KVM_MMU_CR0_ROLE_BITS
.cr0 = kvm_read_cr0_bits(vcpu, KVM_MMU_CR0_ROLE_BITS),
BUILD_BUG_ON((KVM_MMU_CR0_ROLE_BITS & KVM_POSSIBLE_CR0_GUEST_BITS) != X86_CR0_WP);
if ((cr0 ^ old_cr0) & KVM_MMU_CR0_ROLE_BITS)