RHBA-2016:1011 - Bug Fix Advisory

Topic

An updated virtio-win package that fixes several bugs and adds multiple enhancements is now available.

Description

The virtio-win package provides paravirtualized network drivers for most Microsoft Windows operating systems. Paravirtualized drivers are virtualization-aware drivers used by fully virtualized guests running on Red Hat Enterprise Linux. Fully virtualized guests using the paravirtualized drivers gain significantly better I/O performance than fully virtualized guests running without the drivers.

This update fixes the following bugs:

• In some cases, attaching more than four Logical Unit Numbers (LUNs) to the same virtio-scsi controller caused the guest to terminate unexpectedly with a stop error (also known as the blue screen of death). This update adds the pending SCSI Request Block (SRB) queue, which keeps unsubmitted SRBs for future processing, instead of failing them. As a result, the virtio-scsi device driver is able to service up to 254 LUNs attached to the same controller. (BZ#1195920)
• Previously, Windows guests in some cases issued out-of-bounds read and

write requests to a virtio device, which caused the guest to become
unresponsive. Now, the Windows virtio-blk device drive performs logical
block addressing (LBA) sanity checks before submitting requests to QEMU,
and does not submit requests that are out-of-bounds. As a result, the
described problem no longer occurs. (BZ#1067225)

• Using the "netsh" command now properly displays device names regardless of the number of network devices plugged in to the system. (BZ#1109027)

In addition, this update adds the following enhancements:

• The virtio-win package now includes drivers for Windows 10, which allows users of virtio-win to create Windows 10 guests. (BZ#1275050)
• The virtio-win package now contains the qxl driver for Windows Server 2008 R2, and the driver thus does not have to be downloaded manually. (BZ#1170106)
• The NetKVM driver now supports the virtio multi-queue feature. In combination with the Windows OS receives-side scaling (RSS) feature, this enables enhanced performance optimization. (BZ#1096505)

Users of virtio-win are advised to upgrade to this updated package, which fixes these bugs and adds these enhancements.

Solution

Before applying this update, make sure all previously released errata
relevant to your system have been applied.

For details on how to apply this update, refer to:

https://access.redhat.com/articles/11258

Affected Products

• Red Hat Enterprise Linux Server 6 x86_64
• Red Hat Enterprise Linux Workstation 6 x86_64
• Red Hat Enterprise Linux Desktop 6 x86_64
• Red Hat Enterprise Linux Server from RHUI 6 x86_64

Fixes

• BZ - 1067225 - Windows guest performing out-of-bounds accesses on virtio device
• BZ - 1303500 - RHEL6.8 VirtIO-win bug fixes and enhancement tracking

CVEs

(none)

References

• http://www.redhat.com/security/updates/classification/#normal