Re: [Qemu-devel] [PATCH 04/30] add a header file for atomic operations

[Peter Maydell]

On 28 June 2013 21:41, Anthony Liguori <address@hidden> wrote:
> One thing I've been thinking about reviewing this code, what should we
> be doing in virtio.c?
>
> We have barriers but we're relying on st[u][wlb]_phys having atomic
> semantics.  I think it's okay in practice but if we're taking a more
> diligent approach here should we introduce atomic variants that work on
> guest phys addresses?

Those accesses are weird anyway, because they implicitly depend
on going through a path which is cache-coherent with the CPU
that was used to run the guest VCPU. So they're not strictly
speaking writing "guest physical memory" necessarily...

-- PMM