Re: [PATCH 4/4] pci: export untrusted attribute in sysfs

From: Andy Shevchenko <andy.shevchenko@gmail.com>
To: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Rajat Jain <rajatja@google.com>,
	Christoph Hellwig <hch@infradead.org>,
	David Woodhouse <dwmw2@infradead.org>,
	Lu Baolu <baolu.lu@linux.intel.com>,
	Joerg Roedel <joro@8bytes.org>,
	Bjorn Helgaas <bhelgaas@google.com>,
	"Rafael J. Wysocki" <rjw@rjwysocki.net>,
	Len Brown <lenb@kernel.org>,
	iommu@lists.linux-foundation.org,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	linux-pci <linux-pci@vger.kernel.org>,
	ACPI Devel Maling List <linux-acpi@vger.kernel.org>,
	Raj Ashok <ashok.raj@intel.com>,
	"Krishnakumar,
	Lalithambika" <lalithambika.krishnakumar@intel.com>,
	Mika Westerberg <mika.westerberg@linux.intel.com>,
	Jean-Philippe Brucker <jean-philippe@linaro.org>,
	Prashant Malani <pmalani@google.com>,
	Benson Leung <bleung@google.com>, Todd Broch <tbroch@google.com>,
	Alex Levin <levinale@google.com>,
	Mattias Nissler <mnissler@google.com>,
	Rajat Jain <rajatxjain@gmail.com>,
	Bernie Keany <bernie.keany@intel.com>,
	Aaron Durbin <adurbin@google.com>,
	Diego Rivas <diegorivas@google.com>,
	Duncan Laurie <dlaurie@google.com>,
	Furquan Shaikh <furquan@google.com>,
	Jesse Barnes <jsbarnes@google.com>,
	Christian Kellner <christian@kellner.me>,
	Alex Williamson <alex.williamson@redhat.com>,
	"Oliver O'Halloran" <oohall@gmail.com>
Subject: Re: [PATCH 4/4] pci: export untrusted attribute in sysfs
Date: Thu, 18 Jun 2020 12:14:41 +0300
Message-ID: <CAHp75Vf71f2s6yipHJ4Ys1oe1v7L4PiqBCEbo0uBcG7Wpcs5dQ@mail.gmail.com> (raw)
In-Reply-To: <20200618083646.GA1066967@kroah.com>

On Thu, Jun 18, 2020 at 11:36 AM Greg Kroah-Hartman
<gregkh@linuxfoundation.org> wrote:
>
> On Thu, Jun 18, 2020 at 11:12:56AM +0300, Andy Shevchenko wrote:
> > On Wed, Jun 17, 2020 at 10:56 PM Rajat Jain <rajatja@google.com> wrote:
> > > On Wed, Jun 17, 2020 at 12:31 AM Christoph Hellwig <hch@infradead.org> wrote:
> >
> > ...
> >
> > > (and likely call it "external" instead of "untrusted".
> >
> > Which is not okay. 'External' to what? 'untrusted' has been carefully
> > chosen by the meaning of it.
> > What external does mean for M.2. WWAN card in my laptop? It's in ACPI
> > tables, but I can replace it.
>
> Then your ACPI tables should show this, there is an attribute for it,
> right?

There is a _PLD() method, but it's for the USB devices (or optional
for others, I don't remember by heart). So, most of the ACPI tables,
alas, don't show this.

> > This is only one example. Or if firmware of some device is altered,
> > and it's internal (whatever it means) is it trusted or not?
>
> That is what people are using policy for today, if you object to this,
> please bring it up to those developers :)

> > So, please leave it as is (I mean name).
>
> firmware today exports this attribute, why do you not want userspace to
> also know it?
>
> Trust is different, yes, don't get the two mixed up please.  That should
> be a different sysfs attribute for obvious reasons.

Yes, as a bottom line that's what I meant as well.

-- 
With Best Regards,
Andy Shevchenko