virtio-blk: enable multiple vectors when using multiple I/O queues

Currently virtio-pci driver hardcoded 2 vectors for virtio-blk device,
for multiple I/O queues scenario, all the I/O queues will share one
interrupt vector, while here, enable multiple vectors according to
the number of I/O queues.

Signed-off-by: Changpeng Liu <changpeng.liu@intel.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

hw/virtio/virtio-pci.c

@@ -1932,7 +1932,8 @@ static Property virtio_blk_pci_properties[] = {
     DEFINE_PROP_UINT32("class", VirtIOPCIProxy, class_code, 0),
     DEFINE_PROP_BIT("ioeventfd", VirtIOPCIProxy, flags,
                     VIRTIO_PCI_FLAG_USE_IOEVENTFD_BIT, true),
-    DEFINE_PROP_UINT32("vectors", VirtIOPCIProxy, nvectors, 2),
+    DEFINE_PROP_UINT32("vectors", VirtIOPCIProxy, nvectors,
+                       DEV_NVECTORS_UNSPECIFIED),
     DEFINE_PROP_END_OF_LIST(),
 };
 
@@ -1941,6 +1942,10 @@ static void virtio_blk_pci_realize(VirtIOPCIProxy *vpci_dev, Error **errp)
     VirtIOBlkPCI *dev = VIRTIO_BLK_PCI(vpci_dev);
     DeviceState *vdev = DEVICE(&dev->vdev);
 
+    if (vpci_dev->nvectors == DEV_NVECTORS_UNSPECIFIED) {
+        vpci_dev->nvectors = dev->vdev.conf.num_queues + 1;
+    }
+
     qdev_set_parent_bus(vdev, BUS(&vpci_dev->bus));
     object_property_set_bool(OBJECT(vdev), true, "realized", errp);
 }
@@ -1983,7 +1988,8 @@ static const TypeInfo virtio_blk_pci_info = {
 
 static Property vhost_user_blk_pci_properties[] = {
     DEFINE_PROP_UINT32("class", VirtIOPCIProxy, class_code, 0),
-    DEFINE_PROP_UINT32("vectors", VirtIOPCIProxy, nvectors, 2),
+    DEFINE_PROP_UINT32("vectors", VirtIOPCIProxy, nvectors,
+                       DEV_NVECTORS_UNSPECIFIED),
     DEFINE_PROP_END_OF_LIST(),
 };
 
@@ -1992,6 +1998,10 @@ static void vhost_user_blk_pci_realize(VirtIOPCIProxy *vpci_dev, Error **errp)
     VHostUserBlkPCI *dev = VHOST_USER_BLK_PCI(vpci_dev);
     DeviceState *vdev = DEVICE(&dev->vdev);
 
+    if (vpci_dev->nvectors == DEV_NVECTORS_UNSPECIFIED) {
+        vpci_dev->nvectors = dev->vdev.num_queues + 1;
+    }
+
     qdev_set_parent_bus(vdev, BUS(&vpci_dev->bus));
     object_property_set_bool(OBJECT(vdev), true, "realized", errp);
 }

include/hw/compat.h

@@ -6,6 +6,14 @@
         .driver   = "hpet",\
         .property = "hpet-offset-saved",\
         .value    = "false",\
+    },{\
+        .driver   = "virtio-blk-pci",\
+        .property = "vectors",\
+        .value    = "2",\
+    },{\
+        .driver   = "vhost-user-blk-pci",\
+        .property = "vectors",\
+        .value    = "2",\
     },
 
 #define HW_COMPAT_2_10 \