1 .. SPDX-License-Identifier: GPL-2.0
7 The virtual machine "device" also accepts the ioctls KVM_SET_DEVICE_ATTR,
8 KVM_GET_DEVICE_ATTR, and KVM_HAS_DEVICE_ATTR. The interface uses the same
9 struct kvm_device_attr as other devices, but targets VM-wide settings
12 The groups and attributes per virtual machine, if any, are architecture
15 1. GROUP: KVM_S390_VM_MEM_CTRL
16 ==============================
20 1.1. ATTRIBUTE: KVM_S390_VM_MEM_ENABLE_CMMA
21 -------------------------------------------
24 :Returns: -EBUSY if a vcpu is already defined, otherwise 0
26 Enables Collaborative Memory Management Assist (CMMA) for the virtual machine.
28 1.2. ATTRIBUTE: KVM_S390_VM_MEM_CLR_CMMA
29 ----------------------------------------
32 :Returns: -EINVAL if CMMA was not enabled;
35 Clear the CMMA status for all guest pages, so any pages the guest marked
36 as unused are again used any may not be reclaimed by the host.
38 1.3. ATTRIBUTE KVM_S390_VM_MEM_LIMIT_SIZE
39 -----------------------------------------
41 :Parameters: in attr->addr the address for the new limit of guest memory
42 :Returns: -EFAULT if the given address is not accessible;
43 -EINVAL if the virtual machine is of type UCONTROL;
44 -E2BIG if the given guest memory is to big for that machine;
45 -EBUSY if a vcpu is already defined;
46 -ENOMEM if not enough memory is available for a new shadow guest mapping;
49 Allows userspace to query the actual limit and set a new limit for
50 the maximum guest memory size. The limit will be rounded up to
51 2048 MB, 4096 GB, 8192 TB respectively, as this limit is governed by
52 the number of page table levels. In the case that there is no limit we will set
53 the limit to KVM_S390_NO_MEM_LIMIT (U64_MAX).
55 2. GROUP: KVM_S390_VM_CPU_MODEL
56 ===============================
60 2.1. ATTRIBUTE: KVM_S390_VM_CPU_MACHINE (r/o)
61 ---------------------------------------------
63 Allows user space to retrieve machine and kvm specific cpu related information::
65 struct kvm_s390_vm_cpu_machine {
66 __u64 cpuid; # CPUID of host
67 __u32 ibc; # IBC level range offered by host
69 __u64 fac_mask[256]; # set of cpu facilities enabled by KVM
70 __u64 fac_list[256]; # set of cpu facilities offered by host
73 :Parameters: address of buffer to store the machine related cpu data
74 of type struct kvm_s390_vm_cpu_machine*
75 :Returns: -EFAULT if the given address is not accessible from kernel space;
76 -ENOMEM if not enough memory is available to process the ioctl;
79 2.2. ATTRIBUTE: KVM_S390_VM_CPU_PROCESSOR (r/w)
80 ===============================================
82 Allows user space to retrieve or request to change cpu related information for a vcpu::
84 struct kvm_s390_vm_cpu_processor {
85 __u64 cpuid; # CPUID currently (to be) used by this vcpu
86 __u16 ibc; # IBC level currently (to be) used by this vcpu
88 __u64 fac_list[256]; # set of cpu facilities currently (to be) used
92 KVM does not enforce or limit the cpu model data in any form. Take the information
93 retrieved by means of KVM_S390_VM_CPU_MACHINE as hint for reasonable configuration
94 setups. Instruction interceptions triggered by additionally set facility bits that
95 are not handled by KVM need to by imlemented in the VM driver code.
97 :Parameters: address of buffer to store/set the processor related cpu
98 data of type struct kvm_s390_vm_cpu_processor*.
99 :Returns: -EBUSY in case 1 or more vcpus are already activated (only in write case);
100 -EFAULT if the given address is not accessible from kernel space;
101 -ENOMEM if not enough memory is available to process the ioctl;
102 0 in case of success.
