[fedora-virt] Fedora virt status

Mark McLoughlin markmc at redhat.com
Fri Feb 13 18:52:37 UTC 2009

2009-03-03 Feature freeze (18 days)
  2009-03-10 Beta Freeze (25 days)
  2009-04-14 Final freeze (60 days)

Fedora Weekly News

The latest instalment of Fedora Weekly News is out, again with a
detailed virt section:


Thanks to Dale Bewley.


Glauber has been working hard towards merging the qemu and kvm

This week most of the effort involved producing packages for
bochs-bios, openbios and vgabios. See this mail for more details:


The really nasty part - which Eduardo Hobkost ealier worked through
with the etherboot package - is that although the BIOS binaries need
to be built on a specific platform, they need to be available for
install on all architectures. For example, Bochs is built on x86, but
if you run qemu-system-x86_64 on ppc you need it there too.

As an interim measure, all these packages will be first built on the
required architecture, then the packager will download the new build,
pack the images in a tarball and then re-build the package with this
tarball. The second build will package the pre-built binaries on all
arches, rather than building from source.

In future, koji/rpm will support packages with ExclusiveArch that
produce noarch packages. So, e.g. Bochs will be built only on x86 and
the result will be a noarch package. See also:


The pacakge reviews for the three new packages are here:


PCI Device Assignment

The offline discussion around device resetting, unbinding and
filtering finally made it on-list here:


The upshot is that some further kernel work is required before device
assignment will be fully usable in Fedora.

David Woodhouse's work continued on resolving the DMAR issues seen on
some machines with intel_iommu=on:


David's first patch fixes a problem where one platform (Mobile 4
Series Chipset). The problem is that this chipset claims to not need
explicit write buffer flushing, when it does in fact need it. David's
patch just ignores the RWBF hint on that platform. This should fix the
issues seen with Lenovo X200 and the Dell Latitude E6400.

Another problem was found with the iwlwifi driver where the device is
writing to buffers that the driver marks as read-only. David has added
a fix for this issue to rawhide:


Shared Network Interface

David Lutterkort updated libvir-list with his progress:


    After talking with Dan Williams, who is working in NetworkManager,
    it is clear that the network interface functionality for libvirt
    is also useful for NM and would help them with handling
    system-wide interface configuration. To accomodate that, I will
    implement network interface configuration in a separate library
    (inspiringly called 'netcf', until somebody thinks of something
    catchier) and add public API to libvirt that will use netcf to do
    the actual work.

The F11 Feature page has also been updated:



Dan Walsh posted his thoughts on the sVirt patch set to libvir-list:


It appears the patch is in good shape already and could be merged very
soon. Dan Berrange replied with:

  I've reviewed all the submissions James has posted for comments so
  far, and am pretty happy with the way it now integrates with

  If yourself & James are happy with what they're doing from a SELinux
  / security model point of view, then there's no reason they
  shouldn't be posted for final merge now.

kvmclock and !constant_tsc

The fix to disable kvmclock on hosts with no constant_tsc has no been
pushed to Fedora 10:


Upstream, Avi has queued up the workaround for 2.6.29 here:


and the real fix is queued for 2.6.30 here:


Worryingly, Levente Farkas noted that he has constant_tsc and is
still seeing hangs which go away with clocksource=acpi_pm. Further
investigation of this is required.



The issue with pvmmu and CONFIG_SLAB_DEBUG was resolved this week:

  pvmmu causes net driver oops during guest install (new_slab)

Marcelo came up with a guest kernel fix for pvmmu (only batch user pte
updates), built in koji and James Laska ran some test installs using
it. Unfortunately, James couldn't reproduce with latest rawhide and,
obviously, also didn't see the issue with Marcelo's patch.

Marcelo posted his patch upstream and some discussion with Jeremy
Fitzhardinge yielded a patch to add a missing flush_lazy_mmu_mode()
call to change_page_attr():


This patch has since been merged into Linus's tree for 2.6.29.

libvirt 0.6.0

Dan Berrange pushed an libvirt-0.6.0-2 with the following fixes:

  - Fix libvirtd --timeout usage
  - Fix RPC call problems and QEMU startup handling (rhbz #484414)
  - Fix unowned directories (rhbz #483442)

Further issues with this release include:

    AVC denied errors when starting KVM guest
    SELinux issue causing libvirtd launched dnsmasq to fail

    Dan Berrange pointed out the selinux-policy changes
    needed. Miroslav Grepl and Dan Walsh made the changes in
    selinux-policy-3.5.13-45.fc10 which has been pushed to F10

    libvirtd segfault in libdbus after starting kvm guest

    Strangely, it proved to be very difficult to get a good trace of
    the segfault.

