linux-kernel - Re: [PATCH net-next v2 4/5] page_pool: disable sync for cpu for dmabuf memory provider

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: <20241123183351.582aa8ac@kernel.org>
Date: Sat, 23 Nov 2024 18:33:51 -0800
From: Jakub Kicinski <kuba@...nel.org>
To: Samiullah Khawaja <skhawaja@...gle.com>, Mina Almasry
 <almasrymina@...gle.com>
Cc: netdev@...r.kernel.org, Pavel Begunkov <asml.silence@...il.com>, Willem
 de Bruijn <willemb@...gle.com>, Kaiyuan Zhang <kaiyuanz@...gle.com>,
 linux-kernel@...r.kernel.org, "David S. Miller" <davem@...emloft.net>, Eric
 Dumazet <edumazet@...gle.com>, Paolo Abeni <pabeni@...hat.com>, Simon
 Horman <horms@...nel.org>, Jesper Dangaard Brouer <hawk@...nel.org>, Ilias
 Apalodimas <ilias.apalodimas@...aro.org>
Subject: Re: [PATCH net-next v2 4/5] page_pool: disable sync for cpu for
 dmabuf memory provider

On Fri, 22 Nov 2024 14:10:28 -0800 Samiullah Khawaja wrote:
> > > > If you do this you may want to block accepting dmabufs that have CPU
> > > > pages inside them.  
> 
> I believe we should be following the dmabuf API for this purpose, if
> we really want to sync for CPU in. page_pool, and should not assume
> the behaviour of the backing memory.
> 
> The dmabuf exporters are supposed to implement the begin_cpu_access
> (optional) and the sync for cpu is done based on the exporter
> implementation.

DMABUF is a bit of a distraction here.

What's key is that we need to fill in the gap in the driver facing
page_pool API, because DMABUF will not be the only provider we can
plug in.