Re: [PATCH v2 00/11] PCI: Fix ATS deadlock

[Joerg Roedel <jroedel@suse.de>]

Hi Bjorn,

On Mon, Jul 20, 2015 at 07:13:49PM -0500, Bjorn Helgaas wrote:
> Bjorn Helgaas (11):
>       iommu/vt-d: Cache PCI ATS state and Invalidate Queue Depth
>       PCI: Allocate ATS struct during enumeration
>       PCI: Embed ATS info directly into struct pci_dev
>       PCI: Reduce size of ATS structure elements
>       PCI: Rationalize pci_ats_queue_depth() error checking
>       PCI: Inline the ATS setup code into pci_ats_init()
>       PCI: Use pci_physfn() rather than looking up physfn by hand
>       PCI: Clean up ATS error handling
>       PCI: Move ATS declarations to linux/pci.h so they're all together
>       PCI: Stop caching ATS Invalidate Queue Depth
>       PCI: Remove pci_ats_enabled()

So while you are at working on ATS, could we probably also introduce a
way to globally disable ATS on a box from the kernel command line
(pci=noats?)? ATS is basically a way for a device to tunnel through the
IOMMU without access checking (because pre-translated requests are not
checked again).

For security reasons it would be good to have a way to disable ATS
completly if desired.



	Joerg