Re: [Qemu-devel] [PATCH v1] virtio-scsi: Send "REPORTED LUNS CHANGED" sense data upon a disk hotplug.

[Venu Busireddy]

Ping?

On 2022-05-31 15:22:37 -0500, Venu Busireddy wrote:
> When a disk is hotplugged, QEMU reports a VIRTIO_SCSI_EVT_RESET_RESCAN
> event, but does not send the "REPORTED LUNS CHANGED" sense data. This
> does not conform to Section 5.6.6.3 of the VirtIO specification, which
> states "Events will also be reported via sense codes..." SCSI layer on
> Solaris depends on this sense data, and hence does not recognize the
> hotplugged disks (until a reboot).
> 
> As specified in SAM-4, Section 5.14, return a CHECK_CONDITION status with
> a sense data of 0x06/0x3F/0x0E, whenever a command other than INQUIRY,
> REPORT_LUNS, or REQUEST_SENSE is received.
> 
> Signed-off-by: Venu Busireddy <venu.busireddy@oracle.com>
> ---
>  hw/scsi/virtio-scsi.c           | 15 ++++++++++++++-
>  include/hw/virtio/virtio-scsi.h |  1 +
>  2 files changed, 15 insertions(+), 1 deletion(-)
> 
> diff --git a/hw/scsi/virtio-scsi.c b/hw/scsi/virtio-scsi.c
> index 4141dddd517a..7ae1cfa6e584 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;
> @@ -956,6 +968,7 @@ static void virtio_scsi_hotplug(HotplugHandler 
> *hotplug_dev, DeviceState *dev,
>                                 VIRTIO_SCSI_T_TRANSPORT_RESET,
>                                 VIRTIO_SCSI_EVT_RESET_RESCAN);
>          virtio_scsi_release(s);
> +        s->reported_luns_changed = true;
>      }
>  }
>  
> 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 */