From: Paolo Bonzini <pbonzini@redhat.com>
To: "Christian König" <christian.koenig@amd.com>,
linux-kernel@vger.kernel.org, kvm@vger.kernel.org
Cc: Boris Brezillon <boris.brezillon@collabora.com>,
Thomas Zimmermann <tzimmermann@suse.de>,
David Hildenbrand <david@kernel.org>,
Michal Hocko <mhocko@suse.com>, Sergio Lopez <slp@redhat.com>,
Huang Rui <ray.huang@amd.com>,
bcm-kernel-feedback-list@broadcom.com,
dri-devel@lists.freedesktop.org, linux-mm@kvack.org
Subject: Re: [PATCH RFT 3/3] drm/ttm, drm/vmwgfx: directly create writable PTEs when mkwrite is in use
Date: Wed, 5 Aug 2026 16:48:45 +0200 [thread overview]
Message-ID: <12bd995c-e320-47c9-adb1-fff3a14bddc7@redhat.com> (raw)
In-Reply-To: <c1652ce8-0b0a-49a1-a842-bf1a5290cc1a@amd.com>
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
next prev parent reply other threads:[~2026-08-05 14:49 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-07-31 16:43 [PATCH RFT 0/3] mm, drm: ensure .fault() does not have to be followed by .pfn_mkwrite() for write faults Paolo Bonzini
2026-07-31 16:43 ` [PATCH RFT 1/3] mm: export variants of vmf_insert_pfn* for use with pfn_mkwrite() Paolo Bonzini
2026-08-03 12:16 ` David Hildenbrand (Arm)
2026-08-04 13:52 ` Christoph Hellwig
2026-08-04 14:35 ` Paolo Bonzini
2026-07-31 16:43 ` [PATCH RFT 2/3] drm/shmem_helper: use vmf_insert_pfn_mkwrite() Paolo Bonzini
2026-07-31 17:06 ` sashiko-bot
2026-08-03 9:55 ` Boris Brezillon
2026-07-31 16:43 ` [PATCH RFT 3/3] drm/ttm, drm/vmwgfx: directly create writable PTEs when mkwrite is in use Paolo Bonzini
2026-07-31 17:04 ` sashiko-bot
2026-08-05 12:58 ` Christian König
2026-08-05 14:48 ` Paolo Bonzini [this message]
2026-08-03 7:30 ` [PATCH RFT 0/3] mm, drm: ensure .fault() does not have to be followed by .pfn_mkwrite() for write faults Sergio Lopez Pascual
2026-08-03 11:54 ` David Hildenbrand (Arm)
2026-08-03 14:19 ` Paolo Bonzini
2026-08-03 15:18 ` David Hildenbrand (Arm)
2026-08-04 7:50 ` Paolo Bonzini
2026-08-04 12:19 ` David Hildenbrand (Arm)
2026-08-03 16:52 ` Paolo Bonzini
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