Documentation for the s390 DIAGNOSE 0x318 instruction handling. Signed-off-by: Collin Walling <walling@xxxxxxxxxxxxx> Reviewed-by: Cornelia Huck <cohuck@xxxxxxxxxx> Reviewed-by: David Hildenbrand <david@xxxxxxxxxx> --- Documentation/virt/kvm/api.rst | 20 ++++++++++++++++++++ 1 file changed, 20 insertions(+) diff --git a/Documentation/virt/kvm/api.rst b/Documentation/virt/kvm/api.rst index 426f94582b7a..e0b4f2088c46 100644 --- a/Documentation/virt/kvm/api.rst +++ b/Documentation/virt/kvm/api.rst @@ -6150,3 +6150,23 @@ KVM can therefore start protected VMs. This capability governs the KVM_S390_PV_COMMAND ioctl and the KVM_MP_STATE_LOAD MP_STATE. KVM_SET_MP_STATE can fail for protected guests when the state change is invalid. + +8.24 KVM_CAP_S390_DIAG318 +------------------------- + +:Architecture: s390 + +This capability enables a guest to set information about its control program +(i.e. guest kernel type and version). The information is helpful during +system/firmware service events, providing additional data about the guest +environments running on the machine. + +The information is associated with the DIAGNOSE 0x318 instruction, which sets +an 8-byte value consisting of a one-byte Control Program Name Code (CPNC) and +a 7-byte Control Program Version Code (CPVC). The CPNC determines what +environment the control program is running in (e.g. Linux, z/VM...), and the +CPVC is used for information specific to OS (e.g. Linux version, Linux +distribution...) + +If this capability is available, then the CPNC and CPVC can be synchronized +between KVM and userspace via the sync regs mechanism (KVM_SYNC_DIAG318). -- 2.26.2
