On Tue, 2012-07-10 at 19:41 -0500, Scott Wood wrote: > On 07/10/2012 07:36 PM, Benjamin Herrenschmidt wrote: > > On Tue, 2012-07-10 at 19:34 -0500, Scott Wood wrote: > >> Unlike classic, we don't really need the MSR change to be atomic with the > >> branch. This eliminates a trap as a KVM guest (in the absence of > >> hardware hypervisor extensions), where mtmsr is paravirtualized but rfi > >> is not. For a virtualized guest without any paravirtualization, this > >> eliminates an additional two traps (SRR0/1). > > > > In fact, I wonder, what do we write into the MSR at this point that > > wasn't already in it in BookE ? RI ? I wonder if we could get away > > without the mtmsr alltogether... > > Doesn't EE get set there for some exceptions?
It does, tho arguably it shouldn't in most cases :-) I'm happy to turn a bunch of these into explicit local_irq_enable() in the C code though which will turn into a wrteei which is more efficient on BookE. Cheers, Ben. _______________________________________________ Linuxppc-dev mailing list Linuxppc-dev@lists.ozlabs.org https://lists.ozlabs.org/listinfo/linuxppc-dev
