api.rst

4.80 KVM_SET_DEVICE_ATTR/KVM_GET_DEVICE_ATTR
--------------------------------------------

:Capability: KVM_CAP_DEVICE_CTRL, KVM_CAP_VM_ATTRIBUTES for vm device,
             KVM_CAP_VCPU_ATTRIBUTES for vcpu device
:Type: device ioctl, vm ioctl, vcpu ioctl
:Parameters: struct kvm_device_attr
:Returns: 0 on success, -1 on error

Errors:

  =====   =============================================================
  ENXIO   The group or attribute is unknown/unsupported for this device
          or hardware support is missing.
  EPERM   The attribute cannot (currently) be accessed this way
          (e.g. read-only attribute, or attribute that only makes
          sense when the device is in a different state)
  =====   =============================================================

  Other error conditions may be defined by individual device types.

Gets/sets a specified piece of device configuration and/or state.  The
semantics are device-specific.  See individual device documentation in
the "devices" directory.  As with ONE_REG, the size of the data
transferred is defined by the particular attribute.

::

  struct kvm_device_attr {
	__u32	flags;		/* no flags currently defined */
	__u32	group;		/* device-defined */
	__u64	attr;		/* group-defined */
	__u64	addr;		/* userspace address of attr data */
  };

4.81 KVM_HAS_DEVICE_ATTR
------------------------

:Capability: KVM_CAP_DEVICE_CTRL, KVM_CAP_VM_ATTRIBUTES for vm device,
	     KVM_CAP_VCPU_ATTRIBUTES for vcpu device
:Type: device ioctl, vm ioctl, vcpu ioctl
:Parameters: struct kvm_device_attr
:Returns: 0 on success, -1 on error

Errors:

  =====   =============================================================
  ENXIO   The group or attribute is unknown/unsupported for this device
          or hardware support is missing.
  =====   =============================================================

Tests whether a device supports a particular attribute.  A successful
return indicates the attribute is implemented.  It does not necessarily
indicate that the attribute can be read or written in the device's
current state.  "addr" is ignored.

4.82 KVM_ARM_VCPU_INIT
----------------------

:Capability: basic
:Architectures: arm, arm64
:Type: vcpu ioctl
:Parameters: struct kvm_vcpu_init (in)
:Returns: 0 on success; -1 on error

Errors:

  ======     =================================================================
  EINVAL     the target is unknown, or the combination of features is invalid.
  ENOENT     a features bit specified is unknown.
  ======     =================================================================

This tells KVM what type of CPU to present to the guest, and what
optional features it should have.  This will cause a reset of the cpu
registers to their initial values.  If this is not called, KVM_RUN will
return ENOEXEC for that vcpu.

Note that because some registers reflect machine topology, all vcpus
should be created before this ioctl is invoked.

Userspace can call this function multiple times for a given vcpu, including
after the vcpu has been run. This will reset the vcpu to its initial
state. All calls to this function after the initial call must use the same
target and same set of feature flags, otherwise EINVAL will be returned.

Possible features:

	- KVM_ARM_VCPU_POWER_OFF: Starts the CPU in a power-off state.
	  Depends on KVM_CAP_ARM_PSCI.  If not set, the CPU will be powered on
	  and execute guest code when KVM_RUN is called.
	- KVM_ARM_VCPU_EL1_32BIT: Starts the CPU in a 32bit mode.
	  Depends on KVM_CAP_ARM_EL1_32BIT (arm64 only).
	- KVM_ARM_VCPU_PSCI_0_2: Emulate PSCI v0.2 (or a future revision
          backward compatible with v0.2) for the CPU.
	  Depends on KVM_CAP_ARM_PSCI_0_2.
	- KVM_ARM_VCPU_PMU_V3: Emulate PMUv3 for the CPU.
	  Depends on KVM_CAP_ARM_PMU_V3.

	- KVM_ARM_VCPU_PTRAUTH_ADDRESS: Enables Address Pointer authentication
	  for arm64 only.
	  Depends on KVM_CAP_ARM_PTRAUTH_ADDRESS.
	  If KVM_CAP_ARM_PTRAUTH_ADDRESS and KVM_CAP_ARM_PTRAUTH_GENERIC are
	  both present, then both KVM_ARM_VCPU_PTRAUTH_ADDRESS and
	  KVM_ARM_VCPU_PTRAUTH_GENERIC must be requested or neither must be
	  requested.

	- KVM_ARM_VCPU_PTRAUTH_GENERIC: Enables Generic Pointer authentication
	  for arm64 only.
	  Depends on KVM_CAP_ARM_PTRAUTH_GENERIC.
	  If KVM_CAP_ARM_PTRAUTH_ADDRESS and KVM_CAP_ARM_PTRAUTH_GENERIC are
	  both present, then both KVM_ARM_VCPU_PTRAUTH_ADDRESS and
	  KVM_ARM_VCPU_PTRAUTH_GENERIC must be requested or neither must be
	  requested.

