[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: -EINVAL if CMMA was not enabled
         0 otherwise

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. In the case that there is no limit we will set
the limit to KVM_S390_NO_MEM_LIMIT (U64_MAX).

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 facility 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

2.3. ATTRIBUTE: KVM_S390_VM_CPU_MACHINE_FEAT (r/o)

Allows user space to retrieve available cpu features. A feature is available if
provided by the hardware and supported by kvm. In theory, cpu features could
even be completely emulated by kvm.

struct kvm_s390_vm_cpu_feat {
        __u64 feat[16]; # Bitmap (1 = feature available), MSB 0 bit numbering
};

Parameters: address of a buffer to load the feature list from.
Returns:    -EFAULT if the given address is not accessible from kernel space.
	    0 in case of success.

2.4. ATTRIBUTE: KVM_S390_VM_CPU_PROCESSOR_FEAT (r/w)

Allows user space to retrieve or change enabled cpu features for all VCPUs of a
VM. Features that are not available cannot be enabled.

See 2.3. for a description of the parameter struct.

Parameters: address of a buffer to store/load the feature list from.
Returns:    -EFAULT if the given address is not accessible from kernel space.
	    -EINVAL if a cpu feature that is not available is to be enabled.
	    -EBUSY if at least one VCPU has already been defined.
	    0 in case of success.

2.5. ATTRIBUTE: KVM_S390_VM_CPU_MACHINE_SUBFUNC (r/o)

Allows user space to retrieve available cpu subfunctions without any filtering
done by a set IBC. These subfunctions are indicated to the guest VCPU via
query or "test bit" subfunctions and used e.g. by cpacf functions, plo and ptff.

A subfunction block is only valid if KVM_S390_VM_CPU_MACHINE contains the
STFL(E) bit introducing the affected instruction. If the affected instruction
indicates subfunctions via a "query subfunction", the response block is
contained in the returned struct. If the affected instruction
indicates subfunctions via a "test bit" mechanism, the subfunction codes are
contained in the returned struct in MSB 0 bit numbering.

struct kvm_s390_vm_cpu_subfunc {
       u8 plo[32];           # always valid (ESA/390 feature)
       u8 ptff[16];          # valid with TOD-clock steering
       u8 kmac[16];          # valid with Message-Security-Assist
       u8 kmc[16];           # valid with Message-Security-Assist
       u8 km[16];            # valid with Message-Security-Assist
       u8 kimd[16];          # valid with Message-Security-Assist
       u8 klmd[16];          # valid with Message-Security-Assist
       u8 pckmo[16];         # valid with Message-Security-Assist-Extension 3
       u8 kmctr[16];         # valid with Message-Security-Assist-Extension 4
       u8 kmf[16];           # valid with Message-Security-Assist-Extension 4
       u8 kmo[16];           # valid with Message-Security-Assist-Extension 4
       u8 pcc[16];           # valid with Message-Security-Assist-Extension 4
       u8 ppno[16];          # valid with Message-Security-Assist-Extension 5
       u8 reserved[1824];    # reserved for future instructions
};

Parameters: address of a buffer to load the subfunction blocks from.
Returns:    -EFAULT if the given address is not accessible from kernel space.
	    0 in case of success.

2.6. ATTRIBUTE: KVM_S390_VM_CPU_PROCESSOR_SUBFUNC (r/w)

Allows user space to retrieve or change cpu subfunctions to be indicated for
all VCPUs of a VM. This attribute will only be available if kernel and
hardware support are in place.

The kernel uses the configured subfunction blocks for indication to
the guest. A subfunction block will only be used if the associated STFL(E) bit
has not been disabled by user space (so the instruction to be queried is
actually available for the guest).

As long as no data has been written, a read will fail. The IBC will be used
to determine available subfunctions in this case, this will guarantee backward
compatibility.

See 2.5. for a description of the parameter struct.

Parameters: address of a buffer to store/load the subfunction blocks from.
Returns:    -EFAULT if the given address is not accessible from kernel space.
	    -EINVAL when reading, if there was no write yet.
	    -EBUSY if at least one VCPU has already been defined.
	    0 in case of success.

