On 07/26/2017 05:01 AM, Dong Jia Shi wrote:
> Hello Halil,
>
> * Halil Pasic <pa...@linux.vnet.ibm.com> [2017-07-26 00:44:42 +0200]:
>
>> According to the PoP bit positions 0-3 and 8-32 of the format-1 CCW must
>> contain zeros. Bits 0-3 are already covered by cmd_code validity
>> checking, and bit 32 is covered by the CCW address checking.
>>
>> Bits 8-31 correspond to CCW1.flags and CCW1.count. Currently we only
>> check for the absence of certain flags. Let's fix this.
>>
>> Signed-off-by: Halil Pasic <pa...@linux.vnet.ibm.com>
>> ---
>> hw/s390x/css.c | 3 ++-
>> 1 file changed, 2 insertions(+), 1 deletion(-)
>>
>> diff --git a/hw/s390x/css.c b/hw/s390x/css.c
>> index d17e21b7af..1f04ce4a1b 100644
>> --- a/hw/s390x/css.c
>> +++ b/hw/s390x/css.c
>> @@ -884,7 +884,8 @@ static int css_interpret_ccw(SubchDev *sch, hwaddr
>> ccw_addr,
>> ret = -EINVAL;
>> break;
>> }
>> - if (ccw.flags & (CCW_FLAG_CC | CCW_FLAG_DC)) {
>> + if (ccw.flags || ccw.count) {
>> + /* We have already sanitized these if fmt 0. */
> ccw0 does not have the same restrictions as ccw1. We don't sanitize
> these for ccw0.
>
Yes you have misunderstood. For fmt 1 these bits have to be zero
otherwise a program-check condition is to be recognized. Thus we don't
sanitize for fmt 1.
For fmt 0 these bits are ignored. We sanitize them in
for some time now by setting them to zero when making a CCW1
out of an CCW0. If we would recognize a program-check for
fmt 0 that would be wrong.
The comment tells us why this code is good for CCW0 too,
and why can we omit sch->ccw_fmt_1 from the conditon.
Regards,
Halil
> (This comment is still here. Did I misunderstand things? :)
>
>> ret = -EINVAL;
>> break;
>> }
>> --
>> 2.11.2
>>
>
> With the comment removed:
> Reviewed-by: Dong Jia Shi <bjsdj...@linux.vnet.ibm.com>
>
