[fedora-virt] F-11 experience installing a CentOS guest

Daniel P. Berrange berrange at redhat.com
Mon Jun 22 18:38:22 UTC 2009

On Mon, Jun 22, 2009 at 10:14:34AM -0600, Jerry James wrote:
> When I created the virtual machine, I took a look at the hardware
> list.  Even though I had specified an F-11 guest, there was no USB
> tablet on the hardware list.  I thought I was supposed to get that
> automatically, just by specifying the F-11 guest.  No matter; I added
> it manually.  Now I don't need the PS/2 mouse, so let's get rid of it.
>  I can't.  The "Remove" button is grayed out.  What's up with that?

The PS/2 mouse is always present in the underlying emulator, whenever
you have graphics enabled. Fear not, because if the USB tablet is
present & activated by the guest OS, PS/2 mouse will cease to generate
any events. So (functionally) it doesn't matter that its still there

> So I installed CentOS 5.3 in the guest.  For the record, if you have
> SELinux on in your host machine, the CD images have to have type
> virt_content_t.  Something (virt-manager?) apparently set the type
> correctly for me for CD #1, but I got an AVC denial and no CD visible
> to the guest when I tried to change to CD #2.  So I changed all the CD
> image types to virt_content_t by hand and everything went okay after
> that.

libvirt automatically relabels all CD images to virt_content_t since
that is what SELinux wants. It should also be doing this when hotplugging
but its possible we missed a codepath - should file a BZ for this problem

> Installation finished.  I rebooted the machine and got an 800x600
> resolution screen.  Darn.  I looked through Xorg.0.log and found that
> virt-manager gave me the Cirrus video card.  I thought specifying an
> F-11 guest was supposed to give me a generic VESA card.  By adding a
> Monitor section to my xorg.conf and playing with HorizSync and
> VertRefresh, I can manage to get a 1280x800 window, but I really want
> 1280x1024.  It doesn't appear to be possible to achieve that, though,
> as the emulated Cirrus card is reporting a dot clock that can't manage
> that resolution.  How do I get virt-manager to give me the VESA card?
> It doesn't appear to be possible to get that through the interface it
> provides.  Why not?

We don't support the generic VESA card in libvirt at this time. What
the F11 feature was doing was actually using the Cirrus card. All it in
fact did was tweak the xorg cirrus driver such that if it saw it had a
QEMU emulated Cirrus card instead of a normal one, it would run at 
1024x768 instead of 800x600.  We'll further improve on this for F12,
including support for the various video card models.

> The absolute mouse coordinates did NOT work when I first installed the
> machine.  Once I added the Monitor section, they started working.  I
> don't know why, though, as Xorg.0.log says that it is using the
> ExplorerPS/2 protocol, which suggests that X is using the PS/2 mouse
> that virt-manager won't let me remove instead of the USB tablet that I
> added manually.

RHEL5 has absolutely no clue how to correctly configure a USB tablet.
You explicitly do *not* want to use the 'mouse' driver in Xorg. It must
be using the 'evdev' driver, and must be running in 'absolute' coordinate
mode. Anything else will result in pain & suffering. For F11 guests this
is all automatically done by blackmagic. RHEL-5 is too old for any of this
automatic stuff to work. If you have a USB tablet and it is not configured
correctly, the results will in fact be *worse* than a PS/2 mouse. The 
latest virt-viewer/gkt-vnc client knows how to correctly deal with PS/2
mice, although it does need to grab the mouse pointer todo so.

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