• Add hw.clflush_disable loader tunable to avoid panic (trap 9) at map_invalidate_cache_range() even if CPU is not Intel.
• This tunable can be set to -1 (default), 0 and 1. -1 is same as current behavior, which automatically disable CLFLUSH on Intel CPUs without CPUID_SS (should be occured on Xen only). You can specify 1 when this panic happened on non-Intel CPUs (such as AMD's). Because disabling CLFLUSH may reduce performance, you can try with setting 0 on Intel CPUs without SS to use CLFLUSH feature.

Reviewed by: kib
Reported by: karl, kuriyama
Related to: kern/138863