1.188.4. RHBA-2011:0940: xen bug fix update

Updated xen packages that fix a bug are now available for Red Hat Enterprise Linux 5.
Xen is a high-performance and secure open source virtualization framework. Virtualization allows users to run guest operating systems in virtual machines on top of a host operating system.
This update fixes the following bug:
* Previously, the cache flush for IDE devices emulated via the QEMU emulator was performed synchronously. When the flush process took too much time, the virtual CPU was stuck while the fsync utility was running. This behavior sometimes caused guests to terminate unexpectedly on the Windows operating system. With this update, cache flushes for IDE devices are done asynchronously, and the crash no longer occurs in the described scenario. (BZ#712412)
Users of xen are advised to upgrade to these updated packages, which fix this bug. Note that after installation, the xend service must be restarted for this update to take effect.