KVM NFS disk IO driver supporting IO_URING

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

@@ -253,6 +253,8 @@ public class LibvirtComputingResource extends ServerResourceBase implements Serv
 
     protected static final String DEFAULT_OVS_VIF_DRIVER_CLASS_NAME = "com.cloud.hypervisor.kvm.resource.OvsVifDriver";
     protected static final String DEFAULT_BRIDGE_VIF_DRIVER_CLASS_NAME = "com.cloud.hypervisor.kvm.resource.BridgeVifDriver";
+    private final static long HYPERVISOR_LIBVIRT_VERSION_SUPPORTS_IO_URING = 6003000;
+    private final static long HYPERVISOR_QEMU_VERSION_SUPPORTS_IO_URING = 5000000;
 
     protected HypervisorType _hypervisorType;
     protected String _hypervisorURI;
@@ -342,6 +344,14 @@ public class LibvirtComputingResource extends ServerResourceBase implements Serv
     protected MemStat _memStat = new MemStat(_dom0MinMem, _dom0OvercommitMem);
     private final LibvirtUtilitiesHelper libvirtUtilitiesHelper = new LibvirtUtilitiesHelper();
 
+    protected long getHypervisorLibvirtVersion() {
+        return _hypervisorLibvirtVersion;
+    }
+
+    protected long getHypervisorQemuVersion() {
+        return _hypervisorQemuVersion;
+    }
+
     @Override
     public ExecutionResult executeInVR(final String routerIp, final String script, final String args) {
         return executeInVR(routerIp, script, args, _timeout);
@@ -2619,6 +2629,8 @@ public int compare(final DiskTO arg0, final DiskTO arg1) {
                     disk.setDiscard(DiscardType.UNMAP);
                 }
 
+                setDiskIoDriver(disk);
+
                 if (pool.getType() == StoragePoolType.RBD) {
                     /*
                             For RBD pools we use the secret mechanism in libvirt.
@@ -2719,6 +2731,18 @@ private KVMPhysicalDisk getPhysicalDiskPrimaryStore(PrimaryDataStoreTO primaryDa
         return storagePool.getPhysicalDisk(data.getPath());
     }
 
+    /**
+     * Set Disk IO Driver, if supported by the Libvirt/Qemu version.
+     * IO Driver works for:
+     * (i) Qemu >= 5.0;
+     * (ii) Libvirt >= 6.3.0
+     */
+    protected void setDiskIoDriver(DiskDef disk) {
+        if (getHypervisorLibvirtVersion() >= HYPERVISOR_LIBVIRT_VERSION_SUPPORTS_IO_URING && getHypervisorQemuVersion() >= HYPERVISOR_QEMU_VERSION_SUPPORTS_IO_URING) {
+            disk.setIoDriver(DiskDef.IoDriver.IOURING);
+        }
+    }
+
     private KVMPhysicalDisk getPhysicalDiskFromNfsStore(String dataStoreUrl, DataTO data) {
         final String volPath = dataStoreUrl + File.separator + data.getPath();
         final int index = volPath.lastIndexOf("/");

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

@@ -651,6 +651,26 @@ public String toString() {
 
         }
 
+        /**
+         * This enum specifies IO Drivers, each option controls specific policies on I/O.
+         * Qemu guests support "threads" and "native" options Since 0.8.8 ; "io_uring" is supported Since 6.3.0 (QEMU 5.0).
+         */
+        public enum IoDriver {
+            NATIVE("native"),
+            THREADS("threads"),
+            IOURING("io_uring");
+            String ioDriver;
+
+            IoDriver(String driver) {
+                ioDriver = driver;
+            }
+
+            @Override
+            public String toString() {
+                return ioDriver;
+            }
+        }
+
         private DeviceType _deviceType; /* floppy, disk, cdrom */
         private DiskType _diskType;
         private DiskProtocol _diskProtocol;
@@ -681,6 +701,7 @@ public String toString() {
         private String _serial;
         private boolean qemuDriver = true;
         private DiscardType _discard = DiscardType.IGNORE;
+        private IoDriver ioDriver;
 
         public DiscardType getDiscard() {
             return _discard;
@@ -690,6 +711,14 @@ public void setDiscard(DiscardType discard) {
             this._discard = discard;
         }
 
