x86/x86_64/boot-options.rst

1 .. SPDX-License-Identifier: GPL-2.0
39 		Do not opt-in to Local MCE delivery. Use legacy method
47 		in a reboot. On Intel systems it is enabled by default.
55 		Don't overwrite the bios-set CMCI threshold. This boot option
62 		Force-enable recoverable machine check code paths
73 	Use IO-APIC. Default
76 	Don't use the IO-APIC.
85 	See Documentation/arch/x86/i386/IO-APIC.rst
91 	Don't check the IO-APIC timer. This can work around
122    reboot=b[ios] | t[riple] | k[bd] | a[cpi] | e[fi] | p[ci] [, [w]arm | [c]old]
124         Use the CPU reboot vector for warm reset
126         Don't set the cold reboot flag
128         Set the cold reboot flag
132         Use the keyboard controller. cold reset (default)
135         the ACPI reset does not work, the reboot path attempts the reset
136         using the keyboard controller.
139         the EFI reset does not work, the reboot path attempts the reset using
140         the keyboard controller.
142         Use a write to the PCI config space register 0xcf9 to trigger reboot.
147    on reboot so there may be boot problems on some systems.
149    reboot=force
150      Don't stop other CPUs on reboot. This can make reboot more reliable
153    reboot=default
154      There are some built-in platform specific "quirks" - you may see:
155      "reboot: <name> series board detected. Selecting <type> for reboots."
157      newer BIOS, or newer board) using this option will ignore the built-in
158      quirk table, and use the generic default reboot actions.
170     Don't parse the HMAT table for NUMA setup, or soft-reserved memory
174     If given as a memory unit, fills all system RAM with nodes of
178     If given as an integer, fills all system RAM with N fake nodes
217   pci=assign-busses
228 Multiple x86-64 PCI-DMA mapping implementations exist, for example:
232       Kernel boot message: "PCI-DMA: Disabling IOMMU"
235       Kernel boot message: "PCI-DMA: using GART IOMMU"
237    3. <arch/x86_64/kernel/pci-swiotlb.c> : Software IOMMU implementation. Used
238       e.g. if there is no hardware IOMMU in the system and it is need because
240       Kernel boot message: "PCI-DMA: Using software bounce buffering
277       Do scatter-gather (SG) merging. Implies "force" (experimental).
279       Don't do scatter-gather (SG) merging.