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Re: [Qemu-devel] [RFC PATCH v2 10/10] virtio-scsi: Hook up with dataplan
From: |
Paolo Bonzini |
Subject: |
Re: [Qemu-devel] [RFC PATCH v2 10/10] virtio-scsi: Hook up with dataplane |
Date: |
Fri, 19 Sep 2014 11:30:29 +0200 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.0 |
Il 06/08/2014 07:35, Fam Zheng ha scritto:
> This enables the virtio-scsi-dataplane code by setting the iothread
> in virtio-scsi device, and makes any function that is called by
> back from dataplane to cooperate with the caller: they need to be
> vring/iothread aware when handling the requests and using scsi devices
> on the bus.
>
> Signed-off-by: Fam Zheng <address@hidden>
> ---
> hw/scsi/virtio-scsi.c | 74
> ++++++++++++++++++++++++++++++++++++++++++++++++---
> 1 file changed, 71 insertions(+), 3 deletions(-)
>
> diff --git a/hw/scsi/virtio-scsi.c b/hw/scsi/virtio-scsi.c
> index 9e78e21..1f2a9b6 100644
> --- a/hw/scsi/virtio-scsi.c
> +++ b/hw/scsi/virtio-scsi.c
> @@ -62,6 +62,22 @@ void virtio_scsi_free_req(VirtIOSCSIReq *req)
> g_free(req);
> }
>
> +static void virtio_scsi_aio_acquire(VirtIOSCSICommon *vs)
> +{
> + if (vs->dataplane_started) {
> + assert(vs->ctx);
> + aio_context_acquire(vs->ctx);
> + }
> +}
> +
> +static void virtio_scsi_aio_release(VirtIOSCSICommon *vs)
> +{
> + if (vs->dataplane_started) {
> + assert(vs->ctx);
> + aio_context_release(vs->ctx);
> + }
> +}
These are not needed if you do the acquire/release in
virtio_scsi_push_event.
> static void virtio_scsi_complete_req(VirtIOSCSIReq *req)
> {
> VirtIOSCSI *s = req->dev;
> @@ -69,13 +85,19 @@ static void virtio_scsi_complete_req(VirtIOSCSIReq *req)
> VirtIODevice *vdev = VIRTIO_DEVICE(s);
>
> qemu_iovec_from_buf(&req->resp_iov, 0, &req->resp, req->resp_size);
> - virtqueue_push(vq, &req->elem, req->qsgl.size + req->resp_iov.size);
> + if (req->vring) {
> + assert(req->vq == NULL);
> + virtio_scsi_vring_push_notify(req);
> + } else {
> + virtqueue_push(vq, &req->elem, req->qsgl.size + req->resp_iov.size);
> + virtio_notify(vdev, vq);
> + }
> +
> if (req->sreq) {
> req->sreq->hba_private = NULL;
> scsi_req_unref(req->sreq);
> }
> virtio_scsi_free_req(req);
> - virtio_notify(vdev, vq);
> }
>
> static void virtio_scsi_bad_req(void)
> @@ -204,10 +226,16 @@ static void *virtio_scsi_load_request(QEMUFile *f,
> SCSIRequest *sreq)
> static void virtio_scsi_do_tmf(VirtIOSCSI *s, VirtIOSCSIReq *req)
> {
> SCSIDevice *d = virtio_scsi_device_find(s, req->req.tmf.lun);
> + VirtIOSCSICommon *vs = (VirtIOSCSICommon *)s;
> SCSIRequest *r, *next;
> BusChild *kid;
> int target;
>
> + if (vs->dataplane_started && bdrv_get_aio_context(d->conf.bs) !=
> vs->ctx) {
> + aio_context_acquire(vs->ctx);
> + bdrv_set_aio_context(d->conf.bs, vs->ctx);
> + aio_context_release(vs->ctx);
> + }
> /* Here VIRTIO_SCSI_S_OK means "FUNCTION COMPLETE". */
> req->resp.tmf.response = VIRTIO_SCSI_S_OK;
>
> @@ -344,8 +372,13 @@ void virtio_scsi_handle_ctrl_req(VirtIOSCSI *s,
> VirtIOSCSIReq *req)
> static void virtio_scsi_handle_ctrl(VirtIODevice *vdev, VirtQueue *vq)
> {
> VirtIOSCSI *s = (VirtIOSCSI *)vdev;
> + VirtIOSCSICommon *vs = (VirtIOSCSICommon *)vdev;
> VirtIOSCSIReq *req;
>
> + if (vs->ctx) {
> + virtio_scsi_dataplane_start(vs);
> + return;
> + }
> while ((req = virtio_scsi_pop_req(s, vq))) {
> virtio_scsi_handle_ctrl_req(s, req);
> }
> @@ -439,6 +472,11 @@ void virtio_scsi_handle_cmd_req(VirtIOSCSI *s,
> VirtIOSCSIReq *req)
> virtio_scsi_complete_cmd_req(req);
> return;
> }
> + if (vs->dataplane_started && bdrv_get_aio_context(d->conf.bs) !=
> vs->ctx) {
> + aio_context_acquire(vs->ctx);
> + bdrv_set_aio_context(d->conf.bs, vs->ctx);
> + aio_context_release(vs->ctx);
> + }
> req->sreq = scsi_req_new(d, req->req.cmd.tag,
> virtio_scsi_get_lun(req->req.cmd.lun),
> req->req.cdb, req);
> @@ -461,8 +499,13 @@ static void virtio_scsi_handle_cmd(VirtIODevice *vdev,
> VirtQueue *vq)
> {
> /* use non-QOM casts in the data path */
> VirtIOSCSI *s = (VirtIOSCSI *)vdev;
> + VirtIOSCSICommon *vs = (VirtIOSCSICommon *)vdev;
> VirtIOSCSIReq *req;
>
> + if (vs->ctx) {
> + virtio_scsi_dataplane_start(vs);
> + return;
> + }
A migration state change notifier (like in virtio-blk-dataplane) is missing.
