On Thu, Sep 18, 2025 at 03:04:28PM +0200, Peter Krempa wrote:
On Tue, Aug 19, 2025 at 18:22:22 +0200, Andrea Bolognani via Devel wrote:
+ /* Sanity check. If the machine type supports PCI, we need to reflect + * that fact in the XML or other parts of the machine handling code + * might misbehave */
This one is a bit borderline. IMO you can have machine with no default PCI but the possibility to explicily add such a bus.
Can you point to a specific example? I'm not aware of any. To the best of my knowledge, all machines that are PCI-capable come with a root PCI controller out of the gate. There is no QEMU device corresponding to the root PCI controller either, so I don't know how you would even go about adding it if it were opt-in. Perhaps a machine type flag but again, I'm not aware of that actually being a thing.
+ if (qemuDomainSupportsPCI(def) && + !addPCIRoot && + !addPCIeRoot) { + virReportError(VIR_ERR_INTERNAL_ERROR, + _("Machine type '%1$s' supports PCI but no PCI controller added"), + def->os.machine); + return -1; + } + + /* Sanity check. USB controllers are PCI devices, so asking for a + * USB controller to be added but not for a PCI(e) root to be + * added at the same time is likely an oversight */
I'm fairly sure there are non-PCI USB controllers so this one is definitely false. It's just that libvirt supports only USB controllers which are on PCI.
IMO this assumption should be validated with the USB controller itself.
I'm not aware of any non-PCI USB controller out there, certainly not in QEMU. Can you point to one? -- Andrea Bolognani / Red Hat / Virtualization