diff options
Diffstat (limited to 'arch/x86/Kconfig')
| -rw-r--r-- | arch/x86/Kconfig | 23 |
1 files changed, 22 insertions, 1 deletions
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index db7512008ff7..cadea3f3161e 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -1326,7 +1326,28 @@ config MICROCODE_LATE_LOADING is a tricky business and should be avoided if possible. Just the sequence of synchronizing all cores and SMT threads is one fragile dance which does not guarantee that cores might not softlock after the loading. Therefore, - use this at your own risk. Late loading taints the kernel too. + use this at your own risk. Late loading taints the kernel unless the + microcode header indicates that it is safe for late loading via the + minimal revision check. This minimal revision check can be enforced on + the kernel command line with "microcode.minrev=Y". + +config MICROCODE_LATE_FORCE_MINREV + bool "Enforce late microcode loading minimal revision check" + default n + depends on MICROCODE_LATE_LOADING + help + To prevent that users load microcode late which modifies already + in use features, newer microcode patches have a minimum revision field + in the microcode header, which tells the kernel which minimum + revision must be active in the CPU to safely load that new microcode + late into the running system. If disabled the check will not + be enforced but the kernel will be tainted when the minimal + revision check fails. + + This minimal revision check can also be controlled via the + "microcode.minrev" parameter on the kernel command line. + + If unsure say Y. config X86_MSR tristate "/dev/cpu/*/msr - Model-specific register support" |