On Wed, Sep 28, 2011 at 8:55 AM, Jan Beulich <JBeulich@xxxxxxxx> wrote: > >> just use "lock xaddw" there too. > > I'm afraid that's not possible, as that might carry from the low 8 bits > into the upper 8 ones, which must be avoided. Oh damn, you're right. So I guess the "right" way to do things is with cmpxchg, but some nasty mfence setup could do it too. Linus -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html