104 .. _KVM_S390_VM_CPU_MACHINE_FEAT:
106 2.3. ATTRIBUTE: KVM_S390_VM_CPU_MACHINE_FEAT (r/o)
107 --------------------------------------------------
109 Allows user space to retrieve available cpu features. A feature is available if
110 provided by the hardware and supported by kvm. In theory, cpu features could
111 even be completely emulated by kvm.
115 struct kvm_s390_vm_cpu_feat {
116 __u64 feat[16]; # Bitmap (1 = feature available), MSB 0 bit numbering
119 :Parameters: address of a buffer to load the feature list from.
120 :Returns: -EFAULT if the given address is not accessible from kernel space;
121 0 in case of success.
123 2.4. ATTRIBUTE: KVM_S390_VM_CPU_PROCESSOR_FEAT (r/w)
124 ----------------------------------------------------
126 Allows user space to retrieve or change enabled cpu features for all VCPUs of a
127 VM. Features that are not available cannot be enabled.
129 See :ref:`KVM_S390_VM_CPU_MACHINE_FEAT` for
130 a description of the parameter struct.
132 :Parameters: address of a buffer to store/load the feature list from.
133 :Returns: -EFAULT if the given address is not accessible from kernel space;
134 -EINVAL if a cpu feature that is not available is to be enabled;
135 -EBUSY if at least one VCPU has already been defined;
136 0 in case of success.
138 .. _KVM_S390_VM_CPU_MACHINE_SUBFUNC:
140 2.5. ATTRIBUTE: KVM_S390_VM_CPU_MACHINE_SUBFUNC (r/o)
141 -----------------------------------------------------
143 Allows user space to retrieve available cpu subfunctions without any filtering
144 done by a set IBC. These subfunctions are indicated to the guest VCPU via
145 query or "test bit" subfunctions and used e.g. by cpacf functions, plo and ptff.
147 A subfunction block is only valid if KVM_S390_VM_CPU_MACHINE contains the
148 STFL(E) bit introducing the affected instruction. If the affected instruction
149 indicates subfunctions via a "query subfunction", the response block is
150 contained in the returned struct. If the affected instruction
151 indicates subfunctions via a "test bit" mechanism, the subfunction codes are
152 contained in the returned struct in MSB 0 bit numbering.
156 struct kvm_s390_vm_cpu_subfunc {
157 u8 plo[32]; # always valid (ESA/390 feature)
158 u8 ptff[16]; # valid with TOD-clock steering
159 u8 kmac[16]; # valid with Message-Security-Assist
160 u8 kmc[16]; # valid with Message-Security-Assist
161 u8 km[16]; # valid with Message-Security-Assist
162 u8 kimd[16]; # valid with Message-Security-Assist
163 u8 klmd[16]; # valid with Message-Security-Assist
164 u8 pckmo[16]; # valid with Message-Security-Assist-Extension 3
165 u8 kmctr[16]; # valid with Message-Security-Assist-Extension 4
166 u8 kmf[16]; # valid with Message-Security-Assist-Extension 4
167 u8 kmo[16]; # valid with Message-Security-Assist-Extension 4
168 u8 pcc[16]; # valid with Message-Security-Assist-Extension 4
169 u8 ppno[16]; # valid with Message-Security-Assist-Extension 5
170 u8 kma[16]; # valid with Message-Security-Assist-Extension 8
171 u8 kdsa[16]; # valid with Message-Security-Assist-Extension 9
172 u8 reserved[1792]; # reserved for future instructions
175 :Parameters: address of a buffer to load the subfunction blocks from.
176 :Returns: -EFAULT if the given address is not accessible from kernel space;
177 0 in case of success.
179 2.6. ATTRIBUTE: KVM_S390_VM_CPU_PROCESSOR_SUBFUNC (r/w)
180 -------------------------------------------------------
182 Allows user space to retrieve or change cpu subfunctions to be indicated for
183 all VCPUs of a VM. This attribute will only be available if kernel and
184 hardware support are in place.
186 The kernel uses the configured subfunction blocks for indication to
187 the guest. A subfunction block will only be used if the associated STFL(E) bit
188 has not been disabled by user space (so the instruction to be queried is
189 actually available for the guest).
