1Generic vm interface 2==================================== 3 4The virtual machine "device" also accepts the ioctls KVM_SET_DEVICE_ATTR, 5KVM_GET_DEVICE_ATTR, and KVM_HAS_DEVICE_ATTR. The interface uses the same 6struct kvm_device_attr as other devices, but targets VM-wide settings 7and controls. 8 9The groups and attributes per virtual machine, if any, are architecture 10specific. 11 121. GROUP: KVM_S390_VM_MEM_CTRL 13Architectures: s390 14 151.1. ATTRIBUTE: KVM_S390_VM_MEM_ENABLE_CMMA 16Parameters: none 17Returns: -EBUSY if a vcpu is already defined, otherwise 0 18 19Enables Collaborative Memory Management Assist (CMMA) for the virtual machine. 20 211.2. ATTRIBUTE: KVM_S390_VM_MEM_CLR_CMMA 22Parameters: none 23Returns: -EINVAL if CMMA was not enabled 24 0 otherwise 25 26Clear the CMMA status for all guest pages, so any pages the guest marked 27as unused are again used any may not be reclaimed by the host. 28 291.3. ATTRIBUTE KVM_S390_VM_MEM_LIMIT_SIZE 30Parameters: in attr->addr the address for the new limit of guest memory 31Returns: -EFAULT if the given address is not accessible 32 -EINVAL if the virtual machine is of type UCONTROL 33 -E2BIG if the given guest memory is to big for that machine 34 -EBUSY if a vcpu is already defined 35 -ENOMEM if not enough memory is available for a new shadow guest mapping 36 0 otherwise 37 38Allows userspace to query the actual limit and set a new limit for 39the maximum guest memory size. The limit will be rounded up to 402048 MB, 4096 GB, 8192 TB respectively, as this limit is governed by 41the number of page table levels. In the case that there is no limit we will set 42the limit to KVM_S390_NO_MEM_LIMIT (U64_MAX). 43 442. GROUP: KVM_S390_VM_CPU_MODEL 45Architectures: s390 46 472.1. ATTRIBUTE: KVM_S390_VM_CPU_MACHINE (r/o) 48 49Allows user space to retrieve machine and kvm specific cpu related information: 50 51struct kvm_s390_vm_cpu_machine { 52 __u64 cpuid; # CPUID of host 53 __u32 ibc; # IBC level range offered by host 54 __u8 pad[4]; 55 __u64 fac_mask[256]; # set of cpu facilities enabled by KVM 56 __u64 fac_list[256]; # set of cpu facilities offered by host 57} 58 59Parameters: address of buffer to store the machine related cpu data 60 of type struct kvm_s390_vm_cpu_machine* 61Returns: -EFAULT if the given address is not accessible from kernel space 62 -ENOMEM if not enough memory is available to process the ioctl 63 0 in case of success 64 652.2. ATTRIBUTE: KVM_S390_VM_CPU_PROCESSOR (r/w) 66 67Allows user space to retrieve or request to change cpu related information for a vcpu: 68 69struct kvm_s390_vm_cpu_processor { 70 __u64 cpuid; # CPUID currently (to be) used by this vcpu 71 __u16 ibc; # IBC level currently (to be) used by this vcpu 72 __u8 pad[6]; 73 __u64 fac_list[256]; # set of cpu facilities currently (to be) used 74 # by this vcpu 75} 76 77KVM does not enforce or limit the cpu model data in any form. Take the information 78retrieved by means of KVM_S390_VM_CPU_MACHINE as hint for reasonable configuration 79setups. Instruction interceptions triggered by additionally set facility bits that 80are not handled by KVM need to by imlemented in the VM driver code. 81 82Parameters: address of buffer to store/set the processor related cpu 83 data of type struct kvm_s390_vm_cpu_processor*. 84Returns: -EBUSY in case 1 or more vcpus are already activated (only in write case) 85 -EFAULT if the given address is not accessible from kernel space 86 -ENOMEM if not enough memory is available to process the ioctl 87 0 in case of success 88 892.3. ATTRIBUTE: KVM_S390_VM_CPU_MACHINE_FEAT (r/o) 90 91Allows user space to retrieve available cpu features. A feature is available if 92provided by the hardware and supported by kvm. In theory, cpu features could 93even be completely emulated by kvm. 94 95struct kvm_s390_vm_cpu_feat { 96 __u64 feat[16]; # Bitmap (1 = feature available), MSB 0 bit numbering 97}; 98 99Parameters: address of a buffer to load the feature list from. 100Returns: -EFAULT if the given address is not accessible from kernel space. 