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Re: [PATCH v2] virtio-scsi: Send "REPORTED LUNS CHANGED" sense data upon
From: |
Venu Busireddy |
Subject: |
Re: [PATCH v2] virtio-scsi: Send "REPORTED LUNS CHANGED" sense data upon disk hotplug events. |
Date: |
Wed, 21 Sep 2022 09:40:56 -0500 |
On 2022-09-21 16:33:35 +0200, Paolo Bonzini wrote:
> On Fri, Sep 16, 2022 at 3:44 AM Venu Busireddy
> <venu.busireddy@oracle.com> wrote:
> > diff --git a/hw/scsi/virtio-scsi.c b/hw/scsi/virtio-scsi.c
> > index 41f2a5630173..69194c7ae23c 100644
> > --- a/hw/scsi/virtio-scsi.c
> > +++ b/hw/scsi/virtio-scsi.c
> > @@ -608,7 +608,19 @@ static void virtio_scsi_command_complete(SCSIRequest
> > *r, size_t resid)
> >
> > req->resp.cmd.response = VIRTIO_SCSI_S_OK;
> > req->resp.cmd.status = r->status;
> > - if (req->resp.cmd.status == GOOD) {
> > + if (req->dev->reported_luns_changed &&
> > + (req->req.cmd.cdb[0] != INQUIRY) &&
> > + (req->req.cmd.cdb[0] != REPORT_LUNS) &&
> > + (req->req.cmd.cdb[0] != REQUEST_SENSE)) {
> > + req->dev->reported_luns_changed = false;
> > + req->resp.cmd.resid = 0;
> > + req->resp.cmd.status_qualifier = 0;
> > + req->resp.cmd.status = CHECK_CONDITION;
> > + sense_len = scsi_build_sense(sense,
> > SENSE_CODE(REPORTED_LUNS_CHANGED));
> > + qemu_iovec_from_buf(&req->resp_iov, sizeof(req->resp.cmd),
> > + sense, sense_len);
> > + req->resp.cmd.sense_len = virtio_tswap32(vdev, sense_len);
> > + } else if (req->resp.cmd.status == GOOD) {
> > req->resp.cmd.resid = virtio_tswap32(vdev, resid);
> > } else {
> > req->resp.cmd.resid = 0;
>
> Hi,
>
> a unit attention sense must be sent _instead_ of executing the command.
>
> QEMU already has a function scsi_device_set_ua() that handles
> everything; you have to call it, if reported_luns_changed is true,
> from virtio_scsi_handle_cmd_req_prepare() before scsi_req_new().
>
> It will also skip GET_CONFIGURATION and GET_EVENT_STATUS_NOTIFICATION
> commands which are further special-cased in 4.1.6.1 of the MMC
> specification.
Thanks, Paolo. I will test your suggestion (as soon as I finish what I
am working currently), and get back with either more questions, or with
a v3 post.
Venu
> > @@ -956,6 +968,7 @@ static void virtio_scsi_hotplug(HotplugHandler
> > *hotplug_dev, DeviceState *dev,
> > virtio_scsi_push_event(s, sd,
> > VIRTIO_SCSI_T_TRANSPORT_RESET,
> > VIRTIO_SCSI_EVT_RESET_RESCAN);
> > + s->reported_luns_changed = true;
> > virtio_scsi_release(s);
> > }
> > }
> > @@ -973,6 +986,7 @@ static void virtio_scsi_hotunplug(HotplugHandler
> > *hotplug_dev, DeviceState *dev,
> > virtio_scsi_push_event(s, sd,
> > VIRTIO_SCSI_T_TRANSPORT_RESET,
> > VIRTIO_SCSI_EVT_RESET_REMOVED);
> > + s->reported_luns_changed = true;
> > virtio_scsi_release(s);
> > }
> >
> > diff --git a/include/hw/virtio/virtio-scsi.h
> > b/include/hw/virtio/virtio-scsi.h
> > index a36aad9c8695..efbcf9ba069a 100644
> > --- a/include/hw/virtio/virtio-scsi.h
> > +++ b/include/hw/virtio/virtio-scsi.h
> > @@ -81,6 +81,7 @@ struct VirtIOSCSI {
> > SCSIBus bus;
> > int resetting;
> > bool events_dropped;
> > + bool reported_luns_changed;
> >
> > /* Fields for dataplane below */
> > AioContext *ctx; /* one iothread per virtio-scsi-pci for now */
> >
>