191 As long as no data has been written, a read will fail. The IBC will be used
192 to determine available subfunctions in this case, this will guarantee backward
195 See :ref:`KVM_S390_VM_CPU_MACHINE_SUBFUNC` for a
196 description of the parameter struct.
198 :Parameters: address of a buffer to store/load the subfunction blocks from.
199 :Returns: -EFAULT if the given address is not accessible from kernel space;
200 -EINVAL when reading, if there was no write yet;
201 -EBUSY if at least one VCPU has already been defined;
202 0 in case of success.
204 3. GROUP: KVM_S390_VM_TOD
205 =========================
209 3.1. ATTRIBUTE: KVM_S390_VM_TOD_HIGH
210 ------------------------------------
212 Allows user space to set/get the TOD clock extension (u8) (superseded by
213 KVM_S390_VM_TOD_EXT).
215 :Parameters: address of a buffer in user space to store the data (u8) to
216 :Returns: -EFAULT if the given address is not accessible from kernel space;
217 -EINVAL if setting the TOD clock extension to != 0 is not supported
219 3.2. ATTRIBUTE: KVM_S390_VM_TOD_LOW
220 -----------------------------------
222 Allows user space to set/get bits 0-63 of the TOD clock register as defined in
225 :Parameters: address of a buffer in user space to store the data (u64) to
226 :Returns: -EFAULT if the given address is not accessible from kernel space
228 3.3. ATTRIBUTE: KVM_S390_VM_TOD_EXT
229 -----------------------------------
231 Allows user space to set/get bits 0-63 of the TOD clock register as defined in
232 the POP (u64). If the guest CPU model supports the TOD clock extension (u8), it
233 also allows user space to get/set it. If the guest CPU model does not support
234 it, it is stored as 0 and not allowed to be set to a value != 0.
236 :Parameters: address of a buffer in user space to store the data
237 (kvm_s390_vm_tod_clock) to
238 :Returns: -EFAULT if the given address is not accessible from kernel space;
239 -EINVAL if setting the TOD clock extension to != 0 is not supported
241 4. GROUP: KVM_S390_VM_CRYPTO
242 ============================
246 4.1. ATTRIBUTE: KVM_S390_VM_CRYPTO_ENABLE_AES_KW (w/o)
247 ------------------------------------------------------
249 Allows user space to enable aes key wrapping, including generating a new
255 4.2. ATTRIBUTE: KVM_S390_VM_CRYPTO_ENABLE_DEA_KW (w/o)
256 ------------------------------------------------------
258 Allows user space to enable dea key wrapping, including generating a new
264 4.3. ATTRIBUTE: KVM_S390_VM_CRYPTO_DISABLE_AES_KW (w/o)
265 -------------------------------------------------------
267 Allows user space to disable aes key wrapping, clearing the wrapping key.
272 4.4. ATTRIBUTE: KVM_S390_VM_CRYPTO_DISABLE_DEA_KW (w/o)
273 -------------------------------------------------------
275 Allows user space to disable dea key wrapping, clearing the wrapping key.
280 5. GROUP: KVM_S390_VM_MIGRATION
281 ===============================
285 5.1. ATTRIBUTE: KVM_S390_VM_MIGRATION_STOP (w/o)
286 ------------------------------------------------
288 Allows userspace to stop migration mode, needed for PGSTE migration.
289 Setting this attribute when migration mode is not active will have no
295 5.2. ATTRIBUTE: KVM_S390_VM_MIGRATION_START (w/o)
296 -------------------------------------------------
298 Allows userspace to start migration mode, needed for PGSTE migration.
299 Setting this attribute when migration mode is already active will have
303 :Returns: -ENOMEM if there is not enough free memory to start migration mode;
304 -EINVAL if the state of the VM is invalid (e.g. no memory defined);
305 0 in case of success.
307 5.3. ATTRIBUTE: KVM_S390_VM_MIGRATION_STATUS (r/o)
308 --------------------------------------------------
310 Allows userspace to query the status of migration mode.
312 :Parameters: address of a buffer in user space to store the data (u64) to;
313 the data itself is either 0 if migration mode is disabled or 1
315 :Returns: -EFAULT if the given address is not accessible from kernel space;
316 0 in case of success.