view Documentation/x86_64/boot-options.txt @ 524:7f8b544237bf

netfront: Allow netfront in domain 0.

This is useful if your physical network device is in a utility domain.

Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
author Keir Fraser <keir.fraser@citrix.com>
date Tue Apr 15 15:18:58 2008 +0100 (2008-04-15)
parents 831230e53067
line source
1 AMD64 specific boot options
3 There are many others (usually documented in driver documentation), but
4 only the AMD64 specific ones are listed here.
6 Machine check
8 mce=off disable machine check
9 mce=bootlog Enable logging of machine checks left over from booting.
10 Disabled by default on AMD because some BIOS leave bogus ones.
11 If your BIOS doesn't do that it's a good idea to enable though
12 to make sure you log even machine check events that result
13 in a reboot. On Intel systems it is enabled by default.
14 mce=nobootlog
15 Disable boot machine check logging.
16 mce=tolerancelevel (number)
17 0: always panic, 1: panic if deadlock possible,
18 2: try to avoid panic, 3: never panic or exit (for testing)
19 default is 1
20 Can be also set using sysfs which is preferable.
22 nomce (for compatibility with i386): same as mce=off
24 Everything else is in sysfs now.
26 APICs
28 apic Use IO-APIC. Default
30 noapic Don't use the IO-APIC.
32 disableapic Don't use the local APIC
34 nolapic Don't use the local APIC (alias for i386 compatibility)
36 pirq=... See Documentation/i386/IO-APIC.txt
38 noapictimer Don't set up the APIC timer
40 no_timer_check Don't check the IO-APIC timer. This can work around
41 problems with incorrect timer initialization on some boards.
43 apicmaintimer Run time keeping from the local APIC timer instead
44 of using the PIT/HPET interrupt for this. This is useful
45 when the PIT/HPET interrupts are unreliable.
47 noapicmaintimer Don't do time keeping using the APIC timer.
48 Useful when this option was auto selected, but doesn't work.
50 apicpmtimer
51 Do APIC timer calibration using the pmtimer. Implies
52 apicmaintimer. Useful when your PIT timer is totally
53 broken.
55 disable_8254_timer / enable_8254_timer
56 Enable interrupt 0 timer routing over the 8254 in addition to over
57 the IO-APIC. The kernel tries to set a sensible default.
59 Early Console
61 syntax: earlyprintk=vga
62 earlyprintk=serial[,ttySn[,baudrate]]
64 The early console is useful when the kernel crashes before the
65 normal console is initialized. It is not enabled by
66 default because it has some cosmetic problems.
67 Append ,keep to not disable it when the real console takes over.
68 Only vga or serial at a time, not both.
69 Currently only ttyS0 and ttyS1 are supported.
70 Interaction with the standard serial driver is not very good.
71 The VGA output is eventually overwritten by the real console.
73 Timing
75 notsc
76 Don't use the CPU time stamp counter to read the wall time.
77 This can be used to work around timing problems on multiprocessor systems
78 with not properly synchronized CPUs.
80 report_lost_ticks
81 Report when timer interrupts are lost because some code turned off
82 interrupts for too long.
84 nmi_watchdog=NUMBER[,panic]
85 NUMBER can be:
86 0 don't use an NMI watchdog
87 1 use the IO-APIC timer for the NMI watchdog
88 2 use the local APIC for the NMI watchdog using a performance counter. Note
89 This will use one performance counter and the local APIC's performance
90 vector.
91 When panic is specified panic when an NMI watchdog timeout occurs.
92 This is useful when you use a panic=... timeout and need the box
93 quickly up again.
95 nohpet
96 Don't use the HPET timer.
98 Idle loop
100 idle=poll
101 Don't do power saving in the idle loop using HLT, but poll for rescheduling
102 event. This will make the CPUs eat a lot more power, but may be useful
103 to get slightly better performance in multiprocessor benchmarks. It also
104 makes some profiling using performance counters more accurate.
105 Please note that on systems with MONITOR/MWAIT support (like Intel EM64T
106 CPUs) this option has no performance advantage over the normal idle loop.
107 It may also interact badly with hyperthreading.
109 Rebooting
111 reboot=b[ios] | t[riple] | k[bd] [, [w]arm | [c]old]
112 bios Use the CPU reboto vector for warm reset
113 warm Don't set the cold reboot flag
114 cold Set the cold reboot flag
115 triple Force a triple fault (init)
116 kbd Use the keyboard controller. cold reset (default)
118 Using warm reset will be much faster especially on big memory
119 systems because the BIOS will not go through the memory check.
120 Disadvantage is that not all hardware will be completely reinitialized
