xref: /openbmc/linux/arch/s390/Kconfig (revision 5bd8e16d)
1config MMU
2	def_bool y
3
4config ZONE_DMA
5	def_bool y
6
7config LOCKDEP_SUPPORT
8	def_bool y
9
10config STACKTRACE_SUPPORT
11	def_bool y
12
13config HAVE_LATENCYTOP_SUPPORT
14	def_bool y
15
16config RWSEM_GENERIC_SPINLOCK
17	bool
18
19config RWSEM_XCHGADD_ALGORITHM
20	def_bool y
21
22config ARCH_HAS_ILOG2_U32
23	def_bool n
24
25config ARCH_HAS_ILOG2_U64
26	def_bool n
27
28config GENERIC_HWEIGHT
29	def_bool y
30
31config GENERIC_BUG
32	def_bool y if BUG
33
34config GENERIC_BUG_RELATIVE_POINTERS
35	def_bool y
36
37config ARCH_DMA_ADDR_T_64BIT
38	def_bool 64BIT
39
40config GENERIC_LOCKBREAK
41	def_bool y if SMP && PREEMPT
42
43config PGSTE
44	def_bool y if KVM
45
46config ARCH_SUPPORTS_DEBUG_PAGEALLOC
47	def_bool y
48
49config KEXEC
50	def_bool y
51
52config AUDIT_ARCH
53	def_bool y
54
55config NO_IOPORT
56	def_bool y
57
58config PCI_QUIRKS
59	def_bool n
60
61config S390
62	def_bool y
63	select ARCH_DISCARD_MEMBLOCK
64	select ARCH_HAS_ATOMIC64_DEC_IF_POSITIVE
65	select ARCH_HAS_DEBUG_STRICT_USER_COPY_CHECKS
66	select ARCH_HAVE_NMI_SAFE_CMPXCHG
67	select ARCH_INLINE_READ_LOCK
68	select ARCH_INLINE_READ_LOCK_BH
69	select ARCH_INLINE_READ_LOCK_IRQ
70	select ARCH_INLINE_READ_LOCK_IRQSAVE
71	select ARCH_INLINE_READ_TRYLOCK
72	select ARCH_INLINE_READ_UNLOCK
73	select ARCH_INLINE_READ_UNLOCK_BH
74	select ARCH_INLINE_READ_UNLOCK_IRQ
75	select ARCH_INLINE_READ_UNLOCK_IRQRESTORE
76	select ARCH_INLINE_SPIN_LOCK
77	select ARCH_INLINE_SPIN_LOCK_BH
78	select ARCH_INLINE_SPIN_LOCK_IRQ
79	select ARCH_INLINE_SPIN_LOCK_IRQSAVE
80	select ARCH_INLINE_SPIN_TRYLOCK
81	select ARCH_INLINE_SPIN_TRYLOCK_BH
82	select ARCH_INLINE_SPIN_UNLOCK
83	select ARCH_INLINE_SPIN_UNLOCK_BH
84	select ARCH_INLINE_SPIN_UNLOCK_IRQ
85	select ARCH_INLINE_SPIN_UNLOCK_IRQRESTORE
86	select ARCH_INLINE_WRITE_LOCK
87	select ARCH_INLINE_WRITE_LOCK_BH
88	select ARCH_INLINE_WRITE_LOCK_IRQ
89	select ARCH_INLINE_WRITE_LOCK_IRQSAVE
90	select ARCH_INLINE_WRITE_TRYLOCK
91	select ARCH_INLINE_WRITE_UNLOCK
92	select ARCH_INLINE_WRITE_UNLOCK_BH
93	select ARCH_INLINE_WRITE_UNLOCK_IRQ
94	select ARCH_INLINE_WRITE_UNLOCK_IRQRESTORE
95	select ARCH_SAVE_PAGE_KEYS if HIBERNATION
96	select ARCH_WANT_IPC_PARSE_VERSION
97	select BUILDTIME_EXTABLE_SORT
98	select CLONE_BACKWARDS2
99	select GENERIC_CLOCKEVENTS
100	select GENERIC_CPU_DEVICES if !SMP
101	select GENERIC_SMP_IDLE_THREAD
102	select GENERIC_TIME_VSYSCALL_OLD
103	select HAVE_ALIGNED_STRUCT_PAGE if SLUB
104	select HAVE_ARCH_JUMP_LABEL if !MARCH_G5
105	select HAVE_ARCH_MUTEX_CPU_RELAX
106	select HAVE_ARCH_SECCOMP_FILTER
107	select HAVE_ARCH_TRACEHOOK
108	select HAVE_ARCH_TRANSPARENT_HUGEPAGE if 64BIT
109	select HAVE_BPF_JIT if 64BIT && PACK_STACK
110	select HAVE_CMPXCHG_DOUBLE
111	select HAVE_CMPXCHG_LOCAL
112	select HAVE_C_RECORDMCOUNT
