#include "qapi/error.h"
#include "trace.h"
#include "qemu/iov.h"
+#include "qemu/main-loop.h"
#include "qemu/thread.h"
#include "qemu/error-report.h"
#include "hw/virtio/virtio-access.h"
-#include "sysemu/block-backend.h"
#include "hw/virtio/virtio-blk.h"
#include "virtio-blk.h"
#include "block/aio.h"
VirtIODevice *vdev;
QEMUBH *bh; /* bh for guest notification */
unsigned long *batch_notify_vqs;
+ bool batch_notifications;
/* Note that these EventNotifiers are assigned by value. This is
* fine as long as you do not call event_notifier_cleanup on them
/* Raise an interrupt to signal guest, if necessary */
void virtio_blk_data_plane_notify(VirtIOBlockDataPlane *s, VirtQueue *vq)
{
- set_bit(virtio_get_queue_index(vq), s->batch_notify_vqs);
- qemu_bh_schedule(s->bh);
+ if (s->batch_notifications) {
+ set_bit(virtio_get_queue_index(vq), s->batch_notify_vqs);
+ qemu_bh_schedule(s->bh);
+ } else {
+ virtio_notify_irqfd(s->vdev, vq);
+ }
}
static void notify_guest_bh(void *opaque)
unsigned i = j + ctzl(bits);
VirtQueue *vq = virtio_get_queue(s->vdev, i);
- if (virtio_should_notify(s->vdev, vq)) {
- event_notifier_set(virtio_queue_get_guest_notifier(vq));
- }
+ virtio_notify_irqfd(s->vdev, vq);
bits &= bits - 1; /* clear right-most bit */
}
}
/* Context: QEMU global mutex held */
-void virtio_blk_data_plane_create(VirtIODevice *vdev, VirtIOBlkConf *conf,
+bool virtio_blk_data_plane_create(VirtIODevice *vdev, VirtIOBlkConf *conf,
VirtIOBlockDataPlane **dataplane,
Error **errp)
{
*dataplane = NULL;
- if (!conf->iothread) {
- return;
- }
+ if (conf->iothread) {
+ if (!k->set_guest_notifiers || !k->ioeventfd_assign) {
+ error_setg(errp,
+ "device is incompatible with iothread "
+ "(transport does not support notifiers)");
+ return false;
+ }
+ if (!virtio_device_ioeventfd_enabled(vdev)) {
+ error_setg(errp, "ioeventfd is required for iothread");
+ return false;
+ }
- /* Don't try if transport does not support notifiers. */
- if (!k->set_guest_notifiers || !k->ioeventfd_started) {
- error_setg(errp,
- "device is incompatible with dataplane "
- "(transport does not support notifiers)");
- return;
+ /* If dataplane is (re-)enabled while the guest is running there could
+ * be block jobs that can conflict.
+ */
+ if (blk_op_is_blocked(conf->conf.blk, BLOCK_OP_TYPE_DATAPLANE, errp)) {
+ error_prepend(errp, "cannot start virtio-blk dataplane: ");
+ return false;
+ }
}
-
- /* If dataplane is (re-)enabled while the guest is running there could be
- * block jobs that can conflict.
- */
- if (blk_op_is_blocked(conf->conf.blk, BLOCK_OP_TYPE_DATAPLANE, errp)) {
- error_prepend(errp, "cannot start dataplane thread: ");
- return;
+ /* Don't try if transport does not support notifiers. */
+ if (!virtio_device_ioeventfd_enabled(vdev)) {
+ return false;
}
s = g_new0(VirtIOBlockDataPlane, 1);
s->vdev = vdev;
s->conf = conf;
- s->iothread = conf->iothread;
- object_ref(OBJECT(s->iothread));
- s->ctx = iothread_get_aio_context(s->iothread);
+ if (conf->iothread) {
+ s->iothread = conf->iothread;
+ object_ref(OBJECT(s->iothread));
+ s->ctx = iothread_get_aio_context(s->iothread);
+ } else {
+ s->ctx = qemu_get_aio_context();
+ }
s->bh = aio_bh_new(s->ctx, notify_guest_bh, s);
s->batch_notify_vqs = bitmap_new(conf->num_queues);
*dataplane = s;
+
+ return true;
}
/* Context: QEMU global mutex held */
void virtio_blk_data_plane_destroy(VirtIOBlockDataPlane *s)
{
+ VirtIOBlock *vblk;
+
if (!s) {
return;
}
- virtio_blk_data_plane_stop(s);
+ vblk = VIRTIO_BLK(s->vdev);
+ assert(!vblk->dataplane_started);
g_free(s->batch_notify_vqs);
qemu_bh_delete(s->bh);
- object_unref(OBJECT(s->iothread));
+ if (s->iothread) {
+ object_unref(OBJECT(s->iothread));
+ }
g_free(s);
}
-static void virtio_blk_data_plane_handle_output(VirtIODevice *vdev,
+static bool virtio_blk_data_plane_handle_output(VirtIODevice *vdev,
