Re: [PATCH 21/33] qemu: Clean up qemuDomainDefaultUSBControllerModel()

Mostly reduce the number of 'else if' and improve comments. Signed-off-by: Andrea Bolognani <abologna(a)redhat.com&gt; --- src/qemu/qemu_domain.c | 62 ++++++++++++++++++++++++------------------ 1 file changed, 36 insertions(+), 26 deletions(-) diff --git a/src/qemu/qemu_domain.c b/src/qemu/qemu_domain.c index d992b51877..dcf73c0e08 100644 --- a/src/qemu/qemu_domain.c +++ b/src/qemu/qemu_domain.c

@@ -4200,50 +4198,62 @@ qemuDomainDefaultUSBControllerModel(const virDomainDef *def,

- } else if (def->os.arch == VIR_ARCH_AARCH64) { + + /* For ppc64 specifically, returning -1 here will result in

+ * an attempt to use the legacy USB controller rather than an + * outright failure */ + return -1;

+ } + + if (def->os.arch == VIR_ARCH_AARCH64) { + /* Prefer USB3 */ if (virQEMUCapsGet(qemuCaps, QEMU_CAPS_DEVICE_QEMU_XHCI)) return VIR_DOMAIN_CONTROLLER_MODEL_USB_QEMU_XHCI; - else if (virQEMUCapsGet(qemuCaps, QEMU_CAPS_NEC_USB_XHCI)) + if (virQEMUCapsGet(qemuCaps, QEMU_CAPS_NEC_USB_XHCI)) return VIR_DOMAIN_CONTROLLER_MODEL_USB_NEC_XHCI; + + /* We should probably return -1 here and avoid the

+ * possibility of falling back to piix3-uhci (USB1), but + * historically we haven't done that and starting now might + * cause backwards compatibility issues */ } if (ARCH_IS_X86(def->os.arch)) { if (qemuDomainIsQ35(def) && autoAdded) { - /* Prefer adding a USB3 controller if supported, fall back - * to USB2 if there is no USB3 available, and if that's - * unavailable don't add anything. - */ + /* Prefer USB3 */ if (virQEMUCapsGet(qemuCaps, QEMU_CAPS_DEVICE_QEMU_XHCI)) return VIR_DOMAIN_CONTROLLER_MODEL_USB_QEMU_XHCI; if (virQEMUCapsGet(qemuCaps, QEMU_CAPS_NEC_USB_XHCI)) return VIR_DOMAIN_CONTROLLER_MODEL_USB_NEC_XHCI; + + /* Fall back to USB2 */ if (virQEMUCapsGet(qemuCaps, QEMU_CAPS_ICH9_USB_EHCI1)) return VIR_DOMAIN_CONTROLLER_MODEL_USB_ICH9_EHCI1; + + /* If no suitable device is available, simply avoid + * adding the controller */ return -2; } } - /* Default USB controller is piix3-uhci if available. */ + /* piix3-uhci (USB1) is the last ditch effort before giving up */ if (virQEMUCapsGet(qemuCaps, QEMU_CAPS_PIIX3_USB_UHCI)) return VIR_DOMAIN_CONTROLLER_MODEL_USB_PIIX3_UHCI; + /* No suitable model could be found. This will return in either + * an error or the use of the legacy USB controller */

return -1; }