This update for xen fixes the following security issues:

- CVE-2018-3646: Systems with microprocessors utilizing speculative execution
and address translations may have allowed unauthorized disclosure of
information residing in the L1 data cache to an attacker with local user access
with guest OS privilege via a terminal page fault and a side-channel analysis
(bsc#1091107, bsc#1027519).
- Incorrect MSR_DEBUGCTL handling let guests enable BTS allowing a malicious or
buggy guest administrator can lock up the entire host (bsc#1103276)

This update was imported from the SUSE:SLE-12-SP3:Update update project.