From 57f0f512b273f60d52568b8c6b77e17f5636edc0 Mon Sep 17 00:00:00 2001 From: André Fabian Silva Delgado Date: Wed, 5 Aug 2015 17:04:01 -0300 Subject: Initial import --- Documentation/virtual/kvm/devices/vm.txt | 85 ++++++++++++++++++++++++++++++++ 1 file changed, 85 insertions(+) create mode 100644 Documentation/virtual/kvm/devices/vm.txt (limited to 'Documentation/virtual/kvm/devices/vm.txt') diff --git a/Documentation/virtual/kvm/devices/vm.txt b/Documentation/virtual/kvm/devices/vm.txt new file mode 100644 index 000000000..5542c4641 --- /dev/null +++ b/Documentation/virtual/kvm/devices/vm.txt @@ -0,0 +1,85 @@ +Generic vm interface +==================================== + +The virtual machine "device" also accepts the ioctls KVM_SET_DEVICE_ATTR, +KVM_GET_DEVICE_ATTR, and KVM_HAS_DEVICE_ATTR. The interface uses the same +struct kvm_device_attr as other devices, but targets VM-wide settings +and controls. + +The groups and attributes per virtual machine, if any, are architecture +specific. + +1. GROUP: KVM_S390_VM_MEM_CTRL +Architectures: s390 + +1.1. ATTRIBUTE: KVM_S390_VM_MEM_ENABLE_CMMA +Parameters: none +Returns: -EBUSY if a vcpu is already defined, otherwise 0 + +Enables Collaborative Memory Management Assist (CMMA) for the virtual machine. + +1.2. ATTRIBUTE: KVM_S390_VM_MEM_CLR_CMMA +Parameters: none +Returns: 0 + +Clear the CMMA status for all guest pages, so any pages the guest marked +as unused are again used any may not be reclaimed by the host. + +1.3. ATTRIBUTE KVM_S390_VM_MEM_LIMIT_SIZE +Parameters: in attr->addr the address for the new limit of guest memory +Returns: -EFAULT if the given address is not accessible + -EINVAL if the virtual machine is of type UCONTROL + -E2BIG if the given guest memory is to big for that machine + -EBUSY if a vcpu is already defined + -ENOMEM if not enough memory is available for a new shadow guest mapping + 0 otherwise + +Allows userspace to query the actual limit and set a new limit for +the maximum guest memory size. The limit will be rounded up to +2048 MB, 4096 GB, 8192 TB respectively, as this limit is governed by +the number of page table levels. + +2. GROUP: KVM_S390_VM_CPU_MODEL +Architectures: s390 + +2.1. ATTRIBUTE: KVM_S390_VM_CPU_MACHINE (r/o) + +Allows user space to retrieve machine and kvm specific cpu related information: + +struct kvm_s390_vm_cpu_machine { + __u64 cpuid; # CPUID of host + __u32 ibc; # IBC level range offered by host + __u8 pad[4]; + __u64 fac_mask[256]; # set of cpu facilities enabled by KVM + __u64 fac_list[256]; # set of cpu facilities offered by host +} + +Parameters: address of buffer to store the machine related cpu data + of type struct kvm_s390_vm_cpu_machine* +Returns: -EFAULT if the given address is not accessible from kernel space + -ENOMEM if not enough memory is available to process the ioctl + 0 in case of success + +2.2. ATTRIBUTE: KVM_S390_VM_CPU_PROCESSOR (r/w) + +Allows user space to retrieve or request to change cpu related information for a vcpu: + +struct kvm_s390_vm_cpu_processor { + __u64 cpuid; # CPUID currently (to be) used by this vcpu + __u16 ibc; # IBC level currently (to be) used by this vcpu + __u8 pad[6]; + __u64 fac_list[256]; # set of cpu facilities currently (to be) used + # by this vcpu +} + +KVM does not enforce or limit the cpu model data in any form. Take the information +retrieved by means of KVM_S390_VM_CPU_MACHINE as hint for reasonable configuration +setups. Instruction interceptions triggered by additionally set facilitiy bits that +are not handled by KVM need to by imlemented in the VM driver code. + +Parameters: address of buffer to store/set the processor related cpu + data of type struct kvm_s390_vm_cpu_processor*. +Returns: -EBUSY in case 1 or more vcpus are already activated (only in write case) + -EFAULT if the given address is not accessible from kernel space + -ENOMEM if not enough memory is available to process the ioctl + 0 in case of success -- cgit v1.2.3-54-g00ecf