Based on kernel version 4.16.1. Page generated on 2018-04-09 11:53 EST.
1 Generic vm interface 2 ==================================== 3 4 The virtual machine "device" also accepts the ioctls KVM_SET_DEVICE_ATTR, 5 KVM_GET_DEVICE_ATTR, and KVM_HAS_DEVICE_ATTR. The interface uses the same 6 struct kvm_device_attr as other devices, but targets VM-wide settings 7 and controls. 8 9 The groups and attributes per virtual machine, if any, are architecture 10 specific. 11 12 1. GROUP: KVM_S390_VM_MEM_CTRL 13 Architectures: s390 14 15 1.1. ATTRIBUTE: KVM_S390_VM_MEM_ENABLE_CMMA 16 Parameters: none 17 Returns: -EBUSY if a vcpu is already defined, otherwise 0 18 19 Enables Collaborative Memory Management Assist (CMMA) for the virtual machine. 20 21 1.2. ATTRIBUTE: KVM_S390_VM_MEM_CLR_CMMA 22 Parameters: none 23 Returns: -EINVAL if CMMA was not enabled 24 0 otherwise 25 26 Clear the CMMA status for all guest pages, so any pages the guest marked 27 as unused are again used any may not be reclaimed by the host. 28 29 1.3. ATTRIBUTE KVM_S390_VM_MEM_LIMIT_SIZE 30 Parameters: in attr->addr the address for the new limit of guest memory 31 Returns: -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 38 Allows userspace to query the actual limit and set a new limit for 39 the maximum guest memory size. The limit will be rounded up to 40 2048 MB, 4096 GB, 8192 TB respectively, as this limit is governed by 41 the number of page table levels. In the case that there is no limit we will set 42 the limit to KVM_S390_NO_MEM_LIMIT (U64_MAX). 43 44 2. GROUP: KVM_S390_VM_CPU_MODEL 45 Architectures: s390 46 47 2.1. ATTRIBUTE: KVM_S390_VM_CPU_MACHINE (r/o) 48 49 Allows user space to retrieve machine and kvm specific cpu related information: 50 51 struct 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 59 Parameters: address of buffer to store the machine related cpu data 60 of type struct kvm_s390_vm_cpu_machine* 61 Returns: -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 65 2.2. ATTRIBUTE: KVM_S390_VM_CPU_PROCESSOR (r/w) 66 67 Allows user space to retrieve or request to change cpu related information for a vcpu: 68 69 struct 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 77 KVM does not enforce or limit the cpu model data in any form. Take the information 78 retrieved by means of KVM_S390_VM_CPU_MACHINE as hint for reasonable configuration 79 setups. Instruction interceptions triggered by additionally set facility bits that 80 are not handled by KVM need to by imlemented in the VM driver code. 81 82 Parameters: address of buffer to store/set the processor related cpu 83 data of type struct kvm_s390_vm_cpu_processor*. 84 Returns: -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 89 2.3. ATTRIBUTE: KVM_S390_VM_CPU_MACHINE_FEAT (r/o) 90 91 Allows user space to retrieve available cpu features. A feature is available if 92 provided by the hardware and supported by kvm. In theory, cpu features could 93 even be completely emulated by kvm. 94 95 struct kvm_s390_vm_cpu_feat { 96 __u64 feat[16]; # Bitmap (1 = feature available), MSB 0 bit numbering 97 }; 98 99 Parameters: address of a buffer to load the feature list from. 100 Returns: -EFAULT if the given address is not accessible from kernel space. 101 0 in case of success. 102 103 2.4. ATTRIBUTE: KVM_S390_VM_CPU_PROCESSOR_FEAT (r/w) 104 105 Allows user space to retrieve or change enabled cpu features for all VCPUs of a 106 VM. Features that are not available cannot be enabled. 107 108 See 2.3. for a description of the parameter struct. 109 110 Parameters: address of a buffer to store/load the feature list from. 111 Returns: -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. 115 116 2.5. ATTRIBUTE: KVM_S390_VM_CPU_MACHINE_SUBFUNC (r/o) 117 118 Allows user space to retrieve available cpu subfunctions without any filtering 119 done by a set IBC. These subfunctions are indicated to the guest VCPU via 120 query or "test bit" subfunctions and used e.g. by cpacf functions, plo and ptff. 121 122 A subfunction block is only valid if KVM_S390_VM_CPU_MACHINE contains the 123 STFL(E) bit introducing the affected instruction. If the affected instruction 124 indicates subfunctions via a "query subfunction", the response block is 125 contained in the returned struct. If the affected instruction 126 indicates subfunctions via a "test bit" mechanism, the subfunction codes are 127 contained in the returned struct in MSB 0 bit numbering. 128 129 struct 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 reserved[1808]; # reserved for future instructions 145 }; 146 147 Parameters: address of a buffer to load the subfunction blocks from. 148 Returns: -EFAULT if the given address is not accessible from kernel space. 