270 lines
10 KiB
Plaintext
270 lines
10 KiB
Plaintext
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Generic vm interface
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====================================
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The virtual machine "device" also accepts the ioctls KVM_SET_DEVICE_ATTR,
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KVM_GET_DEVICE_ATTR, and KVM_HAS_DEVICE_ATTR. The interface uses the same
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struct kvm_device_attr as other devices, but targets VM-wide settings
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and controls.
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The groups and attributes per virtual machine, if any, are architecture
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specific.
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1. GROUP: KVM_S390_VM_MEM_CTRL
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Architectures: s390
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1.1. ATTRIBUTE: KVM_S390_VM_MEM_ENABLE_CMMA
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Parameters: none
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Returns: -EBUSY if a vcpu is already defined, otherwise 0
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Enables Collaborative Memory Management Assist (CMMA) for the virtual machine.
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1.2. ATTRIBUTE: KVM_S390_VM_MEM_CLR_CMMA
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Parameters: none
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Returns: -EINVAL if CMMA was not enabled
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0 otherwise
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Clear the CMMA status for all guest pages, so any pages the guest marked
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as unused are again used any may not be reclaimed by the host.
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1.3. ATTRIBUTE KVM_S390_VM_MEM_LIMIT_SIZE
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Parameters: in attr->addr the address for the new limit of guest memory
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Returns: -EFAULT if the given address is not accessible
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-EINVAL if the virtual machine is of type UCONTROL
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-E2BIG if the given guest memory is to big for that machine
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-EBUSY if a vcpu is already defined
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-ENOMEM if not enough memory is available for a new shadow guest mapping
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0 otherwise
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Allows userspace to query the actual limit and set a new limit for
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the maximum guest memory size. The limit will be rounded up to
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2048 MB, 4096 GB, 8192 TB respectively, as this limit is governed by
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the number of page table levels. In the case that there is no limit we will set
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the limit to KVM_S390_NO_MEM_LIMIT (U64_MAX).
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2. GROUP: KVM_S390_VM_CPU_MODEL
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Architectures: s390
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2.1. ATTRIBUTE: KVM_S390_VM_CPU_MACHINE (r/o)
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Allows user space to retrieve machine and kvm specific cpu related information:
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struct kvm_s390_vm_cpu_machine {
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__u64 cpuid; # CPUID of host
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__u32 ibc; # IBC level range offered by host
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__u8 pad[4];
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__u64 fac_mask[256]; # set of cpu facilities enabled by KVM
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__u64 fac_list[256]; # set of cpu facilities offered by host
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}
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Parameters: address of buffer to store the machine related cpu data
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of type struct kvm_s390_vm_cpu_machine*
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Returns: -EFAULT if the given address is not accessible from kernel space
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-ENOMEM if not enough memory is available to process the ioctl
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0 in case of success
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2.2. ATTRIBUTE: KVM_S390_VM_CPU_PROCESSOR (r/w)
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Allows user space to retrieve or request to change cpu related information for a vcpu:
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struct kvm_s390_vm_cpu_processor {
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__u64 cpuid; # CPUID currently (to be) used by this vcpu
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__u16 ibc; # IBC level currently (to be) used by this vcpu
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__u8 pad[6];
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__u64 fac_list[256]; # set of cpu facilities currently (to be) used
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# by this vcpu
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}
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KVM does not enforce or limit the cpu model data in any form. Take the information
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retrieved by means of KVM_S390_VM_CPU_MACHINE as hint for reasonable configuration
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setups. Instruction interceptions triggered by additionally set facility bits that
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are not handled by KVM need to by imlemented in the VM driver code.
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Parameters: address of buffer to store/set the processor related cpu
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data of type struct kvm_s390_vm_cpu_processor*.