	- KVM_ARM_VCPU_SVE: Enables SVE for the CPU (arm64 only).
	  Depends on KVM_CAP_ARM_SVE.
	  Requires KVM_ARM_VCPU_FINALIZE(KVM_ARM_VCPU_SVE):

	   * After KVM_ARM_VCPU_INIT:

	      - KVM_REG_ARM64_SVE_VLS may be read using KVM_GET_ONE_REG: the
	        initial value of this pseudo-register indicates the best set of
	        vector lengths possible for a vcpu on this host.

	   * Before KVM_ARM_VCPU_FINALIZE(KVM_ARM_VCPU_SVE):

	      - KVM_RUN and KVM_GET_REG_LIST are not available;

	      - KVM_GET_ONE_REG and KVM_SET_ONE_REG cannot be used to access
	        the scalable archietctural SVE registers
	        KVM_REG_ARM64_SVE_ZREG(), KVM_REG_ARM64_SVE_PREG() or
	        KVM_REG_ARM64_SVE_FFR;

	      - KVM_REG_ARM64_SVE_VLS may optionally be written using
	        KVM_SET_ONE_REG, to modify the set of vector lengths available
	        for the vcpu.

	   * After KVM_ARM_VCPU_FINALIZE(KVM_ARM_VCPU_SVE):

	      - the KVM_REG_ARM64_SVE_VLS pseudo-register is immutable, and can
	        no longer be written using KVM_SET_ONE_REG.

4.83 KVM_ARM_PREFERRED_TARGET
-----------------------------

:Capability: basic
:Architectures: arm, arm64
:Type: vm ioctl
:Parameters: struct struct kvm_vcpu_init (out)
:Returns: 0 on success; -1 on error

Errors:

  ======     ==========================================
  ENODEV     no preferred target available for the host
  ======     ==========================================

This queries KVM for preferred CPU target type which can be emulated
by KVM on underlying host.

The ioctl returns struct kvm_vcpu_init instance containing information
about preferred CPU target type and recommended features for it.  The
kvm_vcpu_init->features bitmap returned will have feature bits set if
the preferred target recommends setting these features, but this is
not mandatory.

The information returned by this ioctl can be used to prepare an instance
of struct kvm_vcpu_init for KVM_ARM_VCPU_INIT ioctl which will result in
in VCPU matching underlying host.


4.84 KVM_GET_REG_LIST
---------------------

:Capability: basic
:Architectures: arm, arm64, mips
:Type: vcpu ioctl
:Parameters: struct kvm_reg_list (in/out)
:Returns: 0 on success; -1 on error

Errors:

  =====      ==============================================================
  E2BIG      the reg index list is too big to fit in the array specified by
             the user (the number required will be written into n).
  =====      ==============================================================

::

  struct kvm_reg_list {
	__u64 n; /* number of registers in reg[] */
	__u64 reg[0];
  };

This ioctl returns the guest registers that are supported for the
KVM_GET_ONE_REG/KVM_SET_ONE_REG calls.


4.85 KVM_ARM_SET_DEVICE_ADDR (deprecated)
-----------------------------------------

:Capability: KVM_CAP_ARM_SET_DEVICE_ADDR
:Architectures: arm, arm64
:Type: vm ioctl
:Parameters: struct kvm_arm_device_address (in)
:Returns: 0 on success, -1 on error

Errors:

  ======  ============================================
  ENODEV  The device id is unknown
  ENXIO   Device not supported on current system
  EEXIST  Address already set
  E2BIG   Address outside guest physical address space
  EBUSY   Address overlaps with other device range
  ======  ============================================

::

  struct kvm_arm_device_addr {
	__u64 id;
	__u64 addr;
  };

Specify a device address in the guest's physical address space where guests
can access emulated or directly exposed devices, which the host kernel needs
to know about. The id field is an architecture specific identifier for a
specific device.

ARM/arm64 divides the id field into two parts, a device id and an
address type id specific to the individual device::

  bits:  | 63        ...       32 | 31    ...    16 | 15    ...    0 |
  field: |        0x00000000      |     device id   |  addr type id  |

ARM/arm64 currently only require this when using the in-kernel GIC
support for the hardware VGIC features, using KVM_ARM_DEVICE_VGIC_V2
as the device id.  When setting the base address for the guest's
mapping of the VGIC virtual CPU and distributor interface, the ioctl
must be called after calling KVM_CREATE_IRQCHIP, but before calling
KVM_RUN on any of the VCPUs.  Calling this ioctl twice for any of the
base addresses will return -EEXIST.

