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* [Qemu-devel] [PATCH] scsi: esp: remove handling of SATN/STOP
@ 2016-06-17  8:19 Paolo Bonzini
  2016-06-17  9:08 ` Amit Shah
  2016-06-17  9:40 ` P J P
  0 siblings, 2 replies; 4+ messages in thread
From: Paolo Bonzini @ 2016-06-17  8:19 UTC (permalink / raw)
  To: qemu-devel; +Cc: amit.shah, Hervé Poussineau, ppandit

The implementation of SATN/STOP is completely busted.  The idea
would be that the next DMA read is for a SCSI message and after
that the adapter would transition to the command phase.

The recent fix to SATN/STOP broke migration, which is one more
reason to drop SATN/STOP handling completely.  It is only used
in practice to send 3-byte messages (target number + tag type
+ tag number) for tagged command queuing on adapters that lack
the SATN3 command, and we do not advertise support for TCQ.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
 hw/scsi/esp.c         | 58 +++++++++------------------------------------------
 include/hw/scsi/esp.h |  3 ---
 2 files changed, 10 insertions(+), 51 deletions(-)

diff --git a/hw/scsi/esp.c b/hw/scsi/esp.c
index baa0a2c..d11151f 100644
--- a/hw/scsi/esp.c
+++ b/hw/scsi/esp.c
@@ -192,23 +192,6 @@ static void handle_s_without_atn(ESPState *s)
     }
 }
 
-static void handle_satn_stop(ESPState *s)
-{
-    if (s->dma && !s->dma_enabled) {
-        s->dma_cb = handle_satn_stop;
-        return;
-    }
-    s->cmdlen = get_cmd(s, s->cmdbuf, sizeof(s->cmdbuf));
-    if (s->cmdlen) {
-        trace_esp_handle_satn_stop(s->cmdlen);
-        s->do_cmd = 1;
-        s->rregs[ESP_RSTAT] = STAT_TC | STAT_CD;
-        s->rregs[ESP_RINTR] = INTR_BS | INTR_FC;
-        s->rregs[ESP_RSEQ] = SEQ_CD;
-        esp_raise_irq(s);
-    }
-}
-
 static void write_response(ESPState *s)
 {
     trace_esp_write_response(s->status);
@@ -246,13 +229,6 @@ static void esp_do_dma(ESPState *s)
     int to_device;
 
     len = s->dma_left;
-    if (s->do_cmd) {
-        trace_esp_do_dma(s->cmdlen, len);
-        assert (s->cmdlen <= sizeof(s->cmdbuf) &&
-                len <= sizeof(s->cmdbuf) - s->cmdlen);
-        s->dma_memory_read(s->dma_opaque, &s->cmdbuf[s->cmdlen], len);
-        return;
-    }
     if (s->async_len == 0) {
         /* Defer until data is available.  */
         return;
@@ -316,7 +292,6 @@ void esp_transfer_data(SCSIRequest *req, uint32_t len)
 {
     ESPState *s = req->hba_private;
 
-    assert(!s->do_cmd);
     trace_esp_transfer_data(s->dma_left, s->ti_size);
     s->async_len = len;
     s->async_buf = scsi_req_get_buf(req);
@@ -346,9 +321,7 @@ static void handle_ti(ESPState *s)
     }
     s->dma_counter = dmalen;
 
-    if (s->do_cmd)
-        minlen = (dmalen < ESP_CMDBUF_SZ) ? dmalen : ESP_CMDBUF_SZ;
-    else if (s->ti_size < 0)
+    if (s->ti_size < 0)
         minlen = (dmalen < -s->ti_size) ? dmalen : -s->ti_size;
     else
         minlen = (dmalen < s->ti_size) ? dmalen : s->ti_size;
@@ -358,13 +331,6 @@ static void handle_ti(ESPState *s)
         s->rregs[ESP_RSTAT] &= ~STAT_TC;
         esp_do_dma(s);
     }
-    if (s->do_cmd) {
-        trace_esp_handle_ti_cmd(s->cmdlen);
-        s->ti_size = 0;
-        s->cmdlen = 0;
-        s->do_cmd = 0;
-        do_cmd(s, s->cmdbuf);
-    }
 }
 
