Messages in this thread | | | Date | Thu, 24 Jun 2021 15:38:18 +0200 | From | Greg KH <> | Subject | Re: [PATCH 3/6] PCI: Indicate that we want to force strict DMA for untrusted devices |
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On Mon, Jun 21, 2021 at 04:52:45PM -0700, Douglas Anderson wrote: > At the moment the generic IOMMU framework reaches into the PCIe device > to check the "untrusted" state and uses this information to figure out > if it should be running the IOMMU in strict or non-strict mode. Let's > instead set the new boolean in "struct device" to indicate when we > want forced strictness. > > NOTE: we still continue to set the "untrusted" bit in PCIe since that > apparently is used for more than just IOMMU strictness. It probably > makes sense for a later patchset to clarify all of the other needs we > have for "untrusted" PCIe devices (perhaps add more booleans into the > "struct device") so we can fully eliminate the need for the IOMMU > framework to reach into a PCIe device.
It feels like the iommu code should not be messing with pci devices at all, please don't do this.
Why does this matter? Why wouldn't a pci device use "strict" iommu at all times? What happens if it does not? Why are PCI devices special?
greg k-h
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