On 03.11.20 13:32, Thomas Huth wrote:
> On 30/10/2020 13.28, Christian Borntraeger wrote:
>> From: "Jason J. Herne" <[email protected]>
>>
>> The architecture states that the iplb location is only written to low
>> core for list directed ipl and not for traditional ccw ipl. If we don't
>> skip this then operating systems that load by reading into low core
>> memory may fail to start.
>
> Just double-checking: But doing write_subsystem_identification()
> unconditionally is ok, right?
Yes, for any channel device IPL the subsystem ID is stored in absolute locations
184-187 so this should be good as virtio is a channel device.
>
>> We should also not write the iplb pointer for network boot as it might
>> overwrite content that we got via network.
>
> FWIW, write_iplb_location() is already just a dummy function in netmain.c,
> so this should not have been an issue in the network bootloader, I hope.
OK. I think we can keep the check for !VIRTIO_ID_NET anyway.
>
>> Signed-off-by: Jason J. Herne <[email protected]>
>> Fixes: 9bfc04f9ef68 ("pc-bios: s390x: Save iplb location in lowcore")
>> Signed-off-by: Christian Borntraeger <[email protected]>
>> ---
>> pc-bios/s390-ccw/main.c | 4 +++-
>> 1 file changed, 3 insertions(+), 1 deletion(-)
>>
>> diff --git a/pc-bios/s390-ccw/main.c b/pc-bios/s390-ccw/main.c
>> index 43c792cf9509..fc4bfaa45529 100644
>> --- a/pc-bios/s390-ccw/main.c
>> +++ b/pc-bios/s390-ccw/main.c
>> @@ -43,7 +43,9 @@ void write_subsystem_identification(void)
>>
>> void write_iplb_location(void)
>> {
>> - lowcore->ptr_iplb = ptr2u32(&iplb);
>> + if (cutype == CU_TYPE_VIRTIO && virtio_get_device_type() !=
>> VIRTIO_ID_NET) {
>> + lowcore->ptr_iplb = ptr2u32(&iplb);
>> + }
>> }
>
> Acked-by: Thomas Huth <[email protected]>
>
> Christian, Cornelia, could you please pick up the patch? I'm not sure
> whether I can do another PR this week for the RC...
>
