linux-kernel - Re: [PATCH Part2 v6 09/49] x86/fault: Add support to handle the RMP fault for user address

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Message-ID: <YvUR6XksBMJ9x0qo@zn.tnic>
Date:   Thu, 11 Aug 2022 16:27:53 +0200
From:   Borislav Petkov <bp@...en8.de>
To:     "Kalra, Ashish" <Ashish.Kalra@....com>
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Subject: Re: [PATCH Part2 v6 09/49] x86/fault: Add support to handle the RMP
 fault for user address

On Wed, Aug 10, 2022 at 10:00:57PM +0000, Kalra, Ashish wrote:
> This is more like a sanity check and returning 1 will cause the fault
> handler to return and ignore the fault for current #PF case. If the
> page got unmapped, the fault will not happen again and there will be
> no retry, so the fault in this case is being ignored.

I know what will happen. I'm asking you to make this explicit in the
code because this separate define documents the situation.

One more return type != 0 won't hurt.

> Ok, so you are suggesting that we remove this check and simply keep
> this function wrapping around __split_huge_pmd(). This becomes a
> generic utility function.

Yes, it is in generic code so it better be generic function. That's why
I'm questioning the vendor-specific check there.

-- 
Regards/Gruss,
    Boris.

https://people.kernel.org/tglx/notes-about-netiquette