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Returns: -EBUSY in case 1 or more vcpus are already activated (only in write case)
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-EFAULT if the given address is not accessible from kernel space
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-ENOMEM if not enough memory is available to process the ioctl
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0 in case of success
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2.3. ATTRIBUTE: KVM_S390_VM_CPU_MACHINE_FEAT (r/o)
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Allows user space to retrieve available cpu features. A feature is available if
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provided by the hardware and supported by kvm. In theory, cpu features could
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even be completely emulated by kvm.
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struct kvm_s390_vm_cpu_feat {
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__u64 feat[16]; # Bitmap (1 = feature available), MSB 0 bit numbering
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};
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Parameters: address of a buffer to load the feature list from.
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Returns: -EFAULT if the given address is not accessible from kernel space.
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0 in case of success.
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2.4. ATTRIBUTE: KVM_S390_VM_CPU_PROCESSOR_FEAT (r/w)
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Allows user space to retrieve or change enabled cpu features for all VCPUs of a
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VM. Features that are not available cannot be enabled.
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See 2.3. for a description of the parameter struct.
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Parameters: address of a buffer to store/load the feature list from.
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Returns: -EFAULT if the given address is not accessible from kernel space.
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-EINVAL if a cpu feature that is not available is to be enabled.
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-EBUSY if at least one VCPU has already been defined.
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0 in case of success.
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2.5. ATTRIBUTE: KVM_S390_VM_CPU_MACHINE_SUBFUNC (r/o)
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Allows user space to retrieve available cpu subfunctions without any filtering
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done by a set IBC. These subfunctions are indicated to the guest VCPU via
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query or "test bit" subfunctions and used e.g. by cpacf functions, plo and ptff.
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A subfunction block is only valid if KVM_S390_VM_CPU_MACHINE contains the
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STFL(E) bit introducing the affected instruction. If the affected instruction
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indicates subfunctions via a "query subfunction", the response block is
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contained in the returned struct. If the affected instruction
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indicates subfunctions via a "test bit" mechanism, the subfunction codes are
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contained in the returned struct in MSB 0 bit numbering.
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struct kvm_s390_vm_cpu_subfunc {
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u8 plo[32]; # always valid (ESA/390 feature)
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u8 ptff[16]; # valid with TOD-clock steering
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u8 kmac[16]; # valid with Message-Security-Assist
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u8 kmc[16]; # valid with Message-Security-Assist
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u8 km[16]; # valid with Message-Security-Assist
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u8 kimd[16]; # valid with Message-Security-Assist
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u8 klmd[16]; # valid with Message-Security-Assist
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u8 pckmo[16]; # valid with Message-Security-Assist-Extension 3
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u8 kmctr[16]; # valid with Message-Security-Assist-Extension 4
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u8 kmf[16]; # valid with Message-Security-Assist-Extension 4
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u8 kmo[16]; # valid with Message-Security-Assist-Extension 4
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u8 pcc[16]; # valid with Message-Security-Assist-Extension 4
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u8 ppno[16]; # valid with Message-Security-Assist-Extension 5
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u8 kma[16]; # valid with Message-Security-Assist-Extension 8
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u8 reserved[1808]; # reserved for future instructions
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};
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Parameters: address of a buffer to load the subfunction blocks from.
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Returns: -EFAULT if the given address is not accessible from kernel space.
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0 in case of success.
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2.6. ATTRIBUTE: KVM_S390_VM_CPU_PROCESSOR_SUBFUNC (r/w)
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Allows user space to retrieve or change cpu subfunctions to be indicated for
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all VCPUs of a VM. This attribute will only be available if kernel and
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hardware support are in place.
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The kernel uses the configured subfunction blocks for indication to
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the guest. A subfunction block will only be used if the associated STFL(E) bit
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has not been disabled by user space (so the instruction to be queried is
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actually available for the guest).
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As long as no data has been written, a read will fail. The IBC will be used
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to determine available subfunctions in this case, this will guarantee backward
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compatibility.
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See 2.5. for a description of the parameter struct.
