Re: [Qemu-devel] [PATCH] esp: Do not overwrite ESP_TCHI after reset

[Hannes Reinecke <hare@suse.de>]

On 11/10/2014 04:37 PM, Hannes Reinecke wrote:
> After a reset ESP_TCHI should contain the unique ID
> of the chip. This value will be overwritten with the
> current tranfer count if the transfer count has
> previously been set.
> The code never checks if the transfer count has
> been set, so the unique ID will always be overwritten
> if the driver sends a DMA NOP after reset.
> 
> Signed-off-by: Hannes Reinecke <hare@suse.de>
> ---
>  hw/scsi/esp.c | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
> 
> diff --git a/hw/scsi/esp.c b/hw/scsi/esp.c
> index 5ab44d8..9798180 100644
> --- a/hw/scsi/esp.c
> +++ b/hw/scsi/esp.c
> @@ -454,7 +454,9 @@ void esp_reg_write(ESPState *s, uint32_t saddr, uint64_t val)
>              /* Reload DMA counter.  */
>              s->rregs[ESP_TCLO] = s->wregs[ESP_TCLO];
>              s->rregs[ESP_TCMID] = s->wregs[ESP_TCMID];
> -            s->rregs[ESP_TCHI] = s->wregs[ESP_TCHI];
> +            if (s->wregs[ESP_TCHI]) {
> +                    s->rregs[ESP_TCHI] = s->wregs[ESP_TCHI];
> +            }
>          } else {
>              s->dma = 0;
>          }
> 
Hmm.
This is actually not quite correct.
I'll be sending an updated patch.

Cheers,

Hannes
-- 
Dr. Hannes Reinecke		      zSeries & Storage
hare@suse.de			      +49 911 74053 688
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