113	select HAVE_DEBUG_KMEMLEAK
114	select HAVE_DYNAMIC_FTRACE
115	select HAVE_FTRACE_MCOUNT_RECORD
116	select HAVE_FUNCTION_GRAPH_TRACER
117	select HAVE_FUNCTION_TRACER
118	select HAVE_FUNCTION_TRACE_MCOUNT_TEST
119	select HAVE_KERNEL_BZIP2
120	select HAVE_KERNEL_GZIP
121	select HAVE_KERNEL_LZ4
122	select HAVE_KERNEL_LZMA
123	select HAVE_KERNEL_LZO
124	select HAVE_KERNEL_XZ
125	select HAVE_KPROBES
126	select HAVE_KRETPROBES
127	select HAVE_KVM if 64BIT
128	select HAVE_MEMBLOCK
129	select HAVE_MEMBLOCK_NODE_MAP
130	select HAVE_MOD_ARCH_SPECIFIC
131	select HAVE_OPROFILE
132	select HAVE_PERF_EVENTS
133	select HAVE_REGS_AND_STACK_ACCESS_API
134	select HAVE_SYSCALL_TRACEPOINTS
135	select HAVE_UID16 if 32BIT
136	select HAVE_VIRT_CPU_ACCOUNTING
137	select INIT_ALL_POSSIBLE
138	select KTIME_SCALAR if 32BIT
139	select MODULES_USE_ELF_RELA
140	select OLD_SIGACTION
141	select OLD_SIGSUSPEND3
142	select SYSCTL_EXCEPTION_TRACE
143	select USE_GENERIC_SMP_HELPERS if SMP
144	select VIRT_CPU_ACCOUNTING
145	select VIRT_TO_BUS
146
147config SCHED_OMIT_FRAME_POINTER
148	def_bool y
149
150source "init/Kconfig"
151
152source "kernel/Kconfig.freezer"
153
154menu "Processor type and features"
155
156config HAVE_MARCH_Z900_FEATURES
157	def_bool n
158
159config HAVE_MARCH_Z990_FEATURES
160	def_bool n
161	select HAVE_MARCH_Z900_FEATURES
162
163config HAVE_MARCH_Z9_109_FEATURES
164	def_bool n
165	select HAVE_MARCH_Z990_FEATURES
166
167config HAVE_MARCH_Z10_FEATURES
168	def_bool n
169	select HAVE_MARCH_Z9_109_FEATURES
170
171config HAVE_MARCH_Z196_FEATURES
172	def_bool n
173	select HAVE_MARCH_Z10_FEATURES
174
175config HAVE_MARCH_ZEC12_FEATURES
176	def_bool n
177	select HAVE_MARCH_Z196_FEATURES
178
179choice
180	prompt "Processor type"
181	default MARCH_G5
182
183config MARCH_G5
184	bool "System/390 model G5 and G6"
185	depends on !64BIT
186	help
187	  Select this to build a 31 bit kernel that works
188	  on all ESA/390 and z/Architecture machines.
189
190config MARCH_Z900
191	bool "IBM zSeries model z800 and z900"
192	select HAVE_MARCH_Z900_FEATURES if 64BIT
193	help
194	  Select this to enable optimizations for model z800/z900 (2064 and
195	  2066 series). This will enable some optimizations that are not
196	  available on older ESA/390 (31 Bit) only CPUs.
197
198config MARCH_Z990
199	bool "IBM zSeries model z890 and z990"
200	select HAVE_MARCH_Z990_FEATURES if 64BIT
201	help
202	  Select this to enable optimizations for model z890/z990 (2084 and
203	  2086 series). The kernel will be slightly faster but will not work
204	  on older machines.
205
206config MARCH_Z9_109
207	bool "IBM System z9"
208	select HAVE_MARCH_Z9_109_FEATURES if 64BIT
209	help
210	  Select this to enable optimizations for IBM System z9 (2094 and
211	  2096 series). The kernel will be slightly faster but will not work
212	  on older machines.
