The current code was a little bit odd. At first we've removed all
possible implicit input devices from domain definition to add them later
back if there was any graphics device defined while parsing XML
description. That's not all, while formating domain definition to XML
description we at first ignore any input devices with bus different to
USB and VIRTIO and few lines later we add implicit input devices to XML.
This seems to me as a lot of code for nothing. This patch may look
to be more complicated than original approach, but this is a preferred
way to modify/add driver specific stuff only in those drivers and not
deal with them in common parsing/formating functions.
The update is to add those implicit input devices into config XML to
follow the real HW configuration visible by guest OS.
There was also inconsistence between our behavior and QEMU's in the way,
that in QEMU there is no way how to disable those implicit input devices
for x86 architecture and they are available always, even without graphics
device. This applies also to XEN hypervisor. VZ driver already does its
part by putting correct implicit devices into live XML.
Signed-off-by: Pavel Hrdina <phrdina@redhat.com>
<controller type='pci' index='0' model='pci-root'/>
is auto-added to pc* machine types.
Without this controller PCI bus 0 is not available and
no PCI addresses are assigned by default.
Since older libvirt supported PCI bus 0 even without
this controller, it is removed from the XML when migrating.
Though numad will manage the memory allocation of task dynamically,
it wants management application (libvirt) to pre-set the memory
policy according to the advisory nodeset returned from querying numad,
(just like pre-bind CPU nodeset for domain process), and thus the
performance could benefit much more from it.
This patch introduces new XML tag 'placement', value 'auto' indicates
whether to set the memory policy with the advisory nodeset from numad,
and its value defaults to the value of <vcpu> placement, or 'static'
if 'nodeset' is specified. Example of the new XML tag's usage:
<numatune>
<memory placement='auto' mode='interleave'/>
</numatune>
Just like what current "numatune" does, the 'auto' numa memory policy
setting uses libnuma's API too.
If <vcpu> "placement" is "auto", and <numatune> is not specified
explicitly, a default <numatume> will be added with "placement"
set as "auto", and "mode" set as "strict".
The following XML can now fully drive numad:
1) <vcpu> placement is 'auto', no <numatune> is specified.
<vcpu placement='auto'>10</vcpu>
2) <vcpu> placement is 'auto', no 'placement' is specified for
<numatune>.
<vcpu placement='auto'>10</vcpu>
<numatune>
<memory mode='interleave'/>
</numatune>
And it's also able to control the CPU placement and memory policy
independently. e.g.
1) <vcpu> placement is 'auto', and <numatune> placement is 'static'
<vcpu placement='auto'>10</vcpu>
<numatune>
<memory mode='strict' nodeset='0-10,^7'/>
</numatune>
2) <vcpu> placement is 'static', and <numatune> placement is 'auto'
<vcpu placement='static' cpuset='0-24,^12'>10</vcpu>
<numatune>
<memory mode='interleave' placement='auto'/>
</numatume>
A follow up patch will change the XML formatting codes to always output
'placement' for <vcpu>, even it's 'static'.
