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Message-ID: <20190427153031.08489e65@coco.lan>
Date: Sat, 27 Apr 2019 15:30:31 -0300
From: Mauro Carvalho Chehab <mchehab+samsung@...nel.org>
To: Changbin Du <changbin.du@...il.com>
Cc: Jonathan Corbet <corbet@....net>, tglx@...utronix.de,
mingo@...hat.com, bp@...en8.de, x86@...nel.org,
linux-doc@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 21/27] Documentation: x86: convert
x86_64/boot-options.txt to reST
Em Fri, 26 Apr 2019 23:31:44 +0800
Changbin Du <changbin.du@...il.com> escreveu:
> This converts the plain text documentation to reStructuredText format and
> add it to Sphinx TOC tree. No essential content change.
>
> Signed-off-by: Changbin Du <changbin.du@...il.com>
> ---
> Documentation/x86/index.rst | 1 +
> Documentation/x86/x86_64/boot-options.rst | 326 ++++++++++++++++++++++
> Documentation/x86/x86_64/boot-options.txt | 278 ------------------
> Documentation/x86/x86_64/index.rst | 10 +
> 4 files changed, 337 insertions(+), 278 deletions(-)
> create mode 100644 Documentation/x86/x86_64/boot-options.rst
> delete mode 100644 Documentation/x86/x86_64/boot-options.txt
> create mode 100644 Documentation/x86/x86_64/index.rst
>
> diff --git a/Documentation/x86/index.rst b/Documentation/x86/index.rst
> index 19323c5b89ce..e7becb146c30 100644
> --- a/Documentation/x86/index.rst
> +++ b/Documentation/x86/index.rst
> @@ -27,3 +27,4 @@ Linux x86 Support
> resctrl_ui
> usb-legacy-support
> i386/index
> + x86_64/index
> diff --git a/Documentation/x86/x86_64/boot-options.rst b/Documentation/x86/x86_64/boot-options.rst
> new file mode 100644
> index 000000000000..2378f30c694a
> --- /dev/null
> +++ b/Documentation/x86/x86_64/boot-options.rst
> @@ -0,0 +1,326 @@
> +.. SPDX-License-Identifier: GPL-2.0
> +
> +===========================
> +AMD64 Specific Boot Options
> +===========================
> +
> +There are many others (usually documented in driver documentation), but
> +only the AMD64 specific ones are listed here.
> +
> +Machine check
> +=============
> +Please see Documentation/x86/x86_64/machinecheck for sysfs runtime tunables.
> +
> + mce=off
> + Disable machine check
> + mce=no_cmci
> + Disable CMCI(Corrected Machine Check Interrupt) that
> + Intel processor supports. Usually this disablement is
> + not recommended, but it might be handy if your hardware
> + is misbehaving.
> + Note that you'll get more problems without CMCI than with
> + due to the shared banks, i.e. you might get duplicated
> + error logs.
> + mce=dont_log_ce
> + Don't make logs for corrected errors. All events reported
> + as corrected are silently cleared by OS.
> + This option will be useful if you have no interest in any
> + of corrected errors.
> + mce=ignore_ce
> + Disable features for corrected errors, e.g. polling timer
> + and CMCI. All events reported as corrected are not cleared
> + by OS and remained in its error banks.
> + Usually this disablement is not recommended, however if
> + there is an agent checking/clearing corrected errors
> + (e.g. BIOS or hardware monitoring applications), conflicting
> + with OS's error handling, and you cannot deactivate the agent,
> + then this option will be a help.
> + mce=no_lmce
> + Do not opt-in to Local MCE delivery. Use legacy method
> + to broadcast MCEs.
> + mce=bootlog
> + Enable logging of machine checks left over from booting.
> + Disabled by default on AMD Fam10h and older because some BIOS
> + leave bogus ones.
> + If your BIOS doesn't do that it's a good idea to enable though
> + to make sure you log even machine check events that result
> + in a reboot. On Intel systems it is enabled by default.
> + mce=nobootlog
> + Disable boot machine check logging.
> + mce=tolerancelevel[,monarchtimeout] (number,number)
> + tolerance levels:
> + 0: always panic on uncorrected errors, log corrected errors
> + 1: panic or SIGBUS on uncorrected errors, log corrected errors
> + 2: SIGBUS or log uncorrected errors, log corrected errors
> + 3: never panic or SIGBUS, log all errors (for testing only)
> + Default is 1
> + Can be also set using sysfs which is preferable.
