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

[Christoph Hellwig]

On Tue, Jun 16, 2020 at 12:27:35PM -0700, Rajat Jain wrote:
> Need clarification. The flag "untrusted" is currently a part of
> pci_dev struct, and is populated within the PCI subsystem.

Yes, and that is the problem.

> 
> 1) Is your suggestion to move this flag as well as the attribute to
> device core (in "struct device")? This would allow other buses to
> populate/use this flag if they want. By default it'll be set to 0 for
> all devices (PCI subsystem will populate it based on platform info,
> like it does today).
> 
> OR
> 
> 2) Are you suggesting to keep the "untrusted" flag within PCI, but
> attach the sysfs attribute to the base device? (&pci_dev->dev)?

(1).  As for IOMMUs and userspace policy it really should not matter
what bus a device is on if it is external and not trustworthy.