1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
|
// 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.
// +build go1.12
// +build !go1.14
// Check go:linkname function signatures when updating Go version.
package kvm
import (
"fmt"
"sync/atomic"
"syscall"
"unsafe"
"gvisor.dev/gvisor/pkg/abi/linux"
)
//go:linkname entersyscall runtime.entersyscall
func entersyscall()
//go:linkname exitsyscall runtime.exitsyscall
func exitsyscall()
// mapRunData maps the vCPU run data.
func mapRunData(fd int) (*runData, error) {
r, _, errno := syscall.RawSyscall6(
syscall.SYS_MMAP,
0,
uintptr(runDataSize),
syscall.PROT_READ|syscall.PROT_WRITE,
syscall.MAP_SHARED,
uintptr(fd),
0)
if errno != 0 {
return nil, fmt.Errorf("error mapping runData: %v", errno)
}
return (*runData)(unsafe.Pointer(r)), nil
}
// unmapRunData unmaps the vCPU run data.
func unmapRunData(r *runData) error {
if _, _, errno := syscall.RawSyscall(
syscall.SYS_MUNMAP,
uintptr(unsafe.Pointer(r)),
uintptr(runDataSize),
0); errno != 0 {
return fmt.Errorf("error unmapping runData: %v", errno)
}
return nil
}
// setUserRegisters sets user registers in the vCPU.
func (c *vCPU) setUserRegisters(uregs *userRegs) error {
if _, _, errno := syscall.RawSyscall(
syscall.SYS_IOCTL,
uintptr(c.fd),
_KVM_SET_REGS,
uintptr(unsafe.Pointer(uregs))); errno != 0 {
return fmt.Errorf("error setting user registers: %v", errno)
}
return nil
}
// getUserRegisters reloads user registers in the vCPU.
//
// This is safe to call from a nosplit context.
//
//go:nosplit
func (c *vCPU) getUserRegisters(uregs *userRegs) syscall.Errno {
if _, _, errno := syscall.RawSyscall(
syscall.SYS_IOCTL,
uintptr(c.fd),
_KVM_GET_REGS,
uintptr(unsafe.Pointer(uregs))); errno != 0 {
return errno
}
return 0
}
// setSystemRegisters sets system registers.
func (c *vCPU) setSystemRegisters(sregs *systemRegs) error {
if _, _, errno := syscall.RawSyscall(
syscall.SYS_IOCTL,
uintptr(c.fd),
_KVM_SET_SREGS,
uintptr(unsafe.Pointer(sregs))); errno != 0 {
return fmt.Errorf("error setting system registers: %v", errno)
}
return nil
}
// atomicAddressSpace is an atomic address space pointer.
type atomicAddressSpace struct {
pointer unsafe.Pointer
}
// set sets the address space value.
//
//go:nosplit
func (a *atomicAddressSpace) set(as *addressSpace) {
atomic.StorePointer(&a.pointer, unsafe.Pointer(as))
}
// get gets the address space value.
//
// Note that this should be considered best-effort, and may have changed by the
// time this function returns.
//
//go:nosplit
func (a *atomicAddressSpace) get() *addressSpace {
return (*addressSpace)(atomic.LoadPointer(&a.pointer))
}
// notify notifies that the vCPU has transitioned modes.
//
// This may be called by a signal handler and therefore throws on error.
//
//go:nosplit
func (c *vCPU) notify() {
_, _, errno := syscall.RawSyscall6(
syscall.SYS_FUTEX,
uintptr(unsafe.Pointer(&c.state)),
linux.FUTEX_WAKE|linux.FUTEX_PRIVATE_FLAG,
^uintptr(0), // Number of waiters.
0, 0, 0)
if errno != 0 {
throw("futex wake error")
}
}
// waitUntilNot waits for the vCPU to transition modes.
//
// The state should have been previously set to vCPUWaiter after performing an
// appropriate action to cause a transition (e.g. interrupt injection).
//
// This panics on error.
func (c *vCPU) waitUntilNot(state uint32) {
_, _, errno := syscall.Syscall6(
syscall.SYS_FUTEX,
uintptr(unsafe.Pointer(&c.state)),
linux.FUTEX_WAIT|linux.FUTEX_PRIVATE_FLAG,
uintptr(state),
0, 0, 0)
if errno != 0 && errno != syscall.EINTR && errno != syscall.EAGAIN {
panic("futex wait error")
}
}
|