> + monarchtimeout:
> + Sets the time in us to wait for other CPUs on machine checks. 0
> + to disable.
> + mce=bios_cmci_threshold
> + Don't overwrite the bios-set CMCI threshold. This boot option
> + prevents Linux from overwriting the CMCI threshold set by the
> + bios. Without this option, Linux always sets the CMCI
> + threshold to 1. Enabling this may make memory predictive failure
> + analysis less effective if the bios sets thresholds for memory
> + errors since we will not see details for all errors.
> + mce=recovery
> + Force-enable recoverable machine check code paths
> +
> + nomce (for compatibility with i386)
> + same as mce=off
> +
> + Everything else is in sysfs now.
> +
> +APICs
> +=====
> +
> + apic
> + Use IO-APIC. Default
> +
> + noapic
> + Don't use the IO-APIC.
> +
> + disableapic
> + Don't use the local APIC
> +
> + nolapic
> + Don't use the local APIC (alias for i386 compatibility)
> +
> + pirq=...
> + See Documentation/x86/i386/IO-APIC.txt
> +
> + noapictimer
> + Don't set up the APIC timer
> +
> + no_timer_check
> + Don't check the IO-APIC timer. This can work around
> + problems with incorrect timer initialization on some boards.
> +
> + apicpmtimer
> + Do APIC timer calibration using the pmtimer. Implies
> + apicmaintimer. Useful when your PIT timer is totally broken.
> +
> +Timing
> +======
> +
> + notsc
> + Deprecated, use tsc=unstable instead.
> +
> + nohpet
> + Don't use the HPET timer.
> +
> +Idle loop
> +=========
> +
> + idle=poll
> + Don't do power saving in the idle loop using HLT, but poll for rescheduling
> + event. This will make the CPUs eat a lot more power, but may be useful
> + to get slightly better performance in multiprocessor benchmarks. It also
> + makes some profiling using performance counters more accurate.
> + Please note that on systems with MONITOR/MWAIT support (like Intel EM64T
> + CPUs) this option has no performance advantage over the normal idle loop.
> + It may also interact badly with hyperthreading.
> +
> +Rebooting
> +=========
> +
> + reboot=b[ios] | t[riple] | k[bd] | a[cpi] | e[fi] [, [w]arm | [c]old]
> + * bios - Use the CPU reboot vector for warm reset
Please use the same convention as the one you used before, e. g.:
* bios
Use the CPU reboot vector for warm reset
and so on.
After such change:
Reviewed-by: Mauro Carvalho Chehab <mchehab+samsung@...nel.org>
> + * warm - Don't set the cold reboot flag
> + * cold - Set the cold reboot flag
> + * triple - Force a triple fault (init)
> + * kbd - Use the keyboard controller. cold reset (default)
> + * acpi - Use the ACPI RESET_REG in the FADT. If ACPI is not configured or
> + the ACPI reset does not work, the reboot path attempts the reset
> + using the keyboard controller.
> + * efi - Use efi reset_system runtime service. If EFI is not configured or
> + the EFI reset does not work, the reboot path attempts the reset using
> + the keyboard controller.
> +
> + Using warm reset will be much faster especially on big memory
> + systems because the BIOS will not go through the memory check.
> + Disadvantage is that not all hardware will be completely reinitialized
> + on reboot so there may be boot problems on some systems.
> +
> + reboot=force
> + Don't stop other CPUs on reboot. This can make reboot more reliable
> + in some cases.
> +
> +Non Executable Mappings
> +=======================
> +
> + noexec=on|off
> + * on - Enable(default)
> + * off - Disable
> +
> +NUMA
> +====
> +
> + numa=off
> + Only set up a single NUMA node spanning all memory.
> +
> + numa=noacpi
> + Don't parse the SRAT table for NUMA setup
> +
> + numa=fake=<size>[MG]
> + If given as a memory unit, fills all system RAM with nodes of
> + size interleaved over physical nodes.
> +
> + numa=fake=<N>
> + If given as an integer, fills all system RAM with N fake nodes
> + interleaved over physical nodes.
> +
> + numa=fake=<N>U
> + If given as an integer followed by 'U', it will divide each
> + physical node into N emulated nodes.
> +
> +ACPI
> +====
> +
> + acpi=off
> + Don't enable ACPI
> + acpi=ht
> + Use ACPI boot table parsing, but don't enable ACPI interpreter
> + acpi=force
> + Force ACPI on (currently not needed)
> + acpi=strict
> + Disable out of spec ACPI workarounds.
