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f2061656 DD |
1 | Generic vm interface |
2 | ==================================== | |
3 | ||
4 | The virtual machine "device" also accepts the ioctls KVM_SET_DEVICE_ATTR, | |
5 | KVM_GET_DEVICE_ATTR, and KVM_HAS_DEVICE_ATTR. The interface uses the same | |
6 | struct kvm_device_attr as other devices, but targets VM-wide settings | |
7 | and controls. | |
8 | ||
9 | The groups and attributes per virtual machine, if any, are architecture | |
10 | specific. | |
4f718eab DD |
11 | |
12 | 1. GROUP: KVM_S390_VM_MEM_CTRL | |
13 | Architectures: s390 | |
14 | ||
365dc163 | 15 | 1.1. ATTRIBUTE: KVM_S390_VM_MEM_ENABLE_CMMA |
4f718eab | 16 | Parameters: none |
365dc163 | 17 | Returns: -EBUSY if a vcpu is already defined, otherwise 0 |
4f718eab | 18 | |
365dc163 | 19 | Enables Collaborative Memory Management Assist (CMMA) for the virtual machine. |
4f718eab | 20 | |
365dc163 DD |
21 | 1.2. ATTRIBUTE: KVM_S390_VM_MEM_CLR_CMMA |
22 | Parameters: none | |
4f718eab DD |
23 | Returns: 0 |
24 | ||
25 | Clear the CMMA status for all guest pages, so any pages the guest marked | |
26 | as unused are again used any may not be reclaimed by the host. | |
8c0a7ce6 DD |
27 | |
28 | 1.3. ATTRIBUTE KVM_S390_VM_MEM_LIMIT_SIZE | |
29 | Parameters: in attr->addr the address for the new limit of guest memory | |
30 | Returns: -EFAULT if the given address is not accessible | |
31 | -EINVAL if the virtual machine is of type UCONTROL | |
32 | -E2BIG if the given guest memory is to big for that machine | |
33 | -EBUSY if a vcpu is already defined | |
34 | -ENOMEM if not enough memory is available for a new shadow guest mapping | |
35 | 0 otherwise | |
36 | ||
37 | Allows userspace to query the actual limit and set a new limit for | |
38 | the maximum guest memory size. The limit will be rounded up to | |
39 | 2048 MB, 4096 GB, 8192 TB respectively, as this limit is governed by | |
40 | the number of page table levels. | |
658b6eda MM |
41 | |
42 | 2. GROUP: KVM_S390_VM_CPU_MODEL | |
43 | Architectures: s390 | |
44 | ||
45 | 2.1. ATTRIBUTE: KVM_S390_VM_CPU_MACHINE (r/o) | |
46 | ||
47 | Allows user space to retrieve machine and kvm specific cpu related information: | |
48 | ||
49 | struct kvm_s390_vm_cpu_machine { | |
50 | __u64 cpuid; # CPUID of host | |
51 | __u32 ibc; # IBC level range offered by host | |
52 | __u8 pad[4]; | |
53 | __u64 fac_mask[256]; # set of cpu facilities enabled by KVM | |
54 | __u64 fac_list[256]; # set of cpu facilities offered by host | |
55 | } | |
56 | ||
57 | Parameters: address of buffer to store the machine related cpu data | |
58 | of type struct kvm_s390_vm_cpu_machine* | |
59 | Returns: -EFAULT if the given address is not accessible from kernel space | |
60 | -ENOMEM if not enough memory is available to process the ioctl | |
61 | 0 in case of success | |
62 | ||
63 | 2.2. ATTRIBUTE: KVM_S390_VM_CPU_PROCESSOR (r/w) | |
64 | ||
65 | Allows user space to retrieve or request to change cpu related information for a vcpu: | |
66 | ||
67 | struct kvm_s390_vm_cpu_processor { | |
68 | __u64 cpuid; # CPUID currently (to be) used by this vcpu | |
69 | __u16 ibc; # IBC level currently (to be) used by this vcpu | |
70 | __u8 pad[6]; | |
71 | __u64 fac_list[256]; # set of cpu facilities currently (to be) used | |
72 | # by this vcpu | |
73 | } | |
74 | ||
75 | KVM does not enforce or limit the cpu model data in any form. Take the information | |
76 | retrieved by means of KVM_S390_VM_CPU_MACHINE as hint for reasonable configuration | |
77 | setups. Instruction interceptions triggered by additionally set facilitiy bits that | |
78 | are not handled by KVM need to by imlemented in the VM driver code. | |
79 | ||
80 | Parameters: address of buffer to store/set the processor related cpu | |
81 | data of type struct kvm_s390_vm_cpu_processor*. | |
82 | Returns: -EBUSY in case 1 or more vcpus are already activated (only in write case) | |
83 | -EFAULT if the given address is not accessible from kernel space | |
84 | -ENOMEM if not enough memory is available to process the ioctl | |
85 | 0 in case of success |