    In the end, the issue turned out to be nasty D-Bus/PolicyKit
    related segfault in libvirtd which hasn't been resolved yet.

    Starting kvm guest sometimes fails - qemu taking too long?

    Guido Gunther committed a patch to fix this in upstream CVS.

    libnuma: Warning: /sys not mounted or no numa system.

    Bogus warning being printed at library load time because  libvirt
    now uses libnuma and libnuma was incorrectly  complaining about
    missing sysfs files on no-numa systems.

    Neil Horman fixed in numactl-2.0.2-3.


Cole merged the VM 'Overview' tab into the 'Hardware' tab and renamed
it to 'Details'. He included some screenshots in his patch posting:


Cole also built a new package in rawhide which uses PolicyKit instead
of consolehelper.

Also, this bug gives some insight into plans for virt-manager:

    root consolehelper breaks remote ssh virt-manager/libvirtd connections

    Cole explains that this will be fixed when virt-manager no longer
    runs as root.

    David Cartwright points out this useful wiki page:



Marcelo has begun using patchwork to manage patches posted to the KVM


Too many patches isn't a bad complaint for a project to have, right?

Avi appears to have tagged kvm-84rc1 in git, so it looks like a new
release is on the way. Don't tell anyone I told you! :-)

Package Reviews

Rich Jones took it upon himself to complete the merge reviews for
libvirt and gnome-applet-vm which had sat idle for 18 months:


That's the spirit!

Cole Robinson also took ownership of gnome-applet-vm from the original
author, Karel Zak, in the process.

Since package reviews are sometimes useful to refer back to, we've
collected together links to all the package reviews for virt related
packages here:


Xen Dom0

Michael Young posted a test kernel RPM containing Dom0 support:


Some discussion on how complete the current dom0 patchset is. Gerd's
summary of the current situation is:

  If it goes well .30 boots as dom0 kernel.  I don't expect much of
  the backend infrastructure makes it into .30 though (i.e. you need
  patches to actually run guests).  At this point the changes needed
  might be non-invasive enough that it might be reasonable to carry
  them as patches in the fedora kernel.

Michael is not to be deterred, though, and is preparing to start
pushing these packages through Koji.

Completely unrelated, Brad Smith brings attention to a common
complaint that "virsh start -c" is needed to allow users to easily get
to BIOS/pygrub screen at boot:


Xen and the Art of the NX Bit

Phill on the fedora-virt points out that the No Execute (NX) bit is
called the Execute Disable (XD) bit in Intel documentation:


By enabling NX, he was able to resolve his F10 guest boot failure:


Ian Campbell posted a patch upstream to fix the issue, but it looks
like it may not have been merged yet.


DOOM-O-METER: 192 open bugs last week, 193 this week. Hrmph!

  qemu-kvm not working with evdev giving wrong key mappings

  Some confusion about whether this is QEMU or evdev's fault,
  which Dan Berrange cleared up with:

    Yes, this *IS*  a QEMU/KVM bug.  It has hardcoded the assumption
    that there is a 1-to-1 mapping of scancodes to keycodes. This just
    happens to be true of the 'kbd' X driver, this is not true in
    general, thus QEMU breaks with evdev.  QEMU must be fixed.

  block-rw-range-check.patch breaks qcow

  Two issues were found with our single out of tree patch for
  KVM. Eduardo, the hero that he is, promptly fixed both.

  ambiguous dialog

  Guido Gunther supplied a patch and after consulting with the GNOME
  HIG posted a second, better patch.

  Qemu monitor "system_powerdown" command does not work

  F11 alpha boots ugly (after install) on xen paravirt

  Jeremy Fitzhardinge has fixed upstream.

  Fix is in 2.6.29-rc4.git4

  RFE: Support usb tablet in graphical setup via qemu

  Xorg has been fixed to properly handle USB tablets.

  We would like to be able to use USB tables by default for
  Fedora guests, but some work needs to be done to check that
  they are configured in absolute mode by default, rather than
  relative mode.

More information about the Fedora-virt mailing list