 void esp_hard_reset(ESPState *s)
@@ -376,7 +342,6 @@ void esp_hard_reset(ESPState *s)
     s->ti_rptr = 0;
     s->ti_wptr = 0;
     s->dma = 0;
-    s->do_cmd = 0;
     s->dma_cb = NULL;
 
     s->rregs[ESP_CFG1] = 7;
@@ -450,13 +415,7 @@ void esp_reg_write(ESPState *s, uint32_t saddr, uint64_t val)
         s->rregs[ESP_RSTAT] &= ~STAT_TC;
         break;
     case ESP_FIFO:
-        if (s->do_cmd) {
-            if (s->cmdlen < ESP_CMDBUF_SZ) {
-                s->cmdbuf[s->cmdlen++] = val & 0xff;
-            } else {
-                trace_esp_error_fifo_overrun();
-            }
-        } else if (s->ti_wptr == TI_BUFSZ - 1) {
+        if (s->ti_wptr == TI_BUFSZ - 1) {
             trace_esp_error_fifo_overrun();
         } else {
             s->ti_size++;
@@ -534,8 +493,7 @@ void esp_reg_write(ESPState *s, uint32_t saddr, uint64_t val)
             break;
         case CMD_SELATNS:
             trace_esp_mem_writeb_cmd_selatns(val);
-            handle_satn_stop(s);
-            break;
+            goto unhandled;
         case CMD_ENSEL:
             trace_esp_mem_writeb_cmd_ensel(val);
             s->rregs[ESP_RINTR] = 0;
@@ -546,6 +504,7 @@ void esp_reg_write(ESPState *s, uint32_t saddr, uint64_t val)
             esp_raise_irq(s);
             break;
         default:
+        unhandled:
             trace_esp_error_unhandled_command(val);
             break;
         }
@@ -585,9 +544,12 @@ const VMStateDescription vmstate_esp = {
         VMSTATE_BUFFER(ti_buf, ESPState),
         VMSTATE_UINT32(status, ESPState),
         VMSTATE_UINT32(dma, ESPState),
-        VMSTATE_BUFFER(cmdbuf, ESPState),
-        VMSTATE_UINT32(cmdlen, ESPState),
-        VMSTATE_UINT32(do_cmd, ESPState),
+        /* Used to be cmdbuf, cmdlen, do_cmd, but the implementation
+         * of "Select with ATN and stop" was totally busted.
+         */
+        VMSTATE_UNUSED(16),
+        VMSTATE_UNUSED(4),
+        VMSTATE_UNUSED(1),
         VMSTATE_UINT32(dma_left, ESPState),
         VMSTATE_END_OF_LIST()
     }
diff --git a/include/hw/scsi/esp.h b/include/hw/scsi/esp.h
index d2c4886..8967167 100644
--- a/include/hw/scsi/esp.h
+++ b/include/hw/scsi/esp.h
@@ -32,9 +32,6 @@ struct ESPState {
     SCSIBus bus;
     SCSIDevice *current_dev;
     SCSIRequest *current_req;
-    uint8_t cmdbuf[ESP_CMDBUF_SZ];
-    uint32_t cmdlen;
-    uint32_t do_cmd;
 
     /* The amount of data left in the current DMA transfer.  */
     uint32_t dma_left;
-- 
2.5.5

^ permalink raw reply related	[flat|nested] 4+ messages in thread

* Re: [Qemu-devel] [PATCH] scsi: esp: remove handling of SATN/STOP
  2016-06-17  8:19 [Qemu-devel] [PATCH] scsi: esp: remove handling of SATN/STOP Paolo Bonzini
@ 2016-06-17  9:08 ` Amit Shah
  2016-06-17  9:55   ` Paolo Bonzini
  2016-06-17  9:40 ` P J P
  1 sibling, 1 reply; 4+ messages in thread
From: Amit Shah @ 2016-06-17  9:08 UTC (permalink / raw)
  To: Paolo Bonzini; +Cc: qemu-devel, Hervé Poussineau, ppandit

