Currently, we have special handling for USB controllers of
s390x guests hardcoded into the command line generator. This is
not great from a layering point of view and, given the complex
interactions between the various parts, just makes things very
confusing.
In order to make things easier to reason about and centralize
decision making, increase the number of possible return values.
Signed-off-by: Andrea Bolognani <abologna@xxxxxxxxxx>
---
src/qemu/qemu_command.c | 5 ++---
src/qemu/qemu_domain.c | 28 +++++++++++++++++++++++++---
src/qemu/qemu_domain.h | 2 +-
3 files changed, 28 insertions(+), 7 deletions(-)
diff --git a/src/qemu/qemu_command.c b/src/qemu/qemu_command.c
index ec4982bbf6..deb8867938 100644
--- a/src/qemu/qemu_command.c
+++ b/src/qemu/qemu_command.c
@@ -2949,8 +2949,7 @@ qemuBuildLegacyUSBControllerCommandLine(virCommand *cmd,
}
if (nusb == 0 &&
- !qemuDomainForbidLegacyUSBController(def) &&
- !ARCH_IS_S390(def->os.arch)) {
+ qemuDomainForbidLegacyUSBController(def) == 0) {
/* We haven't added any USB controller yet, but we haven't been asked
* not to add one either. Add a legacy USB controller, unless we're
* creating a kind of guest we want to keep legacy-free */
@@ -3049,7 +3048,7 @@ qemuBuildControllersByTypeCommandLine(virCommand *cmd,
if (cont->type == VIR_DOMAIN_CONTROLLER_TYPE_USB &&
cont->model == VIR_DOMAIN_CONTROLLER_MODEL_USB_DEFAULT &&
- !qemuDomainForbidLegacyUSBController(def)) {
+ qemuDomainForbidLegacyUSBController(def) <= 0) {
/* An appropriate default USB controller model should already
* have been selected in qemuDomainDeviceDefPostParse(); if
diff --git a/src/qemu/qemu_domain.c b/src/qemu/qemu_domain.c
index 2b7eae295b..5b93529655 100644
--- a/src/qemu/qemu_domain.c
+++ b/src/qemu/qemu_domain.c
@@ -4258,15 +4258,37 @@ qemuDomainDefaultUSBControllerModel(const virDomainDef *def,
}
-bool
+/**
+ * qemuDomainForbidLegacyUSBController:
+ * @def: domain definition
+ *
+ * Tells the command line generator whether it's acceptable to fall
+ * back to the legacy '-usb' option when a specific model hasn't been
+ * provided or automatically selected for the USB controller.
+ *
+ * Returns: 0 if '-usb' can be used,
+ * >0 if '-usb' should be avoided, and
+ * <0 if '-usb' should't be used but the fact that we have
+ * reached the point where that was the only remaining
+ * option shouldn't be considered an overall failure.
+ */
+int
qemuDomainForbidLegacyUSBController(const virDomainDef *def)
{
+ /* Modern guests should never use the legacy controller */
if (qemuDomainIsQ35(def) ||
qemuDomainIsARMVirt(def) ||
qemuDomainIsRISCVVirt(def))
- return true;
+ return 1;
- return false;
+ /* In the case of s390x, we also never want to use the legacy
+ * controller but it's okay if that means that we end up creating
+ * no USB controller at all */
+ if (ARCH_IS_S390(def->os.arch))
+ return -1;
+
+ /* In all other cases, using the legacy controller is okay */
+ return 0;
}
diff --git a/src/qemu/qemu_domain.h b/src/qemu/qemu_domain.h
index 4e61d741f3..ff95c392bd 100644
--- a/src/qemu/qemu_domain.h
+++ b/src/qemu/qemu_domain.h
@@ -839,7 +839,7 @@ bool qemuDomainSupportsPCIMultibus(const virDomainDef *def);
int qemuDomainDefaultSCSIControllerModel(const virDomainDef *def,
const virDomainControllerDef *cont,
virQEMUCaps *qemuCaps);
-bool qemuDomainForbidLegacyUSBController(const virDomainDef *def);
+int qemuDomainForbidLegacyUSBController(const virDomainDef *def);
void qemuDomainUpdateCurrentMemorySize(virDomainObj *vm);
--
2.43.0
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