Pull xen updates from Juergen Gross:
 "This contains some minor code cleanups (fixing return types of
  functions), some fixes for Linux running as Xen PVH guest, and adding
  of a new guest resource mapping feature for Xen tools"

* tag 'for-linus-4.18-rc1-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip:
  xen/PVH: Make GDT selectors PVH-specific
  xen/PVH: Set up GS segment for stack canary
  xen/store: do not store local values in xen_start_info
  xen-netfront: fix xennet_start_xmit()'s return type
  xen/privcmd: add IOCTL_PRIVCMD_MMAP_RESOURCE
  xen: Change return type to vm_fault_t