Security update for xen

Open Source Vulnerabilities SUSE-SU-2019:2960-1

This update for xen fixes the following issues: - CVE-2018-12207: Untrusted virtual machines on Intel CPUs could exploit a race condition in the Instruction Fetch Unit of the Intel CPU to cause a Machine Exception during Page Size Change, causing the CPU core to be non-functional. (bsc#1155945) - CVE-2019-11135: Aborting an asynchronous TSX operation on Intel CPUs with Transactional Memory support could be used to facilitate sidechannel information leaks out of microarchitectural buffers, similar to the previously described 'Microarchitectural Data Sampling' attack. (bsc#1152497). - CVE-2019-18425: 32-bit PV guest user mode could elevate its privileges to that of the guest kernel. (bsc#1154456). - CVE-2019-18421: A malicious PV guest administrator may have been able to escalate their privilege to that of the host. (bsc#1154458). - CVE-2019-18420: Malicious x86 PV guests may have caused a hypervisor crash, resulting in a Denial of Service (Dos). (bsc#1154448)