1.78. kvm

1.78.1. RHBA-2011:1068: kvm bug fix update

Updated kvm packages that fix various bugs are now available for Red Hat Enterprise Linux 5.


This update was released as errata RHBA-2011:1068 — kvm bug fix update.
KVM (Kernel-based Virtual Machine) is a full virtualization solution for Linux on hardware containing virtualization extensions (i.e. nearly all modern hardware). It consists of a loadable kernel module, kvm.ko, that provides the core virtualization infrastructure and a processor specific module, kvm-intel.ko or kvm-amd.ko.

Bug Fixes:

When the Sandra multi-media benchmark utility was run on a Windows guest, the guest terminated unexpectedly when the utility tried to access the Model Specific Register 0x480 (IA32_VMX_BASIC). A patch has been provided to address this issue and the benchmark utility no longer causes a Windows guest to crash.
BZ#666225, BZ#693918
When a migration was attempted during the early boot stage in a virtual machine running Windows XP, the virtual machine failed to boot correctly. This bug has been fixed, and the virtual machine now boots properly in the described scenario.
When a host with a floppy drive attached and Red Hat Enterprise Linux 5.7 installed was being migrated to another host with kernel version 2.6.18-238.14.1 installed, the migration process failed and the host was left in a stopped state. A patch has been provided to address this issue and the migration now finishes successfully in the described scenario.
Due to a regression, when the values for maximum downtime or maximum speed were increased during a migration, the guests experienced heavy stalls and the migration did not finish in a reasonable time. With this update, a patch has been provided and the migration process finishes successfully in the described scenario.
When an iSCSI server was configured and the block device was shared on a host, if a guest on another host performed a write operation on the shared device and the iSCSI server was restarted, the standard output of the QEMU monitor on the source host was flooded with redundant error messages. With this update, calls to write out these messages have been removed from the code, thus fixing this bug.
Previously, when a CD image with a read-only flag set was ejected from a drive on a guest, the read-only flag was preserved. Consequently, the image could not be re-attached to the drive. A patch has been provided to address this issue, and the read-write flag is now set correctly when an image is ejected from a drive, allowing CD images to be changed on-the-fly.
Previously, the QEMU monitor used an incorrect handler to process passwords to encrypted images. Consequently, the monitor became unresponsive on the first command when attempting to start a guest with an encrypted qcow2 (QEMU Copy-on-Write) image. With this update, the command handler and the password handler are used properly, and the guest now starts successfully in the described scenario.
In hot plug mode, when a PCI device was being attached to a QEMU guest with the -no-kvm command line option, the qemu-kvm utility terminated with a segmentation fault. This bug has been fixed, and qemu-kvm now exits properly and returns appropriate error messages in the described scenario.
When the cont command of the QEMU monitor was used to restore a domain saved to a file via the virsh utility, if an incoming migration had been specified for the virtual machine, cont sometimes took effect before the migration was complete. As a consequence, the restore process or the migration sometimes failed. This bug has been fixed, and now the cont command is only accepted after the incoming migration has successfully finished.
Due to flaws in the IDE CD-ROM emulation, the guest kernel and the anaconda installer sometimes failed to recognize the installation media after the optional testing of installation media had been made. Consequently, the installation process became unresponsive and could not continue. With this update, a memory leak in the bdrv_close() function has been fixed, the installation process no longer gets stuck and the retry function can now be properly used if the installation medium is not recognized the first time.
When a system_reset signal was sent to a guest with a pass-through NIC (Network Interface Card) attached, a kernel panic occurred in the guest. This bug has been fixed, and the guest now reboots properly in the described scenario.
When the CHAOS-Concurrent Hardware And OS test job was run in the WHQL (Windows Hardware Quality Labs) test environment on a Windows guest, the run pwrtest child job failed even though the main CHAOS job passed. This bug has been fixed in the KVM BIOS, and the run pwrtest job now passes successfully in the described scenario.
The QEMU emulator did not enqueue mouse events; it simply records the latest mouse state. Prior to this update, double click or dragging mouse events were sometimes lost, especially on high-latency connections. Now, the code for mouse descriptors has been fixed, and lost mouse events occur much less frequently.
Users of kvm are advised to upgrade to these updated packages, which fix these bugs.