[Qemu-devel] Re: [PATCH] lsi53c895a: add support for ABORT messages

[Kevin Wolf <kwolf@redhat.com>]

Am 06.09.2010 16:42, schrieb Bernhard Kohl:
> If these messages are not handled correctly the guest driver may hang.
> 
> Always mandatory:
> - ABORT
> - BUS DEVICE RESET
> 
> Mandatory if tagged queuing is implemented (which disks usually do):
> - ABORT TAG
> - CLEAR QUEUE
> 
> Signed-off-by: Bernhard Kohl <bernhard.kohl@nsn.com>

Nicholas, as you seem to have touched the lsi code recently, care to
review this one? Assuming that you are reasonably familiar with both the
hardware and the code, you should be quicker than me with this.

Kevin

> ---
>  hw/lsi53c895a.c |   57 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
>  1 files changed, 57 insertions(+), 0 deletions(-)
> 
> diff --git a/hw/lsi53c895a.c b/hw/lsi53c895a.c
> index 5eaf69e..40f2d10 100644
> --- a/hw/lsi53c895a.c
> +++ b/hw/lsi53c895a.c
> @@ -846,6 +846,18 @@ static void lsi_do_msgout(LSIState *s)
>  {
>      uint8_t msg;
>      int len;
> +    uint32_t current_tag;
> +    SCSIDevice *current_dev;
> +    lsi_request *p, *p_next;
> +    int id;
> +
> +    if (s->current) {
> +        current_tag = s->current->tag;
> +    } else {
> +        current_tag = s->select_tag;
> +    }
> +    id = (current_tag >> 8) & 0xf;
> +    current_dev = s->bus.devs[id];
>  
>      DPRINTF("MSG out len=%d\n", s->dbc);
>      while (s->dbc) {
> @@ -890,6 +902,51 @@ static void lsi_do_msgout(LSIState *s)
>              BADF("ORDERED queue not implemented\n");
>              s->select_tag |= lsi_get_msgbyte(s) | LSI_TAG_VALID;
>              break;
> +        case 0x0d:
> +            /* The ABORT TAG message clears the current I/O process only. */
> +            DPRINTF("MSG: ABORT TAG tag=0x%x\n", current_tag);
> +            current_dev->info->cancel_io(current_dev, current_tag);
> +            lsi_disconnect(s);
> +            break;
> +        case 0x06:
> +        case 0x0e:
> +        case 0x0c:
> +            /* The ABORT message clears all I/O processes for the selecting
> +               initiator on the specified logical unit of the target. */
> +            if (msg == 0x06) {
> +                DPRINTF("MSG: ABORT tag=0x%x\n", current_tag);
> +            }
> +            /* The CLEAR QUEUE message clears all I/O processes for all
> +               initiators on the specified logical unit of the target. */
> +            if (msg == 0x0e) {
> +                DPRINTF("MSG: CLEAR QUEUE tag=0x%x\n", current_tag);
> +            }
> +            /* The BUS DEVICE RESET message clears all I/O processes for all
> +               initiators on all logical units of the target. */
> +            if (msg == 0x0c) {
> +                DPRINTF("MSG: BUS DEVICE RESET tag=0x%x\n", current_tag);
> +            }
> +
> +            /* clear the current I/O process */
> +            current_dev->info->cancel_io(current_dev, current_tag);
> +
> +            /* As the current implemented devices scsi_disk and scsi_generic
> +               only support one LUN, we don't need to keep track of LUNs.
> +               Clearing I/O processes for other initiators could be possible
> +               for scsi_generic by sending a SG_SCSI_RESET to the /dev/sgX
> +               device, but this is currently not implemented (and seems not
> +               to be really necessary). So let's simply clear all queued
> +               commands for the current device: */
> +            id = current_tag & 0x0000ff00;
> +            QTAILQ_FOREACH_SAFE(p, &s->queue, next, p_next) {
> +                if ((p->tag & 0x0000ff00) == id) {
> +                    current_dev->info->cancel_io(current_dev, p->tag);
> +                    QTAILQ_REMOVE(&s->queue, p, next);
> +                }
> +            }
> +
> +            lsi_disconnect(s);
> +            break;
>          default:
>              if ((msg & 0x80) == 0) {
>                  goto bad;