Security update for xen (important)

This update for xen fixes several issues.

These security issues were fixed:

• CVE-2017-10912: Page transfer might have allowed PV guest to elevate
  privilege (XSA-217, bsc#1042882)
• CVE-2017-10913 CVE-2017-10914: Races in the grant table unmap code
  allowed for informations leaks and potentially privilege escalation
  (XSA-218, bsc#1042893)
• CVE-2017-10915: 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)
• CVE-2017-10917: Missing NULL pointer check in event channel poll allows
  guests to DoS the host (XSA-221, bsc#1042924)
• CVE-2017-10918: Stale P2M mappings due to insufficient error checking
  allowed malicious guest to leak information or elevate privileges
  (XSA-222, bsc#1042931)
• CVE-2017-10920, CVE-2017-10921, CVE-2017-10922: 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

This update was imported from the SUSE:SLE-12-SP2:Update update project.