On Wed, Dec 16, 2020 at 10:56:05AM -0600, Josh Poimboeuf wrote: > On Wed, Dec 16, 2020 at 09:40:59AM +0100, Peter Zijlstra wrote: > > > Could we make it easier by caching the shared > > > per-alt-group CFI state somewhere along the way? > > > > Yes, but when I tried it grew the code required. Runtime costs would be > > less, but I figured that since alternatives are typically few and small, > > that wasn't a real consideration. > > Aren't alternatives going to be everywhere now with paravirt using them? What I meant was, they're either 2-3 wide and only a few instructions long. Which greatly bounds the actual complexity of the algorithm, however daft. > > No real objection, I just didn't do it because 1) it works, and 2) even > > moar lines. > > I'm kind of surprised it would need moar lines. Let me play around with > it and maybe I'll come around ;-) Please do, it could be getting all the niggly bits right exhausted my brain enough to miss the obvious ;-)
