Commit 6f0bb230 authored by Gal Hammer's avatar Gal Hammer Committed by Michael S. Tsirkin
Browse files

virtio: improve virtio devices initialization time 



The loading time of a VM is quite significant when its virtio
devices use a large amount of virt-queues (e.g. a virtio-serial
device with max_ports=511). Most of the time is spend in the
creation of all the required event notifiers (ioeventfd and memory
regions).

This patch pack all the changes to the memory regions in a
single memory transaction.

Reported-by: default avatarSitong Liu <siliu@redhat.com>
Reported-by: default avatarXiaoling Gao <xiagao@redhat.com>
Signed-off-by: default avatarGal Hammer <ghammer@redhat.com>
Reviewed-by: default avatarMichael S. Tsirkin <mst@redhat.com>
Signed-off-by: default avatarMichael S. Tsirkin <mst@redhat.com>
parent 4fe6d78b

hw/virtio/virtio.c

+5 −0
Original line number Diff line number Diff line
@@ -2574,6 +2574,7 @@ static int virtio_device_start_ioeventfd_impl(VirtIODevice *vdev) 
    VirtioBusState *qbus = VIRTIO_BUS(qdev_get_parent_bus(DEVICE(vdev)));

    int n, r, err;



    memory_region_transaction_begin();

    for (n = 0; n < VIRTIO_QUEUE_MAX; n++) {

        VirtQueue *vq = &vdev->vq[n];

        if (!virtio_queue_get_num(vdev, n)) {
@@ -2596,6 +2597,7 @@ static int virtio_device_start_ioeventfd_impl(VirtIODevice *vdev) 
        }

        event_notifier_set(&vq->host_notifier);

    }

    memory_region_transaction_commit();

    return 0;



assign_error:
@@ -2609,6 +2611,7 @@ assign_error: 
        r = virtio_bus_set_host_notifier(qbus, n, false);

        assert(r >= 0);

    }

    memory_region_transaction_commit();

    return err;

}
@@ -2625,6 +2628,7 @@ static void virtio_device_stop_ioeventfd_impl(VirtIODevice *vdev) 
    VirtioBusState *qbus = VIRTIO_BUS(qdev_get_parent_bus(DEVICE(vdev)));

    int n, r;



    memory_region_transaction_begin();

    for (n = 0; n < VIRTIO_QUEUE_MAX; n++) {

        VirtQueue *vq = &vdev->vq[n];
@@ -2635,6 +2639,7 @@ static void virtio_device_stop_ioeventfd_impl(VirtIODevice *vdev) 
        r = virtio_bus_set_host_notifier(qbus, n, false);

        assert(r >= 0);

    }

    memory_region_transaction_commit();

}



void virtio_device_stop_ioeventfd(VirtIODevice *vdev)