Merge branch 'xen'

Merge branch 'xen'

* xen:
  KVM: x86: Update Xen TSC leaves during CPUID emulation
  KVM: x86/xen: Move kvm_xen_hvm_config field into kvm_xen
  KVM: x86/xen: Bury xen_hvm_config behind CONFIG_KVM_XEN=y
  KVM: x86/xen: Consult kvm_xen_enabled when checking for Xen MSR writes
  KVM: x86/xen: Add an #ifdef'd helper to detect writes to Xen MSR
  KVM: x86/xen: Restrict hypercall MSR to unofficial synthetic range
  KVM: x86/xen: Only write Xen hypercall page for guest writes to MSR