From a8f2e5c8fffbaf7fbd4f0efc8efbeebade78008f Mon Sep 17 00:00:00 2001 From: Paolo Bonzini Date: Wed, 6 Apr 2016 12:16:27 +0200 Subject: virtio-scsi: use aio handler for data plane In addition to handling IO in vcpu thread and in io thread, dataplane introduces yet another mode: handling it by AioContext. This reuses the same handler as previous modes, which triggers races as these were not designed to be reentrant. Use a separate handler just for aio, and disable regular handlers when dataplane is active. Reviewed-by: Cornelia Huck Signed-off-by: Paolo Bonzini Reviewed-by: Michael S. Tsirkin Signed-off-by: Michael S. Tsirkin --- hw/scsi/virtio-scsi-dataplane.c | 43 +++++++++++++++++++++++++++++++++++++---- 1 file changed, 39 insertions(+), 4 deletions(-) (limited to 'hw/scsi/virtio-scsi-dataplane.c') diff --git a/hw/scsi/virtio-scsi-dataplane.c b/hw/scsi/virtio-scsi-dataplane.c index b44ac5dfa0..39ad086db7 100644 --- a/hw/scsi/virtio-scsi-dataplane.c +++ b/hw/scsi/virtio-scsi-dataplane.c @@ -38,7 +38,35 @@ void virtio_scsi_set_iothread(VirtIOSCSI *s, IOThread *iothread) } } -static int virtio_scsi_vring_init(VirtIOSCSI *s, VirtQueue *vq, int n) +static void virtio_scsi_data_plane_handle_cmd(VirtIODevice *vdev, + VirtQueue *vq) +{ + VirtIOSCSI *s = (VirtIOSCSI *)vdev; + + assert(s->ctx && s->dataplane_started); + virtio_scsi_handle_cmd_vq(s, vq); +} + +static void virtio_scsi_data_plane_handle_ctrl(VirtIODevice *vdev, + VirtQueue *vq) +{ + VirtIOSCSI *s = VIRTIO_SCSI(vdev); + + assert(s->ctx && s->dataplane_started); + virtio_scsi_handle_ctrl_vq(s, vq); +} + +static void virtio_scsi_data_plane_handle_event(VirtIODevice *vdev, + VirtQueue *vq) +{ + VirtIOSCSI *s = VIRTIO_SCSI(vdev); + + assert(s->ctx && s->dataplane_started); + virtio_scsi_handle_event_vq(s, vq); +} + +static int virtio_scsi_vring_init(VirtIOSCSI *s, VirtQueue *vq, int n, + void (*fn)(VirtIODevice *vdev, VirtQueue *vq)) { BusState *qbus = BUS(qdev_get_parent_bus(DEVICE(s))); VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus); @@ -54,6 +82,7 @@ static int virtio_scsi_vring_init(VirtIOSCSI *s, VirtQueue *vq, int n) } virtio_queue_aio_set_host_notifier_handler(vq, s->ctx, true, true); + virtio_set_queue_aio(vq, fn); return 0; } @@ -71,9 +100,12 @@ static void virtio_scsi_clear_aio(VirtIOSCSI *s) int i; virtio_queue_aio_set_host_notifier_handler(vs->ctrl_vq, s->ctx, false, false); + virtio_set_queue_aio(vs->ctrl_vq, NULL); virtio_queue_aio_set_host_notifier_handler(vs->event_vq, s->ctx, false, false); + virtio_set_queue_aio(vs->event_vq, NULL); for (i = 0; i < vs->conf.num_queues; i++) { virtio_queue_aio_set_host_notifier_handler(vs->cmd_vqs[i], s->ctx, false, false); + virtio_set_queue_aio(vs->cmd_vqs[i], NULL); } } @@ -104,16 +136,19 @@ void virtio_scsi_dataplane_start(VirtIOSCSI *s) } aio_context_acquire(s->ctx); - rc = virtio_scsi_vring_init(s, vs->ctrl_vq, 0); + rc = virtio_scsi_vring_init(s, vs->ctrl_vq, 