linux-kernel - Re: [PATCH RFC v6 05/26] nova-core: mm: Add support to use PRAMIN windows to write to VRAM

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Message-ID: <cea5ddbf-8a6f-409e-bd15-b838a1dd0f65@nvidia.com>
Date: Fri, 30 Jan 2026 19:21:20 -0800
From: John Hubbard <jhubbard@...dia.com>
To: Dave Airlie <airlied@...il.com>, Joel Fernandes <joelagnelf@...dia.com>
Cc: Danilo Krummrich <dakr@...nel.org>, Zhi Wang <zhiw@...dia.com>,
 linux-kernel@...r.kernel.org,
 Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>,
 Maxime Ripard <mripard@...nel.org>, Thomas Zimmermann <tzimmermann@...e.de>,
 Simona Vetter <simona@...ll.ch>, Jonathan Corbet <corbet@....net>,
 Alex Deucher <alexander.deucher@....com>,
 Christian Koenig <christian.koenig@....com>,
 Jani Nikula <jani.nikula@...ux.intel.com>,
 Joonas Lahtinen <joonas.lahtinen@...ux.intel.com>,
 Rodrigo Vivi <rodrigo.vivi@...el.com>, Tvrtko Ursulin
 <tursulin@...ulin.net>, Rui Huang <ray.huang@....com>,
 Matthew Auld <matthew.auld@...el.com>,
 Matthew Brost <matthew.brost@...el.com>,
 Lucas De Marchi <lucas.demarchi@...el.com>,
 Thomas Hellstrom <thomas.hellstrom@...ux.intel.com>,
 Helge Deller <deller@....de>, Alice Ryhl <aliceryhl@...gle.com>,
 Miguel Ojeda <ojeda@...nel.org>, Alex Gaynor <alex.gaynor@...il.com>,
 Boqun Feng <boqun.feng@...il.com>, Gary Guo <gary@...yguo.net>,
 Bjorn Roy Baron <bjorn3_gh@...tonmail.com>, Benno Lossin
 <lossin@...nel.org>, Andreas Hindborg <a.hindborg@...nel.org>,
 Trevor Gross <tmgross@...ch.edu>, Alistair Popple <apopple@...dia.com>,
 Timur Tabi <ttabi@...dia.com>, Edwin Peer <epeer@...dia.com>,
 Alexandre Courbot <acourbot@...dia.com>, Andrea Righi <arighi@...dia.com>,
 Andy Ritger <aritger@...dia.com>, Alexey Ivanov <alexeyi@...dia.com>,
 Balbir Singh <balbirs@...dia.com>, Philipp Stanner <phasta@...nel.org>,
 Elle Rhumsaa <elle@...thered-steel.dev>,
 Daniel Almeida <daniel.almeida@...labora.com>,
 nouveau@...ts.freedesktop.org, dri-devel@...ts.freedesktop.org,
 rust-for-linux@...r.kernel.org, linux-doc@...r.kernel.org,
 amd-gfx@...ts.freedesktop.org, intel-gfx@...ts.freedesktop.org,
 intel-xe@...ts.freedesktop.org, linux-fbdev@...r.kernel.org
Subject: Re: [PATCH RFC v6 05/26] nova-core: mm: Add support to use PRAMIN
 windows to write to VRAM

On 1/30/26 7:00 PM, Dave Airlie wrote:
> On Sat, 31 Jan 2026 at 07:14, Joel Fernandes <joelagnelf@...dia.com> wrote:
>> On 1/29/2026 10:38 PM, John Hubbard wrote:
>>> On 1/29/26 5:59 PM, Joel Fernandes wrote:
>>>> On 1/29/26 8:12 PM, John Hubbard wrote:
>>>>> On 1/29/26 4:26 PM, Joel Fernandes wrote:
>>>>>> [...]
>> Will work on these issues for the v7. Thanks,
> 
> The way this works on nouveau at least (and I haven't yet read the
> nova code in depth).
> 
> Is we have 4 stages of vmm page table mgmt.
> 
> ref - locked with a ref lock - can allocate/free memory - just makes
> sure the page tables exist and are reference counted
> map - locked with a map lock - cannot allocate memory - fill in the
> PTEs in the page table
> unmap - locked with a map lock - cannot allocate memory - removes
> entries in PTEs
> unref - locked with a ref lock - can allocate/free memory - just drops
> references and frees (not sure if it ever merges).
> 
> So maps and unmaps can be in fence signalling paths, but unrefs are
> done in free job from a workqueue.
> 

Nice! Thanks Dave, I guess this is one time we really should have
taken a peek at nouveau for inspiration after all. :)

thanks,
-- 
John Hubbard