Re: [Qemu-devel] [PATCH] Add a memory barrier to guest memory access functions

[Paolo Bonzini]

Il 21/05/2012 03:56, Benjamin Herrenschmidt ha scritto:
> I don't see an obvious need to provide a "relaxed" variant of the
> later at this stage, a quick grep doesn't seem to show that most cases
> where it's used are either not performance sensitive or the barrier
> makes sense, but feel free to prove me wrong :-)

The only problem here is that you have useless memory barriers when
calling cpu_physical_memory_map in a loop (see virtqueue_map_sg).

Paolo