On 04/01/18 05:00 PM, Logan Gunthorpe wrote: > > > On 04/01/18 03:35 PM, Alex Williamson wrote: >> Yep, flipping these ACS bits invalidates any IOMMU groups that depend >> on the isolation of that downstream port and I suspect also any peers >> within the same PCI slot of that port and their downstream devices. The >> entire sub-hierarchy grouping needs to be re-evaluated. This >> potentially affects running devices that depend on that isolation, so >> I'm not sure how that happens dynamically. A boot option might be >> easier. Thanks, > Also, considering this further: if you can point me to a way to tell if a device is in an IOMMU group it should be pretty easy to disallow a device that has been assigned to a group from being used in P2P transactions. Logan
