On 21.10.20 16:14, David Hildenbrand wrote:
> On 21.10.20 15:43, Janosch Frank wrote:
>> Diag318 fencing needs to be determined on the current VM PV state and
>> not on the state that the VM has when we create the CPU model.
>>
>> Signed-off-by: Janosch Frank <[email protected]>
>> Reported-by: Marc Hartmayer <[email protected]>
>> Reviewed-by: Christian Borntraeger <[email protected]>
>> Fixes: fabdada935 ("s390: guest support for diagnose 0x318")
>> Tested-by: Marc Hartmayer <[email protected]>
>> ---
>> hw/s390x/sclp.c | 10 ++++++++++
>> target/s390x/kvm.c | 3 +--
>> 2 files changed, 11 insertions(+), 2 deletions(-)
>>
>> diff --git a/hw/s390x/sclp.c b/hw/s390x/sclp.c
>> index 0cf2290826..69aba402d3 100644
>> --- a/hw/s390x/sclp.c
>> +++ b/hw/s390x/sclp.c
>> @@ -22,6 +22,7 @@
>> #include "hw/s390x/event-facility.h"
>> #include "hw/s390x/s390-pci-bus.h"
>> #include "hw/s390x/ipl.h"
>> +#include "hw/s390x/pv.h"
>>
>> static inline SCLPDevice *get_sclp_device(void)
>> {
>> @@ -142,6 +143,15 @@ static void read_SCP_info(SCLPDevice *sclp, SCCB *sccb)
>> if (s390_has_feat(S390_FEAT_EXTENDED_LENGTH_SCCB)) {
>> s390_get_feat_block(S390_FEAT_TYPE_SCLP_FAC134,
>> &read_info->fac134);
>> + /*
>> + * Diag318 is not available in protected mode and will result
>> + * in an operation exception. As we can dynamically move in
>> + * and out of protected mode, we need to fence the feature
>> + * here rather than when creating the CPU model.
>> + */
>> + if (s390_is_pv()) {
>> + read_info->fac134 &= ~0x80;
>> + }
>
> Hmm, I thought firmware would handle exposing cpu features and similar,
> so we can't temper with it ....
Only the stfle bits.
>
> Can we move that into s390_get_feat_block instead and check against the
> feature bit instead?
No because we want to have this active for !pv and disabled for pv but we switch
this multiple times when doing boot/reboot.
