Re: [Qemu-devel] [PATCH 04/17] scsi: fixup lba calculation for 6 byte CDBs

[Paolo Bonzini <pbonzini@redhat.com>]

On 10/29/2014 08:53 AM, Hannes Reinecke wrote:
> 6 byte CDBs do not have a dedicated area for LBAs, and even if
> it certainly won't be at byte 0.
> 
> Signed-off-by: Hannes Reinecke <hare@suse.de>
> ---
>  hw/scsi/scsi-bus.c | 3 ---
>  1 file changed, 3 deletions(-)
> 
> diff --git a/hw/scsi/scsi-bus.c b/hw/scsi/scsi-bus.c
> index 919a86c..64d0880 100644
> --- a/hw/scsi/scsi-bus.c
> +++ b/hw/scsi/scsi-bus.c
> @@ -1195,9 +1195,6 @@ static uint64_t scsi_cmd_lba(SCSICommand *cmd)
>      uint64_t lba;
>  
>      switch (buf[0] >> 5) {
> -    case 0:
> -        lba = ldl_be_p(&buf[0]) & 0x1fffff;

These are bits 0-20 of the first big endian u32, which means the low
five bits of byte 1, together with byte 2 and byte 3.

The patch as is breaks (obsolete) commands such as READ(6) and WRITE(6).
 Why did you need it?

Paolo

> -        break;
>      case 1:
>      case 2:
>      case 5:
>