2025-02-25 Ordinary Meeting Notes

Date

Feb 25, 2025

Disclosures

Participants

Agenda

Discussion over dropping support for setinvtag

Presentations

	Title	Presenter	File

	Title	Presenter	File
1
2

Notes & Action Items

We had a discussion topic of weirdness due to setinvtag and it’s interaction with 4 bit tagging. In case of 7 bit tagging, invalid mc_tag is possible to due extra bit available in 8 bit mc_tag. However 4 bit tagging chooses an encoding from pointer_tag to denote invalid tagging (due to non-availability of free bit in mc_tag for 4 bit tagging). This also forces a requirement on pointer tag generation flows in hardware and software to avoid invalid tag encoding.

TG reviewed the options of

Dropping setinvtag support and keeping 7 bit tagging. Future sub extension can be done to allow hardware aware invalid tags.

Dropping setinvtag and 7 bit tagging support. Future sub extension can be done to allow 7 bit tagging and introduce invalid tag notion.

TG opted to go with option of dropping setinvtag and keeping 7-bit tagging in specification. If a future sub extension is required to introduce the notion of hardware aware invalid tags, it can be in future. Current use case of hardware invalid tag is only creating red-zones (inaccessible) and particularly an orthogonal usecase. While 7 bit tagging allows implementer to have larger tag size and has more potential value.

Meeting recordings

Video Conferencing, Web Conferencing, Webinars, Screen Sharing

Memory Tagging