Note, this IOCTL is deprecated and the more flexible SET/GET_DEVICE_ATTR API
should be used instead.


4.86 KVM_PPC_RTAS_DEFINE_TOKEN
------------------------------

:Capability: KVM_CAP_PPC_RTAS
:Architectures: ppc
:Type: vm ioctl
:Parameters: struct kvm_rtas_token_args
:Returns: 0 on success, -1 on error

Defines a token value for a RTAS (Run Time Abstraction Services)
service in order to allow it to be handled in the kernel.  The
argument struct gives the name of the service, which must be the name
of a service that has a kernel-side implementation.  If the token
value is non-zero, it will be associated with that service, and
subsequent RTAS calls by the guest specifying that token will be
handled by the kernel.  If the token value is 0, then any token
associated with the service will be forgotten, and subsequent RTAS
calls by the guest for that service will be passed to userspace to be
handled.

4.87 KVM_SET_GUEST_DEBUG
------------------------

:Capability: KVM_CAP_SET_GUEST_DEBUG
:Architectures: x86, s390, ppc, arm64
:Type: vcpu ioctl
:Parameters: struct kvm_guest_debug (in)
:Returns: 0 on success; -1 on error

::

  struct kvm_guest_debug {
       __u32 control;
       __u32 pad;
       struct kvm_guest_debug_arch arch;
  };

Set up the processor specific debug registers and configure vcpu for
handling guest debug events. There are two parts to the structure, the
first a control bitfield indicates the type of debug events to handle
when running. Common control bits are:

  - KVM_GUESTDBG_ENABLE:        guest debugging is enabled
  - KVM_GUESTDBG_SINGLESTEP:    the next run should single-step

The top 16 bits of the control field are architecture specific control
flags which can include the following:

  - KVM_GUESTDBG_USE_SW_BP:     using software breakpoints [x86, arm64]
  - KVM_GUESTDBG_USE_HW_BP:     using hardware breakpoints [x86, s390, arm64]
  - KVM_GUESTDBG_INJECT_DB:     inject DB type exception [x86]
  - KVM_GUESTDBG_INJECT_BP:     inject BP type exception [x86]
  - KVM_GUESTDBG_EXIT_PENDING:  trigger an immediate guest exit [s390]

For example KVM_GUESTDBG_USE_SW_BP indicates that software breakpoints
are enabled in memory so we need to ensure breakpoint exceptions are
correctly trapped and the KVM run loop exits at the breakpoint and not
running off into the normal guest vector. For KVM_GUESTDBG_USE_HW_BP
we need to ensure the guest vCPUs architecture specific registers are
updated to the correct (supplied) values.

The second part of the structure is architecture specific and
typically contains a set of debug registers.

For arm64 the number of debug registers is implementation defined and
can be determined by querying the KVM_CAP_GUEST_DEBUG_HW_BPS and
KVM_CAP_GUEST_DEBUG_HW_WPS capabilities which return a positive number
indicating the number of supported registers.

For ppc, the KVM_CAP_PPC_GUEST_DEBUG_SSTEP capability indicates whether
the single-step debug event (KVM_GUESTDBG_SINGLESTEP) is supported.

When debug events exit the main run loop with the reason
KVM_EXIT_DEBUG with the kvm_debug_exit_arch part of the kvm_run
structure containing architecture specific debug information.

4.88 KVM_GET_EMULATED_CPUID
---------------------------

:Capability: KVM_CAP_EXT_EMUL_CPUID
:Architectures: x86
:Type: system ioctl
:Parameters: struct kvm_cpuid2 (in/out)
:Returns: 0 on success, -1 on error

::

  struct kvm_cpuid2 {
	__u32 nent;
	__u32 flags;
	struct kvm_cpuid_entry2 entries[0];
  };

The member 'flags' is used for passing flags from userspace.

::

  #define KVM_CPUID_FLAG_SIGNIFCANT_INDEX		BIT(0)
  #define KVM_CPUID_FLAG_STATEFUL_FUNC		BIT(1) /* deprecated */
  #define KVM_CPUID_FLAG_STATE_READ_NEXT		BIT(2) /* deprecated */

  struct kvm_cpuid_entry2 {
	__u32 function;
	__u32 index;
	__u32 flags;
	__u32 eax;
	__u32 ebx;
	__u32 ecx;
	__u32 edx;
	__u32 padding[3];
  };

This ioctl returns x86 cpuid features which are emulated by
kvm.Userspace can use the information returned by this ioctl to query
which features are emulated by kvm instead of being present natively.

