[PATCH v1 6/8] iommu: Introduce TDISP T=0 state for confidential IOMMUs

sonang patel sonangp at nvidia.com
Thu Sep 17 03:48:16 PDT 2026


On Wed, 9 Sep 2026 20:32:49 -0700, Nicolin Chen wrote:
> + * @tdisp_t1: device uses its confidential IOMMU's T=1 stream. A zero value
> + *            means T=0, where the T=1 stream remains blocked while the core
> + *            owns required DMA operations such as ATS.

What happens when the TDI transitions to ERROR, and how does this bit
signify it?
A TDI can drop to ERROR asynchronously, and at that point the device is
outside the trust boundary again.

Thanks,
Sonang



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