The host GPU and Apple’s virtualization bridge stay the same. The decision changes when
one guest process asks which Metal paths it can use.
Executes the workload on Apple Silicon
Virtualization.framework
Unchanged
Apple’s paravirtualized graphics bridge
Guest virtual GPU
Unchanged
The same virtual Metal device in both runs
Capability query
One process
What can this workload safely select?
Stock guest answer
Apple 5 · 32 KB
SIMD-group matrix unavailable
Conservative feature selection
→slower llama.cpp kernel
Shim · tested profile
Apple 9 · 64 KB
SIMD-group matrix · bfloat16
Newer tested Metal paths
→faster llama.cpp kernel
Selected capability answers change for one guest process while Apple’s bridge and virtual
device stay in place. Each additional Metal API requires its own virtualization test.