From: Collin Walling <walling@xxxxxxxxxxxxx> 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> Link: https://lore.kernel.org/kvm/20200625150724.10021-2-walling@xxxxxxxxxxxxx/ Message-Id: <20200625150724.10021-2-walling@xxxxxxxxxxxxx> Signed-off-by: Christian Borntraeger <borntraeger@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 d2b733dc7892..51191b56e61c 100644 --- a/Documentation/virt/kvm/api.rst +++ b/Documentation/virt/kvm/api.rst @@ -6173,3 +6173,23 @@ specific interfaces must be consistent, i.e. if one says the feature is supported, than the other should as well and vice versa. For arm64 see Documentation/virt/kvm/devices/vcpu.rst "KVM_ARM_VCPU_PVTIME_CTRL". For x86 see Documentation/virt/kvm/msr.rst "MSR_KVM_STEAL_TIME". + +8.25 KVM_CAP_S390_DIAG318 +------------------------- + +:Architectures: 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). -- 2.25.4
