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https://github.com/AuxXxilium/linux_dsm_epyc7002.git
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658b6eda20
This patch enables cpu model support in kvm/s390 via the vm attribute interface. During KVM initialization, the host properties cpuid, IBC value and the facility list are stored in the architecture specific cpu model structure. During vcpu setup, these properties are taken to initialize the related SIE state. This mechanism allows to adjust the properties from user space and thus to implement different selectable cpu models. This patch uses the IBC functionality to block instructions that have not been implemented at the requested CPU type and GA level compared to the full host capability. Userspace has to initialize the cpu model before vcpu creation. A cpu model change of running vcpus is not possible. Signed-off-by: Michael Mueller <mimu@linux.vnet.ibm.com> Reviewed-by: Cornelia Huck <cornelia.huck@de.ibm.com> Reviewed-by: David Hildenbrand <dahi@linux.vnet.ibm.com> Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
86 lines
3.4 KiB
Plaintext
86 lines
3.4 KiB
Plaintext
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: 0
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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.
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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 facilitiy 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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