Security update for xen (important)

This update for xen fixes several issues.

These security issues were fixed:

• Page transfer might have allowed PV guest to elevate privilege (XSA-217,
  bsc#1042882)
• Races in the grant table unmap code allowed for informations leaks and
  potentially privilege escalation (XSA-218, bsc#1042893)
• Insufficient reference counts during shadow emulation allowed a
  malicious pair of guest to elevate their privileges to the privileges
  that XEN runs under (XSA-219, bsc#1042915)
• Missing NULL pointer check in event channel poll allows guests to DoS
  the host (XSA-221, bsc#1042924)
• Stale P2M mappings due to insufficient error checking allowed malicious
  guest to leak information or elevate privileges (XSA-222, bsc#1042931)
• Grant table operations mishandled reference counts allowing malicious
  guests to escape (XSA-224, bsc#1042938)
• CVE-2017-9330: USB OHCI Emulation in qemu allowed local guest OS users
  to cause a denial of service (infinite loop) by leveraging an incorrect
  return value (bsc#1042160)
• CVE-2017-8309: Memory leak in the audio/audio.c allowed remote attackers
  to cause a denial of service (memory consumption) by repeatedly starting
  and stopping audio capture (bsc#1037243)
• PKRU and BND* leakage between vCPU-s might have leaked information to
  other guests (XSA-220, bsc#1042923)

These non-security issues were fixed:

• bsc#1027519: Included various upstream patches
• bsc#1035642: Ensure that rpmbuild works