0, + virtio_scsi_data_plane_handle_ctrl); if (rc) { goto fail_vrings; } - rc = virtio_scsi_vring_init(s, vs->event_vq, 1); + rc = virtio_scsi_vring_init(s, vs->event_vq, 1, + virtio_scsi_data_plane_handle_event); if (rc) { goto fail_vrings; } for (i = 0; i < vs->conf.num_queues; i++) { - rc = virtio_scsi_vring_init(s, vs->cmd_vqs[i], i + 2); + rc = virtio_scsi_vring_init(s, vs->cmd_vqs[i], i + 2, + virtio_scsi_data_plane_handle_cmd); if (rc) { goto fail_vrings; } -- cgit 1.4.1 From a378b49a4338ef61b86f4c74a1069036c7409141 Mon Sep 17 00:00:00 2001 From: Paolo Bonzini Date: Wed, 6 Apr 2016 12:16:28 +0200 Subject: virtio: merge virtio_queue_aio_set_host_notifier_handler with virtio_queue_set_aio Eliminating the reentrancy is actually a nice thing that we can do with the API that Michael proposed, so let's make it first class. This also hides the complex assign/set_handler conventions from callers of virtio_queue_aio_set_host_notifier_handler, which in fact was always called with assign=true. Reviewed-by: Cornelia Huck Signed-off-by: Paolo Bonzini Reviewed-by: Michael S. Tsirkin Signed-off-by: Michael S. Tsirkin --- hw/block/dataplane/virtio-blk.c | 7 +++---- hw/scsi/virtio-scsi-dataplane.c | 12 ++++-------- hw/virtio/virtio.c | 17 +++++------------ include/hw/virtio/virtio.h | 6 ++---- 4 files changed, 14 insertions(+), 28 deletions(-) (limited to 'hw/scsi/virtio-scsi-dataplane.c') diff --git a/hw/block/dataplane/virtio-blk.c b/hw/block/dataplane/virtio-blk.c index 65c7f7041d..3cb97c9a29 100644 --- a/hw/block/dataplane/virtio-blk.c +++ b/hw/block/dataplane/virtio-blk.c @@ -237,8 +237,8 @@ void virtio_blk_data_plane_start(VirtIOBlockDataPlane *s) /* Get this show started by hooking up our callbacks */ aio_context_acquire(s->ctx); - virtio_set_queue_aio(s->vq, virtio_blk_data_plane_handle_output); - virtio_queue_aio_set_host_notifier_handler(s->vq, s->ctx, true, true); + virtio_queue_aio_set_host_notifier_handler(s->vq, s->ctx, + virtio_blk_data_plane_handle_output); aio_context_release(s->ctx); return; @@ -273,8 +273,7 @@ void virtio_blk_data_plane_stop(VirtIOBlockDataPlane *s) aio_context_acquire(s->ctx); /* Stop notifications for new requests from guest */ - virtio_queue_aio_set_host_notifier_handler(s->vq, s->ctx, false, false); - virtio_set_queue_aio(s->vq, NULL); + virtio_queue_aio_set_host_notifier_handler(s->vq, s->ctx, NULL); /* Drain and switch bs back to the QEMU main loop */ blk_set_aio_context(s->conf->conf.blk, qemu_get_aio_context()); diff --git a/hw/scsi/virtio-scsi-dataplane.c b/hw/scsi/virtio-scsi-dataplane.c index 39ad086db7..1a49f1e4b7 100644 --- a/hw/scsi/virtio-scsi-dataplane.c +++ b/hw/scsi/virtio-scsi-dataplane.c @@ -81,8 +81,7 @@ static int virtio_scsi_vring_init(VirtIOSCSI *s, VirtQueue *vq, int n, return rc; } - virtio_queue_aio_set_host_notifier_handler(vq, s->ctx, true, true); - virtio_set_queue_aio(vq, fn); + virtio_queue_aio_set_host_notifier_handler(vq, s->ctx, fn); return 0; } @@ -99,13 +98,10 @@ static void virtio_scsi_clear_aio(VirtIOSCSI *s) VirtIOSCSICommon *vs = VIRTIO_SCSI_COMMON(s); int i; - virtio_queue_aio_set_host_notifier_handler(vs->ctrl_vq, s->ctx, false, false); - virtio_set_queue_aio(vs->ctrl_vq, NULL); - virtio_queue_aio_set_host_notifier_handler(vs->event_vq, s->ctx, false, false); - virtio_set_queue_aio(vs->event_vq, NULL); + virtio_queue_aio_set_host_notifier_handler(vs->ctrl_vq, s->ctx, NULL); + virtio_queue_aio_set_host_notifier_handler(vs->event_vq, s->ctx, NULL); for (i = 0; i < vs->conf.num_queues; i++) { - virtio_queue_aio_set_host_notifier_handler(vs->cmd_vqs[i], s->ctx, false, false); - virtio_set_queue_aio(vs->cmd_vqs[i], NULL); + virtio_queue_aio_set_host_notifier_handler(vs->cmd_vqs[i], s->ctx, NULL); } } diff --git a/hw/virtio/virtio.c b/hw/virtio/virtio.c index eb04ac07eb..f745c4abd0 100644 --- a/hw/virtio/virtio.c +++ b/hw/virtio/virtio.c @@ -1159,14 +1159,6 @@ VirtQueue *virtio_add_queue(VirtIODevice *vdev, int queue_size, return &vdev->vq[i]; } -void virtio_set_queue_aio(VirtQueue *vq, - void (*handle_output)(VirtIODevice *, VirtQueue *)) -{ - assert(vq->handle_output); - - vq->handle_aio_output = handle_output; -} - void virtio_del_queue(VirtIODevice *vdev, int n) { if (n < 0 || n >= VIRTIO_QUEUE_MAX) { @@ -1809,18 +1801,19 @@ static void virtio_queue_host_notifier_aio_read(EventNotifier *n) } void virtio_queue_aio_set_host_notifier_handler(VirtQueue *vq, AioContext *ctx, - bool assign, bool set_handler) + void (*handle_output)(VirtIODevice *, + VirtQueue *)) { - if (assign && set_handler) { + if (handle_output) { + vq->handle_aio_output = handle_output; aio_set_event_notifier(ctx, &vq->host_notifier, true, virtio_queue_host_notifier_aio_read); } else { aio_set_event_notifier(ctx, &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. */ virtio_queue_host_notifier_aio_read(&vq->host_notifier); + vq->handle_aio_output = NULL; } } diff --git a/include/hw/virtio/virtio.h b/include/hw/virtio/virtio.h index fa3f93b846..6a37065c23 100644 --- a/include/hw/virtio/virtio.h +++ b/include/hw/virtio/virtio.h @@ -142,9 +142,6 @@ VirtQueue *virtio_add_queue(VirtIODevice *vdev, int queue_size, void (*handle_output)(VirtIODevice *, VirtQueue *)); -void virtio_set_queue_aio(VirtQueue *vq, - void (*handle_output)(VirtIODevice *, VirtQueue *)); - void virtio_del_queue(VirtIODevice *vdev, int n); void *virtqueue_alloc_element(size_t sz, unsigned out_num, unsigned in_num); @@ -254,7 +251,8 @@ EventNotifier *virtio_queue_get_host_notifier(VirtQueue *vq); void virtio_queue_set_host_notifier_fd_handler(VirtQueue *vq, bool assign, bool set_handler); void virtio_queue_aio_set_host_notifier_handler(VirtQueue *vq, AioContext *ctx, - bool assign, bool set_handler); + void (*fn)(VirtIODevice *, + VirtQueue *)); void virtio_irq(VirtQueue *vq); VirtQueue *virtio_vector_first_queue(VirtIODevice *vdev, uint16_t vector); VirtQueue *virtio_vector_next_queue(VirtQueue *vq); -- cgit 1.4.1