Userspace invokes KVM_GET_EMULATED_CPUID by passing a kvm_cpuid2
structure with the 'nent' field indicating the number of entries in
the variable-size array 'entries'. If the number of entries is too low
to describe the cpu capabilities, an error (E2BIG) is returned. If the
number is too high, the 'nent' field is adjusted and an error (ENOMEM)
is returned. If the number is just right, the 'nent' field is adjusted
to the number of valid entries in the 'entries' array, which is then
filled.

The entries returned are the set CPUID bits of the respective features
which kvm emulates, as returned by the CPUID instruction, with unknown
or unsupported feature bits cleared.

Features like x2apic, for example, may not be present in the host cpu
but are exposed by kvm in KVM_GET_SUPPORTED_CPUID because they can be
emulated efficiently and thus not included here.

The fields in each entry are defined as follows:

  function:
	 the eax value used to obtain the entry
  index:
	 the ecx value used to obtain the entry (for entries that are
         affected by ecx)
  flags:
    an OR of zero or more of the following:

        KVM_CPUID_FLAG_SIGNIFCANT_INDEX:
           if the index field is valid

   eax, ebx, ecx, edx:

         the values returned by the cpuid instruction for
         this function/index combination

4.89 KVM_S390_MEM_OP
--------------------

:Capability: KVM_CAP_S390_MEM_OP
:Architectures: s390
:Type: vcpu ioctl
:Parameters: struct kvm_s390_mem_op (in)
:Returns: = 0 on success,
          < 0 on generic error (e.g. -EFAULT or -ENOMEM),
          > 0 if an exception occurred while walking the page tables

Read or write data from/to the logical (virtual) memory of a VCPU.

Parameters are specified via the following structure::

  struct kvm_s390_mem_op {
	__u64 gaddr;		/* the guest address */
	__u64 flags;		/* flags */
	__u32 size;		/* amount of bytes */
	__u32 op;		/* type of operation */
	__u64 buf;		/* buffer in userspace */
	__u8 ar;		/* the access register number */
	__u8 reserved[31];	/* should be set to 0 */
  };

The type of operation is specified in the "op" field. It is either
KVM_S390_MEMOP_LOGICAL_READ for reading from logical memory space or
KVM_S390_MEMOP_LOGICAL_WRITE for writing to logical memory space. The
KVM_S390_MEMOP_F_CHECK_ONLY flag can be set in the "flags" field to check
whether the corresponding memory access would create an access exception
(without touching the data in the memory at the destination). In case an
access exception occurred while walking the MMU tables of the guest, the
ioctl returns a positive error number to indicate the type of exception.
This exception is also raised directly at the corresponding VCPU if the
flag KVM_S390_MEMOP_F_INJECT_EXCEPTION is set in the "flags" field.

The start address of the memory region has to be specified in the "gaddr"
field, and the length of the region in the "size" field (which must not
be 0). The maximum value for "size" can be obtained by checking the
KVM_CAP_S390_MEM_OP capability. "buf" is the buffer supplied by the
userspace application where the read data should be written to for
KVM_S390_MEMOP_LOGICAL_READ, or where the data that should be written is
stored for a KVM_S390_MEMOP_LOGICAL_WRITE. When KVM_S390_MEMOP_F_CHECK_ONLY
is specified, "buf" is unused and can be NULL. "ar" designates the access
register number to be used; the valid range is 0..15.

The "reserved" field is meant for future extensions. It is not used by
KVM with the currently defined set of flags.

4.90 KVM_S390_GET_SKEYS
-----------------------

:Capability: KVM_CAP_S390_SKEYS
:Architectures: s390
:Type: vm ioctl
:Parameters: struct kvm_s390_skeys
:Returns: 0 on success, KVM_S390_GET_KEYS_NONE if guest is not using storage
          keys, negative value on error

This ioctl is used to get guest storage key values on the s390
architecture. The ioctl takes parameters via the kvm_s390_skeys struct::

  struct kvm_s390_skeys {
	__u64 start_gfn;
	__u64 count;
	__u64 skeydata_addr;
	__u32 flags;
	__u32 reserved[9];
  };

The start_gfn field is the number of the first guest frame whose storage keys
you want to get.

The count field is the number of consecutive frames (starting from start_gfn)
whose storage keys to get. The count field must be at least 1 and the maximum
allowed value is defined as KVM_S390_SKEYS_ALLOC_MAX. Values outside this range
will cause the ioctl to return -EINVAL.

The skeydata_addr field is the address to a buffer large enough to hold count
bytes. This buffer will be filled with storage key data by the ioctl.

4.91 KVM_S390_SET_SKEYS
-----------------------

:Capability: KVM_CAP_S390_SKEYS
:Architectures: s390
:Type: vm ioctl
:Parameters: struct kvm_s390_skeys
:Returns: 0 on success, negative value on error

This ioctl is used to set guest storage key values on the s390
architecture. The ioctl takes parameters via the kvm_s390_skeys struct.
See section on KVM_S390_GET_SKEYS for struct definition.

