Re: [Qemu-devel] [Qemu-block] [PATCH] qtest/ide-test: ppc64be correction for ATAPI tests

[John Snow <jsnow@redhat.com>]

On 10/02/2015 06:55 AM, Kevin Wolf wrote:
> Am 28.09.2015 um 19:38 hat John Snow geschrieben:
>> the 16bit ide data register is LE by definition.
>>
>> Signed-off-by: John Snow <jsnow@redhat.com>
>> ---
>>  tests/ide-test.c | 4 ++--
>>  1 file changed, 2 insertions(+), 2 deletions(-)
>>
>> diff --git a/tests/ide-test.c b/tests/ide-test.c
>> index 5594738..b6e9e1a 100644
>> --- a/tests/ide-test.c
>> +++ b/tests/ide-test.c
>> @@ -633,7 +633,7 @@ static void send_scsi_cdb_read10(uint64_t lba, int nblocks)
>>  
>>      /* Send Packet */
>>      for (i = 0; i < sizeof(Read10CDB)/2; i++) {
>> -        outw(IDE_BASE + reg_data, ((uint16_t *)&pkt)[i]);
>> +        outw(IDE_BASE + reg_data, cpu_to_le16(((uint16_t *)&pkt)[i]));
>>      }
>>  }
>>  
>> @@ -733,7 +733,7 @@ static void cdrom_pio_impl(int nblocks)
>>          size_t offset = i * (limit / 2);
>>          size_t rem = (rxsize / 2) - offset;
>>          for (j = 0; j < MIN((limit / 2), rem); j++) {
>> -            rx[offset + j] = inw(IDE_BASE + reg_data);
>> +            rx[offset + j] = le16_to_cpu(inw(IDE_BASE + reg_data));
>>          }
>>          ide_wait_intr(IDE_PRIMARY_IRQ);
>>      }
> 
> Why doesn't the access in test_identify() need a fix?
> 
> Kevin
> 

The strings are stored as BE16 chunks but transmitted via an LE16
register, so if we want to decode the original string, we can apply
*either* an LE16 or a BE16 swap to obtain the byte-ordered string.

Yes, that took me a minute to figure out.

We *could* apply a le16_to_cpu filter to re-obtain the raw original
data, but then we'd just have to run it back through be16_to_cpu to get
the string out anyway.

In this test, we just cheat and run be16_to_cpu, which works.

--js