diff options
Diffstat (limited to 'Documentation/virtual/kvm/devices/vm.txt')
| -rw-r--r-- | Documentation/virtual/kvm/devices/vm.txt | 87 |
1 files changed, 86 insertions, 1 deletions
diff --git a/Documentation/virtual/kvm/devices/vm.txt b/Documentation/virtual/kvm/devices/vm.txt index a9ea8774a45f..b6cda49f2ba4 100644 --- a/Documentation/virtual/kvm/devices/vm.txt +++ b/Documentation/virtual/kvm/devices/vm.txt @@ -20,7 +20,8 @@ Enables Collaborative Memory Management Assist (CMMA) for the virtual machine. 1.2. ATTRIBUTE: KVM_S390_VM_MEM_CLR_CMMA Parameters: none -Returns: 0 +Returns: -EINVAL if CMMA was not enabled + 0 otherwise Clear the CMMA status for all guest pages, so any pages the guest marked as unused are again used any may not be reclaimed by the host. @@ -85,6 +86,90 @@ Returns: -EBUSY in case 1 or more vcpus are already activated (only in write -ENOMEM if not enough memory is available to process the ioctl 0 in case of success +2.3. ATTRIBUTE: KVM_S390_VM_CPU_MACHINE_FEAT (r/o) + +Allows user space to retrieve available cpu features. A feature is available if +provided by the hardware and supported by kvm. In theory, cpu features could +even be completely emulated by kvm. + +struct kvm_s390_vm_cpu_feat { + __u64 feat[16]; # Bitmap (1 = feature available), MSB 0 bit numbering +}; + +Parameters: address of a buffer to load the feature list from. +Returns: -EFAULT if the given address is not accessible from kernel space. + 0 in case of success. + +2.4. ATTRIBUTE: KVM_S390_VM_CPU_PROCESSOR_FEAT (r/w) + +Allows user space to retrieve or change enabled cpu features for all VCPUs of a +VM. Features that are not available cannot be enabled. + +See 2.3. for a description of the parameter struct. + +Parameters: address of a buffer to store/load the feature list from. +Returns: -EFAULT if the given address is not accessible from kernel space. + -EINVAL if a cpu feature that is not available is to be enabled. + -EBUSY if at least one VCPU has already been defined. + 0 in case of success. + +2.5. ATTRIBUTE: KVM_S390_VM_CPU_MACHINE_SUBFUNC (r/o) + +Allows user space to retrieve available cpu subfunctions without any filtering +done by a set IBC. These subfunctions are indicated to the guest VCPU via +query or "test bit" subfunctions and used e.g. by cpacf functions, plo and ptff. + +A subfunction block is only valid if KVM_S390_VM_CPU_MACHINE contains the +STFL(E) bit introducing the affected instruction. If the affected instruction +indicates subfunctions via a "query subfunction", the response block is +contained in the returned struct. If the affected instruction +indicates subfunctions via a "test bit" mechanism, the subfunction codes are +contained in the returned struct in MSB 0 bit numbering. + +struct kvm_s390_vm_cpu_subfunc { + u8 plo[32]; # always valid (ESA/390 feature) + u8 ptff[16]; # valid with TOD-clock steering + u8 kmac[16]; # valid with Message-Security-Assist + u8 kmc[16]; # valid with Message-Security-Assist + u8 km[16]; # valid with Message-Security-Assist + u8 kimd[16]; # valid with Message-Security-Assist + u8 klmd[16]; # valid with Message-Security-Assist + u8 pckmo[16]; # valid with Message-Security-Assist-Extension 3 + u8 kmctr[16]; # valid with Message-Security-Assist-Extension 4 + u8 kmf[16]; # valid with Message-Security-Assist-Extension 4 + u8 kmo[16]; # valid with Message-Security-Assist-Extension 4 + u8 pcc[16]; # valid with Message-Security-Assist-Extension 4 + u8 ppno[16]; # valid with Message-Security-Assist-Extension 5 + u8 reserved[1824]; # reserved for future instructions +}; + +Parameters: address of a buffer to load the subfunction blocks from. +Returns: -EFAULT if the given address is not accessible from kernel space. + 0 in case of success. + +2.6. ATTRIBUTE: KVM_S390_VM_CPU_PROCESSOR_SUBFUNC (r/w) + +Allows user space to retrieve or change cpu subfunctions to be indicated for +all VCPUs of a VM. This attribute will only be available if kernel and +hardware support are in place. + +The kernel uses the configured subfunction blocks for indication to +the guest. A subfunction block will only be used if the associated STFL(E) bit +has not been disabled by user space (so the instruction to be queried is +actually available for the guest). + +As long as no data has been written, a read will fail. The IBC will be used +to determine available subfunctions in this case, this will guarantee backward +compatibility. + +See 2.5. for a description of the parameter struct. + +Parameters: address of a buffer to store/load the subfunction blocks from. +Returns: -EFAULT if the given address is not accessible from kernel space. + -EINVAL when reading, if there was no write yet. + -EBUSY if at least one VCPU has already been defined. + 0 in case of success. + 3. GROUP: KVM_S390_VM_TOD Architectures: s390 |