213
214config MARCH_Z10
215	bool "IBM System z10"
216	select HAVE_MARCH_Z10_FEATURES if 64BIT
217	help
218	  Select this to enable optimizations for IBM System z10 (2097 and
219	  2098 series). The kernel will be slightly faster but will not work
220	  on older machines.
221
222config MARCH_Z196
223	bool "IBM zEnterprise 114 and 196"
224	select HAVE_MARCH_Z196_FEATURES if 64BIT
225	help
226	  Select this to enable optimizations for IBM zEnterprise 114 and 196
227	  (2818 and 2817 series). The kernel will be slightly faster but will
228	  not work on older machines.
229
230config MARCH_ZEC12
231	bool "IBM zBC12 and zEC12"
232	select HAVE_MARCH_ZEC12_FEATURES if 64BIT
233	help
234	  Select this to enable optimizations for IBM zBC12 and zEC12 (2828 and
235	  2827 series). The kernel will be slightly faster but will not work on
236	  older machines.
237
238endchoice
239
240config 64BIT
241	def_bool y
242	prompt "64 bit kernel"
243	help
244	  Select this option if you have an IBM z/Architecture machine
245	  and want to use the 64 bit addressing mode.
246
247config 32BIT
248	def_bool y if !64BIT
249
250config COMPAT
251	def_bool y
252	prompt "Kernel support for 31 bit emulation"
253	depends on 64BIT
254	select COMPAT_BINFMT_ELF if BINFMT_ELF
255	select ARCH_WANT_OLD_COMPAT_IPC
256	select COMPAT_OLD_SIGACTION
257	help
258	  Select this option if you want to enable your system kernel to
259	  handle system-calls from ELF binaries for 31 bit ESA.  This option
260	  (and some other stuff like libraries and such) is needed for
261	  executing 31 bit applications.  It is safe to say "Y".
262
263config SYSVIPC_COMPAT
264	def_bool y if COMPAT && SYSVIPC
265
266config KEYS_COMPAT
267	def_bool y if COMPAT && KEYS
268
269config SMP
270	def_bool y
271	prompt "Symmetric multi-processing support"
272	---help---
273	  This enables support for systems with more than one CPU. If you have
274	  a system with only one CPU, like most personal computers, say N. If
275	  you have a system with more than one CPU, say Y.
276
277	  If you say N here, the kernel will run on single and multiprocessor
278	  machines, but will use only one CPU of a multiprocessor machine. If
279	  you say Y here, the kernel will run on many, but not all,
280	  singleprocessor machines. On a singleprocessor machine, the kernel
281	  will run faster if you say N here.
282
283	  See also the SMP-HOWTO available at
284	  <http://www.tldp.org/docs.html#howto>.
285
286	  Even if you don't know what to do here, say Y.
287
288config NR_CPUS
289	int "Maximum number of CPUs (2-64)"
290	range 2 64
291	depends on SMP
292	default "32" if !64BIT
293	default "64" if 64BIT
294	help
295	  This allows you to specify the maximum number of CPUs which this
296	  kernel will support.  The maximum supported value is 64 and the
297	  minimum value which makes sense is 2.
298
299	  This is purely to save memory - each supported CPU adds
300	  approximately sixteen kilobytes to the kernel image.
301
302config HOTPLUG_CPU
303	def_bool y
304	prompt "Support for hot-pluggable CPUs"
305	depends on SMP
306	help
307	  Say Y here to be able to turn CPUs off and on. CPUs
308	  can be controlled through /sys/devices/system/cpu/cpu#.
309	  Say N if you want to disable CPU hotplug.
310
311config SCHED_MC
312	def_bool n
313
314config SCHED_BOOK
315	def_bool y
316	prompt "Book scheduler support"
317	depends on SMP
318	select SCHED_MC
319	help
320	  Book scheduler support improves the CPU scheduler's decision making
321	  when dealing with machines that have several books.
322
323source kernel/Kconfig.preempt
324
325config MATHEMU
326	def_bool y
327	prompt "IEEE FPU emulation"
328	depends on MARCH_G5
329	help
330	  This option is required for IEEE compliant floating point arithmetic
331	  on older ESA/390 machines. Say Y unless you know your machine doesn't
332	  need this.
