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