On Tue, Nov 27, 2018 at 10:04:59AM +0100, Paolo Bonzini wrote: > On 26/11/18 23:43, Michael S. Tsirkin wrote: > > On Mon, Nov 26, 2018 at 02:20:38PM +0100, Paolo Bonzini wrote: > >> vhost does not have to be supported only if KVM is present, in fact > >> vhost-user does not even need any kind of kernel support. This series > >> changes this. The rationale is that, when vhost-user-test.c will be > >> converted to qgraph, it will be able to test vhost-user support > >> for virtio-mmio backend even on x86. > > > > The reason for limiting it to KVM was very simple: > > it has the same set of problems with ordering > > as mttcg. > > > > So I guess it's fine but I think we must then limit it > > to when tcg emits fence instructions. > > > > Otherwise we'll get subtle race conditions. > > Got it, I'll take a look. However, right now you _can_ use vhost with > tcg as long as e.g. qemu-system-x86_64 is compiled with KVM support, so > this patch is not changing anything in this respect; the bug is > independent of this series. > > Paolo >
Well qemu built with KVM implies host architecture == guest architecture, right? That should ensure race conditions do not happen in a very hacky way. -- MST
