Re: [PATCH 6/7] x86/spec_ctrl: Add sysctl knobs to enable/disable SPEC_CTRL feature

Andrea Arcangeli
2018-01-04T18:34:40Z

On Thu, Jan 04, 2018 at 09:56:47AM -0800, Tim Chen wrote:
> There are 2 ways to control IBRS
>
> 1. At boot time
> noibrs kernel boot parameter will disable IBRS usage
>
> Otherwise if the above parameters are not specified, the system
> will enable ibrs and ibpb usage if the cpu supports it.
>
> 2. At run time
> echo 0 > /sys/kernel/debug/ibrs_enabled will turn off IBRS
> echo 1 > /sys/kernel/debug/ibrs_enabled will turn on IBRS in kernel
> echo 2 > /sys/kernel/debug/ibrs_enabled will turn on IBRS in both userspace and kernel

debug/x86/?

Reviewed-by: Andrea Arcangeli <aarcange@redhat.com>

Thanks,
Andrea