149 0 in case of success. 150 151 2.6. ATTRIBUTE: KVM_S390_VM_CPU_PROCESSOR_SUBFUNC (r/w) 152 153 Allows user space to retrieve or change cpu subfunctions to be indicated for 154 all VCPUs of a VM. This attribute will only be available if kernel and 155 hardware support are in place. 156 157 The kernel uses the configured subfunction blocks for indication to 158 the guest. A subfunction block will only be used if the associated STFL(E) bit 159 has not been disabled by user space (so the instruction to be queried is 160 actually available for the guest). 161 162 As long as no data has been written, a read will fail. The IBC will be used 163 to determine available subfunctions in this case, this will guarantee backward 164 compatibility. 165 166 See 2.5. for a description of the parameter struct. 167 168 Parameters: address of a buffer to store/load the subfunction blocks from. 169 Returns: -EFAULT if the given address is not accessible from kernel space. 170 -EINVAL when reading, if there was no write yet. 171 -EBUSY if at least one VCPU has already been defined. 172 0 in case of success. 173 174 3. GROUP: KVM_S390_VM_TOD 175 Architectures: s390 176 177 3.1. ATTRIBUTE: KVM_S390_VM_TOD_HIGH 178 179 Allows user space to set/get the TOD clock extension (u8) (superseded by 180 KVM_S390_VM_TOD_EXT). 181 182 Parameters: address of a buffer in user space to store the data (u8) to 183 Returns: -EFAULT if the given address is not accessible from kernel space 184 -EINVAL if setting the TOD clock extension to != 0 is not supported 185 186 3.2. ATTRIBUTE: KVM_S390_VM_TOD_LOW 187 188 Allows user space to set/get bits 0-63 of the TOD clock register as defined in 189 the POP (u64). 190 191 Parameters: address of a buffer in user space to store the data (u64) to 192 Returns: -EFAULT if the given address is not accessible from kernel space 193 194 3.3. ATTRIBUTE: KVM_S390_VM_TOD_EXT 195 Allows user space to set/get bits 0-63 of the TOD clock register as defined in 196 the POP (u64). If the guest CPU model supports the TOD clock extension (u8), it 197 also allows user space to get/set it. If the guest CPU model does not support 198 it, it is stored as 0 and not allowed to be set to a value != 0. 199 200 Parameters: address of a buffer in user space to store the data 201 (kvm_s390_vm_tod_clock) to 202 Returns: -EFAULT if the given address is not accessible from kernel space 203 -EINVAL if setting the TOD clock extension to != 0 is not supported 204 205 4. GROUP: KVM_S390_VM_CRYPTO 206 Architectures: s390 207 208 4.1. ATTRIBUTE: KVM_S390_VM_CRYPTO_ENABLE_AES_KW (w/o) 209 210 Allows user space to enable aes key wrapping, including generating a new 211 wrapping key. 212 213 Parameters: none 214 Returns: 0 215 216 4.2. ATTRIBUTE: KVM_S390_VM_CRYPTO_ENABLE_DEA_KW (w/o) 217 218 Allows user space to enable dea key wrapping, including generating a new 219 wrapping key. 220 221 Parameters: none 222 Returns: 0 223 224 4.3. ATTRIBUTE: KVM_S390_VM_CRYPTO_DISABLE_AES_KW (w/o) 225 226 Allows user space to disable aes key wrapping, clearing the wrapping key. 227 228 Parameters: none 229 Returns: 0 230 231 4.4. ATTRIBUTE: KVM_S390_VM_CRYPTO_DISABLE_DEA_KW (w/o) 232 233 Allows user space to disable dea key wrapping, clearing the wrapping key. 234 235 Parameters: none 236 Returns: 0 237 238 5. GROUP: KVM_S390_VM_MIGRATION 239 Architectures: s390 240 241 5.1. ATTRIBUTE: KVM_S390_VM_MIGRATION_STOP (w/o) 242 243 Allows userspace to stop migration mode, needed for PGSTE migration. 244 Setting this attribute when migration mode is not active will have no 245 effects. 246 247 Parameters: none 248 Returns: 0 249 250 5.2. ATTRIBUTE: KVM_S390_VM_MIGRATION_START (w/o) 251 252 Allows userspace to start migration mode, needed for PGSTE migration. 253 Setting this attribute when migration mode is already active will have 254 no effects. 255 256 Parameters: none 257 Returns: -ENOMEM if there is not enough free memory to start migration mode 258 -EINVAL if the state of the VM is invalid (e.g. no memory defined) 259 0 in case of success. 260 261 5.3. ATTRIBUTE: KVM_S390_VM_MIGRATION_STATUS (r/o) 262 263 Allows userspace to query the status of migration mode. 264 265 Parameters: address of a buffer in user space to store the data (u64) to; 266 the data itself is either 0 if migration mode is disabled or 1 267 if it is enabled 268 Returns: -EFAULT if the given address is not accessible from kernel space 269 0 in case of success.