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

[Tim Chen]

On 01/04/2018 10:34 AM, Andrea Arcangeli wrote:
> 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@xxxxxxxxxx>
> 
> Thanks,
> Andrea
> 

Yes, will correct.

Thanks.