Mostly reduce the number of 'else if' and improve comments.
Signed-off-by: Andrea Bolognani <abolo...@redhat.com>
---
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
@@ -4183,11 +4183,9 @@ qemuDomainDefaultUSBControllerModel(const virDomainDef
*def,
virQEMUCaps *qemuCaps,
unsigned int parseFlags)
{
- /* Pick a suitable default model for the USB controller if none
- * has been selected by the user and we have the qemuCaps for
- * figuring out which controllers are supported.
- *
- * We rely on device availability instead of setting the model
+ bool abiUpdate = !!(parseFlags & VIR_DOMAIN_DEF_PARSE_ABI_UPDATE);
+
+ /* We rely on device availability instead of setting the model
* unconditionally because, for some machine types, there's a
* chance we will get away with using the legacy USB controller
* when the relevant device is not available.
@@ -4200,50 +4198,62 @@ qemuDomainDefaultUSBControllerModel(const virDomainDef
*def,
* address is found */
return VIR_DOMAIN_CONTROLLER_MODEL_USB_NONE;
}
- } else if (ARCH_IS_PPC64(def->os.arch)) {
- /* To not break migration we need to set default USB controller
- * for ppc64 to pci-ohci if we cannot change ABI of the VM.
- * The nec-usb-xhci or qemu-xhci controller is used as default
- * only for newly defined domains or devices. */
- if ((parseFlags & VIR_DOMAIN_DEF_PARSE_ABI_UPDATE) &&
- virQEMUCapsGet(qemuCaps, QEMU_CAPS_DEVICE_QEMU_XHCI)) {
+ }
+
+ if (ARCH_IS_PPC64(def->os.arch)) {
+ /* In order not to break migration compatibility, we need to
+ * set default USB controller to pci-ohci (USB2) for existing
+ * guests. New guests can use USB3 instead */
+ if (abiUpdate && virQEMUCapsGet(qemuCaps, QEMU_CAPS_DEVICE_QEMU_XHCI))
return VIR_DOMAIN_CONTROLLER_MODEL_USB_QEMU_XHCI;
- } else if ((parseFlags & VIR_DOMAIN_DEF_PARSE_ABI_UPDATE) &&
- virQEMUCapsGet(qemuCaps, QEMU_CAPS_NEC_USB_XHCI)) {
+ if (abiUpdate && virQEMUCapsGet(qemuCaps, QEMU_CAPS_NEC_USB_XHCI))
return VIR_DOMAIN_CONTROLLER_MODEL_USB_NEC_XHCI;
- } else if (virQEMUCapsGet(qemuCaps, QEMU_CAPS_PCI_OHCI)) {
+ if (virQEMUCapsGet(qemuCaps, QEMU_CAPS_PCI_OHCI))
return VIR_DOMAIN_CONTROLLER_MODEL_USB_PCI_OHCI;
- } else {
- /* Explicitly fallback to legacy USB controller for PPC64. */
- return -1;
- }
- } 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;
}
--
2.43.0
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