The start_gfn field is the number of the first guest frame whose storage keys
you want to set.

The count field is the number of consecutive frames (starting from start_gfn)
whose storage keys to get. The count field must be at least 1 and the maximum
allowed value is defined as KVM_S390_SKEYS_ALLOC_MAX. Values outside this range
will cause the ioctl to return -EINVAL.

The skeydata_addr field is the address to a buffer containing count bytes of
storage keys. Each byte in the buffer will be set as the storage key for a
single frame starting at start_gfn for count frames.

Note: If any architecturally invalid key value is found in the given data then
the ioctl will return -EINVAL.

4.92 KVM_S390_IRQ
-----------------

:Capability: KVM_CAP_S390_INJECT_IRQ
:Architectures: s390
:Type: vcpu ioctl
:Parameters: struct kvm_s390_irq (in)
:Returns: 0 on success, -1 on error

Errors:


  ======  =================================================================
  EINVAL  interrupt type is invalid
          type is KVM_S390_SIGP_STOP and flag parameter is invalid value,
          type is KVM_S390_INT_EXTERNAL_CALL and code is bigger
          than the maximum of VCPUs
  EBUSY   type is KVM_S390_SIGP_SET_PREFIX and vcpu is not stopped,
          type is KVM_S390_SIGP_STOP and a stop irq is already pending,
          type is KVM_S390_INT_EXTERNAL_CALL and an external call interrupt
          is already pending
  ======  =================================================================

Allows to inject an interrupt to the guest.

Using struct kvm_s390_irq as a parameter allows
to inject additional payload which is not
possible via KVM_S390_INTERRUPT.

Interrupt parameters are passed via kvm_s390_irq::

  struct kvm_s390_irq {
	__u64 type;
	union {
		struct kvm_s390_io_info io;
		struct kvm_s390_ext_info ext;
		struct kvm_s390_pgm_info pgm;
		struct kvm_s390_emerg_info emerg;
		struct kvm_s390_extcall_info extcall;
		struct kvm_s390_prefix_info prefix;
		struct kvm_s390_stop_info stop;
		struct kvm_s390_mchk_info mchk;
		char reserved[64];
	} u;
  };

type can be one of the following:

- KVM_S390_SIGP_STOP - sigp stop; parameter in .stop
- KVM_S390_PROGRAM_INT - program check; parameters in .pgm
- KVM_S390_SIGP_SET_PREFIX - sigp set prefix; parameters in .prefix
- KVM_S390_RESTART - restart; no parameters
- KVM_S390_INT_CLOCK_COMP - clock comparator interrupt; no parameters
- KVM_S390_INT_CPU_TIMER - CPU timer interrupt; no parameters
- KVM_S390_INT_EMERGENCY - sigp emergency; parameters in .emerg
- KVM_S390_INT_EXTERNAL_CALL - sigp external call; parameters in .extcall
- KVM_S390_MCHK - machine check interrupt; parameters in .mchk

This is an asynchronous vcpu ioctl and can be invoked from any thread.

4.94 KVM_S390_GET_IRQ_STATE
---------------------------

:Capability: KVM_CAP_S390_IRQ_STATE
:Architectures: s390
:Type: vcpu ioctl
:Parameters: struct kvm_s390_irq_state (out)
:Returns: >= number of bytes copied into buffer,
          -EINVAL if buffer size is 0,
          -ENOBUFS if buffer size is too small to fit all pending interrupts,
          -EFAULT if the buffer address was invalid

This ioctl allows userspace to retrieve the complete state of all currently
pending interrupts in a single buffer. Use cases include migration
and introspection. The parameter structure contains the address of a
userspace buffer and its length::

  struct kvm_s390_irq_state {
	__u64 buf;
	__u32 flags;        /* will stay unused for compatibility reasons */
	__u32 len;
	__u32 reserved[4];  /* will stay unused for compatibility reasons */
  };

Userspace passes in the above struct and for each pending interrupt a
struct kvm_s390_irq is copied to the provided buffer.

The structure contains a flags and a reserved field for future extensions. As
the kernel never checked for flags == 0 and QEMU never pre-zeroed flags and
reserved, these fields can not be used in the future without breaking
compatibility.

If -ENOBUFS is returned the buffer provided was too small and userspace
may retry with a bigger buffer.

4.95 KVM_S390_SET_IRQ_STATE
---------------------------

:Capability: KVM_CAP_S390_IRQ_STATE
:Architectures: s390
:Type: vcpu ioctl
:Parameters: struct kvm_s390_irq_state (in)
:Returns: 0 on success,
          -EFAULT if the buffer address was invalid,
          -EINVAL for an invalid buffer length (see below),
          -EBUSY if there were already interrupts pending,
          errors occurring when actually injecting the
          interrupt. See KVM_S390_IRQ.