On (Fri) 17 Jun 2016 [10:19:17], Paolo Bonzini wrote:
> The implementation of SATN/STOP is completely busted.  The idea
> would be that the next DMA read is for a SCSI message and after
> that the adapter would transition to the command phase.
> 
> The recent fix to SATN/STOP broke migration, which is one more
> reason to drop SATN/STOP handling completely.  It is only used
> in practice to send 3-byte messages (target number + tag type
> + tag number) for tagged command queuing on adapters that lack
> the SATN3 command, and we do not advertise support for TCQ.
> 
> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

[...]

> @@ -585,9 +544,12 @@ const VMStateDescription vmstate_esp = {
>          VMSTATE_BUFFER(ti_buf, ESPState),
>          VMSTATE_UINT32(status, ESPState),
>          VMSTATE_UINT32(dma, ESPState),
> -        VMSTATE_BUFFER(cmdbuf, ESPState),
> -        VMSTATE_UINT32(cmdlen, ESPState),
> -        VMSTATE_UINT32(do_cmd, ESPState),
> +        /* Used to be cmdbuf, cmdlen, do_cmd, but the implementation
> +         * of "Select with ATN and stop" was totally busted.
> +         */
> +        VMSTATE_UNUSED(16),
> +        VMSTATE_UNUSED(4),
> +        VMSTATE_UNUSED(1),

Why 1?

		Amit

^ permalink raw reply	[flat|nested] 4+ messages in thread

* Re: [Qemu-devel] [PATCH] scsi: esp: remove handling of SATN/STOP
  2016-06-17  8:19 [Qemu-devel] [PATCH] scsi: esp: remove handling of SATN/STOP Paolo Bonzini
  2016-06-17  9:08 ` Amit Shah
@ 2016-06-17  9:40 ` P J P
  1 sibling, 0 replies; 4+ messages in thread
From: P J P @ 2016-06-17  9:40 UTC (permalink / raw)
  To: Paolo Bonzini; +Cc: qemu-devel, amit.shah, Hervé Poussineau

