105 lines
2.9 KiB
Go
105 lines
2.9 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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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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"gvisor.googlesource.com/gvisor/pkg/abi/linux"
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"gvisor.googlesource.com/gvisor/pkg/sentry/platform/ring0/pagetables"
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)
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//go:linkname entersyscall runtime.entersyscall
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func entersyscall()
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//go:linkname exitsyscall runtime.exitsyscall
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func exitsyscall()
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// TranslateToVirtual implements pagetables.Translater.TranslateToPhysical.
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func (m *machine) TranslateToPhysical(ptes *pagetables.PTEs) uintptr {
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// The length doesn't matter because all these translations require
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// only a single page, which is guaranteed to be satisfied.
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physical, _, ok := TranslateToPhysical(uintptr(unsafe.Pointer(ptes)))
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if !ok {
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panic("unable to translate pagetables.Node to physical address")
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}
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return physical
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}
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// mapRunData maps the vCPU run data.
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func mapRunData(fd int) (*runData, error) {
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r, _, errno := syscall.RawSyscall6(
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syscall.SYS_MMAP,
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0,
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uintptr(runDataSize),
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syscall.PROT_READ|syscall.PROT_WRITE,
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syscall.MAP_SHARED,
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uintptr(fd),
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0)
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if errno != 0 {
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return nil, fmt.Errorf("error mapping runData: %v", errno)
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}
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return (*runData)(unsafe.Pointer(r)), nil
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}
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// unmapRunData unmaps the vCPU run data.
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func unmapRunData(r *runData) error {
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if _, _, errno := syscall.RawSyscall(
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syscall.SYS_MUNMAP,
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uintptr(unsafe.Pointer(r)),
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uintptr(runDataSize),
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0); errno != 0 {
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return fmt.Errorf("error unmapping runData: %v", errno)
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}
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return nil
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}
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// notify notifies that the vCPU has transitioned modes.
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//
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// This may be called by a signal handler and therefore throws on error.
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//
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//go:nosplit
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func (c *vCPU) notify() {
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_, _, errno := syscall.RawSyscall6(
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syscall.SYS_FUTEX,
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uintptr(unsafe.Pointer(&c.state)),
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linux.FUTEX_WAKE,
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^uintptr(0), // Number of waiters.
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0, 0, 0)
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if errno != 0 {
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throw("futex wake error")
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}
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}
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// waitUntilNot waits for the vCPU to transition modes.
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//
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// The state should have been previously set to vCPUWaiter after performing an
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// appropriate action to cause a transition (e.g. interrupt injection).
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//
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// This panics on error.
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func (c *vCPU) waitUntilNot(state uint32) {
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_, _, errno := syscall.Syscall6(
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syscall.SYS_FUTEX,
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uintptr(unsafe.Pointer(&c.state)),
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linux.FUTEX_WAIT,
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uintptr(state),
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0, 0, 0)
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if errno != 0 && errno != syscall.EINTR && errno != syscall.EAGAIN {
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panic("futex wait error")
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}
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}
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