This ioctl allows userspace to set the complete state of all cpu-local
interrupts currently pending for the vcpu. It is intended for restoring
interrupt state after a migration. The input parameter is a userspace buffer
containing a struct kvm_s390_irq_state::

  struct kvm_s390_irq_state {
	__u64 buf;
	__u32 flags;        /* will stay unused for compatibility reasons */
	__u32 len;
	__u32 reserved[4];  /* will stay unused for compatibility reasons */
  };

The restrictions for flags and reserved apply as well.
(see KVM_S390_GET_IRQ_STATE)

The userspace memory referenced by buf contains a struct kvm_s390_irq
for each interrupt to be injected into the guest.
If one of the interrupts could not be injected for some reason the
ioctl aborts.

len must be a multiple of sizeof(struct kvm_s390_irq). It must be > 0
and it must not exceed (max_vcpus + 32) * sizeof(struct kvm_s390_irq),
which is the maximum number of possibly pending cpu-local interrupts.

4.96 KVM_SMI
------------

:Capability: KVM_CAP_X86_SMM
:Architectures: x86
:Type: vcpu ioctl
:Parameters: none
:Returns: 0 on success, -1 on error

Queues an SMI on the thread's vcpu.

4.97 KVM_CAP_PPC_MULTITCE
-------------------------

:Capability: KVM_CAP_PPC_MULTITCE
:Architectures: ppc
:Type: vm

This capability means the kernel is capable of handling hypercalls
H_PUT_TCE_INDIRECT and H_STUFF_TCE without passing those into the user
space. This significantly accelerates DMA operations for PPC KVM guests.
User space should expect that its handlers for these hypercalls
are not going to be called if user space previously registered LIOBN
in KVM (via KVM_CREATE_SPAPR_TCE or similar calls).

In order to enable H_PUT_TCE_INDIRECT and H_STUFF_TCE use in the guest,
user space might have to advertise it for the guest. For example,
IBM pSeries (sPAPR) guest starts using them if "hcall-multi-tce" is
present in the "ibm,hypertas-functions" device-tree property.

The hypercalls mentioned above may or may not be processed successfully
in the kernel based fast path. If they can not be handled by the kernel,
they will get passed on to user space. So user space still has to have
an implementation for these despite the in kernel acceleration.

This capability is always enabled.

4.98 KVM_CREATE_SPAPR_TCE_64
----------------------------

:Capability: KVM_CAP_SPAPR_TCE_64
:Architectures: powerpc
:Type: vm ioctl
:Parameters: struct kvm_create_spapr_tce_64 (in)
:Returns: file descriptor for manipulating the created TCE table

This is an extension for KVM_CAP_SPAPR_TCE which only supports 32bit
windows, described in 4.62 KVM_CREATE_SPAPR_TCE

This capability uses extended struct in ioctl interface::

  /* for KVM_CAP_SPAPR_TCE_64 */
  struct kvm_create_spapr_tce_64 {
	__u64 liobn;
	__u32 page_shift;
	__u32 flags;
	__u64 offset;	/* in pages */
	__u64 size; 	/* in pages */
  };

The aim of extension is to support an additional bigger DMA window with
a variable page size.
KVM_CREATE_SPAPR_TCE_64 receives a 64bit window size, an IOMMU page shift and
a bus offset of the corresponding DMA window, @size and @offset are numbers
of IOMMU pages.

@flags are not used at the moment.

The rest of functionality is identical to KVM_CREATE_SPAPR_TCE.

4.99 KVM_REINJECT_CONTROL
-------------------------

:Capability: KVM_CAP_REINJECT_CONTROL
:Architectures: x86
:Type: vm ioctl
:Parameters: struct kvm_reinject_control (in)
:Returns: 0 on success,
         -EFAULT if struct kvm_reinject_control cannot be read,
         -ENXIO if KVM_CREATE_PIT or KVM_CREATE_PIT2 didn't succeed earlier.

i8254 (PIT) has two modes, reinject and !reinject.  The default is reinject,
where KVM queues elapsed i8254 ticks and monitors completion of interrupt from
vector(s) that i8254 injects.  Reinject mode dequeues a tick and injects its
interrupt whenever there isn't a pending interrupt from i8254.
!reinject mode injects an interrupt as soon as a tick arrives.

::

  struct kvm_reinject_control {
	__u8 pit_reinject;
	__u8 reserved[31];
  };

pit_reinject = 0 (!reinject mode) is recommended, unless running an old
operating system that uses the PIT for timing (e.g. Linux 2.4.x).