+        public DiskDef.IoDriver getIoDriver() {
+            return ioDriver;
+        }
+
+        public void setIoDriver(IoDriver ioDriver) {
+            this.ioDriver = ioDriver;
+        }
+
         public void setDeviceType(DeviceType deviceType) {
             _deviceType = deviceType;
         }
@@ -1001,6 +1030,11 @@ public String toString() {
                 if(_discard != null && _discard != DiscardType.IGNORE) {
                     diskBuilder.append("discard='" + _discard.toString() + "' ");
                 }
+
+                if(ioDriver != null) {
+                    diskBuilder.append(String.format("io='%s'", ioDriver));
+                }
+
                 diskBuilder.append("/>\n");
             }
 

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

@@ -202,6 +202,9 @@ public class LibvirtComputingResourceTest {
     @Mock
     LibvirtVMDef vmDef;
 
+    private final static long HYPERVISOR_LIBVIRT_VERSION_SUPPORTS_IOURING = 6003000;
+    private final static long HYPERVISOR_QEMU_VERSION_SUPPORTS_IOURING = 5000000;
+
     String hyperVisorType = "kvm";
     Random random = new Random();
     final String memInfo = "MemTotal:        5830236 kB\n" +
@@ -5209,4 +5212,37 @@ public void testAddExtraConfigComponentNotEmptyExtraConfig() {
         libvirtComputingResource.addExtraConfigComponent(extraConfig, vmDef);
         Mockito.verify(vmDef, times(1)).addComp(any());
     }
+
+    @Test
+    public void setDiskIoDriverTestIoUring() {
+        DiskDef diskDef = configureAndTestSetDiskIoDriverTest(HYPERVISOR_LIBVIRT_VERSION_SUPPORTS_IOURING, HYPERVISOR_QEMU_VERSION_SUPPORTS_IOURING);
+        Assert.assertEquals(DiskDef.IoDriver.IOURING, diskDef.getIoDriver());
+    }
+
+    @Test
+    public void setDiskIoDriverTestLibvirtSupportsIoUring() {
+        DiskDef diskDef = configureAndTestSetDiskIoDriverTest(123l, HYPERVISOR_QEMU_VERSION_SUPPORTS_IOURING);
+        Assert.assertNotEquals(DiskDef.IoDriver.IOURING, diskDef.getIoDriver());
+    }
+
+    @Test
+    public void setDiskIoDriverTestQemuSupportsIoUring() {
+        DiskDef diskDef = configureAndTestSetDiskIoDriverTest(HYPERVISOR_LIBVIRT_VERSION_SUPPORTS_IOURING, 123l);
+        Assert.assertNotEquals(DiskDef.IoDriver.IOURING, diskDef.getIoDriver());
+    }
+
+    @Test
+    public void setDiskIoDriverTestNoSupportToIoUring() {
+        DiskDef diskDef = configureAndTestSetDiskIoDriverTest(123l, 123l);
+        Assert.assertNotEquals(DiskDef.IoDriver.IOURING, diskDef.getIoDriver());
+    }
+
+    private DiskDef configureAndTestSetDiskIoDriverTest(long hypervisorLibvirtVersion, long hypervisorQemuVersion) {
+        DiskDef diskDef = new DiskDef();
+        LibvirtComputingResource libvirtComputingResourceSpy = Mockito.spy(new LibvirtComputingResource());
+        Mockito.when(libvirtComputingResourceSpy.getHypervisorLibvirtVersion()).thenReturn(hypervisorLibvirtVersion);
+        Mockito.when(libvirtComputingResourceSpy.getHypervisorQemuVersion()).thenReturn(hypervisorQemuVersion);
+        libvirtComputingResourceSpy.setDiskIoDriver(diskDef);
+        return diskDef;
+    }
 }