On Thu, Sep 18, 2025 at 03:57:10PM +0200, Peter Krempa wrote: > On Tue, Aug 19, 2025 at 18:22:28 +0200, Andrea Bolognani via Devel wrote: > > Extract the logic from qemuDomainControllerDefPostParse() to > > a dedicated helper. The behavior is unchanged. > > I don't see it changed anywhere else ... is it just to separate stuff?
I'm not sure I understand the question. Yes, this commit is intended to merely factor out the existing code into a dedicated helper, without altering the behavior. Then later commits perform the modifications we want. > > +/** > > + * qemuDomainDefaultUSBControllerModel: > > + * @def: domain definition > > + * @qemuCaps: QEMU capabilities, or NULL > > + * @parseFlags: parse flags > > + * > > + * Choose a reasonable model to use for a USB controller where a > > + * specific one hasn't been provided by the user. > > + * > > + * The choice is based on a number of factors, including the guest's > > + * architecture and machine type. @qemuCaps, if provided, might be > > + * taken into consideration too. > > This statement is a bit misleading. In cases where qemuCaps is NULL you > must not be doing any decisions that depend on the caps that wouldn't be > undone by another run of this function with caps present. > > In cases where the caps for given qemu are not present and the XML > parsed is one of the persistent configs loaded from disk, the postparse > code will be re-tried at next startup attempt where it has to be present > for the VM to work. > > If you'd pick an incorrect model based on missing caps that'd be > remembered and not fixed on startup, but it would behave differently if > the caps are present. Got it. In practice things should already work correctly with the current code, and continue to do so even after my patches, since neither this helper nor its AutoAdded variant are ever called when qemuCaps is NULL. Based on this and the fact that you provided a R-b for the patch, it should be enough for me to update the comment so that it's not misleading, right? Basically s/, if provided, might/will/g -- Andrea Bolognani / Red Hat / Virtualization
