qemu: Don't use legacy USB for RISC-V guests

The architecture is new enough that we don't need to
concern ourselves with backwards compatibility in any
capacity.

Signed-off-by: Andrea Bolognani <abologna@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>

src/qemu/qemu_command.c

@@ -3046,7 +3046,8 @@ qemuBuildControllerDevCommandLine(virCommandPtr cmd,
             if (cont->type == VIR_DOMAIN_CONTROLLER_TYPE_USB &&
                 cont->model == VIR_DOMAIN_CONTROLLER_MODEL_USB_DEFAULT &&
                 !qemuDomainIsQ35(def) &&
-                !qemuDomainIsARMVirt(def)) {
+                !qemuDomainIsARMVirt(def) &&
+                !qemuDomainIsRISCVVirt(def)) {
 
                 /* An appropriate default USB controller model should already
                  * have been selected in qemuDomainDeviceDefPostParse(); if
@@ -3085,6 +3086,7 @@ qemuBuildControllerDevCommandLine(virCommandPtr cmd,
     if (usbcontroller == 0 &&
         !qemuDomainIsQ35(def) &&
         !qemuDomainIsARMVirt(def) &&
+        !qemuDomainIsRISCVVirt(def) &&
         !ARCH_IS_S390(def->os.arch)) {
         /* 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

tests/qemuxml2argvdata/riscv64-virt.args

@@ -21,7 +21,6 @@ server,nowait \
 -no-shutdown \
 -kernel /var/lib/libvirt/images/bbl \
 -append 'console=ttyS0 ro root=/dev/vda' \
--usb \
 -drive file=/var/lib/libvirt/images/stage4-disk.img,format=raw,if=none,\
 id=drive-virtio-disk0 \
 -device virtio-blk-device,drive=drive-virtio-disk0,id=virtio-disk0,bootindex=1 \