157 lines
4.2 KiB
Go
157 lines
4.2 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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"gvisor.googlesource.com/gvisor/pkg/abi/linux"
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"gvisor.googlesource.com/gvisor/pkg/sentry/time"
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)
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// setMemoryRegion initializes a region.
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//
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// This may be called from bluepillHandler, and therefore returns an errno
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// directly (instead of wrapping in an error) to avoid allocations.
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//
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//go:nosplit
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func (m *machine) setMemoryRegion(slot int, physical, length, virtual uintptr) syscall.Errno {
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userRegion := userMemoryRegion{
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slot: uint32(slot),
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flags: 0,
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guestPhysAddr: uint64(physical),
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memorySize: uint64(length),
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userspaceAddr: uint64(virtual),
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}
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// Set the region.
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_, _, errno := syscall.RawSyscall(
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syscall.SYS_IOCTL,
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uintptr(m.fd),
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_KVM_SET_USER_MEMORY_REGION,
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uintptr(unsafe.Pointer(&userRegion)))
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return errno
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}
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// loadSegments copies the current segments.
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//
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// This may be called from within the signal context and throws on error.
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//
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//go:nosplit
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func (c *vCPU) loadSegments() {
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if _, _, errno := syscall.RawSyscall(
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syscall.SYS_ARCH_PRCTL,
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linux.ARCH_GET_FS,
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uintptr(unsafe.Pointer(&c.CPU.Registers().Fs_base)),
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0); errno != 0 {
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throw("getting FS segment")
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}
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if _, _, errno := syscall.RawSyscall(
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syscall.SYS_ARCH_PRCTL,
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linux.ARCH_GET_GS,
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uintptr(unsafe.Pointer(&c.CPU.Registers().Gs_base)),
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0); errno != 0 {
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throw("getting GS segment")
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}
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}
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// setUserRegisters sets user registers in the vCPU.
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func (c *vCPU) setUserRegisters(uregs *userRegs) error {
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if _, _, errno := syscall.RawSyscall(
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syscall.SYS_IOCTL,
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uintptr(c.fd),
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_KVM_SET_REGS,
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uintptr(unsafe.Pointer(uregs))); errno != 0 {
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return fmt.Errorf("error setting user registers: %v", errno)
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}
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return nil
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}
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// setSystemRegisters sets system registers.
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func (c *vCPU) setSystemRegisters(sregs *systemRegs) error {
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if _, _, errno := syscall.RawSyscall(
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syscall.SYS_IOCTL,
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uintptr(c.fd),
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_KVM_SET_SREGS,
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uintptr(unsafe.Pointer(sregs))); errno != 0 {
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return fmt.Errorf("error setting system registers: %v", errno)
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}
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return nil
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}
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// setCPUID sets the CPUID to be used by the guest.
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func (c *vCPU) setCPUID() error {
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if _, _, errno := syscall.RawSyscall(
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syscall.SYS_IOCTL,
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uintptr(c.fd),
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_KVM_SET_CPUID2,
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uintptr(unsafe.Pointer(&cpuidSupported))); errno != 0 {
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return fmt.Errorf("error setting CPUID: %v", errno)
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}
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return nil
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}
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// setSystemTime sets the TSC for the vCPU.
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//
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// FIXME: This introduces a slight TSC offset between host and
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// guest, which may vary per vCPU.
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func (c *vCPU) setSystemTime() error {
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const _MSR_IA32_TSC = 0x00000010
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registers := modelControlRegisters{
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nmsrs: 1,
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}
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registers.entries[0] = modelControlRegister{
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index: _MSR_IA32_TSC,
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data: uint64(time.Rdtsc()),
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}
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if _, _, errno := syscall.RawSyscall(
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syscall.SYS_IOCTL,
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uintptr(c.fd),
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_KVM_SET_MSRS,
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uintptr(unsafe.Pointer(®isters))); errno != 0 {
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return fmt.Errorf("error setting system time: %v", errno)
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}
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return nil
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}
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// setSignalMask sets the vCPU signal mask.
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//
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// This must be called prior to running the vCPU.
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func (c *vCPU) setSignalMask() error {
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// The layout of this structure implies that it will not necessarily be
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// the same layout chosen by the Go compiler. It gets fudged here.
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var data struct {
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length uint32
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mask1 uint32
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mask2 uint32
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_ uint32
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}
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data.length = 8 // Fixed sigset size.
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data.mask1 = ^uint32(bounceSignalMask & 0xffffffff)
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data.mask2 = ^uint32(bounceSignalMask >> 32)
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if _, _, errno := syscall.RawSyscall(
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syscall.SYS_IOCTL,
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uintptr(c.fd),
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_KVM_SET_SIGNAL_MASK,
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uintptr(unsafe.Pointer(&data))); errno != 0 {
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return fmt.Errorf("error setting signal mask: %v", errno)
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}
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return nil
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}
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