Security update for Xen (important)

This update fixes various bugs in XEN:

The following security issues have been fixed:

• A denial of service (Host Crash) in the XEN
  hypervisor. (CVE-2011-2901)
• A bug was found in the way Xen handles CPUID
  instruction emulation during VM exits. An unprivileged
  guest user can potentially use this flaw to crash the
  guest. (CVE-2011-1936)
• A 64-bit guest can get one of its vcpus into
  non-kernel mode without first providing a valid non-kernel
  pagetable. The observed failure mode was usually a hard
  lockup of the host (host denial of service). (CVE-2011-1166)

It fixes also the following bugs:

• bnc#654798 - SLES 10 SP3 XEN: Device /dev/xvdp is
  already connected error when starting multiple vm’s
• bnc#684297 - HVM taking too long to dump vmcore