On 02/23/2018 11:55 AM, David Hildenbrand wrote:
> On 23.02.2018 09:11, Christian Borntraeger wrote:
>> commit 35b3fde6203b ("KVM: s390: wire up bpb feature") has no
>> documentation for KVM_CAP_S390_BPB. While adding this let's also add
>> other missing capabilities like KVM_CAP_S390_PSW, KVM_CAP_S390_GMAP and
>> KVM_CAP_S390_COW.
>>
>> Signed-off-by: Christian Borntraeger <borntraeger@xxxxxxxxxx>
>> ---
>> Documentation/virtual/kvm/api.txt | 29 +++++++++++++++++++++++++++++
>> 1 file changed, 29 insertions(+)
>>
>> diff --git a/Documentation/virtual/kvm/api.txt b/Documentation/virtual/kvm/api.txt
>> index e5f1743e0b3e..4f329882016c 100644
>> --- a/Documentation/virtual/kvm/api.txt
>> +++ b/Documentation/virtual/kvm/api.txt
>> @@ -4419,3 +4419,32 @@ Parameters: none
>> This capability indicates if the flic device will be able to get/set the
>> AIS states for migration via the KVM_DEV_FLIC_AISM_ALL attribute and allows
>> to discover this without having to create a flic device.
>> +
>> +8.14 KVM_CAP_S390_PSW
>> +
>> +Architectures: s390
>> +
>> +This capability indicates that the PSW is exposed via the kvm_run structure.
>> +
>> +8.15 KVM_CAP_S390_GMAP
>> +
>> +Architectures: s390
>> +
>> +This capability indicates that the user space memory used as guest mapping can
>> +be anywhere in the user memory address space, as long as the memory slots are
>> +aligned and sized to a segment (1MB) boundary.
>> +
>> +8.16 KVM_CAP_S390_COW
>> +
>> +Architectures: s390
>> +
>> +This capability indicates that the user space memory used as guest mapping can
>> +use copy-on-write semantics as well as dirty pages tracking via read-only page
>> +tables.
>> +
>> +8.17 KVM_CAP_S390_BPB
>> +
>> +Architectures: s390
>> +
>> +This capability indicates that kvm will implement the interfaces to handle
>> +reset, migration and nested KVM for branch prediction blocking.
>>
>
> Maybe add a comment about bpb being exposed via CPU model (stfl) and
> that it should not be used without this capability?
Something like:
"The stfle facility 82 should not be provided to the guest without this capability".
?
