> So here is the simple list of questions all to be answered with YES or > NO. I don't want to see any of the 'but, though ...'. We all know by now > that it's CPU dependent and slow and whatever and that IBRS_ATT will be in > future CPUs. So get your act together and tell a clear YES or NO.
I will answer for current cpus, so those not having IBRS_ATT > > 1) Does IBRS=1 when set once act as a set-and-forget option ? NO > 1a) If the answer to #1 is yes, is it more secure than toggling it? NO > > 1b) If the answer to #1 is yes, is retpoline required ? NO - Once you have IBRS done PROPERLY (toggled) you don't need retpoline > > 1c) If the answer to #1 is yes, is RSB stuffing required ? Only for the VM exit case > > 2) Does toggle mode of IBRS require retpoline ? NO > > 3) Does toggle mode of IBRS require RSB stuffing ? Only for the VM exit case > > 4) Exist CPUs which require IBRS to be selected automatically ? I do not understand your question exactly
