linux-kernel - Re: [PATCH RFC] staging: Add driver to communicate with the T2 Security Chip

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:
 <PN3PR01MB9597793C256B5A16048ADBFDB8D72@PN3PR01MB9597.INDPRD01.PROD.OUTLOOK.COM>
Date: Sun, 9 Mar 2025 09:03:29 +0000
From: Aditya Garg <gargaditya08@...e.com>
To: "gregkh@...uxfoundation.org" <gregkh@...uxfoundation.org>
CC: "bhelgaas@...gle.com" <bhelgaas@...gle.com>, "joro@...tes.org"
	<joro@...tes.org>, "will@...nel.org" <will@...nel.org>,
	"robin.murphy@....com" <robin.murphy@....com>,
	"andriy.shevchenko@...ux.intel.com" <andriy.shevchenko@...ux.intel.com>,
	"linux-staging@...ts.linux.dev" <linux-staging@...ts.linux.dev>, Linux Kernel
 Mailing List <linux-kernel@...r.kernel.org>, "linux-pci@...r.kernel.org"
	<linux-pci@...r.kernel.org>, "iommu@...ts.linux.dev" <iommu@...ts.linux.dev>,
	Aun-Ali Zaidi <admin@...eit.net>, "paul@...rm.io" <paul@...rm.io>, Orlando
 Chamberlain <orlandoch.dev@...il.com>
Subject: Re: [PATCH RFC] staging: Add driver to communicate with the T2
 Security Chip



> On 9 Mar 2025, at 2:24 PM, gregkh@...uxfoundation.org wrote:
> 
> On Sun, Mar 09, 2025 at 08:40:31AM +0000, Aditya Garg wrote:
>> From: Paul Pawlowski <paul@...rm.io>
>> 
>> This patch adds a driver named apple-bce, to add support for the T2
>> Security Chip found on certain Macs.
>> 
>> The driver has 3 main components:
>> 
>> BCE (Buffer Copy Engine) - this is what the files in the root directory
>> are for. This estabilishes a basic communication channel with the T2.
>> VHCI and Audio both require this component.
> 
> So this is a new "bus" type?  Or a platform resource?  Or something
> else?

It's a PCI device
> 
>> VHCI - this is a virtual USB host controller; keyboard, mouse and
>> other system components are provided by this component (other
>> drivers use this host controller to provide more functionality).
> 
> I don't understand, why does a security chip have a USB virtual
> interface in it?  What "devices" hang off of it that are found and
> enumerated by the host OS?

The t2 chip not only handles security, but also has a usb hub, which connects the internal keyboard, trackpad, touchbar, webcam, and other internal devices. The external usb ports are separate.
> 
> And what other drivers use this controller, just normal Linux drivers,
> or vendor-specific ones?

The already upstream drivers like hid-Apple etc will use this, basically depending upon what usb device is exposed.
> 
>> Audio - a driver for the T2 audio interface, currently only audio
>> output is supported.
> 
> Again, is this a platform device or does it sit on the BCE "bus" you
> will create here?
Again, audio video encoders are also a part of this chip.

You can say this chip is more of a co processor.
> 
> thanks,
> 
> greg k-h