> + acpi_sci={edge,level,high,low}
> + Set up ACPI SCI interrupt.
> + acpi=noirq
> + Don't route interrupts
> + acpi=nocmcff
> + Disable firmware first mode for corrected errors. This
> + disables parsing the HEST CMC error source to check if
> + firmware has set the FF flag. This may result in
> + duplicate corrected error reports.
> +
> +PCI
> +===
> +
> + pci=off
> + Don't use PCI
> + pci=conf1
> + Use conf1 access.
> + pci=conf2
> + Use conf2 access.
> + pci=rom
> + Assign ROMs.
> + pci=assign-busses
> + Assign busses
> + pci=irqmask=MASK
> + Set PCI interrupt mask to MASK
> + pci=lastbus=NUMBER
> + Scan up to NUMBER busses, no matter what the mptable says.
> + pci=noacpi
> + Don't use ACPI to set up PCI interrupt routing.
> +
> +IOMMU (input/output memory management unit)
> +===========================================
> +Multiple x86-64 PCI-DMA mapping implementations exist, for example:
> +
> + 1. <lib/dma-direct.c>: use no hardware/software IOMMU at all
> + (e.g. because you have < 3 GB memory).
> + Kernel boot message: "PCI-DMA: Disabling IOMMU"
> +
> + 2. <arch/x86/kernel/amd_gart_64.c>: AMD GART based hardware IOMMU.
> + Kernel boot message: "PCI-DMA: using GART IOMMU"
> +
> + 3. <arch/x86_64/kernel/pci-swiotlb.c> : Software IOMMU implementation. Used
> + e.g. if there is no hardware IOMMU in the system and it is need because
> + you have >3GB memory or told the kernel to us it (iommu=soft))
> + Kernel boot message: "PCI-DMA: Using software bounce buffering
> + for IO (SWIOTLB)"
> +
> + 4. <arch/x86_64/pci-calgary.c> : IBM Calgary hardware IOMMU. Used in IBM
> + pSeries and xSeries servers. This hardware IOMMU supports DMA address
> + mapping with memory protection, etc.
> + Kernel boot message: "PCI-DMA: Using Calgary IOMMU"
> +
> +::
> +
> + iommu=[<size>][,noagp][,off][,force][,noforce]
> + [,memaper[=<order>]][,merge][,fullflush][,nomerge]
> + [,noaperture][,calgary]
> +
> +General iommu options:
> +
> + off
> + Don't initialize and use any kind of IOMMU.
> + noforce
> + Don't force hardware IOMMU usage when it is not needed. (default).
> + force
> + Force the use of the hardware IOMMU even when it is
> + not actually needed (e.g. because < 3 GB memory).
> + soft
> + Use software bounce buffering (SWIOTLB) (default for
> + Intel machines). This can be used to prevent the usage
> + of an available hardware IOMMU.
> +
> +iommu options only relevant to the AMD GART hardware IOMMU:
> +
> + <size>
> + Set the size of the remapping area in bytes.
> + allowed
> + Overwrite iommu off workarounds for specific chipsets.
> + fullflush
> + Flush IOMMU on each allocation (default).
> + nofullflush
> + Don't use IOMMU fullflush.
> + memaper[=<order>]
> + Allocate an own aperture over RAM with size 32MB<<order.
> + (default: order=1, i.e. 64MB)
> + merge
> + Do scatter-gather (SG) merging. Implies "force" (experimental).
> + nomerge
> + Don't do scatter-gather (SG) merging.
> + noaperture
> + Ask the IOMMU not to touch the aperture for AGP.
> + noagp
> + Don't initialize the AGP driver and use full aperture.
> + panic
> + Always panic when IOMMU overflows.
> + calgary
> + Use the Calgary IOMMU if it is available
> +
> +iommu options only relevant to the software bounce buffering (SWIOTLB) IOMMU
> +implementation:
> +
> + swiotlb=<pages>[,force]
> + <pages>
> + Prereserve that many 128K pages for the software IO bounce buffering.
> + force
> + Force all IO through the software TLB.
> +
> +Settings for the IBM Calgary hardware IOMMU currently found in IBM
> +pSeries and xSeries machines
> +
> + calgary=[64k,128k,256k,512k,1M,2M,4M,8M]
> + Set the size of each PCI slot's translation table when using the
> + Calgary IOMMU. This is the size of the translation table itself
> + in main memory. The smallest table, 64k, covers an IO space of
> + 32MB; the largest, 8MB table, can cover an IO space of 4GB.
