On 15.08.2013, at 17:48, Andreas Färber wrote: > Am 15.08.2013 17:30, schrieb Alexander Graf: >> >> On 15.08.2013, at 17:11, Andreas Färber wrote: >> >>> Am 15.08.2013 15:12, schrieb Anthony Liguori: >>>> Everyone is talking past each other and no one is addressing the real >>>> problem. There are two distinct issues here: >>>> >>>> 1) We have two ABIs that cannot be changed unless there's a very good >>>> reason to. Alexey's original patch breaks both. The guest ABI >>>> cannot change given a fixed command line. >>>> >>>> IOW, the exposed PVR value for -cpu POWER7 cannot change across >>>> versions of QEMU or when running on different hardware. This breaks >>>> live migration and save/resume. >>>> >>>> We also cannot break the command line interface. If the last version >>>> of QEMU supported -cpu POWER7_v2.1, then we must continue to support >>>> that. >>> >>> 1a) How should -cpu 0xDEADBEEF or -cpu DEADBEEF behave. >>> >>> I expect it to error out as before >>> rather than applying the same fuzz/mask that -cpu host might. >> >> I actually think it'd make sense to apply the same fuzz/mask, don't you >> think? > > I think "-cpu host" has the semantics of give-me-what-the-host-has. But > -cpu 0xDEADBEEF is asking for PVR DEADBEEF and having it silently return > a guest-visible DEADBEBE is going to be undesired.
-cpu host on 0xDEADBEEF should give us a 0xDEADBEEF cpu. -cpu 0xDEADBEEF should give us a 0xDEADBEEF cpu :). Alex
