Feature request for enabling SCTLR_ELx.nAA

[Richard Henderson]

Hi guys,

It would be helpful to have a prctl for enabling nAA.  Since we already have 
task->thread.sctlr_user, it would seem that this would not require any additional overhead 
during __switch_to().

My use case is the QEMU JIT, and being able to make use of LDAR/STLR instead of explicit 
DBM in some cases.  At the moment, I can only make this replacement when the address is 
provably aligned, which is tricky to do with the time budget of a JIT, so the replacement 
rarely triggers.  This ought to make a difference when emulating strongly ordered guests 
like x86.

Thanks,


r~