Re: [Qemu-devel] Re: [libvirt] Libvirt debug API

[Chris Lalancette]

On 04/12/2010 08:41 AM, Daniel P. Berrange wrote:
>>> I don't think there's much to be gained from having an XML element to
>>> turn on/off use of these APIs. If an app doesn't want to use them, it
>>> can simply not link to libvirt-qemu.so
>>
>> The reason I wanted to do this was mostly for debug/support reasons.
>> That is, with this element in place we can easily tell from the dumpxml
>> output whether a person was using the "unreliable" API's, and thus we can
>> tell them to try and reproduce without that in place.
> 
> That doesn't tell you whether they have actually used any API or not.
> It is also inconvenient if you start a guest without it, and only later
> realize you want to use the extra APIs. If we want to track the actual
> usage, then the first time a direct monitor command is issued, we should
> simply log a warning message. 

The problem with logging a message is that it is easy to lose it.  What I'm
trying to avoid here is debugging somebody's setup for hours only to find
out that they did a "pci_del" behind libvirt's back.  Maybe we can just make the
<monitorpassthrough/> a read-only flag; it is ignored in the parsing, but
it is set by "GetXMLDesc" when it detects that the virDomainQemuInvokeMonitor
has been called.

-- 
Chris Lalancette