333
334source kernel/Kconfig.hz
335
336endmenu
337
338menu "Memory setup"
339
340config ARCH_SPARSEMEM_ENABLE
341	def_bool y
342	select SPARSEMEM_VMEMMAP_ENABLE
343	select SPARSEMEM_VMEMMAP
344	select SPARSEMEM_STATIC if !64BIT
345
346config ARCH_SPARSEMEM_DEFAULT
347	def_bool y
348
349config ARCH_SELECT_MEMORY_MODEL
350	def_bool y
351
352config ARCH_ENABLE_MEMORY_HOTPLUG
353	def_bool y if SPARSEMEM
354
355config ARCH_ENABLE_MEMORY_HOTREMOVE
356	def_bool y
357
358config FORCE_MAX_ZONEORDER
359	int
360	default "9"
361
362source "mm/Kconfig"
363
364config PACK_STACK
365	def_bool y
366	prompt "Pack kernel stack"
367	help
368	  This option enables the compiler option -mkernel-backchain if it
369	  is available. If the option is available the compiler supports
370	  the new stack layout which dramatically reduces the minimum stack
371	  frame size. With an old compiler a non-leaf function needs a
372	  minimum of 96 bytes on 31 bit and 160 bytes on 64 bit. With
373	  -mkernel-backchain the minimum size drops to 16 byte on 31 bit
374	  and 24 byte on 64 bit.
375
376	  Say Y if you are unsure.
377
378config CHECK_STACK
379	def_bool y
380	prompt "Detect kernel stack overflow"
381	help
382	  This option enables the compiler option -mstack-guard and
383	  -mstack-size if they are available. If the compiler supports them
384	  it will emit additional code to each function prolog to trigger
385	  an illegal operation if the kernel stack is about to overflow.
386
387	  Say N if you are unsure.
388
389config STACK_GUARD
390	int "Size of the guard area (128-1024)"
391	range 128 1024
392	depends on CHECK_STACK
393	default "256"
394	help
395	  This allows you to specify the size of the guard area at the lower
396	  end of the kernel stack. If the kernel stack points into the guard
397	  area on function entry an illegal operation is triggered. The size
398	  needs to be a power of 2. Please keep in mind that the size of an
399	  interrupt frame is 184 bytes for 31 bit and 328 bytes on 64 bit.
400	  The minimum size for the stack guard should be 256 for 31 bit and
401	  512 for 64 bit.
402
403config WARN_DYNAMIC_STACK
404	def_bool n
405	prompt "Emit compiler warnings for function with dynamic stack usage"
406	help
407	  This option enables the compiler option -mwarn-dynamicstack. If the
408	  compiler supports this options generates warnings for functions
409	  that dynamically allocate stack space using alloca.
410
411	  Say N if you are unsure.
412
413endmenu
414
415menu "I/O subsystem"
416
417config QDIO
418	def_tristate y
419	prompt "QDIO support"
420	---help---
421	  This driver provides the Queued Direct I/O base support for
422	  IBM System z.
423
424	  To compile this driver as a module, choose M here: the
425	  module will be called qdio.
426
427	  If unsure, say Y.
428
429menuconfig PCI
430	bool "PCI support"
431	default n
432	depends on 64BIT
433	select PCI_MSI
434	help
435	  Enable PCI support.
436
437if PCI
438
439config PCI_NR_FUNCTIONS
440	int "Maximum number of PCI functions (1-4096)"
441	range 1 4096
442	default "64"
443	help
444	  This allows you to specify the maximum number of PCI functions which
445	  this kernel will support.
446
447config PCI_NR_MSI
448	int "Maximum number of MSI interrupts (64-32768)"
449	range 64 32768
450	default "256"
451	help
452	  This defines the number of virtual interrupts the kernel will
453	  provide for MSI interrupts. If you configure your system to have
454	  too few drivers will fail to allocate MSI interrupts for all
455	  PCI devices.
456
457source "drivers/pci/Kconfig"
458source "drivers/pci/pcie/Kconfig"
459source "drivers/pci/hotplug/Kconfig"
460
461endif	# PCI
462
463config PCI_DOMAINS
464	def_bool PCI
465
466config HAS_IOMEM
467	def_bool PCI
468
469config IOMMU_HELPER
470	def_bool PCI
471
472config HAS_DMA
473	def_bool PCI
474	select HAVE_DMA_API_DEBUG
475
476config NEED_SG_DMA_LENGTH
477	def_bool PCI
478
479config HAVE_DMA_ATTRS
480	def_bool PCI
481
482config NEED_DMA_MAP_STATE
483	def_bool PCI
484
485config CHSC_SCH
486	def_tristate m
487	prompt "Support for CHSC subchannels"
488	help
489	  This driver allows usage of CHSC subchannels. A CHSC subchannel
490	  is usually present on LPAR only.