4.100 KVM_PPC_CONFIGURE_V3_MMU
------------------------------

:Capability: KVM_CAP_PPC_RADIX_MMU or KVM_CAP_PPC_HASH_MMU_V3
:Architectures: ppc
:Type: vm ioctl
:Parameters: struct kvm_ppc_mmuv3_cfg (in)
:Returns: 0 on success,
         -EFAULT if struct kvm_ppc_mmuv3_cfg cannot be read,
         -EINVAL if the configuration is invalid

This ioctl controls whether the guest will use radix or HPT (hashed
page table) translation, and sets the pointer to the process table for
the guest.

::

  struct kvm_ppc_mmuv3_cfg {
	__u64	flags;
	__u64	process_table;
  };

There are two bits that can be set in flags; KVM_PPC_MMUV3_RADIX and
KVM_PPC_MMUV3_GTSE.  KVM_PPC_MMUV3_RADIX, if set, configures the guest
to use radix tree translation, and if clear, to use HPT translation.
KVM_PPC_MMUV3_GTSE, if set and if KVM permits it, configures the guest
to be able to use the global TLB and SLB invalidation instructions;
if clear, the guest may not use these instructions.

The process_table field specifies the address and size of the guest
process table, which is in the guest's space.  This field is formatted
as the second doubleword of the partition table entry, as defined in
the Power ISA V3.00, Book III section 5.7.6.1.

4.101 KVM_PPC_GET_RMMU_INFO
---------------------------

:Capability: KVM_CAP_PPC_RADIX_MMU
:Architectures: ppc
:Type: vm ioctl
:Parameters: struct kvm_ppc_rmmu_info (out)
:Returns: 0 on success,
	 -EFAULT if struct kvm_ppc_rmmu_info cannot be written,
	 -EINVAL if no useful information can be returned

This ioctl returns a structure containing two things: (a) a list
containing supported radix tree geometries, and (b) a list that maps
page sizes to put in the "AP" (actual page size) field for the tlbie
(TLB invalidate entry) instruction.

::

  struct kvm_ppc_rmmu_info {
	struct kvm_ppc_radix_geom {
		__u8	page_shift;
		__u8	level_bits[4];
		__u8	pad[3];
	}	geometries[8];
	__u32	ap_encodings[8];
  };

The geometries[] field gives up to 8 supported geometries for the
radix page table, in terms of the log base 2 of the smallest page
size, and the number of bits indexed at each level of the tree, from
the PTE level up to the PGD level in that order.  Any unused entries
will have 0 in the page_shift field.

The ap_encodings gives the supported page sizes and their AP field
encodings, encoded with the AP value in the top 3 bits and the log
base 2 of the page size in the bottom 6 bits.

4.102 KVM_PPC_RESIZE_HPT_PREPARE
--------------------------------

:Capability: KVM_CAP_SPAPR_RESIZE_HPT
:Architectures: powerpc
:Type: vm ioctl
:Parameters: struct kvm_ppc_resize_hpt (in)
:Returns: 0 on successful completion,
	 >0 if a new HPT is being prepared, the value is an estimated
         number of milliseconds until preparation is complete,
         -EFAULT if struct kvm_reinject_control cannot be read,
	 -EINVAL if the supplied shift or flags are invalid,
	 -ENOMEM if unable to allocate the new HPT,
	 -ENOSPC if there was a hash collision

::

  struct kvm_ppc_rmmu_info {
	struct kvm_ppc_radix_geom {
		__u8	page_shift;
		__u8	level_bits[4];
		__u8	pad[3];
	}	geometries[8];
	__u32	ap_encodings[8];
  };

The geometries[] field gives up to 8 supported geometries for the
radix page table, in terms of the log base 2 of the smallest page
size, and the number of bits indexed at each level of the tree, from
the PTE level up to the PGD level in that order.  Any unused entries
will have 0 in the page_shift field.

The ap_encodings gives the supported page sizes and their AP field
encodings, encoded with the AP value in the top 3 bits and the log
base 2 of the page size in the bottom 6 bits.

4.102 KVM_PPC_RESIZE_HPT_PREPARE
--------------------------------

:Capability: KVM_CAP_SPAPR_RESIZE_HPT
:Architectures: powerpc
:Type: vm ioctl
:Parameters: struct kvm_ppc_resize_hpt (in)
:Returns: 0 on successful completion,
	 >0 if a new HPT is being prepared, the value is an estimated
         number of milliseconds until preparation is complete,
         -EFAULT if struct kvm_reinject_control cannot be read,
	 -EINVAL if the supplied shift or flags are invalid,when moving existing
         HPT entries to the new HPT,
	 -EIO on other error conditions

Used to implement the PAPR extension for runtime resizing of a guest's
Hashed Page Table (HPT).  Specifically this starts, stops or monitors
the preparation of a new potential HPT for the guest, essentially
implementing the H_RESIZE_HPT_PREPARE hypercall.

