The Design and Implementation of the Anykernel and Rump Kernels

More documents

Recommendations

Info

78 since the representation might not be the same in the kernel and the hypercall library. Even different versions of NetBSD have different representations, for example due to increasing time_t from 32bit to 64bit. Therefore, to have a well-defined interface when running on a non-native host, the hypercall interface should only use data types which are the same regardless of ABI. For example, the C99 constant width type uint64_t is preferred over time_t. Since the hypercall executes in the same process as the rump kernel, byte order is not an issue, and the native one can be used. 3. A separate interface helps future investigation of running rump kernels on non-POSIX platforms, such as microkernels. This investigation, however, will require adjustments to the hypercall interface. While the need for adjustments is foreseeable, the exact forms of the adjustments are not, and that is the reason they are not already in place. The header file sys/rump/include/rump/rumpuser.h defines the hypercall interfaces. All hypercalls by convention begin with the string “rumpuser”. This prevents hypercall interface references in the rump kernel from falling under the jurisdiction of symbol renaming. We divide the hypercall interfaces into mandatory and optional ones. The routines that must be implemented by the rumpuser library are: • memory management: allocate aligned memory, free • thread management: create and join threads, TLS access • synchronization routines: mutex, read/write lock, condition variable. This class is illustrated in Figure 3.3. • exit: terminate the host container. In a POSIX environment depending on the parameters termination is done by calling either abort() or exit().
79 void rumpuser_mutex_init(struct rumpuser_mtx **); void rumpuser_mutex_init_kmutex(struct rumpuser_mtx **); void rumpuser_mutex_enter(struct rumpuser_mtx *); int rumpuser_mutex_tryenter(struct rumpuser_mtx *); void rumpuser_mutex_exit(struct rumpuser_mtx *); void rumpuser_mutex_destroy(struct rumpuser_mtx *); struct lwp *rumpuser_mutex_owner(struct rumpuser_mtx *); void rumpuser_rw_init(struct rumpuser_rw **); void rumpuser_rw_enter(struct rumpuser_rw *, int); int rumpuser_rw_tryenter(struct rumpuser_rw *, int); void rumpuser_rw_exit(struct rumpuser_rw *); void rumpuser_rw_destroy(struct rumpuser_rw *); int rumpuser_rw_held(struct rumpuser_rw *); int rumpuser_rw_rdheld(struct rumpuser_rw *); int rumpuser_rw_wrheld(struct rumpuser_rw *); void rumpuser_cv_init(struct rumpuser_cv **); void rumpuser_cv_destroy(struct rumpuser_cv *); void rumpuser_cv_wait(struct rumpuser_cv *, struct rumpuser_mtx *); int rumpuser_cv_timedwait(struct rumpuser_cv *, struct rumpuser_mtx *, int64_t, int64_t); void rumpuser_cv_signal(struct rumpuser_cv *); void rumpuser_cv_broadcast(struct rumpuser_cv *); int rumpuser_cv_has_waiters(struct rumpuser_cv *); Figure 3.3: Hypercall locking interfaces. These interfaces use opaque lock data types to map NetBSD kernel locking operations to hypervisor operations. Strictly speaking, the necessity of thread support and locking depends on the drivers being executed. We offer the following anecdote and discussion. At one point when working on rump kernel support, support for gdb in NetBSD was broken so that threaded programs could not be single-stepped (the problem has since been fixed). As a way to work around the problem, the variable RUMP_THREADS was created. If it is set to 0, the rump kernel silently ignores kernel thread creation requests. Despite the lack of threads, for example file system drivers still function, because they do not directly depend on worker threads. The ability to run without threads allowed attaching the broken debugger to rump kernels and single-stepping them.
Page 1:
Department of Computer Science and
Page 11 and 12:
9 Preface Meet the new boss Same as
Page 13:
11 Then there is my dear Xi, who, s
Page 16 and 17:
14 2.3.3 InterruptsandPreemption...
Page 18 and 19:
16 4.1.1 Implementation Effort ....
Page 20 and 21:
18 Appendix C Patches to the 5.99.4
Page 22 and 23:
20 ISA LGPL LRU LWP MD MI MMU NIC O
Page 25 and 26:
23 List of Figures 2.1 Rumpkernelhi
