On 04/10/2016 13:30, Laurent Vivier wrote: > But sometime, user wants to use a real accelerator without knowing > if he really can, with, for instance accel=kvm:tcg. > In this case, and if the accelerator is not available we > have a noisy "XXX accelerator not found". > > By allowing the user to ask the "best" accelerator for the given > target, we can avoid this problem. > > This patch introduces a new parameter for the "accel" property, the > "best" keyword. > > You can ask to use the best accelerator with "-M accel=best", > or if you want to use your favorite accelerator and if it is not > available, the best one, you can use, for instance > "-M accel=kvm:best".
I don't think there's a single definition of a "best" accelerator. For example, some "-cpu" features may be available only with TCG. In that case, "kvm:tcg" has a clear meaning ("kvm" if it exists, otherwise "tcg") but "best" doesn't. I agree with Daniel that unit tests should use "tcg" exclusively, at least as a default. Paolo