- Issued:
- 2010-05-21
- Updated:
- 2010-05-21
RHBA-2010:0434 - Bug Fix Advisory
Synopsis
kvm bug fix update
Type/Severity
Bug Fix Advisory
Topic
Updated kvm packages that resolve two issues are now available.
Description
KVM (Kernel-based Virtual Machine) is a full virtualization solution for
Linux on AMD64 and Intel 64 systems. KVM is a Linux kernel module built for
the standard Red Hat Enterprise Linux kernel. KVM can run multiple
unmodified, virtualized guest Windows and Linux operating systems.
These updated packages fix the following bugs:
- some Linux-based para-virtualised guests (eg Fedora 11 and Fedora 12)
which accessed para-virtualised (PV) MMU page tables crashed during startup
when launched on AMD-based hosts which had Rapid Virtualization Indexing
(RVI, formerly known as Nested Page Tables or NPT) disabled. (RVI is AMD's
hardware-assisted virtualization technology for allowing guests to modify
their own MMU page tables. It was called NPT during development.)
The crash occurred because a system call made by such guests (via the
hypercall driver) attempted to write to a read-only page. With this update,
the PV MMU reporting capability was disabled and Linux-based guests which
make these calls no longer cause KVM to inject a page fault and crash.
(BZ#578577)
- an error in irq_source_id size verification meant guest operating systems
with eight assigned virtual functions (VF) hung on boot. This update
corrects the error: verification is now done using bit numbers, not bytes
and guests with eight VFs bound to the pci-stub driver boot (and can use
the assigned virtual devices) as expected. (BZ#579862)
All KVM users should upgrade to these updated packages, which contain
backported patches to resolve these issues.
Solution
Before applying this update, make sure all previously-released errata
relevant to your system have been applied.
This update is available via the Red Hat Network. Details on how to
use the Red Hat Network to apply this update are available at
http://kbase.redhat.com/faq/docs/DOC-11259
Affected Products
- Red Hat Enterprise Linux for x86_64 - Extended Update Support 5.4 x86_64
Fixes
- BZ - 578577 - Linux pvmmu guests (FC11, FC12, etc) crash on boot on AMD hosts with NPT disabled
- BZ - 579862 - SR-IOV -- Guest exit and host hang on if boot VM with 8 VFs assigned
CVEs
(none)
References
(none)
The Red Hat security contact is secalert@redhat.com. More contact details at https://access.redhat.com/security/team/contact/.