Page 27:
25 4.14 Time to execute 5M system c
Page 31 and 32: 29 1 Introduction In its classic ro
Page 33 and 34: 31 and application-level drivers. T
Page 35 and 36: 33 We define an anykernel to be an
Page 37 and 38: 35 Our implementation supports rump
Page 39 and 40: 37 The project was done in small in
Page 41 and 42: 39 2 The Anykernel and Rump Kernels
Page 43 and 44: 41 building on top of the entities
Page 45 and 46: 43 Drivers in a rump kernel remain
Page 47 and 48: 45 Figure 2.1: Rump k
Page 49 and 50: 47 in Section 3.2.3. Whenever discu
Page 51 and 52: 49 int rumpns_bpfopen(dev_t, int, i
Page 53 and 54: 51 Figure 2.4:
Page 55 and 56: 53 while the application logic stil
Page 57 and 58: 55 We must solve the lack of a rump
Page 59 and 60: 57 2.3.1 Kernel threads Up until no
Page 61 and 62: 59 void * pool_cache_get_paddr(pool
Page 63 and 64: 61 2.3.4 An Example We present an e
Page 65 and 66: 63 Figure 2.6: Prov
Page 67: 65 The straightforward use of exist
Page 70 and 71: 68 We identified three obstacles fo
Page 72 and 73: 70 for loadable kernel modules (dis
Page 74 and 75: 72 e.g. the routine for mapping a p
Page 76 and 77: 74 3.2.1 C Symbol Namespaces In the
Page 78 and 79: 76 the double underscore namespace
Page 82 and 83: 80 The following rumpuser interface
Page 84 and 85: 82 The entry point rump_schedule()
Page 86 and 87: 84 3.3.1 CPU Scheduling Recall from
Page 88 and 89: 86 The fastpath is taken in cases w
Page 90 and 91: 88 Releasing a CPU requires the fol
Page 92 and 93: 90 10 8 seconds 6 4 2 0 1CPU 2CPU n
Page 94 and 95: 92 Hardware interrupt handlers are
Page 96 and 97: 94 Due to the design choice that a
Page 98 and 99: 96 in. Therefore, we should critica
Page 100 and 101: 98 Pager window create+access time
Page 102 and 103: 100 A rump kernel can be configured
Page 104 and 105: 102 Since all pages managed by the
Page 106 and 107: 104 not in control of thread schedu
Page 108 and 109: 106 synchronization part of the alg
Page 110 and 111: 108 /* * Run a cross call to cycle
Page 112 and 113: 110 kernel needs to do is make sure
Page 114 and 115: 112 The kernel with uniprocessor lo
Page 116 and 117: 114 the header file while open() c
Page 118 and 119: 116 The same wrapper works both for
Page 120 and 121: 118 5. Some calling conventions (e.
Page 122 and 123: 120 int rump_pub_lwproc_rfork(int a
Page 124 and 125: 122 By convention, file system devi
Page 126 and 127: 124 ule directory tree from /stand
Page 128 and 129: 126 After these steps have been per
Page 130 and 131:
128 Host Dynamic Linker Using the h
Page 132 and 133:
130 for (i = 0; i < SYS_NSYSENT; i+
Page 134 and 135:
132 into a rump kernel and the driv
Page 136 and 137:
134 sys/arch/x86/include/cpu.h: #de
Page 138 and 139:
136 3.8.4 Rump Component Init Routi
Page 140 and 141:
138 RUMP_COMPONENT(RUMP_COMPONENT_N
Page 142 and 143:
140 We have three distinct cases we
Page 144 and 145:
142 # ifconfig tap0 create # ifconf
Page 146 and 147:
144 Unprivileged use of host’s ne
Page 148 and 149:
146 DOMAIN_DEFINE(sockindomain); co
Page 150 and 151:
148 issue another write before the
Page 152 and 153:
150 using an interface called USBDI
Page 154 and 155:
152 The kernel device configuration
Page 156 and 157:
154 # $NetBSD: UMASS.ioconf,v 1.4 2
Page 158 and 159:
156 USB Host Controller Hub0 (root)
Page 160 and 161:
158 Figure 3.30: File s
Page 162 and 163:
160 in-kernel mount: /dev/sd0e /m/u
Page 164 and 165:
162 structure being created by rump
Page 166 and 167:
164 3.12.1 Client-Kernel Locators B
Page 168 and 169:
166 A tmpfs server listening on INA
Page 170 and 171:
168 Request Arguments Response Desc
Page 172 and 173:
170 Host syscall rump syscall 1. op
Page 174 and 175:
172 A client’s initial connection
Page 176 and 177:
174 their system calls to a rump ke
Page 178 and 179:
176 stdin/stdout, the new file desc
Page 180 and 181:
178 Supporting fork() Recall, the f
Page 182 and 183:
180 As with fork, most of the kerne
Page 184 and 185:
182 Anecdotal analysis For several
Page 186 and 187:
184
Page 188 and 189:
186 SLOC 8000 7000 6000 5000 4000 3
Page 190 and 191:
188 Total commits to the kernel 9,6
Page 192 and 193:
190 120 build time (minutes) 100 80
Page 194 and 195:
192 4.2.2 makefs For a source tree
Page 196 and 197:
