Re: [PATCH 4/4] x86/speculation: Add PSF mitigation kernel parameters

From: Randy Dunlap
Date: Wed Apr 21 2021 - 12:04:50 EST


Hi,

On 4/21/21 2:01 AM, Ramakrishna Saripalli wrote:
> From: Ramakrishna Saripalli <rk.saripalli@xxxxxxx>
>
> PSF mitigation introduces a new kernel parameter called
> predict_store_fwd.
>
> Signed-off-by: Ramakrishna Saripalli<rk.saripalli@xxxxxxx>
> ---
> Documentation/admin-guide/kernel-parameters.txt | 5 +++++
> 1 file changed, 5 insertions(+)
>
> diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
> index 04545725f187..58f6bd02385b 100644
> --- a/Documentation/admin-guide/kernel-parameters.txt
> +++ b/Documentation/admin-guide/kernel-parameters.txt
> @@ -3940,6 +3940,11 @@
> Format: {"off"}
> Disable Hardware Transactional Memory
>
> + predict_store_fwd [X86] This option controls PSF mitigation
> + off - Turns on PSF mitigation.
> + on - Turns off PSF mitigation.
> + default : on.

This should be formatted more like:

+ predict_store_fwd= [X86] This option controls PSF mitigation
+ off - Turns on PSF mitigation.
+ on - Turns off PSF mitigation.
+ default: on.

But why does "off" turn it on and "on" turn it off?


> +
> preempt= [KNL]
> Select preemption mode if you have CONFIG_PREEMPT_DYNAMIC
> none - Limited to cond_resched() calls
>

thanks.
--
~Randy