121 on reboot so there may be boot problems on some systems.
123 reboot=force
125 Don't stop other CPUs on reboot. This can make reboot more reliable
126 in some cases.
128 Non Executable Mappings
130 noexec=on|off
132 on Enable(default)
133 off Disable
135 SMP
137 nosmp Only use a single CPU
139 maxcpus=NUMBER only use upto NUMBER CPUs
141 cpumask=MASK only use cpus with bits set in mask
143 additional_cpus=NUM Allow NUM more CPUs for hotplug
144 (defaults are specified by the BIOS, see Documentation/x86_64/cpu-hotplug-spec)
146 NUMA
148 numa=off Only set up a single NUMA node spanning all memory.
150 numa=noacpi Don't parse the SRAT table for NUMA setup
152 numa=fake=X Fake X nodes and ignore NUMA setup of the actual machine.
154 numa=hotadd=percent
155 Only allow hotadd memory to preallocate page structures upto
156 percent of already available memory.
157 numa=hotadd=0 will disable hotadd memory.
159 ACPI
161 acpi=off Don't enable ACPI
162 acpi=ht Use ACPI boot table parsing, but don't enable ACPI
163 interpreter
164 acpi=force Force ACPI on (currently not needed)
166 acpi=strict Disable out of spec ACPI workarounds.
168 acpi_sci={edge,level,high,low} Set up ACPI SCI interrupt.
170 acpi=noirq Don't route interrupts
172 PCI
174 pci=off Don't use PCI
175 pci=conf1 Use conf1 access.
176 pci=conf2 Use conf2 access.
177 pci=rom Assign ROMs.
178 pci=assign-busses Assign busses
179 pci=irqmask=MASK Set PCI interrupt mask to MASK
180 pci=lastbus=NUMBER Scan upto NUMBER busses, no matter what the mptable says.
181 pci=noacpi Don't use ACPI to set up PCI interrupt routing.
185 iommu=[size][,noagp][,off][,force][,noforce][,leak][,memaper[=order]][,merge]
186 [,forcesac][,fullflush][,nomerge][,noaperture]
187 size set size of iommu (in bytes)
188 noagp don't initialize the AGP driver and use full aperture.
189 off don't use the IOMMU
190 leak turn on simple iommu leak tracing (only when CONFIG_IOMMU_LEAK is on)
191 memaper[=order] allocate an own aperture over RAM with size 32MB^order.
192 noforce don't force IOMMU usage. Default.
193 force Force IOMMU.
194 merge Do SG merging. Implies force (experimental)
195 nomerge Don't do SG merging.
196 forcesac For SAC mode for masks <40bits (experimental)
197 fullflush Flush IOMMU on each allocation (default)
198 nofullflush Don't use IOMMU fullflush
199 allowed overwrite iommu off workarounds for specific chipsets.
200 soft Use software bounce buffering (default for Intel machines)
201 noaperture Don't touch the aperture for AGP.
203 swiotlb=pages[,force]
205 pages Prereserve that many 128K pages for the software IO bounce buffering.
206 force Force all IO through the software TLB.
208 calgary=[64k,128k,256k,512k,1M,2M,4M,8M]
209 calgary=[translate_empty_slots]
210 calgary=[disable=<PCI bus number>]
212 64k,...,8M - Set the size of each PCI slot's translation table
213 when using the Calgary IOMMU. This is the size of the translation
214 table itself in main memory. The smallest table, 64k, covers an IO
215 space of 32MB; the largest, 8MB table, can cover an IO space of
216 4GB. Normally the kernel will make the right choice by itself.
218 translate_empty_slots - Enable translation even on slots that have
219 no devices attached to them, in case a device will be hotplugged
220 in the future.
222 disable=<PCI bus number> - Disable translation on a given PHB. For
223 example, the built-in graphics adapter resides on the first bridge
224 (PCI bus number 0); if translation (isolation) is enabled on this
225 bridge, X servers that access the hardware directly from user
226 space might stop working. Use this option if you have devices that
227 are accessed from userspace directly on some PCI host bridge.
229 Debugging
231 oops=panic Always panic on oopses. Default is to just kill the process,
232 but there is a small probability of deadlocking the machine.
233 This will also cause panics on machine check exceptions.
234 Useful together with panic=30 to trigger a reboot.
236 kstack=N Print that many words from the kernel stack in oops dumps.
238 pagefaulttrace Dump all page faults. Only useful for extreme debugging
239 and will create a lot of output.
241 call_trace=[old|both|newfallback|new]
242 old: use old inexact backtracer
243 new: use new exact dwarf2 unwinder
244 both: print entries from both
245 newfallback: use new unwinder but fall back to old if it gets
246 stuck (default)
248 Misc
250 noreplacement Don't replace instructions with more appropriate ones
251 for the CPU. This may be useful on asymmetric MP systems
252 where some CPU have less capabilities than the others.