Re: [PATCH 6/6] x86/bugs: Clean-up verw mitigations

[Nikolay Borisov <nik.borisov@suse.com>]

On 2.10.24 г. 17:46 ч., Daniel Sneddon wrote:
> On 10/2/24 07:20, Nikolay Borisov wrote:
>>> +	if (boot_cpu_has_bug(X86_BUG_MDS)) {
>>>    		mds_mitigation = MDS_MITIGATION_FULL;
>>>    		mds_select_mitigation();
>>> +	}  else {
>>> +		mds_mitigation = MDS_MITIGATION_OFF;
>>>    	}
>>
>> BUt with this logic if CONFIG_MITIGATION_MDS is deselected meaning
>> mds_mitigations will have the value MDS_MITIGATION_OFF, yet now you will
>> set it to _FULL thereby overriding the compile-time value of the user.
>> So shouldn't this condition be augmented to alsoo consider
>> CONFIG_MITIGATION_MDS compile time value?
> 
> CONFIG_MITIGATION_MDS is used to set the value of the mds_mitigation variable.
> Same goes for all the other mitigations touched here. Those variables are
> checked in verw_mitigations_disabled() which is called just before this code. If
> all of them are configured off, we return without enabling any of the mitigations.

Ah, indeed.

Reviewed-by: Nikolay Borisov <nik.borisov@suse.com>