diff options
Diffstat (limited to 'Documentation/admin-guide/kernel-parameters.txt')
-rw-r--r-- | Documentation/admin-guide/kernel-parameters.txt | 95 |
1 files changed, 90 insertions, 5 deletions
diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt index 13984b6cc322..db9d53b879f8 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -567,7 +567,13 @@ loops can be debugged more effectively on production systems. - clearcpuid=BITNUM [X86] + clocksource.max_cswd_read_retries= [KNL] + Number of clocksource_watchdog() retries due to + external delays before the clock will be marked + unstable. Defaults to three retries, that is, + four attempts to read the clock under test. + + clearcpuid=BITNUM[,BITNUM...] [X86] Disable CPUID feature X for the kernel. See arch/x86/include/asm/cpufeatures.h for the valid bit numbers. Note the Linux specific bits are not necessarily @@ -1481,6 +1487,8 @@ architectures force reset to be always executed i8042.unlock [HW] Unlock (ignore) the keylock i8042.kbdreset [HW] Reset device connected to KBD port + i8042.probe_defer + [HW] Allow deferred probing upon i8042 probe errors i810= [HW,DRM] @@ -2106,8 +2114,12 @@ Default is 1 (enabled) kvm-intel.emulate_invalid_guest_state= - [KVM,Intel] Enable emulation of invalid guest states - Default is 0 (disabled) + [KVM,Intel] Disable emulation of invalid guest state. + Ignored if kvm-intel.enable_unrestricted_guest=1, as + guest state is never invalid for unrestricted guests. + This param doesn't apply to nested guests (L2), as KVM + never emulates invalid L2 guest state. + Default is 1 (enabled) kvm-intel.flexpriority= [KVM,Intel] Disable FlexPriority feature (TPR shadow). @@ -2667,6 +2679,9 @@ mds=off [X86] tsx_async_abort=off [X86] kvm.nx_huge_pages=off [X86] + no_entry_flush [PPC] + no_uaccess_flush [PPC] + mmio_stale_data=off [X86] Exceptions: This does not have any effect on @@ -2688,6 +2703,7 @@ Equivalent to: l1tf=flush,nosmt [X86] mds=full,nosmt [X86] tsx_async_abort=full,nosmt [X86] + mmio_stale_data=full,nosmt [X86] mminit_loglevel= [KNL] When CONFIG_DEBUG_MEMORY_INIT is set, this @@ -2697,6 +2713,40 @@ log everything. Information is printed at KERN_DEBUG so loglevel=8 may also need to be specified. + mmio_stale_data= + [X86,INTEL] Control mitigation for the Processor + MMIO Stale Data vulnerabilities. + + Processor MMIO Stale Data is a class of + vulnerabilities that may expose data after an MMIO + operation. Exposed data could originate or end in + the same CPU buffers as affected by MDS and TAA. + Therefore, similar to MDS and TAA, the mitigation + is to clear the affected CPU buffers. + + This parameter controls the mitigation. The + options are: + + full - Enable mitigation on vulnerable CPUs + + full,nosmt - Enable mitigation and disable SMT on + vulnerable CPUs. + + off - Unconditionally disable mitigation + + On MDS or TAA affected machines, + mmio_stale_data=off can be prevented by an active + MDS or TAA mitigation as these vulnerabilities are + mitigated with the same mechanism so in order to + disable this mitigation, you need to specify + mds=off and tsx_async_abort=off too. + + Not specifying this option is equivalent to + mmio_stale_data=full. + + For details see: + Documentation/admin-guide/hw-vuln/processor_mmio_stale_data.rst + module.sig_enforce [KNL] When CONFIG_MODULE_SIG is set, this means that modules without (valid) signatures will fail to load. @@ -2989,6 +3039,8 @@ noefi Disable EFI runtime services support. + no_entry_flush [PPC] Don't flush the L1-D cache when entering the kernel. + noexec [IA-64] noexec [X86] @@ -3038,6 +3090,9 @@ nospec_store_bypass_disable [HW] Disable all mitigations for the Speculative Store Bypass vulnerability + no_uaccess_flush + [PPC] Don't flush the L1-D cache after accessing user data. + noxsave [BUGS=X86] Disables x86 extended register state save and restore using xsave. The kernel will fallback to enabling legacy floating-point and sse state. @@ -3787,6 +3842,12 @@ fully seed the kernel's CRNG. Default is controlled by CONFIG_RANDOM_TRUST_CPU. + random.trust_bootloader={on,off} + [KNL] Enable or disable trusting the use of a + seed passed by the bootloader (if available) to + fully seed the kernel's CRNG. Default is controlled + by CONFIG_RANDOM_TRUST_BOOTLOADER. + ras=option[,option,...] [KNL] RAS-specific options cec_disable [X86] @@ -4474,8 +4535,12 @@ Specific mitigations can also be selected manually: retpoline - replace indirect branches - retpoline,generic - google's original retpoline - retpoline,amd - AMD-specific minimal thunk + retpoline,generic - Retpolines + retpoline,lfence - LFENCE; indirect branch + retpoline,amd - alias for retpoline,lfence + eibrs - enhanced IBRS + eibrs,retpoline - enhanced IBRS + Retpolines + eibrs,lfence - enhanced IBRS + LFENCE Not specifying this option is equivalent to spectre_v2=auto. @@ -5144,6 +5209,7 @@ device); j = NO_REPORT_LUNS (don't use report luns command, uas only); + k = NO_SAME (do not use WRITE_SAME, uas only) l = NOT_LOCKABLE (don't try to lock and unlock ejectable media, not on uas); m = MAX_SECTORS_64 (don't transfer more @@ -5444,6 +5510,10 @@ This option is obsoleted by the "nopv" option, which has equivalent effect for XEN platform. + xen_no_vector_callback + [KNL,X86,XEN] Disable the vector callback for Xen + event channel interrupts. + xen_scrub_pages= [XEN] Boolean option to control scrubbing pages before giving them back to Xen, for use by other domains. Can be also changed at runtime @@ -5462,6 +5532,21 @@ as generic guest with no PV drivers. Currently support XEN HVM, KVM, HYPER_V and VMWARE guest. + xen.balloon_boot_timeout= [XEN] + The time (in seconds) to wait before giving up to boot + in case initial ballooning fails to free enough memory. + Applies only when running as HVM or PVH guest and + started with less memory configured than allowed at + max. Default is 180. + + xen.event_eoi_delay= [XEN] + How long to delay EOI handling in case of event + storms (jiffies). Default is 10. + + xen.event_loop_timeout= [XEN] + After which time (jiffies) the event handling loop + should start to delay EOI handling. Default is 2. + xirc2ps_cs= [NET,PCMCIA] Format: <irq>,<irq_mask>,<io>,<full_duplex>,<do_sound>,<lockup_hack>[,<irq2>[,<irq3>[,<irq4>]]] |