From: Mika Westerberg <mika.westerberg@linux.intel.com>
To: Esther Shimanovich <eshimanovich@chromium.org>
Cc: Dmitry Torokhov <dmitry.torokhov@gmail.com>,
Mario Limonciello <mario.limonciello@amd.com>,
Lukas Wunner <lukas@wunner.de>,
Bjorn Helgaas <bhelgaas@google.com>,
linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org,
Rajat Jain <rajatja@google.com>
Subject: Re: [PATCH v4] PCI: Relabel JHL6540 on Lenovo X1 Carbon 7,8
Date: Mon, 22 Jan 2024 08:10:05 +0200 [thread overview]
Message-ID: <20240122061005.GF2543524@black.fi.intel.com> (raw)
In-Reply-To: <CA+Y6NJHhTaroqJKEvOebRvbTdgkxW8tqFvq5MrOVE9swmwmtOw@mail.gmail.com>
On Fri, Jan 19, 2024 at 11:03:18AM -0500, Esther Shimanovich wrote:
> On Thu, Jan 18, 2024 at 1:01 AM Mika Westerberg
> <mika.westerberg@linux.intel.com> wrote:
> >
> > Well that's pretty much all Intel Titan Ridge and Maple Ridge based
> > systems. Some early ones did not use IOMMU but all the rest do.
> ...
> > Before Intel Ice Lake it was all discrete and it is still discrete with
> > the Barlow Ridge controller who will have exact same ExternalFacing port
> > as the previous models.
>
> Next week I'll try those devices in our inventory to see if I can find
> another one with this bug. I'll get back to you on that!
>
> On Fri, Jan 19, 2024 at 2:58 AM Mika Westerberg
> <mika.westerberg@linux.intel.com> wrote:
> >
> > Now if I understand the reason behind this patch is actually not about
> > "removability" that much than about identifying a trusted vs. untrusted
> > device and attaching a driver to those. I was under impression that
> > there is already a solution to this in ChromeOS kernel. It has an
> > allowlist of drivers that are allowed to attach these devices and that
> > includes the PCIe port drivers, xhci_hcd and the thunderbolt driver,
> > possibly something else too. Is this not working for your case?
>
> This device shouldn’t be treated as a removable thunderbolt device
> that is enabled by policy because it is an internal device that should
> be trusted in the first place.
> Even so, while learning about this problem I tried modifying the
> ChromeOS policy but it ended up not fixing the issue because it seems
> like there is an expectation for it to see an existing “fixed”
> thunderbolt port before it loads anything else. But the fixed
> thunderbolt port is prevented from enumerating during bootup, before
> the policy has a chance to work.
Have you contacted the Chrome kernel folks about this? Perhaps they
have thought about this already?
> On Fri, Jan 19, 2024 at 5:23 AM Mika Westerberg
> <mika.westerberg@linux.intel.com> wrote:
> >
> > The below "might" work:
> >
> > 1. A device that is directly behind a PCIe root or downstream port that
> > has ->external_facing == 1.
> >
> > 2. It is a PCIe endpoint.
> >
> > 3. It is a sibling to or has any of the below PCI IDs (see
> > drivers/thunderbolt/nhi.h for the definitions):
>
> External pci devices seem to have the same kinds of chips in them. So
> this wouldn’t distinguish the “fixed but discrete” embedded pci
> devices from the “removable” pcie through usb devices. My monitor with
> thunderbolt capabilities has the JHL7540 chip in it. From the kernel's
> perspective, I have only found that the subsystem id is what
> distinguishes these devices.
>
> That is, unless I am missing something in your proposal that would
> distinguish a fixed JHL6540 chip from an external JHL6540 chip. Please
> correct me on any assumptions I get wrong!
Yes, you are missing the 1. that it needs to be directly behind the PCIe
root or downstream port that is marked as ->external_facing, and the
fact that there can't be NHI's (that's the host controller with the IDs
I listed in 3.) anywhere else except starting the topology according the
USB4 spec (and the same applies to Thunderbolt 1-3).
next prev parent reply other threads:[~2024-01-22 6:10 UTC|newest]
Thread overview: 52+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-12-21 20:53 [PATCH v4] PCI: Relabel JHL6540 on Lenovo X1 Carbon 7,8 Esther Shimanovich
2023-12-21 23:15 ` Dmitry Torokhov
2023-12-27 0:15 ` Bjorn Helgaas
2023-12-28 13:25 ` Lukas Wunner
2023-12-28 13:39 ` Mika Westerberg
2024-01-17 21:21 ` Esther Shimanovich
2024-01-18 6:00 ` Mika Westerberg
2024-01-18 15:47 ` Mario Limonciello
2024-01-18 16:12 ` Dmitry Torokhov
2024-01-18 16:21 ` Dmitry Torokhov
2024-01-19 5:37 ` Mika Westerberg
2024-01-19 7:48 ` Mika Westerberg
2024-01-19 10:22 ` Mika Westerberg
2024-01-19 16:03 ` Esther Shimanovich
2024-01-22 6:10 ` Mika Westerberg [this message]
2024-01-22 23:50 ` Mario Limonciello
2024-01-23 6:18 ` Mika Westerberg
2024-01-25 23:45 ` Esther Shimanovich
2024-04-15 22:34 ` Esther Shimanovich
2024-04-16 5:03 ` Mika Westerberg
2024-04-18 19:43 ` Esther Shimanovich
2024-04-19 4:49 ` Mika Westerberg
2024-04-22 19:17 ` Esther Shimanovich
2024-04-22 19:21 ` Mario Limonciello
2024-04-23 5:33 ` Mika Westerberg
2024-04-23 8:31 ` Lukas Wunner
2024-04-23 8:40 ` Mika Westerberg
2024-04-23 16:59 ` Mario Limonciello
2024-04-24 8:56 ` Mika Westerberg
2024-04-25 21:16 ` Esther Shimanovich
2024-04-26 4:52 ` Mika Westerberg
2024-04-26 15:58 ` Esther Shimanovich
2024-04-27 5:35 ` Lukas Wunner
2024-04-27 7:41 ` Mika Westerberg
2024-04-27 7:08 ` Lukas Wunner
2024-04-27 15:09 ` Lukas Wunner
2024-05-01 22:23 ` Esther Shimanovich
2024-05-02 4:38 ` Mika Westerberg
2024-05-02 9:54 ` Mario Limonciello
2024-05-02 10:07 ` Mika Westerberg
2024-05-08 5:14 ` Lukas Wunner
2024-05-10 5:26 ` Mika Westerberg
2024-05-10 15:44 ` Esther Shimanovich
2024-05-11 4:38 ` Mika Westerberg
2024-05-11 5:43 ` Mika Westerberg
2024-05-15 18:53 ` Esther Shimanovich
2024-05-15 20:35 ` Lukas Wunner
2024-05-15 20:51 ` Lukas Wunner
2024-05-15 21:44 ` Esther Shimanovich
2024-05-16 8:30 ` Mika Westerberg
2024-05-16 10:03 ` Mika Westerberg
2024-05-16 9:16 ` Mika Westerberg
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20240122061005.GF2543524@black.fi.intel.com \
--to=mika.westerberg@linux.intel.com \
--cc=bhelgaas@google.com \
--cc=dmitry.torokhov@gmail.com \
--cc=eshimanovich@chromium.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-pci@vger.kernel.org \
--cc=lukas@wunner.de \
--cc=mario.limonciello@amd.com \
--cc=rajatja@google.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).