+-- On Fri, 17 Jun 2016, Paolo Bonzini wrote --+
| diff --git a/hw/scsi/esp.c b/hw/scsi/esp.c
| index baa0a2c..d11151f 100644
| --- a/hw/scsi/esp.c
| +++ b/hw/scsi/esp.c
| @@ -192,23 +192,6 @@ static void handle_s_without_atn(ESPState *s)
|      }
|  }
|  
| -static void handle_satn_stop(ESPState *s)
| -{
| -    if (s->dma && !s->dma_enabled) {
| -        s->dma_cb = handle_satn_stop;
| -        return;
| -    }
| -    s->cmdlen = get_cmd(s, s->cmdbuf, sizeof(s->cmdbuf));
| -    if (s->cmdlen) {
| -        trace_esp_handle_satn_stop(s->cmdlen);
| -        s->do_cmd = 1;
| -        s->rregs[ESP_RSTAT] = STAT_TC | STAT_CD;
| -        s->rregs[ESP_RINTR] = INTR_BS | INTR_FC;
| -        s->rregs[ESP_RSEQ] = SEQ_CD;
| -        esp_raise_irq(s);
| -    }
| -}
| -
|  static void write_response(ESPState *s)
|  {
|      trace_esp_write_response(s->status);
| @@ -246,13 +229,6 @@ static void esp_do_dma(ESPState *s)
|      int to_device;
|  
|      len = s->dma_left;
| -    if (s->do_cmd) {
| -        trace_esp_do_dma(s->cmdlen, len);
| -        assert (s->cmdlen <= sizeof(s->cmdbuf) &&
| -                len <= sizeof(s->cmdbuf) - s->cmdlen);
| -        s->dma_memory_read(s->dma_opaque, &s->cmdbuf[s->cmdlen], len);
| -        return;
| -    }
|      if (s->async_len == 0) {
|          /* Defer until data is available.  */
|          return;
| @@ -316,7 +292,6 @@ void esp_transfer_data(SCSIRequest *req, uint32_t len)
|  {
|      ESPState *s = req->hba_private;
|  
| -    assert(!s->do_cmd);
|      trace_esp_transfer_data(s->dma_left, s->ti_size);
|      s->async_len = len;
|      s->async_buf = scsi_req_get_buf(req);
| @@ -346,9 +321,7 @@ static void handle_ti(ESPState *s)
|      }
|      s->dma_counter = dmalen;
|  
| -    if (s->do_cmd)
| -        minlen = (dmalen < ESP_CMDBUF_SZ) ? dmalen : ESP_CMDBUF_SZ;
| -    else if (s->ti_size < 0)
| +    if (s->ti_size < 0)
|          minlen = (dmalen < -s->ti_size) ? dmalen : -s->ti_size;
|      else
|          minlen = (dmalen < s->ti_size) ? dmalen : s->ti_size;
| @@ -358,13 +331,6 @@ static void handle_ti(ESPState *s)
|          s->rregs[ESP_RSTAT] &= ~STAT_TC;
|          esp_do_dma(s);
|      }
| -    if (s->do_cmd) {
| -        trace_esp_handle_ti_cmd(s->cmdlen);
| -        s->ti_size = 0;
| -        s->cmdlen = 0;
| -        s->do_cmd = 0;
| -        do_cmd(s, s->cmdbuf);
| -    }
|  }
|  
|  void esp_hard_reset(ESPState *s)
| @@ -376,7 +342,6 @@ void esp_hard_reset(ESPState *s)
|      s->ti_rptr = 0;
|      s->ti_wptr = 0;
|      s->dma = 0;
| -    s->do_cmd = 0;
|      s->dma_cb = NULL;
|  
|      s->rregs[ESP_CFG1] = 7;
| @@ -450,13 +415,7 @@ void esp_reg_write(ESPState *s, uint32_t saddr, uint64_t val)
|          s->rregs[ESP_RSTAT] &= ~STAT_TC;
|          break;
|      case ESP_FIFO:
| -        if (s->do_cmd) {
| -            if (s->cmdlen < ESP_CMDBUF_SZ) {
| -                s->cmdbuf[s->cmdlen++] = val & 0xff;
| -            } else {
| -                trace_esp_error_fifo_overrun();
| -            }
| -        } else if (s->ti_wptr == TI_BUFSZ - 1) {
| +        if (s->ti_wptr == TI_BUFSZ - 1) {
|              trace_esp_error_fifo_overrun();
|          } else {
|              s->ti_size++;
| @@ -534,8 +493,7 @@ void esp_reg_write(ESPState *s, uint32_t saddr, uint64_t val)
|              break;
|          case CMD_SELATNS:
|              trace_esp_mem_writeb_cmd_selatns(val);
| -            handle_satn_stop(s);
| -            break;
| +            goto unhandled;
|          case CMD_ENSEL:
|              trace_esp_mem_writeb_cmd_ensel(val);
|              s->rregs[ESP_RINTR] = 0;
| @@ -546,6 +504,7 @@ void esp_reg_write(ESPState *s, uint32_t saddr, uint64_t val)
|              esp_raise_irq(s);
|              break;
|          default:
| +        unhandled:
|              trace_esp_error_unhandled_command(val);
|              break;
|          }
| @@ -585,9 +544,12 @@ const VMStateDescription vmstate_esp = {
|          VMSTATE_BUFFER(ti_buf, ESPState),
|          VMSTATE_UINT32(status, ESPState),
|          VMSTATE_UINT32(dma, ESPState),
| -        VMSTATE_BUFFER(cmdbuf, ESPState),
| -        VMSTATE_UINT32(cmdlen, ESPState),
| -        VMSTATE_UINT32(do_cmd, ESPState),
| +        /* Used to be cmdbuf, cmdlen, do_cmd, but the implementation
| +         * of "Select with ATN and stop" was totally busted.
| +         */
| +        VMSTATE_UNUSED(16),
| +        VMSTATE_UNUSED(4),
| +        VMSTATE_UNUSED(1),
|          VMSTATE_UINT32(dma_left, ESPState),
|          VMSTATE_END_OF_LIST()
|      }

