lkml.org 
[lkml]   [2023]   [Feb]   [28]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH 1/1] iommu/vt-d: Add opt-in for ATS support on discrete devices
On Tue, Feb 28, 2023 at 10:33:41AM +0800, Lu Baolu wrote:
> In normal processing of PCIe ATS requests, the IOMMU performs address
> translation and returns the device a physical memory address which
> will be stored in that device's IOTLB. The device may subsequently
> issue Translated DMA request containing physical memory address. The
> IOMMU only checks that the device was allowed to issue such requests
> and does not attempt to validate the physical address.
>
> The Intel IOMMU implementation only allows PCIe ATS on several SOC-
> integrated devices which are opt-in’ed through the ACPI tables to
> prevent any compromised device from accessing arbitrary physical
> memory.
>
> Add a kernel option intel_iommu=relax_ats to allow users to have an
> opt-in to allow turning on ATS at as wish, especially for CSP-owned
> vertical devices. In any case, risky devices are not allowed to use
> ATS.

Why is this an intel specific option? all it does is effectively
disable untrusted? Why not a global option? All iommu with ATS will
need this?

Also, why doesn't a "CSP" set their ACPI to make the devices they want
to use ATS with trusted instead of this?

Jason

\
 
 \ /
  Last update: 2023-03-27 00:38    [W:0.066 / U:0.408 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site