virtio: introduce vector to virtqueues mapping

Currently we will try to traverse all virtqueues to find a subset that
using a specific vector. This is sub optimal when we will support
hundreds or even thousands of virtqueues. So this patch introduces a
method which could be used by transport to get all virtqueues that
using a same vector. This is done through QLISTs and the number of
QLISTs was queried through a transport specific method. When guest
setting vectors, the virtqueue will be linked and helpers for traverse
the list was also introduced.

The first user will be virtio pci which will use this to speed up
MSI-X masking and unmasking handling.

Cc: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

diff --git a/hw/virtio/virtio-pci.c b/hw/virtio/virtio-pci.c
index c7c3f7249be3865dc80069b09ec0ee20dbe8e733..6ae24a04927c3e8da8673c34536bc24497be9590 100644 (file)
--- a/hw/virtio/virtio-pci.c
+++ b/hw/virtio/virtio-pci.c
@@ -908,6 +908,13 @@ static const TypeInfo virtio_9p_pci_info = {
  * virtio-pci: This is the PCIDevice which has a virtio-pci-bus.
  */
 
+static int virtio_pci_query_nvectors(DeviceState *d)
+{
+    VirtIOPCIProxy *proxy = VIRTIO_PCI(d);
+
+    return proxy->nvectors;
+}
+
 /* This is called by virtio-bus just after the device is plugged. */
 static void virtio_pci_device_plugged(DeviceState *d)
 {
@@ -1498,6 +1505,7 @@ static void virtio_pci_bus_class_init(ObjectClass *klass, void *data)
     k->vmstate_change = virtio_pci_vmstate_change;
     k->device_plugged = virtio_pci_device_plugged;
     k->device_unplugged = virtio_pci_device_unplugged;
+    k->query_nvectors = virtio_pci_query_nvectors;
 }
 
 static const TypeInfo virtio_pci_bus_info = {

diff --git a/hw/virtio/virtio.c b/hw/virtio/virtio.c
index 17c1260c0d2afa7cba4058cb2f0c7c06322fbd35..6985e76b64d20435964320f282615c16642b419f 100644 (file)
--- a/hw/virtio/virtio.c
+++ b/hw/virtio/virtio.c
@@ -89,6 +89,7 @@ struct VirtQueue
     VirtIODevice *vdev;
     EventNotifier guest_notifier;
     EventNotifier host_notifier;
+    QLIST_ENTRY(VirtQueue) node;
 };
 
 /* virt queue functions */
@@ -605,7 +606,7 @@ void virtio_reset(void *opaque)
         vdev->vq[i].vring.used = 0;
         vdev->vq[i].last_avail_idx = 0;
         vdev->vq[i].pa = 0;
-        vdev->vq[i].vector = VIRTIO_NO_VECTOR;
+        virtio_queue_set_vector(vdev, i, VIRTIO_NO_VECTOR);
         vdev->vq[i].signalled_used = 0;
         vdev->vq[i].signalled_used_valid = false;
         vdev->vq[i].notification = true;
@@ -730,6 +731,16 @@ void virtio_queue_set_num(VirtIODevice *vdev, int n, int num)
     virtqueue_init(&vdev->vq[n]);
 }
 
+VirtQueue *virtio_vector_first_queue(VirtIODevice *vdev, uint16_t vector)
+{
+    return QLIST_FIRST(&vdev->vector_queues[vector]);
+}
+
+VirtQueue *virtio_vector_next_queue(VirtQueue *vq)
+{
+    return QLIST_NEXT(vq, node);
+}
+
 int virtio_queue_get_num(VirtIODevice *vdev, int n)
 {
     return vdev->vq[n].vring.num;
@@ -780,8 +791,19 @@ uint16_t virtio_queue_vector(VirtIODevice *vdev, int n)
 
 void virtio_queue_set_vector(VirtIODevice *vdev, int n, uint16_t vector)
 {
-    if (n < VIRTIO_PCI_QUEUE_MAX)
+    VirtQueue *vq = &vdev->vq[n];
+
+    if (n < VIRTIO_PCI_QUEUE_MAX) {
+        if (vdev->vector_queues &&
+            vdev->vq[n].vector != VIRTIO_NO_VECTOR) {
+            QLIST_REMOVE(vq, node);
+        }
         vdev->vq[n].vector = vector;
+        if (vdev->vector_queues &&
+            vector != VIRTIO_NO_VECTOR) {
+            QLIST_INSERT_HEAD(&vdev->vector_queues[vector], vq, node);
+        }
+    }
 }
 
 VirtQueue *virtio_add_queue(VirtIODevice *vdev, int queue_size,
@@ -1088,6 +1110,7 @@ void virtio_cleanup(VirtIODevice *vdev)
     qemu_del_vm_change_state_handler(vdev->vmstate);
     g_free(vdev->config);
     g_free(vdev->vq);
+    g_free(vdev->vector_queues);
 }
 
 static void virtio_vmstate_change(void *opaque, int running, RunState state)
@@ -1125,7 +1148,16 @@ void virtio_instance_init_common(Object *proxy_obj, void *data,
 void virtio_init(VirtIODevice *vdev, const char *name,
                  uint16_t device_id, size_t config_size)
 {
+    BusState *qbus = qdev_get_parent_bus(DEVICE(vdev));
+    VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus);
     int i;
+    int nvectors = k->query_nvectors ? k->query_nvectors(qbus->parent) : 0;
+
+    if (nvectors) {
+        vdev->vector_queues =
+            g_malloc0(sizeof(*vdev->vector_queues) * nvectors);
+    }
+
     vdev->device_id = device_id;
     vdev->status = 0;
     vdev->isr = 0;

diff --git a/include/hw/virtio/virtio-bus.h b/include/hw/virtio/virtio-bus.h
index 0d2e7b49b234cc549bf612cf18762b7a77ed08fe..a4588ca4d9421772f1bc50bc28cee29ae4313bc9 100644 (file)
--- a/include/hw/virtio/virtio-bus.h
+++ b/include/hw/virtio/virtio-bus.h
@@ -62,6 +62,7 @@ typedef struct VirtioBusClass {
      * This is called by virtio-bus just before the device is unplugged.
      */
     void (*device_unplugged)(DeviceState *d);
+    int (*query_nvectors)(DeviceState *d);
     /*
      * Does the transport have variable vring alignment?
      * (ie can it ever call virtio_queue_set_align()?)

diff --git a/include/hw/virtio/virtio.h b/include/hw/virtio/virtio.h
index d95f8b6d50623fad23a8b6ae61a126f596d96e0d..9706c293950d758b8035114ef9a20db90b325958 100644 (file)
--- a/include/hw/virtio/virtio.h
+++ b/include/hw/virtio/virtio.h
@@ -84,6 +84,7 @@ struct VirtIODevice
     VMChangeStateEntry *vmstate;
     char *bus_name;
     uint8_t device_endian;
+    QLIST_HEAD(, VirtQueue) * vector_queues;
 };
 
 typedef struct VirtioDeviceClass {
@@ -218,6 +219,8 @@ void virtio_queue_set_host_notifier_fd_handler(VirtQueue *vq, bool assign,
                                                bool set_handler);
 void virtio_queue_notify_vq(VirtQueue *vq);
 void virtio_irq(VirtQueue *vq);
+VirtQueue *virtio_vector_first_queue(VirtIODevice *vdev, uint16_t vector);
+VirtQueue *virtio_vector_next_queue(VirtQueue *vq);
 
 static inline void virtio_add_feature(uint32_t *features, unsigned int fbit)
 {