Re: [PATCH RFT 3/3] drm/ttm, drm/vmwgfx: directly create writable PTEs when mkwrite is in use

Paolo Bonzini <[email protected]> Wed, 5 Aug 2026 16:48:45 +0200
Newsgroups gmane.comp.emulators.kvm.devel,gmane.linux.kernel,gmane.comp.video.dri.devel,gmane.linux.kernel.mm
Message-ID <[email protected]>
On 8/5/26 14:58, Christian König wrote:
> On 7/31/26 18:43, Paolo Bonzini wrote:
>> This ensures that fixup_user_fault() users see a writable PTE when 
>> they request one.  The flip side is that vmw_bo_vm_fault() now has 
>> to record by hand the write fault, because .pfn_mkwrite() is not
>> invoked.
>> 
>> Prefaulting works as before because only the first entry comes out
>> writable, while the following ones still end up executing 
>> the .pfn_mkwrite() callback.
> 
> Please split that patch for TTM/VMWGFX. The TTM part looks
> reasonable, but VMGFX is a completely different beast.

Note that the TTM change alone would break vmwgfx without the other 
part.  This is not obvious, and it's why I placed them together given 
the TTM part is just one line of code, but if you prefer I can split 
them (the TTM change can go second).

Let me know if "looks reasonable" counts as "Acked-by" for that part or not.

By the way, see also 
https://lists.freedesktop.org/archives/dri-devel/2026-August/586696.html 
- it touches the same code, and the mistake was noticed by sashiko when 
reviewing this one.

Paolo