int kvm_set_msr(struct kvm_vcpu *vcpu, struct msr_data *msr)
{
	switch (msr->index) {
	case MSR_FS_BASE:
	case MSR_GS_BASE:
	case MSR_KERNEL_GS_BASE:
	case MSR_CSTAR:
	case MSR_LSTAR:
		if (is_noncanonical_address(msr->data))
			return 1;
		break;
	case MSR_IA32_SYSENTER_EIP:
	case MSR_IA32_SYSENTER_ESP:
		/*
		 * IA32_SYSENTER_ESP and IA32_SYSENTER_EIP cause #GP if
		 * non-canonical address is written on Intel but not on
		 * AMD (which ignores the top 32-bits, because it does
		 * not implement 64-bit SYSENTER).
		 *
		 * 64-bit code should hence be able to write a non-canonical
		 * value on AMD.  Making the address canonical ensures that
		 * vmentry does not fail on Intel after writing a non-canonical
		 * value, and that something deterministic happens if the guest
		 * invokes 64-bit SYSENTER.
		 */
		msr->data = get_canonical(msr->data);
	}
	return kvm_x86_ops->set_msr(vcpu, msr);
}

Unknown