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
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
|
// Copyright 2019 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.
//go:build arm64
// +build arm64
package kvm
import (
"runtime"
"sync/atomic"
"golang.org/x/sys/unix"
"gvisor.dev/gvisor/pkg/abi/linux"
"gvisor.dev/gvisor/pkg/hostarch"
"gvisor.dev/gvisor/pkg/ring0"
"gvisor.dev/gvisor/pkg/ring0/pagetables"
"gvisor.dev/gvisor/pkg/sentry/arch/fpu"
"gvisor.dev/gvisor/pkg/sentry/platform"
)
type machineArchState struct {
//initialvCPUs is the machine vCPUs which has initialized but not used
initialvCPUs map[int]*vCPU
}
type vCPUArchState struct {
// PCIDs is the set of PCIDs for this vCPU.
//
// This starts above fixedKernelPCID.
PCIDs *pagetables.PCIDs
// floatingPointState is the floating point state buffer used in guest
// to host transitions. See usage in bluepill_arm64.go.
floatingPointState fpu.State
}
const (
// fixedKernelPCID is a fixed kernel PCID used for the kernel page
// tables. We must start allocating user PCIDs above this in order to
// avoid any conflict (see below).
fixedKernelPCID = 1
// poolPCIDs is the number of PCIDs to record in the database. As this
// grows, assignment can take longer, since it is a simple linear scan.
// Beyond a relatively small number, there are likely few perform
// benefits, since the TLB has likely long since lost any translations
// from more than a few PCIDs past.
poolPCIDs = 128
)
func (m *machine) mapUpperHalf(pageTable *pagetables.PageTables) {
applyPhysicalRegions(func(pr physicalRegion) bool {
pageTable.Map(
hostarch.Addr(ring0.KernelStartAddress|pr.virtual),
pr.length,
pagetables.MapOpts{AccessType: hostarch.AnyAccess, Global: true},
pr.physical)
return true // Keep iterating.
})
}
// Get all read-only physicalRegions.
func rdonlyRegionsForSetMem() (phyRegions []physicalRegion) {
var rdonlyRegions []region
applyVirtualRegions(func(vr virtualRegion) {
if excludeVirtualRegion(vr) {
return
}
if !vr.accessType.Write && vr.accessType.Read {
rdonlyRegions = append(rdonlyRegions, vr.region)
}
// TODO(gvisor.dev/issue/2686): PROT_NONE should be specially treated.
// Workaround: treated as rdonly temporarily.
if !vr.accessType.Write && !vr.accessType.Read && !vr.accessType.Execute {
rdonlyRegions = append(rdonlyRegions, vr.region)
}
})
for _, r := range rdonlyRegions {
physical, _, ok := translateToPhysical(r.virtual)
if !ok {
continue
}
phyRegions = append(phyRegions, physicalRegion{
region: region{
virtual: r.virtual,
length: r.length,
},
physical: physical,
})
}
return phyRegions
}
// Get all available physicalRegions.
func availableRegionsForSetMem() (phyRegions []physicalRegion) {
var excludeRegions []region
applyVirtualRegions(func(vr virtualRegion) {
if !vr.accessType.Write {
excludeRegions = append(excludeRegions, vr.region)
}
})
phyRegions = computePhysicalRegions(excludeRegions)
return phyRegions
}
// nonCanonical generates a canonical address return.
//
//go:nosplit
func nonCanonical(addr uint64, signal int32, info *linux.SignalInfo) (hostarch.AccessType, error) {
*info = linux.SignalInfo{
Signo: signal,
Code: linux.SI_KERNEL,
}
info.SetAddr(addr) // Include address.
return hostarch.NoAccess, platform.ErrContextSignal
}
// isInstructionAbort returns true if it is an instruction abort.
//
//go:nosplit
func isInstructionAbort(code uint64) bool {
value := (code & _ESR_ELx_EC_MASK) >> _ESR_ELx_EC_SHIFT
return value == _ESR_ELx_EC_IABT_LOW
}
// isWriteFault returns whether it is a write fault.
//
//go:nosplit
func isWriteFault(code uint64) bool {
if isInstructionAbort(code) {
return false
}
return (code & _ESR_ELx_WNR) != 0
}
// fault generates an appropriate fault return.
//
//go:nosplit
func (c *vCPU) fault(signal int32, info *linux.SignalInfo) (hostarch.AccessType, error) {
bluepill(c) // Probably no-op, but may not be.
faultAddr := c.GetFaultAddr()
code, user := c.ErrorCode()
if !user {
// The last fault serviced by this CPU was not a user
// fault, so we can't reliably trust the faultAddr or
// the code provided here. We need to re-execute.
return hostarch.NoAccess, platform.ErrContextInterrupt
}
// Reset the pointed SignalInfo.
*info = linux.SignalInfo{Signo: signal}
info.SetAddr(uint64(faultAddr))
ret := code & _ESR_ELx_FSC
switch ret {
case _ESR_SEGV_MAPERR_L0, _ESR_SEGV_MAPERR_L1, _ESR_SEGV_MAPERR_L2, _ESR_SEGV_MAPERR_L3:
info.Code = 1 //SEGV_MAPERR
case _ESR_SEGV_ACCERR_L1, _ESR_SEGV_ACCERR_L2, _ESR_SEGV_ACCERR_L3, _ESR_SEGV_PEMERR_L1, _ESR_SEGV_PEMERR_L2, _ESR_SEGV_PEMERR_L3:
info.Code = 2 // SEGV_ACCERR.
default:
info.Code = 2
}
accessType := hostarch.AccessType{
Read: !isWriteFault(uint64(code)),
Write: isWriteFault(uint64(code)),
Execute: isInstructionAbort(uint64(code)),
}
return accessType, platform.ErrContextSignal
}
// getMaxVCPU get max vCPU number
func (m *machine) getMaxVCPU() {
rmaxVCPUs := runtime.NumCPU()
smaxVCPUs, _, errno := unix.RawSyscall(unix.SYS_IOCTL, uintptr(m.fd), _KVM_CHECK_EXTENSION, _KVM_CAP_MAX_VCPUS)
// compare the max vcpu number from runtime and syscall, use smaller one.
if errno != 0 {
m.maxVCPUs = rmaxVCPUs
} else {
if rmaxVCPUs < int(smaxVCPUs) {
m.maxVCPUs = rmaxVCPUs
} else {
m.maxVCPUs = int(smaxVCPUs)
}
}
}
// getNewVCPU() scan for an available vCPU from initialvCPUs
func (m *machine) getNewVCPU() *vCPU {
for CID, c := range m.initialvCPUs {
if atomic.CompareAndSwapUint32(&c.state, vCPUReady, vCPUUser) {
delete(m.initialvCPUs, CID)
return c
}
}
return nil
}
|
