Security update for xen (important)

This update for xen to version 4.9.1 (bsc#1027519) fixes several issues.

This new feature was added:

• Support migration of HVM domains larger than 1 TB

These security issues were fixed:

• bsc#1068187: Failure to recognize errors in the Populate on Demand (PoD)
  code allowed for DoS (XSA-246)
• bsc#1068191: Missing p2m error checking in PoD code allowed unprivileged
  guests to retain a writable mapping of freed memory leading to
  information leaks, privilege escalation or DoS (XSA-247).
• CVE-2017-15289: The mode4and5 write functions allowed local OS guest
  privileged users to cause a denial of service (out-of-bounds write
  access and Qemu process crash) via vectors related to dst calculation
  (bsc#1063123)
• CVE-2017-15597: A grant copy operation being done on a grant of a dying
  domain allowed a malicious guest administrator to corrupt hypervisor
  memory, allowing for DoS or potentially privilege escalation and
  information leaks (bsc#1061075).

This non-security issue was fixed:

• bsc#1055047: Fixed --initrd-inject option in virt-install