linux-kernel - Re: [PATCH 1/1] x86/pti: Fix kernel warnings for pti= and nopti cmdline options.

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Message-ID: <71214e64-0546-0767-3543-963329dab9a3@cs.kuleuven.be>
Date:   Fri, 18 Aug 2023 15:33:04 -0700
From:   Jo Van Bulck <jo.vanbulck@...kuleuven.be>
To:     Sohil Mehta <sohil.mehta@...el.com>, linux-kernel@...r.kernel.org,
        dave.hansen@...ux.intel.com, luto@...nel.org, peterz@...radead.org,
        mingo@...hat.com
Cc:     x86@...nel.org, bp@...en8.de, tglx@...utronix.de, hpa@...or.com
Subject: Re: [PATCH 1/1] x86/pti: Fix kernel warnings for pti= and nopti
 cmdline options.

On 14.08.23 14:12, Sohil Mehta wrote:
> On 8/12/2023 8:54 AM, Jo Van Bulck wrote:
>>   arch/x86/mm/pti.c | 55 ++++++++++++++++++++++++-----------------------
>>   1 file changed, 28 insertions(+), 27 deletions(-)
>>
> 
> This version is very similar to the original patch and much simpler.
> Sorry about the unnecessary churn.
> 
> Apart from the minor nits below,
> Reviewed-by: Sohil Mehta <sohil.mehta@...el.com>

No problem, thanks for the help!

> 
>> +	if (cpu_mitigations_off())
>>   		pti_mode = PTI_FORCE_OFF;
>> +	if (pti_mode == PTI_FORCE_OFF) {
>>   		pti_print_if_insecure("disabled on command line.");
>>   		return;
>>   	}
> 
> A new line here would be useful.

Added in next revision.

> Was there an issue with the flow you had in the original patch? It was
> avoiding the goto label and flow was a bit more linear.

No, the original flow also works and I agree that an explicit PTI_AUTO 
check may indeed be preferable. Reverting this in the next patch iteration.

Best,
Jo