On Mon, 2016-09-12 at 09:39 +0100, Alex Bennée wrote: > > They are now in Richard's tcg-next queue > > Message-Id: <1473282648-23487-1-git-send-email-...@twiddle.net> > Subject: [Qemu-devel] [PULL 00/18] tcg queued patches > > All the backends support the new fence op, so far only ARM, Alpha and > x86 emit the fence TCGOps as these are best added by someone who > understands the frontend well.
Hrm, I should probably have a look ;-) A bit swamped this week, I'll see what I can do. Cheers, Ben. > > > > > > > > > > > > > > > > > I think this does matter, IIRC a kernel spin unlock on ppc is a > > > > barrier + plain store, no load locked or store conditional. > > > > > > > > > > > > > > > > > > > > > Specifically a racing store which happens to store the same > > > > > > value > > > > > > which was already in memory should clobber the reservation, > > > > > > but won't > > > > > > with this implementation. > > > > > > > > > > > > I had a long discussion at KVM Forum with Emilio Costa > > > > > > about this, in > > > > > > which I discovered just how hard it is to strictly > > > > > > implement > > > > > > store-conditional semantics in terms of anything else. So, > > > > > > this is > > > > > > probably a reasonable substitute, but we should note the > > > > > > fact that > > > > > > it's not 100%. > > > > > > > > > > I will update the commit log. > > > > > > > > > > Regards, > > > > > Nikunj > > > > > > > > > > > > > > -- > Alex Bennée
