From: Mario Limonciello <mario.limonciello@amd.com>
To: Esther Shimanovich <eshimanovich@chromium.org>,
Mika Westerberg <mika.westerberg@linux.intel.com>
Cc: Dmitry Torokhov <dmitry.torokhov@gmail.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 Apr 2024 14:21:18 -0500 [thread overview]
Message-ID: <7d68a112-0f48-46bf-9f6d-d99b88828761@amd.com> (raw)
In-Reply-To: <CA+Y6NJEpWpfPqHO6=Z1XFCXZDUq1+g6EFryB+Urq1=h0PhT+fg@mail.gmail.com>
On 4/22/2024 14:17, Esther Shimanovich wrote:
> Thanks for the explanation! I still don't fully understand how that
> would work for my use case.
>
> Perhaps it would be better for me to describe the case I am trying to
> protect against.
>
> To rehash, this quirk was written for devices with discrete
> Thunderbolt controllers.
>
> For example,
> CometLake_CPU -> AlpineRidge_Chip -> USB-C Port
> This device has the ExternalFacingPort property in ACPI.
> My quirk relabels the Alpine Ridge chip as "fixed" and
> external-facing, so that devices attached to the USB-C port could be
> labeled as "removable"
>
> Let's say we have a TigerLake CPU, which has integrated
> Thunderbolt/USB4 capabilities:
>
> TigerLake_ThunderboltCPU -> USB-C Port
> This device also has the ExternalFacingPort property in ACPI and lacks
> the usb4-host-interface property in the ACPI.
>
> My worry is that someone could take an Alpine Ridge Chip Thunderbolt
> Dock and attach it to the TigerLake CPU
>
> TigerLake_ThunderboltCPU -> USB-C Port -> AlpineRidge_Dock
>
> If that were to happen, this quirk would incorrectly label the Alpine
> Ridge Dock as "fixed" instead of "removable".
>
> My thinking was that we could prevent this scenario from occurring if
> we filtered this quirk not to apply on CPU's like Tiger Lake, with
> integrated Thunderbolt/USB4 capabilities.
>
> ExternalFacingPort is found both on the Comet Lake ACPI and also on
> the Tiger Lake ACPI. So I can't use that to distinguish between CPUs
> which don't have integrated Thunderbolt, like Comet Lake, and CPUs
> with integrated Thunderbolt, like Tiger Lake.
>
> I am looking for something that can tell me if the device's Root Port
> has the Thunderbolt controller upstream to it or not.
> Is there anything like that?
> Or perhaps should I add a check which compares the name of the
> device's CPU with a list of CPUs that this quirk can be applied to?
> Or is there some way I can identify the Thunderbolt controller, then
> determine if it's upstream or downstream from the root port?
> Or are Alpine Ridge docks not something to worry about at all?
My thought was once you have a device as untrusted, everything else
connected to it should "also" be untrusted.
next prev parent reply other threads:[~2024-04-22 19:21 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
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 [this message]
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
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