194 not include later debugging [76
Page 198 and 199:
196 the necessary tools such as mak
Page 200 and 201:
198 proach of supplying alternate c
Page 202 and 203:
200 are not out-of-the-box compatib
Page 204 and 205:
202 golem> mount -t msdos -o rump /
Page 206 and 207:
204 Full OS By a full OS we mean a
Page 208 and 209:
206 • Rapid prototyping: One of t
Page 210 and 211:
208 4.5.3 Testing: Case Studies We
Page 212 and 213:
210 static void scsitest_request(st
Page 214 and 215:
212 waits for the timeout and check
Page 216 and 217:
214 • We noticed that even in sup
Page 218 and 219:
216 which were discovered during wr
Page 220 and 221:
218 version swap no swap NetBSD 5.1
Page 222 and 223:
220 It needs to be stressed that Ta
Page 224 and 225:
222 Network clusters Bootstrapping
Page 226 and 227:
224 8 7 Standard components Self-co
Page 228 and 229:
226 Rump kernel calls, as expected,
Page 230 and 231:
228 Traditional FFS We measure the
Page 232 and 233:
230 80 70 60 seconds 50 40 30 20 10
Page 234 and 235:
232 The results are presented in Fi
Page 236 and 237:
234 behavior is required by the act
Page 238 and 239:
236
Page 240 and 241:
238 Rialto [29] is an operating sys
Page 242 and 243:
240 One argument for partitioned op
Page 244 and 245:
242 View OS The View OS [37] approa
Page 246 and 247:
244 OSKit Instead of making system
Page 248 and 249:
246 discussing the type incompatibi
Page 250 and 251:
248 difference to the abovementione
Page 252 and 253:
250 At runtime, a rump kernel can a
Page 254 and 255:
252 For testing and development we
Page 256 and 257:
254
Page 258 and 259:
256 Art of Virtualization. In: Proc
Page 260 and 261:
258 [30] Adam Dunkels. 2001. Design
Page 262 and 263:
260 [47] Galen C. Hunt and James R.
Page 264 and 265:
262 [67] Steven McCanne and Van Jac
Page 266 and 267:
264 [87] NetBSD Project. URL http:/
Page 268 and 269:
266 of the 6th Workshop on Programm
Page 270 and 271:
268
Page 272 and 273:
A-2 RUMP.DHCPCLIENT(1) NetBSD Gener
Page 274 and 275:
A-4 RUMP.HALT(1) NetBSD General Com
Page 276 and 277:
A-6 RUMP_SERVER(1) NetBSD General C
Page 278 and 279:
A-8 RUMP_SERVER(1) NetBSD General C
Page 280 and 281:
A-10 SHMIF_DUMPBUS(1) NetBSD Genera
Page 282 and 283:
A-12 P2K(3) NetBSD Library Function
Page 284 and 285:
A-14 P2K(3) NetBSD Library Function
Page 286 and 287:
A-16 RUMP(3) NetBSD Library Functio
Page 288 and 289:
A-18 RUMP(3) NetBSD Library Functio
Page 290 and 291:
A-20 RUMP_ETFS(3) NetBSD Library Fu
Page 292 and 293:
A-22 RUMP_ETFS(3) NetBSD Library Fu
Page 294 and 295:
A-24 RUMP_LWPROC(3) NetBSD Library
Page 296 and 297:
A-26 RUMP_LWPROC(3) NetBSD Library
Page 298 and 299:
A-28 RUMPCLIENT(3) NetBSD Library F
Page 300 and 301:
A-30 RUMPCLIENT(3) NetBSD Library F
Page 302 and 303:
A-32 RUMPHIJACK(3) NetBSD Library F
Page 304 and 305:
Page 306 and 307:
Page 308 and 309:
A-38 UKFS(3) NetBSD Library Functio
Page 310 and 311:
Page 312 and 313:
Page 314 and 315:
Page 316 and 317:
Page 318 and 319:
A-48 SHMIF(4) NetBSD Kernel Interfa
Page 320 and 321:
A-50 RUMP_SP(7) NetBSD Miscellaneou
Page 322 and 323:
A-52 RUMP_SP(7) NetBSD Miscellaneou
Page 324 and 325:
B-2 TCP connections use standard TC
Page 326 and 327:
B-4 rump clients. This means that j
Page 328 and 329:
B-6 ponents. That can be done simpl
Page 330 and 331:
B-8 Our goal is to add another part
Page 332 and 333:
B-10 golem> export RUMP_SERVER=unix
Page 334 and 335:
B-12 golem> rump.dd if=/dev/rcgd0d
Page 336 and 337:
B-14 demogorgon# cgdconfig cgd0 /de
Page 338 and 339:
B-16 rump_server -lrumpnet -lrumpne
Page 340 and 341:
B-18 golem> rump.ifconfig virt0 cre
Page 342 and 343:
B-20 Congratulations, that’s it.
Page 344 and 345:
B-22 purely in userspace, it does n
Page 346 and 347:
B-24 We then proceed to create a mo
Page 348 and 349:
B-26 Then, the only thing left is t
Page 350 and 351:
B-28 -d key=/dk,hostpath=${NFSX}/ff
Page 352 and 353:
B-30 configuration. golem> sh rumpn
Page 354 and 355:
B-32
Page 356 and 357:
C-2 This is a quick fix for making
Page 358 and 359:
C-4 This fixes the conditionally co
Page 362:
Aalto-DD 171/2012 9HSTFMG*aejbgi+ I
show all

The Design and Implementation of the Anykernel and Rump Kernels

Create successful ePaper yourself

Delete template?

Save as template?