If called with shift > 0 when there is no pending HPT for the guest,
this begins preparation of a new pending HPT of size 2^(shift) bytes.
It then returns a positive integer with the estimated number of
milliseconds until preparation is complete.

If called when there is a pending HPT whose size does not match that
requested in the parameters, discards the existing pending HPT and
creates a new one as above.

If called when there is a pending HPT of the size requested, will:

  * If preparation of the pending HPT is already complete, return 0
  * If preparation of the pending HPT has failed, return an error
    code, then discard the pending HPT.
  * If preparation of the pending HPT is still in progress, return an
    estimated number of milliseconds until preparation is complete.

If called with shift == 0, discards any currently pending HPT and
returns 0 (i.e. cancels any in-progress preparation).

flags is reserved for future expansion, currently setting any bits in
flags will result in an -EINVAL.

Normally this will be called repeatedly with the same parameters until
it returns <= 0.  The first call will initiate preparation, subsequent
ones will monitor preparation until it completes or fails.

::

  struct kvm_ppc_resize_hpt {
	__u64 flags;
	__u32 shift;
	__u32 pad;
  };

4.103 KVM_PPC_RESIZE_HPT_COMMIT
-------------------------------

:Capability: KVM_CAP_SPAPR_RESIZE_HPT
:Architectures: powerpc
:Type: vm ioctl
:Parameters: struct kvm_ppc_resize_hpt (in)
:Returns: 0 on successful completion,
         -EFAULT if struct kvm_reinject_control cannot be read,
	 -EINVAL if the supplied shift or flags are invalid,
	 -ENXIO is there is no pending HPT, or the pending HPT doesn't
         have the requested size,
	 -EBUSY if the pending HPT is not fully prepared,
	 -ENOSPC if there was a hash collision when moving existing
         HPT entries to the new HPT,
	 -EIO on other error conditions

Used to implement the PAPR extension for runtime resizing of a guest's
Hashed Page Table (HPT).  Specifically this requests that the guest be
transferred to working with the new HPT, essentially implementing the
H_RESIZE_HPT_COMMIT hypercall.

This should only be called after KVM_PPC_RESIZE_HPT_PREPARE has
returned 0 with the same parameters.  In other cases
KVM_PPC_RESIZE_HPT_COMMIT will return an error (usually -ENXIO or
-EBUSY, though others may be possible if the preparation was started,
but failed).

This will have undefined effects on the guest if it has not already
placed itself in a quiescent state where no vcpu will make MMU enabled
memory accesses.

On succsful completion, the pending HPT will become the guest's active
HPT and the previous HPT will be discarded.

On failure, the guest will still be operating on its previous HPT.

::

  struct kvm_ppc_resize_hpt {
	__u64 flags;
	__u32 shift;
	__u32 pad;
  };

4.104 KVM_X86_GET_MCE_CAP_SUPPORTED
-----------------------------------

:Capability: KVM_CAP_MCE
:Architectures: x86
:Type: system ioctl
:Parameters: u64 mce_cap (out)
:Returns: 0 on success, -1 on error

Returns supported MCE capabilities. The u64 mce_cap parameter
has the same format as the MSR_IA32_MCG_CAP register. Supported
capabilities will have the corresponding bits set.

4.105 KVM_X86_SETUP_MCE
-----------------------

:Capability: KVM_CAP_MCE
:Architectures: x86
:Type: vcpu ioctl
:Parameters: u64 mcg_cap (in)
:Returns: 0 on success,
         -EFAULT if u64 mcg_cap cannot be read,
         -EINVAL if the requested number of banks is invalid,
         -EINVAL if requested MCE capability is not supported.

Initializes MCE support for use. The u64 mcg_cap parameter
has the same format as the MSR_IA32_MCG_CAP register and
specifies which capabilities should be enabled. The maximum
supported number of error-reporting banks can be retrieved when
checking for KVM_CAP_MCE. The supported capabilities can be
retrieved with KVM_X86_GET_MCE_CAP_SUPPORTED.

4.106 KVM_X86_SET_MCE
---------------------

:Capability: KVM_CAP_MCE
:Architectures: x86
:Type: vcpu ioctl
:Parameters: struct kvm_x86_mce (in)
:Returns: 0 on success,
         -EFAULT if struct kvm_x86_mce cannot be read,
         -EINVAL if the bank number is invalid,
         -EINVAL if VAL bit is not set in status field.

Inject a machine check error (MCE) into the guest. The input
parameter is::

  struct kvm_x86_mce {
	__u64 status;
	__u64 addr;
	__u64 misc;
	__u64 mcg_status;
	__u8 bank;
	__u8 pad1[7];
	__u64 pad2[3];