We check the ATS state (enabled/disabled) and fetch the PCI ATS Invalidate
Queue Depth in performance-sensitive paths. It's easy to cache these,
which removes dependencies on PCI.
Remember the ATS enabled state. When enabling, read the queue depth once
and cache it in the device_domain_info struct. This is similar to what
amd_iommu.c does.
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Joerg Roedel <jroedel@suse.de>
Acked-by: Joerg Roedel <jroedel@suse.de>
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