2025-05-07 Official Meeting Notes
Date
May 7, 2025
Disclosures
Participants
Agenda
Approval
Updates and PoWs
Reminders (5 min) - via email if not enough time
TSC Overflow
Meeting by Correspondence (Rafael, Greg)
(New PoW) Server SOC II TG (Ved Shanbhogue, Rivos)
(New PoW) Automotive SIG (Thomas Roecker, Sam Visalli)
Presentations
Title | Presenter | File | |
|---|---|---|---|
| 1 | Speculation Barriers - Proposal Of WorkOverview | Ved Shanbhogue |
|
Votes
Notes & Action Items
Action Items
None.
Summary
Quick recap
The meeting covered various administrative matters, including welcoming a new representative, approving minutes, and discussing upcoming elections. Technical discussions focused on matrix extensions, speculation barriers, instruction trace systems, and longer instruction encodings, with task groups formed or proposed to address these topics. The meeting also touched on developer relations, communication strategies, and upcoming events.
Opening Remarks
Jeff welcomed new TSC representative Marcel and discussed the agenda. The team approved the April 5th meeting minutes and discussed the disbanding of two groups, the Debug TG and the RVV Intrinsics TG, as they have completed their work. The team also discussed the upcoming elections for three positions and the strategic priorities for the coming year. Jeff also mentioned the call for candidates for the three elected positions and the process for the elections.
Matrix Extensions Update
Andrea provided an update on the matrix and matrix extensions. He discussed the technical content and process of the discussions, emphasizing that no decisions were made and no votes were requested. He also mentioned the creation of a survey to collect opinions from all members, which showed interest in the vector matrix extension. Andrea stressed the importance of integrating these extensions into software frameworks and the need for a unified message. He also mentioned the possibility of creating a new task group for the vector matrix extension. Charlie raised concerns about the polling process, suggesting it should be appropriate and follow the process. Guy expressed difficulty in interpreting the poll results and suggested that the IME and AME groups should determine their own charters through a formal vote.
Andrea, Guy, and Charlie had a constructive discussion about revisiting the charter of the Ame and Ime task groups. They considered the possibility of extending the charter and the formation of a third task group. The board is putting pressure on the task groups to present their ratification plans, with a focus on math fix extensions. The unified API for tool chains and runtime was also discussed, with the task groups planning to form a group to work on this. The conversation ended with Vedvyas presenting a proposal of work or speculation barriers.
Speculation Barriers TG Proposal
Vedvyas proposed a work for speculation barriers to defend against transient execution attacks, such as Spectre and Meltdown. The attack technique involves a 5-step process, including preparing the micro-architectural state, invoking a trigger instruction, executing additional instructions, and eventually flushing the transient instructions. The objective of the speculation barriers is to ensure that speculative execution does not expose data through timing channels, enabling system designers to mitigate these attacks, particularly important for high assurance systems or critical infrastructure. The work will involve developing a threat model, evaluating the performance of the new instructions, and updating the spy accumulator and the sales reference model. The Tg will collaborate with the privacy, apps, and tool organizations.
Vedvyas discussed the challenges of micro-architecture in addressing in-domain attacks and the need for new instructions to provide better control over speculation boundaries. Siqi asked about the advantages of introducing new instructions compared to a micro-architectural approach, to which Vedvyas explained that the new instructions help address the problem of in-domain attacks in a more performant way. Ravi clarified that the approach is complementary to other discussions in the security HC. Jeff clarified that the next step would be to proceed to community review after TSC approval.