Re: [PATCH v2 36/42] esp: add maxlen parameter to get_cmd()

[Laurent Vivier]

Le 09/02/2021 à 20:30, Mark Cave-Ayland a écrit :
> Some guests use a mixture of DMA and non-DMA transfers in combination with the
> SATN and stop command to transfer message out phase and command phase bytes to
> the target. Prepare for the next commit by adding a maxlen parameter to
> get_cmd() to allow partial transfers.
> 
> Signed-off-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
> ---
>  hw/scsi/esp.c | 20 +++++++++++---------
>  1 file changed, 11 insertions(+), 9 deletions(-)
> 
> diff --git a/hw/scsi/esp.c b/hw/scsi/esp.c
> index 617fdcb3ed..058b482fda 100644
> --- a/hw/scsi/esp.c
> +++ b/hw/scsi/esp.c
> @@ -194,7 +194,7 @@ static int esp_select(ESPState *s)
>      return 0;
>  }
>  
> -static uint32_t get_cmd(ESPState *s)
> +static uint32_t get_cmd(ESPState *s, uint32_t maxlen)
>  {
>      uint8_t *buf = s->cmdbuf;
>      uint32_t dmalen;
> @@ -202,8 +202,8 @@ static uint32_t get_cmd(ESPState *s)
>  
>      target = s->wregs[ESP_WBUSID] & BUSID_DID;
>      if (s->dma) {
> -        dmalen = esp_get_tc(s);
> -        if (dmalen > ESP_CMDBUF_SZ) {
> +        dmalen = MIN(esp_get_tc(s), maxlen);
> +        if (dmalen == 0) {
>              return 0;
>          }
>          if (s->dma_memory_read) {
> @@ -216,12 +216,14 @@ static uint32_t get_cmd(ESPState *s)
>              return 0;
>          }
>      } else {
> -        dmalen = s->ti_size;
> -        if (dmalen > TI_BUFSZ) {
> +        dmalen = MIN(s->ti_size, maxlen);
> +        if (dmalen == 0) {
>              return 0;
>          }
>          memcpy(buf, s->ti_buf, dmalen);
> -        buf[0] = buf[2] >> 5;
> +        if (dmalen >= 3) {
> +            buf[0] = buf[2] >> 5;
> +        }
>      }
>      trace_esp_get_cmd(dmalen, target);
>  
> @@ -290,7 +292,7 @@ static void handle_satn(ESPState *s)
>          return;
>      }
>      s->pdma_cb = satn_pdma_cb;
> -    cmdlen = get_cmd(s);
> +    cmdlen = get_cmd(s, ESP_CMDBUF_SZ);
>      if (cmdlen > 0) {
>          s->cmdlen = cmdlen;
>          do_cmd(s);
> @@ -320,7 +322,7 @@ static void handle_s_without_atn(ESPState *s)
>          return;
>      }
>      s->pdma_cb = s_without_satn_pdma_cb;
> -    cmdlen = get_cmd(s);
> +    cmdlen = get_cmd(s, ESP_CMDBUF_SZ);
>      if (cmdlen > 0) {
>          s->cmdlen = cmdlen;
>          do_busid_cmd(s, s->cmdbuf, 0);
> @@ -355,7 +357,7 @@ static void handle_satn_stop(ESPState *s)
>          return;
>      }
>      s->pdma_cb = satn_stop_pdma_cb;
> -    cmdlen = get_cmd(s);
> +    cmdlen = get_cmd(s, ESP_CMDBUF_SZ);
>      if (cmdlen > 0) {
>          trace_esp_handle_satn_stop(s->cmdlen);
>          s->cmdlen = cmdlen;
> 

Reviewed-by: Laurent Vivier <laurent@vivier.eu>