linux-kernel - Re: [PATCH v8 01/13] x86: export set_direct_map_valid

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Message-ID: <e402f9b9-84a1-4234-8caf-bb9f2a1e9a2f@amazon.com>
Date: Wed, 14 Jan 2026 13:57:08 +0000
From: Nikita Kalyazin <kalyazin@...zon.com>
To: Dave Hansen <dave.hansen@...el.com>, "Kalyazin, Nikita"
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Subject: Re: [PATCH v8 01/13] x86: export set_direct_map_valid_noflush to KVM
 module



On 05/12/2025 17:26, Dave Hansen wrote:
> On 12/5/25 08:57, Kalyazin, Nikita wrote:
> ...
>> +EXPORT_SYMBOL_FOR_MODULES(set_direct_map_valid_noflush, "kvm");
> 
> I think this export is a bad idea. The interface is abhorrent enough,
> but exporting it just invites abuse and bugs.
> 
> I think what this really needs is a pair of helpers that are just:
> 
>          folio_zap_direct_map()
> and
>          folio_restore_direct_map()
> 
> that take a folio. *Those* can get exported to modules and those should
> internally flush the TLB and not expect callers to do it.

Thanks, implemented in the v9.