On 25/03/20 17:14, Sean Christopherson wrote: >> Doh, right. I think the only solution for that one is to degrade it to >> WARN_ON(1). > I reproduced the error, give me a bit to play with the code to see if the > BUILD_BUG can be preserved. I'm curious as to why kvm_cpu_cap_mask() is > special, and why it only fails with this config. > I could not reproduce it, but I would not be surprised if there are other configurations where the compiler cannot constant-propagate from the reverse_cpuid struct into __cpuid_entry_get_reg. Paolo