101 0 in case of success. 102 1032.4. ATTRIBUTE: KVM_S390_VM_CPU_PROCESSOR_FEAT (r/w) 104 105Allows user space to retrieve or change enabled cpu features for all VCPUs of a 106VM. Features that are not available cannot be enabled. 107 108See 2.3. for a description of the parameter struct. 109 110Parameters: address of a buffer to store/load the feature list from. 111Returns: -EFAULT if the given address is not accessible from kernel space. 112 -EINVAL if a cpu feature that is not available is to be enabled. 113 -EBUSY if at least one VCPU has already been defined. 114 0 in case of success. 115 1162.5. ATTRIBUTE: KVM_S390_VM_CPU_MACHINE_SUBFUNC (r/o) 117 118Allows user space to retrieve available cpu subfunctions without any filtering 119done by a set IBC. These subfunctions are indicated to the guest VCPU via 120query or "test bit" subfunctions and used e.g. by cpacf functions, plo and ptff. 121 122A subfunction block is only valid if KVM_S390_VM_CPU_MACHINE contains the 123STFL(E) bit introducing the affected instruction. If the affected instruction 124indicates subfunctions via a "query subfunction", the response block is 125contained in the returned struct. If the affected instruction 126indicates subfunctions via a "test bit" mechanism, the subfunction codes are 127contained in the returned struct in MSB 0 bit numbering. 128 129struct kvm_s390_vm_cpu_subfunc { 130 u8 plo[32]; # always valid (ESA/390 feature) 131 u8 ptff[16]; # valid with TOD-clock steering 132 u8 kmac[16]; # valid with Message-Security-Assist 133 u8 kmc[16]; # valid with Message-Security-Assist 134 u8 km[16]; # valid with Message-Security-Assist 135 u8 kimd[16]; # valid with Message-Security-Assist 136 u8 klmd[16]; # valid with Message-Security-Assist 137 u8 pckmo[16]; # valid with Message-Security-Assist-Extension 3 138 u8 kmctr[16]; # valid with Message-Security-Assist-Extension 4 139 u8 kmf[16]; # valid with Message-Security-Assist-Extension 4 140 u8 kmo[16]; # valid with Message-Security-Assist-Extension 4 141 u8 pcc[16]; # valid with Message-Security-Assist-Extension 4 142 u8 ppno[16]; # valid with Message-Security-Assist-Extension 5 143 u8 kma[16]; # valid with Message-Security-Assist-Extension 8 144 u8 kdsa[16]; # valid with Message-Security-Assist-Extension 9 145 u8 reserved[1792]; # reserved for future instructions 146}; 147 148Parameters: address of a buffer to load the subfunction blocks from. 149Returns: -EFAULT if the given address is not accessible from kernel space. 150 0 in case of success. 151 1522.6. ATTRIBUTE: KVM_S390_VM_CPU_PROCESSOR_SUBFUNC (r/w) 153 154Allows user space to retrieve or change cpu subfunctions to be indicated for 155all VCPUs of a VM. This attribute will only be available if kernel and 156hardware support are in place. 157 158The kernel uses the configured subfunction blocks for indication to 159the guest. A subfunction block will only be used if the associated STFL(E) bit 160has not been disabled by user space (so the instruction to be queried is 161actually available for the guest). 162 163As long as no data has been written, a read will fail. The IBC will be used 164to determine available subfunctions in this case, this will guarantee backward 165compatibility. 166 167See 2.5. for a description of the parameter struct. 