491	  The driver creates a device /dev/chsc, which may be used to
492	  obtain I/O configuration information about the machine and
493	  to issue asynchronous chsc commands (DANGEROUS).
494	  You will usually only want to use this interface on a special
495	  LPAR designated for system management.
496
497	  To compile this driver as a module, choose M here: the
498	  module will be called chsc_sch.
499
500	  If unsure, say N.
501
502config SCM_BUS
503	def_bool y
504	depends on 64BIT
505	prompt "SCM bus driver"
506	help
507	  Bus driver for Storage Class Memory.
508
509config EADM_SCH
510	def_tristate m
511	prompt "Support for EADM subchannels"
512	depends on SCM_BUS
513	help
514	  This driver allows usage of EADM subchannels. EADM subchannels act
515	  as a communication vehicle for SCM increments.
516
517	  To compile this driver as a module, choose M here: the
518	  module will be called eadm_sch.
519
520endmenu
521
522menu "Dump support"
523
524config CRASH_DUMP
525	bool "kernel crash dumps"
526	depends on 64BIT && SMP
527	select KEXEC
528	select ZFCPDUMP
529	help
530	  Generate crash dump after being started by kexec.
531	  Crash dump kernels are loaded in the main kernel with kexec-tools
532	  into a specially reserved region and then later executed after
533	  a crash by kdump/kexec.
534	  For more details see Documentation/kdump/kdump.txt
535
536config ZFCPDUMP
537	def_bool n
538	prompt "zfcpdump support"
539	depends on SMP
540	help
541	  Select this option if you want to build an zfcpdump enabled kernel.
542	  Refer to <file:Documentation/s390/zfcpdump.txt> for more details on this.
543
544endmenu
545
546menu "Executable file formats / Emulations"
547
548source "fs/Kconfig.binfmt"
549
550config SECCOMP
551	def_bool y
552	prompt "Enable seccomp to safely compute untrusted bytecode"
553	depends on PROC_FS
554	help
555	  This kernel feature is useful for number crunching applications
556	  that may need to compute untrusted bytecode during their
557	  execution. By using pipes or other transports made available to
558	  the process as file descriptors supporting the read/write
559	  syscalls, it's possible to isolate those applications in
560	  their own address space using seccomp. Once seccomp is
561	  enabled via /proc/<pid>/seccomp, it cannot be disabled
562	  and the task is only allowed to execute a few safe syscalls
563	  defined by each seccomp mode.
564
565	  If unsure, say Y.
566
567endmenu
568
569menu "Power Management"
570
571config ARCH_HIBERNATION_POSSIBLE
572	def_bool y if 64BIT
573
574source "kernel/power/Kconfig"
575
576endmenu
577
578source "net/Kconfig"
579
580config PCMCIA
581	def_bool n
582
583config CCW
584	def_bool y
585
586source "drivers/Kconfig"
587
588source "fs/Kconfig"
589
590source "arch/s390/Kconfig.debug"
591
592source "security/Kconfig"
593
594source "crypto/Kconfig"
595
596source "lib/Kconfig"
597
598menu "Virtualization"
599
600config PFAULT
601	def_bool y
602	prompt "Pseudo page fault support"
603	help
604	  Select this option, if you want to use PFAULT pseudo page fault
605	  handling under VM. If running native or in LPAR, this option
606	  has no effect. If your VM does not support PFAULT, PAGEEX
607	  pseudo page fault handling will be used.
608	  Note that VM 4.2 supports PFAULT but has a bug in its
609	  implementation that causes some problems.
610	  Everybody who wants to run Linux under VM != VM4.2 should select
611	  this option.
612
613config SHARED_KERNEL
614	bool "VM shared kernel support"
615	depends on !JUMP_LABEL
616	help
617	  Select this option, if you want to share the text segment of the
618	  Linux kernel between different VM guests. This reduces memory
619	  usage with lots of guests but greatly increases kernel size.
