KVM_POSSIBLE_CR0_GUEST_BITS
static_assert(!(KVM_POSSIBLE_CR0_GUEST_BITS & X86_CR0_PDPTR_BITS));
ulong tmask = mask & KVM_POSSIBLE_CR0_GUEST_BITS;
BUILD_BUG_ON((KVM_MMU_CR0_ROLE_BITS & KVM_POSSIBLE_CR0_GUEST_BITS) != X86_CR0_WP);
unsigned long bits = KVM_POSSIBLE_CR0_GUEST_BITS;