3. GROUP: KVM_S390_VM_TOD
Architectures: s390

3.1. ATTRIBUTE: KVM_S390_VM_TOD_HIGH

Allows user space to set/get the TOD clock extension (u8).

Parameters: address of a buffer in user space to store the data (u8) to
Returns:    -EFAULT if the given address is not accessible from kernel space
	    -EINVAL if setting the TOD clock extension to != 0 is not supported

3.2. ATTRIBUTE: KVM_S390_VM_TOD_LOW

Allows user space to set/get bits 0-63 of the TOD clock register as defined in
the POP (u64).

Parameters: address of a buffer in user space to store the data (u64) to
Returns:    -EFAULT if the given address is not accessible from kernel space

4. GROUP: KVM_S390_VM_CRYPTO
Architectures: s390

4.1. ATTRIBUTE: KVM_S390_VM_CRYPTO_ENABLE_AES_KW (w/o)

Allows user space to enable aes key wrapping, including generating a new
wrapping key.

Parameters: none
Returns:    0

4.2. ATTRIBUTE: KVM_S390_VM_CRYPTO_ENABLE_DEA_KW (w/o)

Allows user space to enable dea key wrapping, including generating a new
wrapping key.

Parameters: none
Returns:    0

4.3. ATTRIBUTE: KVM_S390_VM_CRYPTO_DISABLE_AES_KW (w/o)

Allows user space to disable aes key wrapping, clearing the wrapping key.

Parameters: none
Returns:    0

4.4. ATTRIBUTE: KVM_S390_VM_CRYPTO_DISABLE_DEA_KW (w/o)

Allows user space to disable dea key wrapping, clearing the wrapping key.