> while ((req = virtio_scsi_pop_req(s, vq))) {
> virtio_scsi_handle_cmd_req(s, req);
> }
> @@ -513,6 +556,9 @@ static void virtio_scsi_reset(VirtIODevice *vdev)
> VirtIOSCSI *s = VIRTIO_SCSI(vdev);
> VirtIOSCSICommon *vs = VIRTIO_SCSI_COMMON(vdev);
>
> + if (vs->ctx) {
> + virtio_scsi_dataplane_stop(vs);
> + }
> s->resetting++;
> qbus_reset_all(&s->bus.qbus);
> s->resetting--;
> @@ -555,7 +601,11 @@ void virtio_scsi_push_event(VirtIOSCSI *s, SCSIDevice
> *dev,
> return;
> }
>
> - req = virtio_scsi_pop_req(s, vs->event_vq);
> + if (vs->dataplane_started) {
> + req = virtio_scsi_pop_req_vring(s, vs->event_vring);
> + } else {
> + req = virtio_scsi_pop_req(s, vs->event_vq);
> + }
> if (!req) {
> s->events_dropped = true;
> return;
> @@ -592,7 +642,12 @@ void virtio_scsi_push_event(VirtIOSCSI *s, SCSIDevice
> *dev,
> static void virtio_scsi_handle_event(VirtIODevice *vdev, VirtQueue *vq)
> {
> VirtIOSCSI *s = VIRTIO_SCSI(vdev);
> + VirtIOSCSICommon *vs = (VirtIOSCSICommon *)vdev;
>
> + if (vs->ctx) {
> + virtio_scsi_dataplane_start(vs);
> + return;
> + }
> if (s->events_dropped) {
> virtio_scsi_push_event(s, NULL, VIRTIO_SCSI_T_NO_EVENT, 0);
> }
> @@ -602,11 +657,14 @@ static void virtio_scsi_change(SCSIBus *bus, SCSIDevice
> *dev, SCSISense sense)
> {
> VirtIOSCSI *s = container_of(bus, VirtIOSCSI, bus);
> VirtIODevice *vdev = VIRTIO_DEVICE(s);
> + VirtIOSCSICommon *vs = (VirtIOSCSICommon *)vdev;
>
> if (((vdev->guest_features >> VIRTIO_SCSI_F_CHANGE) & 1) &&
> dev->type != TYPE_ROM) {
> + virtio_scsi_aio_acquire(vs);
> virtio_scsi_push_event(s, dev, VIRTIO_SCSI_T_PARAM_CHANGE,
> sense.asc | (sense.ascq << 8));
> + virtio_scsi_aio_release(vs);
> }
> }
>
> @@ -614,10 +672,13 @@ static void virtio_scsi_hotplug(SCSIBus *bus,
> SCSIDevice *dev)
> {
> VirtIOSCSI *s = container_of(bus, VirtIOSCSI, bus);
> VirtIODevice *vdev = VIRTIO_DEVICE(s);
> + VirtIOSCSICommon *vs = (VirtIOSCSICommon *)vdev;
>
> if ((vdev->guest_features >> VIRTIO_SCSI_F_HOTPLUG) & 1) {
> + virtio_scsi_aio_acquire(vs);
> virtio_scsi_push_event(s, dev, VIRTIO_SCSI_T_TRANSPORT_RESET,
> VIRTIO_SCSI_EVT_RESET_RESCAN);
> + virtio_scsi_aio_release(vs);
> }
> }
>
> @@ -625,10 +686,13 @@ static void virtio_scsi_hot_unplug(SCSIBus *bus,
> SCSIDevice *dev)
> {
> VirtIOSCSI *s = container_of(bus, VirtIOSCSI, bus);
> VirtIODevice *vdev = VIRTIO_DEVICE(s);
> + VirtIOSCSICommon *vs = (VirtIOSCSICommon *)vdev;
>
> if ((vdev->guest_features >> VIRTIO_SCSI_F_HOTPLUG) & 1) {
> + virtio_scsi_aio_acquire(vs);
> virtio_scsi_push_event(s, dev, VIRTIO_SCSI_T_TRANSPORT_RESET,
> VIRTIO_SCSI_EVT_RESET_REMOVED);
> + virtio_scsi_aio_release(vs);
> }
> }
>
> @@ -671,6 +735,10 @@ void virtio_scsi_common_realize(DeviceState *dev, Error
> **errp,
> s->cmd_vqs[i] = virtio_add_queue(vdev, VIRTIO_SCSI_VQ_SIZE,
> cmd);
> }
> +
> + if (s->conf.iothread) {
> + virtio_scsi_set_iothread(s, s->conf.iothread);
> + }
> }
>
> static void virtio_scsi_device_realize(DeviceState *dev, Error **errp)
>
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