From: Mika Westerberg <mika.westerberg@linux.intel.com>
To: Lukas Wunner <lukas@wunner.de>
Cc: Esther Shimanovich <eshimanovich@chromium.org>,
Mario Limonciello <mario.limonciello@amd.com>,
Dmitry Torokhov <dmitry.torokhov@gmail.com>,
Bjorn Helgaas <bhelgaas@google.com>,
linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org,
Rajat Jain <rajatja@google.com>,
Gil Fine <gil.fine@linux.intel.com>
Subject: Re: [PATCH v4] PCI: Relabel JHL6540 on Lenovo X1 Carbon 7,8
Date: Sat, 27 Apr 2024 10:41:45 +0300 [thread overview]
Message-ID: <20240427074145.GD3969176@black.fi.intel.com> (raw)
In-Reply-To: <ZiyOpZlHVH2yaC1B@wunner.de>
On Sat, Apr 27, 2024 at 07:35:33AM +0200, Lukas Wunner wrote:
> On Fri, Apr 26, 2024 at 07:52:07AM +0300, Mika Westerberg wrote:
> > On Thu, Apr 25, 2024 at 05:16:24PM -0400, Esther Shimanovich wrote:
> > > I did find one example of a docking station that uses the DSL6540
> > > chip, which has PCI IDs defined in include/linux/pci_ids.h:
> > > #define PCI_DEVICE_ID_INTEL_ALPINE_RIDGE_4C_NHI 0x1577
> > > #define PCI_DEVICE_ID_INTEL_ALPINE_RIDGE_4C_BRIDGE 0x1578
> > > It seems like it has an NHI, despite being in an external, removable
> > > docking station. This appears to contradict what you say about only
> > > having "NHI" on a host router. I am assuming that by host router, you
> > > mean the fixed discrete, fixed thunderbolt chip, or the thunderbolt
> > > controller upstream to the root port. Please correct me if I got
> > > anything wrong!
> >
> > So it goes same way with other discrete chips from Intel at least. It is
> > the same silicon but the NHI is disabled on device routers.
> >
> > That said, it is entirely possible for a "malicious" device to pretend
> > to have one so we need to be careful.
>
> If a device (accidentally or maliciously) exposes an NHI, the thunderbolt
> driver will try to bind to it.
>
> Do we take any precautions to prevent that?
Not at the moment but it will be behind the IOMMU so it cannot access
any other memory that what is reserved for it.
> AFAICS we'd be allocating a duplicate root_switch with route 0.
> Seems dangerous if two driver instances talk to the same Root Switch.
I don't think it even works because it cannot have topology ID of 0 if
it is a device router which it is in this case since it is being first
enumerated by the "real" host.
That said we have not tested this either so can be 100% sure.
next prev parent reply other threads:[~2024-04-27 7:41 UTC|newest]
Thread overview: 41+ 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
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 [this message]
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
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