From: Andrea Bolognani <abologna@redhat.com>
Date: Fri, 25 Jul 2025 15:47:03 +0000 (+0200)
Subject: qemu: Remove fallback to piix3-uhci for Arm virt guests
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=198e68197c5835bea16a8531efb342ba397f5af5;p=thirdparty%2Flibvirt.git

qemu: Remove fallback to piix3-uhci for Arm virt guests

This is another case where the current behavior can be traced
back to the fact that x86 was the only architecture to really
be taken into account for a long time: in reality, using an
Intel-specific USB1 controller for a modern, PCIe-native,
virtualization-friendly Arm guest just doesn't make any sense.

Signed-off-by: Andrea Bolognani <abologna@redhat.com>
Reviewed-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
---

diff --git a/src/qemu/qemu_domain.c b/src/qemu/qemu_domain.c
index 9927ab3cbb..b1a92279a7 100644
--- a/src/qemu/qemu_domain.c
+++ b/src/qemu/qemu_domain.c
@@ -4331,6 +4331,16 @@ qemuDomainDefaultUSBControllerModel(const virDomainDef *def,
         return VIR_DOMAIN_CONTROLLER_MODEL_USB_DEFAULT;
     }
 
+    if (qemuDomainIsARMVirt(def)) {
+        /* Use qemu-xhci or nec-xhci (USB3) with no fallback */
+        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;
+
+        return VIR_DOMAIN_CONTROLLER_MODEL_USB_DEFAULT;
+    }
+
     if (ARCH_IS_ARM(def->os.arch)) {
         /* Prefer qemu-xhci or nec-xhci (USB3) */
         if (virQEMUCapsGet(qemuCaps, QEMU_CAPS_DEVICE_QEMU_XHCI))
diff --git a/tests/qemuxmlconfdata/usb-controller-default-fallback-virt-aarch64.aarch64-latest.args b/tests/qemuxmlconfdata/usb-controller-default-fallback-virt-aarch64.aarch64-latest.args
index 63ea7be2aa..44689d81f9 100644
--- a/tests/qemuxmlconfdata/usb-controller-default-fallback-virt-aarch64.aarch64-latest.args
+++ b/tests/qemuxmlconfdata/usb-controller-default-fallback-virt-aarch64.aarch64-latest.args
@@ -27,9 +27,8 @@ XDG_CONFIG_HOME=/var/lib/libvirt/qemu/domain--1-test/.config \
 -no-shutdown \
 -boot strict=on \
 -device '{"driver":"pcie-root-port","port":8,"chassis":1,"id":"pci.1","bus":"pcie.0","multifunction":true,"addr":"0x1"}' \
--device '{"driver":"pcie-pci-bridge","id":"pci.2","bus":"pci.1","addr":"0x0"}' \
--device '{"driver":"pcie-root-port","port":9,"chassis":3,"id":"pci.3","bus":"pcie.0","addr":"0x1.0x1"}' \
--device '{"driver":"piix3-usb-uhci","id":"usb","bus":"pci.2","addr":"0x1"}' \
+-device '{"driver":"pcie-root-port","port":9,"chassis":2,"id":"pci.2","bus":"pcie.0","addr":"0x1.0x1"}' \
+-device '{"driver":"nec-usb-xhci","id":"usb","bus":"pci.1","addr":"0x0"}' \
 -audiodev '{"id":"audio1","driver":"none"}' \
 -sandbox on,obsolete=deny,elevateprivileges=deny,spawn=deny,resourcecontrol=deny \
 -msg timestamp=on
diff --git a/tests/qemuxmlconfdata/usb-controller-default-fallback-virt-aarch64.aarch64-latest.xml b/tests/qemuxmlconfdata/usb-controller-default-fallback-virt-aarch64.aarch64-latest.xml
index cea6dde62d..943c433f40 100644
--- a/tests/qemuxmlconfdata/usb-controller-default-fallback-virt-aarch64.aarch64-latest.xml
+++ b/tests/qemuxmlconfdata/usb-controller-default-fallback-virt-aarch64.aarch64-latest.xml
@@ -20,8 +20,8 @@
   <on_crash>destroy</on_crash>
   <devices>
     <emulator>/usr/bin/qemu-system-aarch64</emulator>
-    <controller type='usb' index='0' model='piix3-uhci'>
-      <address type='pci' domain='0x0000' bus='0x02' slot='0x01' function='0x0'/>
+    <controller type='usb' index='0' model='nec-xhci'>
+      <address type='pci' domain='0x0000' bus='0x01' slot='0x00' function='0x0'/>
     </controller>
     <controller type='pci' index='0' model='pcie-root'/>
     <controller type='pci' index='1' model='pcie-root-port'>
@@ -29,13 +29,9 @@
       <target chassis='1' port='0x8'/>
       <address type='pci' domain='0x0000' bus='0x00' slot='0x01' function='0x0' multifunction='on'/>
     </controller>
-    <controller type='pci' index='2' model='pcie-to-pci-bridge'>
-      <model name='pcie-pci-bridge'/>
-      <address type='pci' domain='0x0000' bus='0x01' slot='0x00' function='0x0'/>
-    </controller>
-    <controller type='pci' index='3' model='pcie-root-port'>
+    <controller type='pci' index='2' model='pcie-root-port'>
       <model name='pcie-root-port'/>
-      <target chassis='3' port='0x9'/>
+      <target chassis='2' port='0x9'/>
       <address type='pci' domain='0x0000' bus='0x00' slot='0x01' function='0x1'/>
     </controller>
     <audio id='1' type='none'/>
diff --git a/tests/qemuxmlconftest.c b/tests/qemuxmlconftest.c
index 0bf4afbf24..55c622176a 100644
--- a/tests/qemuxmlconftest.c
+++ b/tests/qemuxmlconftest.c
@@ -2174,7 +2174,7 @@ mymain(void)
     DO_TEST_FULL("usb-controller-default-fallback-virt-aarch64", ".aarch64-latest",
                  ARG_CAPS_ARCH, "aarch64",
                  ARG_CAPS_VER, "latest",
-                 ARG_QEMU_CAPS_DEL, QEMU_CAPS_DEVICE_QEMU_XHCI, QEMU_CAPS_NEC_USB_XHCI, QEMU_CAPS_LAST,
+                 ARG_QEMU_CAPS_DEL, QEMU_CAPS_DEVICE_QEMU_XHCI, QEMU_CAPS_LAST,
                  ARG_END);
     DO_TEST_FULL("usb-controller-default-unavailable-virt-aarch64", ".aarch64-latest",
                  ARG_CAPS_ARCH, "aarch64",