Database/Control plane, storage & DevOps
Linux iommu/vt-d (dev-IOTLB flush in scalable mode): The scalable-mode half of the device-IOTLB invalidation problem —
Impact
The scalable-mode half of the device-IOTLB invalidation problem — ATS invalidation is issued or skipped based on device accessibility, and the earlier fix in this area left a gap. Scalable mode is what modern Intel platforms use for PASID-based device assignment, so this is the current-generation path for handing NIC and accelerator functions to tenants. Same underlying concern: a device retaining stale translations after the host revoked them.
Who can reach it
A tenant with a scalable-mode-assigned, ATS-capable PCIe function.
What to do
Kernel upgrade plus host reboot, rolling across passthrough-capable nodes. Verify after patching that IOMMU is in enforcing (not passthrough/iommu=pt) mode for tenant-assigned devices — a surprising number of performance-tuned GPU hosts run with IOMMU translation effectively disabled, which makes this class of bug moot only because the isolation was never there.
References
This entry is curated: imported from vendor advisories with machine assistance, not yet individually verified. Confirm against your vendor's advisory before acting, and report anything wrong.