> + Normally the kernel will make the right choice by itself.
> + calgary=[translate_empty_slots]
> + Enable translation even on slots that have no devices attached to
> + them, in case a device will be hotplugged in the future.
> + calgary=[disable=<PCI bus number>]
> + Disable translation on a given PHB. For
> + example, the built-in graphics adapter resides on the first bridge
> + (PCI bus number 0); if translation (isolation) is enabled on this
> + bridge, X servers that access the hardware directly from user
> + space might stop working. Use this option if you have devices that
> + are accessed from userspace directly on some PCI host bridge.
> + panic
> + Always panic when IOMMU overflows
> +
> +
> +Miscellaneous
> +=============
> +
> + nogbpages
> + Do not use GB pages for kernel direct mappings.
> + gbpages
> + Use GB pages for kernel direct mappings.
> diff --git a/Documentation/x86/x86_64/boot-options.txt b/Documentation/x86/x86_64/boot-options.txt
> deleted file mode 100644
> index abc53886655e..000000000000
> --- a/Documentation/x86/x86_64/boot-options.txt
> +++ /dev/null
> @@ -1,278 +0,0 @@
> -AMD64 specific boot options
> -
> -There are many others (usually documented in driver documentation), but
> -only the AMD64 specific ones are listed here.
> -
> -Machine check
> -
> - Please see Documentation/x86/x86_64/machinecheck for sysfs runtime tunables.
> -
> - mce=off
> - Disable machine check
> - mce=no_cmci
> - Disable CMCI(Corrected Machine Check Interrupt) that
> - Intel processor supports. Usually this disablement is
> - not recommended, but it might be handy if your hardware
> - is misbehaving.
> - Note that you'll get more problems without CMCI than with
> - due to the shared banks, i.e. you might get duplicated
> - error logs.
> - mce=dont_log_ce
> - Don't make logs for corrected errors. All events reported
> - as corrected are silently cleared by OS.
> - This option will be useful if you have no interest in any
> - of corrected errors.
> - mce=ignore_ce
> - Disable features for corrected errors, e.g. polling timer
> - and CMCI. All events reported as corrected are not cleared
> - by OS and remained in its error banks.
> - Usually this disablement is not recommended, however if
> - there is an agent checking/clearing corrected errors
> - (e.g. BIOS or hardware monitoring applications), conflicting
> - with OS's error handling, and you cannot deactivate the agent,
> - then this option will be a help.
> - mce=no_lmce
> - Do not opt-in to Local MCE delivery. Use legacy method
> - to broadcast MCEs.
> - mce=bootlog
> - Enable logging of machine checks left over from booting.
> - Disabled by default on AMD Fam10h and older because some BIOS
> - leave bogus ones.
> - If your BIOS doesn't do that it's a good idea to enable though
> - to make sure you log even machine check events that result
> - in a reboot. On Intel systems it is enabled by default.
> - mce=nobootlog
> - Disable boot machine check logging.
> - mce=tolerancelevel[,monarchtimeout] (number,number)
> - tolerance levels:
> - 0: always panic on uncorrected errors, log corrected errors
> - 1: panic or SIGBUS on uncorrected errors, log corrected errors
> - 2: SIGBUS or log uncorrected errors, log corrected errors
> - 3: never panic or SIGBUS, log all errors (for testing only)
> - Default is 1
> - Can be also set using sysfs which is preferable.
> - monarchtimeout:
> - Sets the time in us to wait for other CPUs on machine checks. 0
> - to disable.
> - mce=bios_cmci_threshold
> - Don't overwrite the bios-set CMCI threshold. This boot option
> - prevents Linux from overwriting the CMCI threshold set by the
> - bios. Without this option, Linux always sets the CMCI
> - threshold to 1. Enabling this may make memory predictive failure
> - analysis less effective if the bios sets thresholds for memory
> - errors since we will not see details for all errors.
> - mce=recovery
> - Force-enable recoverable machine check code paths
> -
> - nomce (for compatibility with i386): same as mce=off
> -
> - Everything else is in sysfs now.
> -
> -APICs
> -
> - apic Use IO-APIC. Default
> -
> - noapic Don't use the IO-APIC.