  Looks okay.

| diff --git a/include/hw/scsi/esp.h b/include/hw/scsi/esp.h
| index d2c4886..8967167 100644
| --- a/include/hw/scsi/esp.h
| +++ b/include/hw/scsi/esp.h
| @@ -32,9 +32,6 @@ struct ESPState {
|      SCSIBus bus;
|      SCSIDevice *current_dev;
|      SCSIRequest *current_req;
| -    uint8_t cmdbuf[ESP_CMDBUF_SZ];
| -    uint32_t cmdlen;
| -    uint32_t do_cmd;

The macro 'ESP_CMDBUF_SZ' can be removed.

diff --git a/include/hw/scsi/esp.h b/include/hw/scsi/esp.h
index d2c4886..61cb8b4 100644
--- a/include/hw/scsi/esp.h
+++ b/include/hw/scsi/esp.h
@@ -14,7 +14,6 @@ void esp_init(hwaddr espaddr, int it_shift,

 #define ESP_REGS 16
 #define TI_BUFSZ 16
-#define ESP_CMDBUF_SZ 32


Thank you.
--
Prasad J Pandit / Red Hat Product Security Team
47AF CE69 3A90 54AA 9045 1053 DD13 3D32 FE5B 041F

^ permalink raw reply related	[flat|nested] 4+ messages in thread

* Re: [Qemu-devel] [PATCH] scsi: esp: remove handling of SATN/STOP
  2016-06-17  9:08 ` Amit Shah
@ 2016-06-17  9:55   ` Paolo Bonzini
  0 siblings, 0 replies; 4+ messages in thread
From: Paolo Bonzini @ 2016-06-17  9:55 UTC (permalink / raw)
  To: Amit Shah; +Cc: Hervé Poussineau, qemu-devel, ppandit



On 17/06/2016 11:08, Amit Shah wrote:
> On (Fri) 17 Jun 2016 [10:19:17], Paolo Bonzini wrote:
>> The implementation of SATN/STOP is completely busted.  The idea
>> would be that the next DMA read is for a SCSI message and after
>> that the adapter would transition to the command phase.
>>
>> The recent fix to SATN/STOP broke migration, which is one more
>> reason to drop SATN/STOP handling completely.  It is only used
>> in practice to send 3-byte messages (target number + tag type
>> + tag number) for tagged command queuing on adapters that lack
>> the SATN3 command, and we do not advertise support for TCQ.
>>
>> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
> 
> [...]
> 
>> @@ -585,9 +544,12 @@ const VMStateDescription vmstate_esp = {
>>          VMSTATE_BUFFER(ti_buf, ESPState),
>>          VMSTATE_UINT32(status, ESPState),
>>          VMSTATE_UINT32(dma, ESPState),
>> -        VMSTATE_BUFFER(cmdbuf, ESPState),
>> -        VMSTATE_UINT32(cmdlen, ESPState),
>> -        VMSTATE_UINT32(do_cmd, ESPState),
>> +        /* Used to be cmdbuf, cmdlen, do_cmd, but the implementation
>> +         * of "Select with ATN and stop" was totally busted.
>> +         */
>> +        VMSTATE_UNUSED(16),
>> +        VMSTATE_UNUSED(4),
>> +        VMSTATE_UNUSED(1),
> 
> Why 1?

Because I thought it was a bool.  My mistake.

Paolo

^ permalink raw reply	[flat|nested] 4+ messages in thread

end of thread, other threads:[~2016-06-17  9:55 UTC | newest]

Thread overview: 4+ messages (download: mbox.gz follow: Atom feed
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2016-06-17  8:19 [Qemu-devel] [PATCH] scsi: esp: remove handling of SATN/STOP Paolo Bonzini
2016-06-17  9:08 ` Amit Shah
2016-06-17  9:55   ` Paolo Bonzini
2016-06-17  9:40 ` P J P

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