168 169Parameters: address of a buffer to store/load the subfunction blocks from. 170Returns: -EFAULT if the given address is not accessible from kernel space. 171 -EINVAL when reading, if there was no write yet. 172 -EBUSY if at least one VCPU has already been defined. 173 0 in case of success. 174 1753. GROUP: KVM_S390_VM_TOD 176Architectures: s390 177 1783.1. ATTRIBUTE: KVM_S390_VM_TOD_HIGH 179 180Allows user space to set/get the TOD clock extension (u8) (superseded by 181KVM_S390_VM_TOD_EXT). 182 183Parameters: address of a buffer in user space to store the data (u8) to 184Returns: -EFAULT if the given address is not accessible from kernel space 185 -EINVAL if setting the TOD clock extension to != 0 is not supported 186 1873.2. ATTRIBUTE: KVM_S390_VM_TOD_LOW 188 189Allows user space to set/get bits 0-63 of the TOD clock register as defined in 190the POP (u64). 191 192Parameters: address of a buffer in user space to store the data (u64) to 193Returns: -EFAULT if the given address is not accessible from kernel space 194 1953.3. ATTRIBUTE: KVM_S390_VM_TOD_EXT 196Allows user space to set/get bits 0-63 of the TOD clock register as defined in 197the POP (u64). If the guest CPU model supports the TOD clock extension (u8), it 198also allows user space to get/set it. If the guest CPU model does not support 199it, it is stored as 0 and not allowed to be set to a value != 0. 200 201Parameters: address of a buffer in user space to store the data 202 (kvm_s390_vm_tod_clock) to 203Returns: -EFAULT if the given address is not accessible from kernel space 204 -EINVAL if setting the TOD clock extension to != 0 is not supported 205 2064. GROUP: KVM_S390_VM_CRYPTO 207Architectures: s390 208 2094.1. ATTRIBUTE: KVM_S390_VM_CRYPTO_ENABLE_AES_KW (w/o) 210 211Allows user space to enable aes key wrapping, including generating a new 212wrapping key. 213 214Parameters: none 215Returns: 0 216 2174.2. ATTRIBUTE: KVM_S390_VM_CRYPTO_ENABLE_DEA_KW (w/o) 218 219Allows user space to enable dea key wrapping, including generating a new 220wrapping key. 221 222Parameters: none 223Returns: 0 224 2254.3. ATTRIBUTE: KVM_S390_VM_CRYPTO_DISABLE_AES_KW (w/o) 226 227Allows user space to disable aes key wrapping, clearing the wrapping key. 228 229Parameters: none 230Returns: 0 231 2324.4. ATTRIBUTE: KVM_S390_VM_CRYPTO_DISABLE_DEA_KW (w/o) 233 234Allows user space to disable dea key wrapping, clearing the wrapping key. 235 236Parameters: none 237Returns: 0 238 2395. GROUP: KVM_S390_VM_MIGRATION 240Architectures: s390 241 2425.1. ATTRIBUTE: KVM_S390_VM_MIGRATION_STOP (w/o) 243 244Allows userspace to stop migration mode, needed for PGSTE migration. 245Setting this attribute when migration mode is not active will have no 246effects. 247 248Parameters: none 249Returns: 0 250 2515.2. ATTRIBUTE: KVM_S390_VM_MIGRATION_START (w/o) 252 253Allows userspace to start migration mode, needed for PGSTE migration. 254Setting this attribute when migration mode is already active will have 255no effects. 256 257Dirty tracking must be enabled on all memslots, else -EINVAL is returned. When 258dirty tracking is disabled on any memslot, migration mode is automatically 259stopped. 260 261Parameters: none 262Returns: -ENOMEM if there is not enough free memory to start migration mode 263 -EINVAL if the state of the VM is invalid (e.g. no memory defined) 264 0 in case of success. 265 2665.3. ATTRIBUTE: KVM_S390_VM_MIGRATION_STATUS (r/o) 267 268Allows userspace to query the status of migration mode. 269 270Parameters: address of a buffer in user space to store the data (u64) to; 271 the data itself is either 0 if migration mode is disabled or 1 272 if it is enabled 273Returns: -EFAULT if the given address is not accessible from kernel space 274 0 in case of success. 275