorf("getting supported CPUID: %v", errno)
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}
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// The number should now be correct.
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_, _, errno = syscall.RawSyscall(
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syscall.SYS_IOCTL,
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uintptr(fd),
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_KVM_GET_SUPPORTED_CPUID,
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uintptr(unsafe.Pointer(&cpuidSupported)))
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if errno != 0 {
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// Didn't work with the right number.
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return fmt.Errorf("getting supported CPUID (2nd attempt): %v", errno)
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}
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// Calculate whether guestPCID is supported.
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//
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// FIXME: These should go through the much more pleasant
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// cpuid package interfaces, once a way to accept raw kvm CPUID entries
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// is plumbed (or some rough equivalent).
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for i := 0; i < int(cpuidSupported.nr); i++ {
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entry := cpuidSupported.entries[i]
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if entry.function == 1 && entry.index == 0 && entry.ecx&(1<<17) != 0 {
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hasGuestPCID = true // Found matching PCID in guest feature set.
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}
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}
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// Success.
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return nil
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}
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