Parameters: none
Returns:    0
Commit	Line	Data
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
365dc163 DD	22	Parameters: none
f9cbd9b0 DH	23	Returns: -EINVAL if CMMA was not enabled
f9cbd9b0 DH	24	0 otherwise
4f718eab DD	25
	26	Clear the CMMA status for all guest pages, so any pages the guest marked
	27	as unused are again used any may not be reclaimed by the host.
8c0a7ce6 DD	28
	29	1.3. ATTRIBUTE KVM_S390_VM_MEM_LIMIT_SIZE
	30	Parameters: in attr->addr the address for the new limit of guest memory
	31	Returns: -EFAULT if the given address is not accessible
	32	-EINVAL if the virtual machine is of type UCONTROL
	33	-E2BIG if the given guest memory is to big for that machine
	34	-EBUSY if a vcpu is already defined
	35	-ENOMEM if not enough memory is available for a new shadow guest mapping
	36	0 otherwise
	37
	38	Allows userspace to query the actual limit and set a new limit for
	39	the maximum guest memory size. The limit will be rounded up to
	40	2048 MB, 4096 GB, 8192 TB respectively, as this limit is governed by
a3a92c31 DD	41	the number of page table levels. In the case that there is no limit we will set
a3a92c31 DD	42	the limit to KVM_S390_NO_MEM_LIMIT (U64_MAX).
658b6eda MM	43
	44	2. GROUP: KVM_S390_VM_CPU_MODEL
	45	Architectures: s390
	46
	47	2.1. ATTRIBUTE: KVM_S390_VM_CPU_MACHINE (r/o)
	48
	49	Allows user space to retrieve machine and kvm specific cpu related information:
	50
	51	struct kvm_s390_vm_cpu_machine {
	52	__u64 cpuid; # CPUID of host
	53	__u32 ibc; # IBC level range offered by host
	54	__u8 pad[4];
	55	__u64 fac_mask[256]; # set of cpu facilities enabled by KVM
	56	__u64 fac_list[256]; # set of cpu facilities offered by host
	57	}
	58
	59	Parameters: address of buffer to store the machine related cpu data
	60	of type struct kvm_s390_vm_cpu_machine*
	61	Returns: -EFAULT if the given address is not accessible from kernel space
	62	-ENOMEM if not enough memory is available to process the ioctl
	63	0 in case of success
	64
	65	2.2. ATTRIBUTE: KVM_S390_VM_CPU_PROCESSOR (r/w)
	66
	67	Allows user space to retrieve or request to change cpu related information for a vcpu:
	68
	69	struct kvm_s390_vm_cpu_processor {
	70	__u64 cpuid; # CPUID currently (to be) used by this vcpu
	71	__u16 ibc; # IBC level currently (to be) used by this vcpu
	72	__u8 pad[6];
	73	__u64 fac_list[256]; # set of cpu facilities currently (to be) used
	74	# by this vcpu
	75	}
	76
	77	KVM does not enforce or limit the cpu model data in any form. Take the information
	78	retrieved by means of KVM_S390_VM_CPU_MACHINE as hint for reasonable configuration
5d4f6f3d	79	setups. Instruction interceptions triggered by additionally set facility bits that
658b6eda MM	80	are not handled by KVM need to by imlemented in the VM driver code.
	81
	82	Parameters: address of buffer to store/set the processor related cpu
	83	data of type struct kvm_s390_vm_cpu_processor*.
	84	Returns: -EBUSY in case 1 or more vcpus are already activated (only in write case)
	85	-EFAULT if the given address is not accessible from kernel space
	86	-ENOMEM if not enough memory is available to process the ioctl
	87	0 in case of success
aad3c1d9	88
15c9705f DH	89	2.3. ATTRIBUTE: KVM_S390_VM_CPU_MACHINE_FEAT (r/o)
	90
	91	Allows user space to retrieve available cpu features. A feature is available if
	92	provided by the hardware and supported by kvm. In theory, cpu features could
	93	even be completely emulated by kvm.
	94
	95	struct kvm_s390_vm_cpu_feat {
	96	__u64 feat[16]; # Bitmap (1 = feature available), MSB 0 bit numbering
	97	};
	98
	99	Parameters: address of a buffer to load the feature list from.
	100	Returns: -EFAULT if the given address is not accessible from kernel space.
	101	0 in case of success.
	102
	103	2.4. ATTRIBUTE: KVM_S390_VM_CPU_PROCESSOR_FEAT (r/w)
	104
	105	Allows user space to retrieve or change enabled cpu features for all VCPUs of a
	106	VM. Features that are not available cannot be enabled.
	107
	108	See 2.3. for a description of the parameter struct.
	109
	110	Parameters: address of a buffer to store/load the feature list from.
	111	Returns: -EFAULT if the given address is not accessible from kernel space.
	112	-EINVAL if a cpu feature that is not available is to be enabled.
	113	-EBUSY if at least one VCPU has already been defined.
	114	0 in case of success.
	115
0a763c78 DH	116	2.5. ATTRIBUTE: KVM_S390_VM_CPU_MACHINE_SUBFUNC (r/o)
	117
	118	Allows user space to retrieve available cpu subfunctions without any filtering