VirtQueue *vq)
{
VirtIOBlock *s = (VirtIOBlock *)vdev;
assert(s->dataplane);
assert(s->dataplane_started);
- virtio_blk_handle_vq(s, vq);
+ return virtio_blk_handle_vq(s, vq);
}
/* Context: QEMU global mutex held */
-void virtio_blk_data_plane_start(VirtIOBlockDataPlane *s)
+int virtio_blk_data_plane_start(VirtIODevice *vdev)
{
- BusState *qbus = BUS(qdev_get_parent_bus(DEVICE(s->vdev)));
+ VirtIOBlock *vblk = VIRTIO_BLK(vdev);
+ VirtIOBlockDataPlane *s = vblk->dataplane;
+ BusState *qbus = BUS(qdev_get_parent_bus(DEVICE(vblk)));
VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus);
- VirtIOBlock *vblk = VIRTIO_BLK(s->vdev);
unsigned i;
unsigned nvqs = s->conf->num_queues;
+ Error *local_err = NULL;
int r;
if (vblk->dataplane_started || s->starting) {
- return;
+ return 0;
}
s->starting = true;
+ if (!virtio_vdev_has_feature(vdev, VIRTIO_RING_F_EVENT_IDX)) {
+ s->batch_notifications = true;
+ } else {
+ s->batch_notifications = false;
+ }
+
/* Set up guest notifier (irq) */
r = k->set_guest_notifiers(qbus->parent, nvqs, true);
if (r != 0) {
- fprintf(stderr, "virtio-blk failed to set guest notifier (%d), "
- "ensure -enable-kvm is set\n", r);
+ error_report("virtio-blk failed to set guest notifier (%d), "
+ "ensure -accel kvm is set.", r);
goto fail_guest_notifiers;
}
fprintf(stderr, "virtio-blk failed to set host notifier (%d)\n", r);
while (i--) {
virtio_bus_set_host_notifier(VIRTIO_BUS(qbus), i, false);
+ virtio_bus_cleanup_host_notifier(VIRTIO_BUS(qbus), i);
}
goto fail_guest_notifiers;
}
vblk->dataplane_started = true;
trace_virtio_blk_data_plane_start(s);
- blk_set_aio_context(s->conf->conf.blk, s->ctx);
+ r = blk_set_aio_context(s->conf->conf.blk, s->ctx, &local_err);
+ if (r < 0) {
+ error_report_err(local_err);
+ goto fail_guest_notifiers;
+ }
/* Kick right away to begin processing requests already in vring */
for (i = 0; i < nvqs; i++) {
virtio_blk_data_plane_handle_output);
}
aio_context_release(s->ctx);
- return;
+ return 0;
fail_guest_notifiers:
vblk->dataplane_disabled = true;
s->starting = false;
vblk->dataplane_started = true;
+ return -ENOSYS;
+}
+
+/* Stop notifications for new requests from guest.
+ *
+ * Context: BH in IOThread
+ */
+static void virtio_blk_data_plane_stop_bh(void *opaque)
+{
+ VirtIOBlockDataPlane *s = opaque;
+ unsigned i;
+
+ for (i = 0; i < s->conf->num_queues; i++) {
+ VirtQueue *vq = virtio_get_queue(s->vdev, i);
+
+ virtio_queue_aio_set_host_notifier_handler(vq, s->ctx, NULL);
+ }
}
/* Context: QEMU global mutex held */
-void virtio_blk_data_plane_stop(VirtIOBlockDataPlane *s)
+void virtio_blk_data_plane_stop(VirtIODevice *vdev)
{
- BusState *qbus = BUS(qdev_get_parent_bus(DEVICE(s->vdev)));
+ VirtIOBlock *vblk = VIRTIO_BLK(vdev);
+ VirtIOBlockDataPlane *s = vblk->dataplane;
+ BusState *qbus = qdev_get_parent_bus(DEVICE(vblk));
VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus);
- VirtIOBlock *vblk = VIRTIO_BLK(s->vdev);
unsigned i;
unsigned nvqs = s->conf->num_queues;
trace_virtio_blk_data_plane_stop(s);
aio_context_acquire(s->ctx);
+ aio_wait_bh_oneshot(s->ctx, virtio_blk_data_plane_stop_bh, s);
- /* Stop notifications for new requests from guest */
- for (i = 0; i < nvqs; i++) {
- VirtQueue *vq = virtio_get_queue(s->vdev, i);
-
- virtio_queue_aio_set_host_notifier_handler(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());
+ /* Drain and try to switch bs back to the QEMU main loop. If other users
+ * keep the BlockBackend in the iothread, that's ok */
+ blk_set_aio_context(s->conf->conf.blk, qemu_get_aio_context(), NULL);
aio_context_release(s->ctx);
for (i = 0; i < nvqs; i++) {
virtio_bus_set_host_notifier(VIRTIO_BUS(qbus), i, false);
+ virtio_bus_cleanup_host_notifier(VIRTIO_BUS(qbus), i);
}
/* Clean up guest notifier (irq) */
projects / qemu.git / blobdiff