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virtio-scsi: always use dataplane path if ioeventfd is active

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Override start_ioeventfd and stop_ioeventfd to start/stop the
whole dataplane logic.  This has some positive side effects:

- no need anymore for virtio_add_queue_aio (i.e. a revert of
  commit 1c627137c1)

- no need anymore to switch from generic ioeventfd handlers to
  dataplane

It detects some errors better:

    $ qemu-system-x86_64 -object iothread,id=io \
          -device virtio-scsi-pci,ioeventfd=off,iothread=io
    qemu-system-x86_64: -device virtio-scsi-pci,ioeventfd=off,iothread=io:
    ioeventfd is required for iothread

while previously it would have started just fine.

Reviewed-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
This commit is contained in:
Paolo Bonzini 2016-10-21 22:48:10 +02:00 • committed by Michael S. Tsirkin
parent 9ffe337c08
commit ad07cd69ec
3 changed files with 48 additions and 38 deletions
Download patch file Download diff file Expand all files Collapse all files

56
hw/scsi/virtio-scsi-dataplane.c
View file

@ -12,6 +12,7 @@
*/
#include "qemu/osdep.h"
#include "qapi/error.h"
#include "hw/virtio/virtio-scsi.h"
#include "qemu/error-report.h"
#include "sysemu/block-backend.h"
@ -21,20 +22,30 @@
#include "hw/virtio/virtio-access.h"
/* Context: QEMU global mutex held */
void virtio_scsi_set_iothread(VirtIOSCSI *s, IOThread *iothread)
void virtio_scsi_dataplane_setup(VirtIOSCSI *s, Error **errp)
{
BusState *qbus = BUS(qdev_get_parent_bus(DEVICE(s)));
VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus);
VirtIOSCSICommon *vs = VIRTIO_SCSI_COMMON(s);
VirtIODevice *vdev = VIRTIO_DEVICE(s);
BusState *qbus = qdev_get_parent_bus(DEVICE(vdev));
VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus);
assert(!s->ctx);
s->ctx = iothread_get_aio_context(vs->conf.iothread);
/* Don't try if transport does not support notifiers. */
if (!k->set_guest_notifiers || !k->ioeventfd_assign) {
fprintf(stderr, "virtio-scsi: Failed to set iothread "
"(transport does not support notifiers)");
exit(1);
if (vs->conf.iothread) {
if (!k->set_guest_notifiers || !k->ioeventfd_assign) {
error_setg(errp,
"device is incompatible with iothread "
"(transport does not support notifiers)");
return;
}
if (!virtio_device_ioeventfd_enabled(vdev)) {
error_setg(errp, "ioeventfd is required for iothread");
return;
}
s->ctx = iothread_get_aio_context(vs->conf.iothread);
} else {
if (!virtio_device_ioeventfd_enabled(vdev)) {
return;
}
s->ctx = qemu_get_aio_context();
}
}
@ -105,19 +116,19 @@ static void virtio_scsi_clear_aio(VirtIOSCSI *s)
}
/* Context: QEMU global mutex held */
void virtio_scsi_dataplane_start(VirtIOSCSI *s)
int virtio_scsi_dataplane_start(VirtIODevice *vdev)
{
int i;
int rc;
BusState *qbus = BUS(qdev_get_parent_bus(DEVICE(s)));
BusState *qbus = qdev_get_parent_bus(DEVICE(vdev));
VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus);
VirtIOSCSICommon *vs = VIRTIO_SCSI_COMMON(s);
VirtIOSCSICommon *vs = VIRTIO_SCSI_COMMON(vdev);
VirtIOSCSI *s = VIRTIO_SCSI(vdev);
if (s->dataplane_started ||
s->dataplane_starting ||
s->dataplane_fenced ||
s->ctx != iothread_get_aio_context(vs->conf.iothread)) {
return;
s->dataplane_fenced) {
return 0;
}
s->dataplane_starting = true;
@ -152,7 +163,7 @@ void virtio_scsi_dataplane_start(VirtIOSCSI *s)
s->dataplane_starting = false;
s->dataplane_started = true;
aio_context_release(s->ctx);
return;
return 0;
fail_vrings:
virtio_scsi_clear_aio(s);
@ -165,14 +176,16 @@ fail_guest_notifiers:
s->dataplane_fenced = true;
s->dataplane_starting = false;
s->dataplane_started = true;
return -ENOSYS;
}
/* Context: QEMU global mutex held */
void virtio_scsi_dataplane_stop(VirtIOSCSI *s)
void virtio_scsi_dataplane_stop(VirtIODevice *vdev)
{
BusState *qbus = BUS(qdev_get_parent_bus(DEVICE(s)));
BusState *qbus = qdev_get_parent_bus(DEVICE(vdev));
VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus);
VirtIOSCSICommon *vs = VIRTIO_SCSI_COMMON(s);
VirtIOSCSICommon *vs = VIRTIO_SCSI_COMMON(vdev);
VirtIOSCSI *s = VIRTIO_SCSI(vdev);
int i;
if (!s->dataplane_started || s->dataplane_stopping) {
@ -186,7 +199,6 @@ void virtio_scsi_dataplane_stop(VirtIOSCSI *s)
return;
}
s->dataplane_stopping = true;
assert(s->ctx == iothread_get_aio_context(vs->conf.iothread));
aio_context_acquire(s->ctx);