Fix domain parsing for GPU

Author: vishesh92

plugins/hypervisors/kvm/src/main/java/com/cloud/hypervisor/kvm/resource/LibvirtGpuDef.java

@@ -79,17 +79,27 @@ private void generatePciXml(StringBuilder gpuBuilder) {
         gpuBuilder.append("  <driver name='vfio'/>\n");
         gpuBuilder.append("  <source>\n");
 
-        // Parse the bus address (e.g., 00:02.0) into domain, bus, slot, function
+        // Parse the bus address into domain, bus, slot, function. Two input formats are accepted:
+        //   - "dddd:bb:ss.f"  full PCI address with domain (e.g. 0000:00:02.0)
+        //   - "bb:ss.f"       legacy short BDF; domain defaults to 0000
         String domain = "0x0000";
         String bus = "0x00";
         String slot = "0x00";
         String function = "0x0";
 
         if (busAddress != null && !busAddress.isEmpty()) {
             String[] parts = busAddress.split(":");
-            if (parts.length > 1) {
+            String slotFunction = null;
+            if (parts.length == 3) {
+                domain = "0x" + parts[0];
+                bus = "0x" + parts[1];
+                slotFunction = parts[2];
+            } else if (parts.length == 2) {
                 bus = "0x" + parts[0];
-                String[] slotFunctionParts = parts[1].split("\\.");
+                slotFunction = parts[1];
+            }
+            if (slotFunction != null) {
+                String[] slotFunctionParts = slotFunction.split("\\.");
                 if (slotFunctionParts.length > 0) {
                     slot = "0x" + slotFunctionParts[0];
                     if (slotFunctionParts.length > 1) {

plugins/hypervisors/kvm/src/test/java/com/cloud/hypervisor/kvm/resource/LibvirtGpuDefTest.java

@@ -115,6 +115,110 @@ public void testGpuDef_withComplexPciAddress() {
         assertTrue(gpuXml.contains("</hostdev>"));
     }
 
+    @Test
+    public void testGpuDef_withFullPciAddressDomainZero() {
+        LibvirtGpuDef gpuDef = new LibvirtGpuDef();
+        VgpuTypesInfo pciGpuInfo = new VgpuTypesInfo(
+                GpuDevice.DeviceType.PCI,
+                "passthrough",
+                "passthrough",
+                "0000:00:02.0",
+                "10de",
+                "NVIDIA Corporation",
+                "1b38",
+                "Tesla T4"
+        );
+        gpuDef.defGpu(pciGpuInfo);
+
+        String gpuXml = gpuDef.toString();
+
+        assertTrue(gpuXml.contains("<address domain='0x0000' bus='0x00' slot='0x02' function='0x0'/>"));
+    }
+
+    @Test
+    public void testGpuDef_withFullPciAddressNonZeroDomain() {
+        LibvirtGpuDef gpuDef = new LibvirtGpuDef();
+        VgpuTypesInfo pciGpuInfo = new VgpuTypesInfo(
+                GpuDevice.DeviceType.PCI,
+                "passthrough",
+                "passthrough",
+                "0001:65:00.0",
+                "10de",
+                "NVIDIA Corporation",
+                "1b38",
+                "Tesla T4"
+        );
+        gpuDef.defGpu(pciGpuInfo);
+
+        String gpuXml = gpuDef.toString();
+
+        assertTrue(gpuXml.contains("<address domain='0x0001' bus='0x65' slot='0x00' function='0x0'/>"));
+    }
+
+    @Test
+    public void testGpuDef_withFullPciAddressWideDomain() {
+        LibvirtGpuDef gpuDef = new LibvirtGpuDef();
+        VgpuTypesInfo pciGpuInfo = new VgpuTypesInfo(
+                GpuDevice.DeviceType.PCI,
+                "passthrough",
+                "passthrough",
+                "10000:af:00.1",
+                "10de",
+                "NVIDIA Corporation",
+                "1b38",
+                "Tesla T4"
+        );
+        gpuDef.defGpu(pciGpuInfo);
+
+        String gpuXml = gpuDef.toString();
+
+        assertTrue(gpuXml.contains("<address domain='0x10000' bus='0xaf' slot='0x00' function='0x1'/>"));
+    }
+
+    @Test
+    public void testGpuDef_withFullPciAddressVfNonZeroDomain() {
+        LibvirtGpuDef gpuDef = new LibvirtGpuDef();
+        VgpuTypesInfo vfGpuInfo = new VgpuTypesInfo(
+                GpuDevice.DeviceType.PCI,
+                "VF-Profile",
+                "VF-Profile",
+                "0002:81:00.3",
+                "10de",
+                "NVIDIA Corporation",
+                "1eb8",
+                "Tesla T4"
+        );
+        gpuDef.defGpu(vfGpuInfo);
+
+        String gpuXml = gpuDef.toString();
+
+        // Non-passthrough NVIDIA VFs should be unmanaged
+        assertTrue(gpuXml.contains("<hostdev mode='subsystem' type='pci' managed='no' display='off'>"));
+        assertTrue(gpuXml.contains("<address domain='0x0002' bus='0x81' slot='0x00' function='0x3'/>"));
+    }
+
+    @Test
+    public void testGpuDef_withLegacyShortBdfDefaultsDomainToZero() {
+        // Backward compatibility: short BDF with no domain segment must still
+        // produce a valid libvirt address with domain 0x0000.
+        LibvirtGpuDef gpuDef = new LibvirtGpuDef();
+        VgpuTypesInfo pciGpuInfo = new VgpuTypesInfo(
+                GpuDevice.DeviceType.PCI,
+                "passthrough",
+                "passthrough",
+                "af:00.0",
+                "10de",
+                "NVIDIA Corporation",
+                "1b38",
+                "Tesla T4"
+        );
+        gpuDef.defGpu(pciGpuInfo);
+
+        String gpuXml = gpuDef.toString();
+
+        assertTrue(gpuXml.contains("<address domain='0x0000' bus='0xaf' slot='0x00' function='0x0'/>"));
+    }
+
     @Test
     public void testGpuDef_withNullDeviceType() {
         LibvirtGpuDef gpuDef = new LibvirtGpuDef();