620	  Also if a kernel was IPL'ed from a shared segment the kexec system
621	  call will not work.
622	  You should only select this option if you know what you are
623	  doing and want to exploit this feature.
624
625config CMM
626	def_tristate n
627	prompt "Cooperative memory management"
628	help
629	  Select this option, if you want to enable the kernel interface
630	  to reduce the memory size of the system. This is accomplished
631	  by allocating pages of memory and put them "on hold". This only
632	  makes sense for a system running under VM where the unused pages
633	  will be reused by VM for other guest systems. The interface
634	  allows an external monitor to balance memory of many systems.
635	  Everybody who wants to run Linux under VM should select this
636	  option.
637
638config CMM_IUCV
639	def_bool y
640	prompt "IUCV special message interface to cooperative memory management"
641	depends on CMM && (SMSGIUCV=y || CMM=SMSGIUCV)
642	help
643	  Select this option to enable the special message interface to
644	  the cooperative memory management.
645
646config APPLDATA_BASE
647	def_bool n
648	prompt "Linux - VM Monitor Stream, base infrastructure"
649	depends on PROC_FS
650	help
651	  This provides a kernel interface for creating and updating z/VM APPLDATA
652	  monitor records. The monitor records are updated at certain time
653	  intervals, once the timer is started.
654	  Writing 1 or 0 to /proc/appldata/timer starts(1) or stops(0) the timer,
655	  i.e. enables or disables monitoring on the Linux side.
656	  A custom interval value (in seconds) can be written to
657	  /proc/appldata/interval.
658
659	  Defaults are 60 seconds interval and timer off.
660	  The /proc entries can also be read from, showing the current settings.
661
662config APPLDATA_MEM
663	def_tristate m
664	prompt "Monitor memory management statistics"
665	depends on APPLDATA_BASE && VM_EVENT_COUNTERS
666	help
667	  This provides memory management related data to the Linux - VM Monitor
668	  Stream, like paging/swapping rate, memory utilisation, etc.
669	  Writing 1 or 0 to /proc/appldata/memory creates(1) or removes(0) a z/VM
670	  APPLDATA monitor record, i.e. enables or disables monitoring this record
671	  on the z/VM side.
672
673	  Default is disabled.
674	  The /proc entry can also be read from, showing the current settings.
675
676	  This can also be compiled as a module, which will be called
677	  appldata_mem.o.
678
679config APPLDATA_OS
680	def_tristate m
681	prompt "Monitor OS statistics"
682	depends on APPLDATA_BASE
683	help
684	  This provides OS related data to the Linux - VM Monitor Stream, like
685	  CPU utilisation, etc.
686	  Writing 1 or 0 to /proc/appldata/os creates(1) or removes(0) a z/VM
687	  APPLDATA monitor record, i.e. enables or disables monitoring this record
688	  on the z/VM side.
689
690	  Default is disabled.
691	  This can also be compiled as a module, which will be called
692	  appldata_os.o.
693
694config APPLDATA_NET_SUM
695	def_tristate m
696	prompt "Monitor overall network statistics"
697	depends on APPLDATA_BASE && NET
698	help
699	  This provides network related data to the Linux - VM Monitor Stream,
700	  currently there is only a total sum of network I/O statistics, no
701	  per-interface data.
702	  Writing 1 or 0 to /proc/appldata/net_sum creates(1) or removes(0) a z/VM
703	  APPLDATA monitor record, i.e. enables or disables monitoring this record
704	  on the z/VM side.
705
706	  Default is disabled.
707	  This can also be compiled as a module, which will be called
708	  appldata_net_sum.o.
709
710config S390_HYPFS_FS
711	def_bool y
712	prompt "s390 hypervisor file system support"
713	select SYS_HYPERVISOR
714	help
715	  This is a virtual file system intended to provide accounting
716	  information in an s390 hypervisor environment.
717
718source "arch/s390/kvm/Kconfig"
719
720config S390_GUEST
721	def_bool y
722	prompt "s390 support for virtio devices"
723	depends on 64BIT
724	select TTY
725	select VIRTUALIZATION
726	select VIRTIO
727	select VIRTIO_CONSOLE
728	help
729	  Enabling this option adds support for virtio based paravirtual device
730	  drivers on s390.
731
732	  Select this option if you want to run the kernel as a guest under
733	  the KVM hypervisor.
734
735endmenu
736