On 10.02.20 18:31, Cornelia Huck wrote:
> On Mon, 10 Feb 2020 11:54:39 -0500
> Christian Borntraeger <borntraeger@xxxxxxxxxx> wrote:
>
>> The query parameter block might contain additional information and can
>> be extended in the future. If the size of the block does not suffice we
>> get an error code of rc=0x100. The buffer will contain all information
>> up to the specified size and the hypervisor/guest simply do not need the
>> additional information as they do not know about the new data. That
>> means that we can (and must) accept rc=0x100 as success.
>>
>> Cc: stable@xxxxxxxxxxxxxxx
>> Fixes: 5abb9351dfd9 ("s390/uv: introduce guest side ultravisor code")
>> Signed-off-by: Christian Borntraeger <borntraeger@xxxxxxxxxx>
>> ---
>> arch/s390/boot/uv.c | 2 +-
>> 1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/arch/s390/boot/uv.c b/arch/s390/boot/uv.c
>> index af9e1cc93c68..c003593664cd 100644
>> --- a/arch/s390/boot/uv.c
>> +++ b/arch/s390/boot/uv.c
>> @@ -21,7 +21,7 @@ void uv_query_info(void)
>> if (!test_facility(158))
>> return;
>>
>> - if (uv_call(0, (uint64_t)&uvcb))
>> + if (uv_call(0, (uint64_t)&uvcb) && uvcb.header.rc != 0x100)
>
> Add a comment like
>
> /* rc==0x100 means that there is additional data we do not process */
ack.
>
> to avoid headscratching in the future?
>
>> return;
>>
>> if (IS_ENABLED(CONFIG_KVM)) {
>
> Reviewed-by: Cornelia Huck <cohuck@xxxxxxxxxx>
>
