Re: [PATCH v1 2/3] virt: tsm: Increase TSM_REPORT_OUTBLOB_MAX to 16MB

[dan.j.williams]

Kuppuswamy Sathyanarayanan wrote:
> Confidential Computing (CoCo) attestation is evolving toward
> standardized models such as DICE (Device Identifier Composition Engine)
> and Post-Quantum Cryptography (PQC), which rely on layered certificate
> chains and larger cryptographic signatures.
> 
> A typical PQC certificate can range from 5KB to 15KB, and DICE-based
> architectures accumulate these certificates across multiple boot
> stages. In such configurations, the total attestation evidence can
> reach several megabytes, exceeding the current 32KB limit.
> 
> Increase TSM_REPORT_OUTBLOB_MAX to 16MB to accommodate these larger
> certificate chains. This provides sufficient headroom to handle
> evolving requirements without requiring frequent updates to the limit.
> 
> TSM_REPORT_OUTBLOB_MAX is used by the configfs read interface to cap
> the maximum allowed binary blob size for outblob, auxblob and
> manifestblob attributes. Hence, the per-open-file worst case memory
> allocation increases from 32KB to 16MB. Multiple concurrent readers
> multiply this cost (e.g., N readers of an M-byte blob incur NxM bytes
> of vmalloc-backed memory). However, allocations are performed on demand
> and remain proportional to the actual blob length, not the configured
> maximum.

Looks ok, again I will change the subject to:

"configfs-tsm-report: Increase TSM_REPORT_OUTBLOB_MAX to 16MB"