On Mon, 09 Feb 2026 22:14:04 +0000,
Colton Lewis <[email protected]> wrote:
>
> We may want a partitioned PMU but not have FEAT_FGT to untrap the
> specific registers that would normally be untrapped. Add a handler for
> those registers in the fast path so we can still get a performance
> boost from partitioning.
>
> The idea is to handle traps for all the PMU registers quickly by
> writing directly to the hardware when possible instead of hooking into
> the emulated vPMU as the standard handlers in sys_regs.c do.
This seems extremely premature. My assumption is that PMU traps are
rare, and that doing a full exit should be acceptable. Until you
demonstrate the contrary, I don't want this sort of massive bloat in
the most performance-critical path.
"Start walking before you try to run".
M.
--
Without deviation from the norm, progress is not possible.
