Commit 872dd82c authored by Fam Zheng's avatar Fam Zheng Committed by Michael S. Tsirkin
Browse files

virtio: Introduce virtio_add_queue_aio 



Using this function instead of virtio_add_queue marks the vq as aio
based. This differentiation will be useful in later patches.

Distinguish between virtqueue processing in the iohandler context and main loop
AioContext.  iohandler context is isolated from AioContexts and therefore does
not run during aio_poll().

Signed-off-by: default avatarFam Zheng <famz@redhat.com>
Reviewed-by: default avatarMichael S. Tsirkin <mst@redhat.com>
Signed-off-by: default avatarMichael S. Tsirkin <mst@redhat.com>
Reviewed-by: default avatarCornelia Huck <cornelia.huck@de.ibm.com>
Reviewed-by: default avatarStefan Hajnoczi <stefanha@redhat.com>
Acked-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent bf1780b0

hw/virtio/virtio.c

+34 −4
Original line number Diff line number Diff line
@@ -97,6 +97,7 @@ struct VirtQueue 
    uint16_t vector;

    VirtIOHandleOutput handle_output;

    VirtIOHandleOutput handle_aio_output;

    bool use_aio;

    VirtIODevice *vdev;

    EventNotifier guest_notifier;

    EventNotifier host_notifier;
@@ -1130,8 +1131,9 @@ void virtio_queue_set_vector(VirtIODevice *vdev, int n, uint16_t vector) 
    }

}



VirtQueue *virtio_add_queue(VirtIODevice *vdev, int queue_size,

                            VirtIOHandleOutput handle_output)

static VirtQueue *virtio_add_queue_internal(VirtIODevice *vdev, int queue_size,

                                            VirtIOHandleOutput handle_output,

                                            bool use_aio)

{

    int i;
@@ -1148,10 +1150,28 @@ VirtQueue *virtio_add_queue(VirtIODevice *vdev, int queue_size, 
    vdev->vq[i].vring.align = VIRTIO_PCI_VRING_ALIGN;

    vdev->vq[i].handle_output = handle_output;

    vdev->vq[i].handle_aio_output = NULL;

    vdev->vq[i].use_aio = use_aio;



    return &vdev->vq[i];

}



/* Add a virt queue and mark AIO.

 * An AIO queue will use the AioContext based event interface instead of the

 * default IOHandler and EventNotifier interface.

 */

VirtQueue *virtio_add_queue_aio(VirtIODevice *vdev, int queue_size,

                                VirtIOHandleOutput handle_output)

{

    return virtio_add_queue_internal(vdev, queue_size, handle_output, true);

}



/* Add a normal virt queue (on the contrary to the AIO version above. */

VirtQueue *virtio_add_queue(VirtIODevice *vdev, int queue_size,

                            VirtIOHandleOutput handle_output)

{

    return virtio_add_queue_internal(vdev, queue_size, handle_output, false);

}



void virtio_del_queue(VirtIODevice *vdev, int n)

{

    if (n < 0 || n >= VIRTIO_QUEUE_MAX) {
@@ -1830,12 +1850,22 @@ static void virtio_queue_host_notifier_read(EventNotifier *n) 
void virtio_queue_set_host_notifier_fd_handler(VirtQueue *vq, bool assign,

                                               bool set_handler)

{

    AioContext *ctx = qemu_get_aio_context();

    if (assign && set_handler) {

        if (vq->use_aio) {

            aio_set_event_notifier(ctx, &vq->host_notifier, true,

                                   virtio_queue_host_notifier_read);

        } else {

            event_notifier_set_handler(&vq->host_notifier, true,

                                       virtio_queue_host_notifier_read);

        }

    } else {

        if (vq->use_aio) {

            aio_set_event_notifier(ctx, &vq->host_notifier, true, NULL);

        } else {

            event_notifier_set_handler(&vq->host_notifier, true, NULL);

        }

    }

    if (!assign) {

        /* Test and clear notifier before after disabling event,

         * in case poll callback didn't have time to run. */

include/hw/virtio/virtio.h

+3 −0
Original line number Diff line number Diff line
@@ -143,6 +143,9 @@ typedef void (*VirtIOHandleOutput)(VirtIODevice *, VirtQueue *); 
VirtQueue *virtio_add_queue(VirtIODevice *vdev, int queue_size,

                            VirtIOHandleOutput handle_output);



VirtQueue *virtio_add_queue_aio(VirtIODevice *vdev, int queue_size,

                                VirtIOHandleOutput handle_output);



void virtio_del_queue(VirtIODevice *vdev, int n);



void *virtqueue_alloc_element(size_t sz, unsigned out_num, unsigned in_num);