linux-kernel - Re: [PATCH v9 5/9] mailbox: add CIX mailbox driver

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

Message-Id: <6b5f38f7-0557-483b-9252-cfade7a24cf5@app.fastmail.com>
Date: Mon, 14 Jul 2025 17:39:53 +0200
From: "Arnd Bergmann" <arnd@...db.de>
To: "Jassi Brar" <jassisinghbrar@...il.com>,
 "Guomin Chen" <guomin.chen@...tech.com>
Cc: "Rob Herring" <robh@...nel.org>, krzk+dt@...nel.org,
 "Conor Dooley" <conor+dt@...nel.org>,
 "Catalin Marinas" <catalin.marinas@....com>, "Will Deacon" <will@...nel.org>,
 "Peter Chen" <peter.chen@...tech.com>, linux-arm-kernel@...ts.infradead.org,
 devicetree@...r.kernel.org, linux-kernel@...r.kernel.org,
 cix-kernel-upstream@...tech.com, "Marc Zyngier" <maz@...nel.org>,
 "Sudeep Holla" <sudeep.holla@....com>,
 "Kajetan Puchalski" <kajetan.puchalski@....com>,
 "Enric Balletbo" <eballetb@...hat.com>, "Gary Yang" <gary.yang@...tech.com>,
 "Lihua Liu" <Lihua.Liu@...tech.com>
Subject: Re: [PATCH v9 5/9] mailbox: add CIX mailbox driver

On Sun, Jul 13, 2025, at 19:00, Jassi Brar wrote:
> On Tue, Jul 8, 2025 at 8:54 AM Guomin chen <guomin.chen@...tech.com> wrote:
> ....
>> > > +/* [0~7] Fast channel
>> > > + * [8] doorbell base channel
>> > > + * [9]fifo base channel
>> > > + * [10] register base channel
>> > > + */
>> > > +#define MBOX_FAST_IDX          7
>> > > +#define MBOX_DB_IDX            8
>> > > +#define MBOX_FIFO_IDX          9
>> > > +#define MBOX_REG_IDX           10
>> > > +#define CIX_MBOX_CHANS         11
>> > > +
>> > if it is not really a single controller owning different channels,
>> > maybe implement only what you currently use.
>> >
>> As mentioned in the previous email, a single controller can support
>> multiple different channels.
>>
> OK. I am not too worried about having all variants in one driver esp
> when it is manageable and share the code.
> Unless I am overlooking something. Arnd?

My main worry here is that the types are all quite different: while
the doorbell and fast mailboxes are what a lot of other drivers have,
the FIFO mode does not seem to be a good fit for the mailbox subsystem
but instead looks like a more generic firmware interface with variable
length messages.

For those, I think a higher-level driver with fixed data structures
passed through the hardware interface seems more appropriate.

Are there any other mailbox drivers that just use the mailbox to
tunnel variable-length messages?

     Arnd