	119	done by a set IBC. These subfunctions are indicated to the guest VCPU via
	120	query or "test bit" subfunctions and used e.g. by cpacf functions, plo and ptff.
	121
	122	A subfunction block is only valid if KVM_S390_VM_CPU_MACHINE contains the
	123	STFL(E) bit introducing the affected instruction. If the affected instruction
	124	indicates subfunctions via a "query subfunction", the response block is
	125	contained in the returned struct. If the affected instruction
	126	indicates subfunctions via a "test bit" mechanism, the subfunction codes are
	127	contained in the returned struct in MSB 0 bit numbering.
	128
	129	struct kvm_s390_vm_cpu_subfunc {
	130	u8 plo[32]; # always valid (ESA/390 feature)
	131	u8 ptff[16]; # valid with TOD-clock steering
	132	u8 kmac[16]; # valid with Message-Security-Assist
	133	u8 kmc[16]; # valid with Message-Security-Assist
	134	u8 km[16]; # valid with Message-Security-Assist
	135	u8 kimd[16]; # valid with Message-Security-Assist
	136	u8 klmd[16]; # valid with Message-Security-Assist
	137	u8 pckmo[16]; # valid with Message-Security-Assist-Extension 3
	138	u8 kmctr[16]; # valid with Message-Security-Assist-Extension 4
	139	u8 kmf[16]; # valid with Message-Security-Assist-Extension 4
	140	u8 kmo[16]; # valid with Message-Security-Assist-Extension 4
	141	u8 pcc[16]; # valid with Message-Security-Assist-Extension 4
	142	u8 ppno[16]; # valid with Message-Security-Assist-Extension 5
	143	u8 reserved[1824]; # reserved for future instructions
	144	};
	145
	146	Parameters: address of a buffer to load the subfunction blocks from.
	147	Returns: -EFAULT if the given address is not accessible from kernel space.
	148	0 in case of success.
	149
	150	2.6. ATTRIBUTE: KVM_S390_VM_CPU_PROCESSOR_SUBFUNC (r/w)
	151
	152	Allows user space to retrieve or change cpu subfunctions to be indicated for
	153	all VCPUs of a VM. This attribute will only be available if kernel and
	154	hardware support are in place.
	155
	156	The kernel uses the configured subfunction blocks for indication to
	157	the guest. A subfunction block will only be used if the associated STFL(E) bit
	158	has not been disabled by user space (so the instruction to be queried is
	159	actually available for the guest).
	160
	161	As long as no data has been written, a read will fail. The IBC will be used
	162	to determine available subfunctions in this case, this will guarantee backward
	163	compatibility.
	164
	165	See 2.5. for a description of the parameter struct.
	166
	167	Parameters: address of a buffer to store/load the subfunction blocks from.
	168	Returns: -EFAULT if the given address is not accessible from kernel space.
	169	-EINVAL when reading, if there was no write yet.
	170	-EBUSY if at least one VCPU has already been defined.
	171	0 in case of success.
	172
aad3c1d9 DH	173	3. GROUP: KVM_S390_VM_TOD
	174	Architectures: s390
	175
	176	3.1. ATTRIBUTE: KVM_S390_VM_TOD_HIGH
	177
	178	Allows user space to set/get the TOD clock extension (u8).
	179
	180	Parameters: address of a buffer in user space to store the data (u8) to
	181	Returns: -EFAULT if the given address is not accessible from kernel space
	182	-EINVAL if setting the TOD clock extension to != 0 is not supported
	183
	184	3.2. ATTRIBUTE: KVM_S390_VM_TOD_LOW
	185
	186	Allows user space to set/get bits 0-63 of the TOD clock register as defined in
	187	the POP (u64).
	188
	189	Parameters: address of a buffer in user space to store the data (u64) to
	190	Returns: -EFAULT if the given address is not accessible from kernel space
eaf2b656 DH	191
	192	4. GROUP: KVM_S390_VM_CRYPTO
	193	Architectures: s390
	194
	195	4.1. ATTRIBUTE: KVM_S390_VM_CRYPTO_ENABLE_AES_KW (w/o)
	196
	197	Allows user space to enable aes key wrapping, including generating a new
	198	wrapping key.
	199
	200	Parameters: none
	201	Returns: 0
	202
	203	4.2. ATTRIBUTE: KVM_S390_VM_CRYPTO_ENABLE_DEA_KW (w/o)
	204
	205	Allows user space to enable dea key wrapping, including generating a new
	206	wrapping key.
	207
	208	Parameters: none
	209	Returns: 0
	210
	211	4.3. ATTRIBUTE: KVM_S390_VM_CRYPTO_DISABLE_AES_KW (w/o)
	212
	213	Allows user space to disable aes key wrapping, clearing the wrapping key.
	214
	215	Parameters: none
	216	Returns: 0
	217
	218	4.4. ATTRIBUTE: KVM_S390_VM_CRYPTO_DISABLE_DEA_KW (w/o)
	219
	220	Allows user space to disable dea key wrapping, clearing the wrapping key.
	221
	222	Parameters: none
	223	Returns: 0