> -
> - disableapic Don't use the local APIC
> -
> - nolapic Don't use the local APIC (alias for i386 compatibility)
> -
> - pirq=... See Documentation/x86/i386/IO-APIC.txt
> -
> - noapictimer Don't set up the APIC timer
> -
> - no_timer_check Don't check the IO-APIC timer. This can work around
> - problems with incorrect timer initialization on some boards.
> - apicpmtimer
> - Do APIC timer calibration using the pmtimer. Implies
> - apicmaintimer. Useful when your PIT timer is totally
> - broken.
> -
> -Timing
> -
> - notsc
> - Deprecated, use tsc=unstable instead.
> -
> - nohpet
> - Don't use the HPET timer.
> -
> -Idle loop
> -
> - idle=poll
> - Don't do power saving in the idle loop using HLT, but poll for rescheduling
> - event. This will make the CPUs eat a lot more power, but may be useful
> - to get slightly better performance in multiprocessor benchmarks. It also
> - makes some profiling using performance counters more accurate.
> - Please note that on systems with MONITOR/MWAIT support (like Intel EM64T
> - CPUs) this option has no performance advantage over the normal idle loop.
> - It may also interact badly with hyperthreading.
> -
> -Rebooting
> -
> - reboot=b[ios] | t[riple] | k[bd] | a[cpi] | e[fi] [, [w]arm | [c]old]
> - bios Use the CPU reboot vector for warm reset
> - warm Don't set the cold reboot flag
> - cold Set the cold reboot flag
> - triple Force a triple fault (init)
> - kbd Use the keyboard controller. cold reset (default)
> - acpi Use the ACPI RESET_REG in the FADT. If ACPI is not configured or the
> - ACPI reset does not work, the reboot path attempts the reset using
> - the keyboard controller.
> - efi Use efi reset_system runtime service. If EFI is not configured or the
> - EFI reset does not work, the reboot path attempts the reset using
> - the keyboard controller.
> -
> - Using warm reset will be much faster especially on big memory
> - systems because the BIOS will not go through the memory check.
> - Disadvantage is that not all hardware will be completely reinitialized
> - on reboot so there may be boot problems on some systems.
> -
> - reboot=force
> -
> - Don't stop other CPUs on reboot. This can make reboot more reliable
> - in some cases.
> -
> -Non Executable Mappings
> -
> - noexec=on|off
> -
> - on Enable(default)
> - off Disable
> -
> -NUMA
> -
> - numa=off Only set up a single NUMA node spanning all memory.
> -
> - numa=noacpi Don't parse the SRAT table for NUMA setup
> -
> - numa=fake=<size>[MG]
> - If given as a memory unit, fills all system RAM with nodes of
> - size interleaved over physical nodes.
> -
> - numa=fake=<N>
> - If given as an integer, fills all system RAM with N fake nodes
> - interleaved over physical nodes.
> -
> - numa=fake=<N>U
> - If given as an integer followed by 'U', it will divide each
> - physical node into N emulated nodes.
> -
> -ACPI
> -
> - acpi=off Don't enable ACPI
> - acpi=ht Use ACPI boot table parsing, but don't enable ACPI
> - interpreter
> - acpi=force Force ACPI on (currently not needed)
> -
> - acpi=strict Disable out of spec ACPI workarounds.
> -
> - acpi_sci={edge,level,high,low} Set up ACPI SCI interrupt.
> -
> - acpi=noirq Don't route interrupts
> -
> - acpi=nocmcff Disable firmware first mode for corrected errors. This
> - disables parsing the HEST CMC error source to check if
> - firmware has set the FF flag. This may result in
> - duplicate corrected error reports.
> -
> -PCI
> -
> - pci=off Don't use PCI
> - pci=conf1 Use conf1 access.
> - pci=conf2 Use conf2 access.
> - pci=rom Assign ROMs.
> - pci=assign-busses Assign busses
> - pci=irqmask=MASK Set PCI interrupt mask to MASK
> - pci=lastbus=NUMBER Scan up to NUMBER busses, no matter what the mptable says.
> - pci=noacpi Don't use ACPI to set up PCI interrupt routing.
> -
> -IOMMU (input/output memory management unit)
> -
> - Multiple x86-64 PCI-DMA mapping implementations exist, for example:
> -
> - 1. <lib/dma-direct.c>: use no hardware/software IOMMU at all
> - (e.g. because you have < 3 GB memory).
> - Kernel boot message: "PCI-DMA: Disabling IOMMU"
> -
> - 2. <arch/x86/kernel/amd_gart_64.c>: AMD GART based hardware IOMMU.