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Parameters: address of a buffer to store/load the subfunction blocks from.
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Returns: -EFAULT if the given address is not accessible from kernel space.
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-EINVAL when reading, if there was no write yet.
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-EBUSY if at least one VCPU has already been defined.
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0 in case of success.
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3. GROUP: KVM_S390_VM_TOD
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Architectures: s390
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3.1. ATTRIBUTE: KVM_S390_VM_TOD_HIGH
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Allows user space to set/get the TOD clock extension (u8) (superseded by
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KVM_S390_VM_TOD_EXT).
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Parameters: address of a buffer in user space to store the data (u8) to
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Returns: -EFAULT if the given address is not accessible from kernel space
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-EINVAL if setting the TOD clock extension to != 0 is not supported
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3.2. ATTRIBUTE: KVM_S390_VM_TOD_LOW
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Allows user space to set/get bits 0-63 of the TOD clock register as defined in
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the POP (u64).
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Parameters: address of a buffer in user space to store the data (u64) to
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Returns: -EFAULT if the given address is not accessible from kernel space
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3.3. ATTRIBUTE: KVM_S390_VM_TOD_EXT
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Allows user space to set/get bits 0-63 of the TOD clock register as defined in
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the POP (u64). If the guest CPU model supports the TOD clock extension (u8), it
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also allows user space to get/set it. If the guest CPU model does not support
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it, it is stored as 0 and not allowed to be set to a value != 0.
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Parameters: address of a buffer in user space to store the data
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(kvm_s390_vm_tod_clock) to
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Returns: -EFAULT if the given address is not accessible from kernel space
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-EINVAL if setting the TOD clock extension to != 0 is not supported
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4. GROUP: KVM_S390_VM_CRYPTO
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Architectures: s390
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4.1. ATTRIBUTE: KVM_S390_VM_CRYPTO_ENABLE_AES_KW (w/o)
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Allows user space to enable aes key wrapping, including generating a new
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wrapping key.
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Parameters: none
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Returns: 0
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4.2. ATTRIBUTE: KVM_S390_VM_CRYPTO_ENABLE_DEA_KW (w/o)
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Allows user space to enable dea key wrapping, including generating a new
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wrapping key.
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Parameters: none
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Returns: 0
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4.3. ATTRIBUTE: KVM_S390_VM_CRYPTO_DISABLE_AES_KW (w/o)
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Allows user space to disable aes key wrapping, clearing the wrapping key.
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Parameters: none
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Returns: 0
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4.4. ATTRIBUTE: KVM_S390_VM_CRYPTO_DISABLE_DEA_KW (w/o)
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Allows user space to disable dea key wrapping, clearing the wrapping key.
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Parameters: none
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Returns: 0
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5. GROUP: KVM_S390_VM_MIGRATION
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Architectures: s390
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5.1. ATTRIBUTE: KVM_S390_VM_MIGRATION_STOP (w/o)
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Allows userspace to stop migration mode, needed for PGSTE migration.
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Setting this attribute when migration mode is not active will have no
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effects.
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Parameters: none
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Returns: 0
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5.2. ATTRIBUTE: KVM_S390_VM_MIGRATION_START (w/o)
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Allows userspace to start migration mode, needed for PGSTE migration.
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Setting this attribute when migration mode is already active will have
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no effects.
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Parameters: none
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Returns: -ENOMEM if there is not enough free memory to start migration mode
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-EINVAL if the state of the VM is invalid (e.g. no memory defined)
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0 in case of success.
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5.3. ATTRIBUTE: KVM_S390_VM_MIGRATION_STATUS (r/o)
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Allows userspace to query the status of migration mode.
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Parameters: address of a buffer in user space to store the data (u64) to;
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the data itself is either 0 if migration mode is disabled or 1
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if it is enabled
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Returns: -EFAULT if the given address is not accessible from kernel space
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0 in case of success.
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