KVM: s390: use facilities and cpu_id per KVM

[deliverable/linux.git] / Documentation / virtual / kvm / devices / vm.txt

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.