> - Kernel boot message: "PCI-DMA: using GART IOMMU"
> -
> - 3. <arch/x86_64/kernel/pci-swiotlb.c> : Software IOMMU implementation. Used
> - e.g. if there is no hardware IOMMU in the system and it is need because
> - you have >3GB memory or told the kernel to us it (iommu=soft))
> - Kernel boot message: "PCI-DMA: Using software bounce buffering
> - for IO (SWIOTLB)"
> -
> - 4. <arch/x86_64/pci-calgary.c> : IBM Calgary hardware IOMMU. Used in IBM
> - pSeries and xSeries servers. This hardware IOMMU supports DMA address
> - mapping with memory protection, etc.
> - Kernel boot message: "PCI-DMA: Using Calgary IOMMU"
> -
> - iommu=[<size>][,noagp][,off][,force][,noforce]
> - [,memaper[=<order>]][,merge][,fullflush][,nomerge]
> - [,noaperture][,calgary]
> -
> - General iommu options:
> - off Don't initialize and use any kind of IOMMU.
> - noforce Don't force hardware IOMMU usage when it is not needed.
> - (default).
> - force Force the use of the hardware IOMMU even when it is
> - not actually needed (e.g. because < 3 GB memory).
> - soft Use software bounce buffering (SWIOTLB) (default for
> - Intel machines). This can be used to prevent the usage
> - of an available hardware IOMMU.
> -
> - iommu options only relevant to the AMD GART hardware IOMMU:
> - <size> Set the size of the remapping area in bytes.
> - allowed Overwrite iommu off workarounds for specific chipsets.
> - fullflush Flush IOMMU on each allocation (default).
> - nofullflush Don't use IOMMU fullflush.
> - memaper[=<order>] Allocate an own aperture over RAM with size 32MB<<order.
> - (default: order=1, i.e. 64MB)
> - merge Do scatter-gather (SG) merging. Implies "force"
> - (experimental).
> - nomerge Don't do scatter-gather (SG) merging.
> - noaperture Ask the IOMMU not to touch the aperture for AGP.
> - noagp Don't initialize the AGP driver and use full aperture.
> - panic Always panic when IOMMU overflows.
> - calgary Use the Calgary IOMMU if it is available
> -
> - iommu options only relevant to the software bounce buffering (SWIOTLB) IOMMU
> - implementation:
> - swiotlb=<pages>[,force]
> - <pages> Prereserve that many 128K pages for the software IO
> - bounce buffering.
> - force Force all IO through the software TLB.
> -
> - Settings for the IBM Calgary hardware IOMMU currently found in IBM
> - pSeries and xSeries machines:
> -
> - calgary=[64k,128k,256k,512k,1M,2M,4M,8M]
> - calgary=[translate_empty_slots]
> - calgary=[disable=<PCI bus number>]
> - panic Always panic when IOMMU overflows
> -
> - 64k,...,8M - Set the size of each PCI slot's translation table
> - when using the Calgary IOMMU. This is the size of the translation
> - table itself in main memory. The smallest table, 64k, covers an IO
> - space of 32MB; the largest, 8MB table, can cover an IO space of
> - 4GB. Normally the kernel will make the right choice by itself.
> -
> - translate_empty_slots - Enable translation even on slots that have
> - no devices attached to them, in case a device will be hotplugged
> - in the future.
> -
> - disable=<PCI bus number> - Disable translation on a given PHB. For
> - example, the built-in graphics adapter resides on the first bridge
> - (PCI bus number 0); if translation (isolation) is enabled on this
> - bridge, X servers that access the hardware directly from user
> - space might stop working. Use this option if you have devices that
> - are accessed from userspace directly on some PCI host bridge.
> -
> -Miscellaneous
> -
> - nogbpages
> - Do not use GB pages for kernel direct mappings.
> - gbpages
> - Use GB pages for kernel direct mappings.
> diff --git a/Documentation/x86/x86_64/index.rst b/Documentation/x86/x86_64/index.rst
> new file mode 100644
> index 000000000000..a8cf7713cac9
> --- /dev/null
> +++ b/Documentation/x86/x86_64/index.rst
> @@ -0,0 +1,10 @@
> +.. SPDX-License-Identifier: GPL-2.0
> +
> +==============
> +x86_64 Support
> +==============
> +
> +.. toctree::
> + :maxdepth: 2
> +
> + boot-options
Thanks,
Mauro
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