Re: [RFC PATCH 1/5] cxl/core: correct length of DPA field masks

[Shiyang Ruan <ruansy.fnst@fujitsu.com>]

在 2024/2/10 14:34, Dan Williams 写道:
> Shiyang Ruan wrote:
>> The length of Physical Address in General Media Event Record/DRAM Event
>> Record is 64-bit, so the field mask should be defined as such length.
> 
> Can you include this user visible side-effect of this change. Looks like
> this could cause usages of CXL_DPA_FLAGS_MASK to return an incorrect
> result?

Ok.  Will change it to this:

The length of Physical Address in General Media Event Record/DRAM Event 
Record is 64bit, per CXL Spec r3.0 - 8.2.9.2.1.1, Table 8-43.  Currently 
CXL_DPA_FLAGS_MASK is defined as int (32bit), then CXL_DPA_MASK is a int 
too, it will be 0x00000000FFFFFFC0 while using "->dpa & CXL_DPA_MASK" to 
obtain real physical address (to drop flags in lower bits), in this case 
the higher 32bit of ->dpa will be lost.

To avoid this, define CXL_DPA_FLAGS_MASK as 64bit: 0x3FULL.


--
Thanks,
Ruan.

> 
>>
>> Signed-off-by: Shiyang Ruan <ruansy.fnst@fujitsu.com>
>> ---
>>   drivers/cxl/core/trace.h | 6 +++---
>>   1 file changed, 3 insertions(+), 3 deletions(-)
>>
>> diff --git a/drivers/cxl/core/trace.h b/drivers/cxl/core/trace.h
>> index 89445435303a..388a87d972c2 100644
>> --- a/drivers/cxl/core/trace.h
>> +++ b/drivers/cxl/core/trace.h
>> @@ -253,11 +253,11 @@ TRACE_EVENT(cxl_generic_event,
>>    * DRAM Event Record
>>    * CXL rev 3.0 section 8.2.9.2.1.2; Table 8-44
>>    */
>> -#define CXL_DPA_FLAGS_MASK			0x3F
>> +#define CXL_DPA_FLAGS_MASK			0x3FULL
>>   #define CXL_DPA_MASK				(~CXL_DPA_FLAGS_MASK)
>>   
>> -#define CXL_DPA_VOLATILE			BIT(0)
>> -#define CXL_DPA_NOT_REPAIRABLE			BIT(1)
>> +#define CXL_DPA_VOLATILE			BIT_ULL(0)
>> +#define CXL_DPA_NOT_REPAIRABLE			BIT_ULL(1)
>>   #define show_dpa_flags(flags)	__print_flags(flags, "|",		   \
>>   	{ CXL_DPA_VOLATILE,			"VOLATILE"		}, \
>>   	{ CXL_DPA_NOT_REPAIRABLE,		"NOT_REPAIRABLE"	}  \
>> -- 
>> 2.34.1
>>
> 
>