Re: [Qemu-devel] [PATCH] scsi-bus: correct responses for INQUIRY and REQUEST SENSE

[Laszlo Ersek <lersek@redhat.com>]

Hello Hannes,

On 08/18/17 11:37, Hannes Reinecke wrote:
> According to SPC-3 INQUIRY and REQUEST SENSE should return GOOD
> even on unsupported LUNS.
> 
> Signed-off-by: Hannes Reinecke <hare@suse.com>
> ---
>  hw/scsi/scsi-bus.c | 29 +++++++++++++++++++++++++----
>  1 file changed, 25 insertions(+), 4 deletions(-)
> 
> diff --git a/hw/scsi/scsi-bus.c b/hw/scsi/scsi-bus.c
> index e364410a23..ade31c11f5 100644
> --- a/hw/scsi/scsi-bus.c
> +++ b/hw/scsi/scsi-bus.c
> @@ -516,8 +516,10 @@ static size_t scsi_sense_len(SCSIRequest *req)
>  static int32_t scsi_target_send_command(SCSIRequest *req, uint8_t *buf)
>  {
>      SCSITargetReq *r = DO_UPCAST(SCSITargetReq, req, req);
> +    int fixed_sense = (req->cmd.buf[1] & 1) == 0;
>  
> -    if (req->lun != 0) {
> +    if (req->lun != 0 &&
> +        buf[0] != INQUIRY && buf[0] != REQUEST_SENSE) {
>          scsi_req_build_sense(req, SENSE_CODE(LUN_NOT_SUPPORTED));
>          scsi_req_complete(req, CHECK_CONDITION);
>          return 0;
> @@ -535,9 +537,28 @@ static int32_t scsi_target_send_command(SCSIRequest *req, uint8_t *buf)
>          break;
>      case REQUEST_SENSE:
>          scsi_target_alloc_buf(&r->req, scsi_sense_len(req));
> -        r->len = scsi_device_get_sense(r->req.dev, r->buf,
> -                                       MIN(req->cmd.xfer, r->buf_len),
> -                                       (req->cmd.buf[1] & 1) == 0);
> +        if (req->lun != 0) {
> +            const struct SCSISense sense = SENSE_CODE(LUN_NOT_SUPPORTED);
> +
> +            if (fixed_sense) {
> +                r->buf[0] = 0x70;
> +                r->buf[2] = sense.key;
> +                r->buf[10] = 10;
> +                r->buf[12] = sense.asc;
> +                r->buf[13] = sense.ascq;
> +                r->len = MIN(req->cmd.xfer, SCSI_SENSE_LEN);
> +            } else {
> +                r->buf[0] = 0x72;
> +                r->buf[1] = sense.key;
> +                r->buf[2] = sense.asc;
> +                r->buf[3] = sense.ascq;
> +                r->len = 8;
> +            }
> +        } else {
> +            r->len = scsi_device_get_sense(r->req.dev, r->buf,
> +                                           MIN(req->cmd.xfer, r->buf_len),
> +                                           fixed_sense);
> +        }
>          if (r->req.dev->sense_is_ua) {
>              scsi_device_unit_attention_reported(req->dev);
>              r->req.dev->sense_len = 0;
> 

thank you for the quick patch.

I've repeated my original testing steps now, in the following scenarios:

                             edk2:ba40cb31b69d  ovmf:ce13d2d8c81f
qemu:v2.10.0-rc3             [1]                [2]
qemu:v2.10.0-rc3+this patch  [3]                [4]

(Edk2 commit ba40cb31b69d was edk2 master just before I pushed my
respective edk2 patches, and edk2 commit ce13d2d8c81f is current edk2
master, with my respective patches.)

[1] FAIL: as reported originally
[2] PASS: my edk2 patches fix ScsiBusDxe (which is justified in itself),
          and then it deals with QEMU post-ded6ddc5a7b9
[3] PASS: this patch of yours makes the reported symptoms vanish even
          without applying my patches to edk2
[4] PASS: your patch works fine with the current (fixed) ScsiBusDxe as
          well, no regressions found.

Tested-by: Laszlo Ersek <lersek@redhat.com>

If you agree, I'd suggest two additional tags for the commit message:

Reported-by: Laszlo Ersek <lersek@redhat.com>
Fixes: ded6ddc5a7b95217557fa360913d1213e12d4a6d

Thanks!
Laszlo