On 01/29/2013 04:41 PM, Eric Blake wrote:
On 01/29/2013 09:52 AM, Stefan Berger wrote:
Add a file descriptor set to the QEMU private domain structure.
--- src/qemu/qemu_domain.c | 4 ++++ src/qemu/qemu_domain.h | 3 +++ 2 files changed, 7 insertions(+)
In isolation, this patch looks okay. But the real question is what it will be used for. I'm worried that we don't have quite the right implementation design in place yet.
Unfortunately, I think we need much more than storing just a set of integers - we need a full blown hash table, where the key is the fd we passed through, and the value is more details (the file name or other details describing the fd that we are passing, and the resulting qemu fdset number that the fd will belong to). Furthermore, we need to make this storage persist across libvirt reboots, which means it needs to be part of the (internal-only) XML that we save in /var/run/libvirt/qemu/$dom.xml, so we must also modify qemuDomainObjPrivateXMLFormat() to output the contents of this set (or hash table) in a reusable manner.
For that matter, I just realized that we already have an <alias> XMl element in the internal-only XML of each /var/run/libvirt/qemu/dom.xml; which is part of the virDomainDeviceInfo. It seems like this struct would be a useful place for us to add another XML attribute stating what qemu fdset is associated with any given device. That also means that in patch 4/4, we don't have to pass a virIntSet around; any code like qemuBuildChrChardevStr that is already looking up an 'alias' associated with a device can also look up an fdset from the same struct. -- Eric Blake eblake redhat com +1-919-301-3266 Libvirt virtualization library http://libvirt.org