[shadowfacts]

It is not directly accessible from user-space. Making it so requires kernel support. Apple published a set of patches for doing this on Linux: https://developer.apple.com/documentation/virtualization/acc...

Without that kernel support, all processes in the VM (not just Rosetta-translated ones) are opted-in to TSO:

> Without selective enablement, the system opts all processes into this memory mode [TSO], which degrades performance for native ARM processes that don’t need it.

[mrpippy]

Before Sequoia, a Linux VM using Rosetta would have TSO enabled all the time.

With Sequoia, TSO is not enabled for Linux VMs, and that kernel patch (posted in the last few weeks) is required for Rosetta to be able to enable TSO for itself. If the kernel patch isn't present, Rosetta has a non-TSO fallback mode.