Merge tag 'net-next-6.3' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-nextgrafted

Pull networking updates from Jakub Kicinski:
 "Core:

   - Add dedicated kmem_cache for typical/small skb->head, avoid having
     to access struct page at kfree time, and improve memory use.

   - Introduce sysctl to set default RPS configuration for new netdevs.

   - Define Netlink protocol specification format which can be used to
     describe messages used by each family and auto-generate parsers.
     Add tools for generating kernel data structures and uAPI headers.

   - Expose all net/core sysctls inside netns.

   - Remove 4s sleep in netpoll if carrier is instantly detected on
     boot.

   - Add configurable limit of MDB entries per port, and port-vlan.

   - Continue populating drop reasons throughout the stack.

   - Retire a handful of legacy Qdiscs and classifiers.

  Protocols:

   - Support IPv4 big TCP (TSO frames larger than 64kB).

   - Add IP_LOCAL_PORT_RANGE socket option, to control local port range
     on socket by socket basis.

   - Track and report in procfs number of MPTCP sockets used.

   - Support mixing IPv4 and IPv6 flows in the in-kernel MPTCP path
     manager.

   - IPv6: don't check net.ipv6.route.max_size and rely on garbage
     collection to free memory (similarly to IPv4).

   - Support Penultimate Segment Pop (PSP) flavor in SRv6 (RFC8986).

   - ICMP: add per-rate limit counters.

   - Add support for user scanning requests in ieee802154.

   - Remove static WEP support.

   - Support minimal Wi-Fi 7 Extremely High Throughput (EHT) rate
     reporting.

   - WiFi 7 EHT channel puncturing support (client & AP).

  BPF:

   - Add a rbtree data structure following the "next-gen data structure"
     precedent set by recently added linked list, that is, by using
     kfunc + kptr instead of adding a new BPF map type.

   - Expose XDP hints via kfuncs with initial support for RX hash and
     timestamp metadata.

   - Add BPF_F_NO_TUNNEL_KEY extension to bpf_skb_set_tunnel_key to
     better support decap on GRE tunnel devices not operating in collect
     metadata.

   - Improve x86 JIT's codegen for PROBE_MEM runtime error checks.

   - Remove the need for trace_printk_lock for bpf_trace_printk and
     bpf_trace_vprintk helpers.

   - Extend libbpf's bpf_tracing.h support for tracing arguments of
     kprobes/uprobes and syscall as a special case.

   - Significantly reduce the search time for module symbols by
     livepatch and BPF.

   - Enable cpumasks to be used as kptrs, which is useful for tracing
     programs tracking which tasks end up running on which CPUs in
     different time intervals.

   - Add support for BPF trampoline on s390x and riscv64.

   - Add capability to export the XDP features supported by the NIC.

   - Add __bpf_kfunc tag for marking kernel functions as kfuncs.

   - Add cgroup.memory=nobpf kernel parameter option to disable BPF
     memory accounting for container environments.

  Netfilter:

   - Remove the CLUSTERIP target. It has been marked as obsolete for
     years, and we still have WARN splats wrt races of the out-of-band
     /proc interface installed by this target.

   - Add 'destroy' commands to nf_tables. They are identical to the
     existing 'delete' commands, but do not return an error if the
     referenced object (set, chain, rule...) did not exist.

  Driver API:

   - Improve cpumask_local_spread() locality to help NICs set the right
     IRQ affinity on AMD platforms.

   - Separate C22 and C45 MDIO bus transactions more clearly.

   - Introduce new DCB table to control DSCP rewrite on egress.

   - Support configuration of Physical Layer Collision Avoidance (PLCA)
     Reconciliation Sublayer (RS) (802.3cg-2019). Modern version of
     shared medium Ethernet.

   - Support for MAC Merge layer (IEEE 802.3-2018 clause 99). Allowing
     preemption of low priority frames by high priority frames.

   - Add support for controlling MACSec offload using netlink SET.

   - Rework devlink instance refcounts to allow registration and
     de-registration under the instance lock. Split the code into
     multiple files, drop some of the unnecessarily granular locks and
     factor out common parts of netlink operation handling.

   - Add TX frame aggregation parameters (for USB drivers).

   - Add a new attr TCA_EXT_WARN_MSG to report TC (offload) warning
     messages with notifications for debug.

   - Allow offloading of UDP NEW connections via act_ct.

   - Add support for per action HW stats in TC.

   - Support hardware miss to TC action (continue processing in SW from
     a specific point in the action chain).

   - Warn if old Wireless Extension user space interface is used with
     modern cfg80211/mac80211 drivers. Do not support Wireless
     Extensions for Wi-Fi 7 devices at all. Everyone should switch to
     using nl80211 interface instead.

   - Improve the CAN bit timing configuration. Use extack to return
     error messages directly to user space, update the SJW handling,
     including the definition of a new default value that will benefit
     CAN-FD controllers, by increasing their oscillator tolerance.

  New hardware / drivers:

   - Ethernet:
      - nVidia BlueField-3 support (control traffic driver)
      - Ethernet support for imx93 SoCs
      - Motorcomm yt8531 gigabit Ethernet PHY
      - onsemi NCN26000 10BASE-T1S PHY (with support for PLCA)
      - Microchip LAN8841 PHY (incl. cable diagnostics and PTP)
      - Amlogic gxl MDIO mux

   - WiFi:
      - RealTek RTL8188EU (rtl8xxxu)
      - Qualcomm Wi-Fi 7 devices (ath12k)

   - CAN:
      - Renesas R-Car V4H

  Drivers:

   - Bluetooth:
      - Set Per Platform Antenna Gain (PPAG) for Intel controllers.

   - Ethernet NICs:
      - Intel (1G, igc):
         - support TSN / Qbv / packet scheduling features of i226 model
      - Intel (100G, ice):
         - use GNSS subsystem instead of TTY
         - multi-buffer XDP support
         - extend support for GPIO pins to E823 devices
      - nVidia/Mellanox:
         - update the shared buffer configuration on PFC commands
         - implement PTP adjphase function for HW offset control
         - TC support for Geneve and GRE with VF tunnel offload
         - more efficient crypto key management method
         - multi-port eswitch support
      - Netronome/Corigine:
         - add DCB IEEE support
         - support IPsec offloading for NFP3800
      - Freescale/NXP (enetc):
         - support XDP_REDIRECT for XDP non-linear buffers
         - improve reconfig, avoid link flap and waiting for idle
         - support MAC Merge layer
      - Other NICs:
         - sfc/ef100: add basic devlink support for ef100
         - ionic: rx_push mode operation (writing descriptors via MMIO)
         - bnxt: use the auxiliary bus abstraction for RDMA
         - r8169: disable ASPM and reset bus in case of tx timeout
         - cpsw: support QSGMII mode for J721e CPSW9G
         - cpts: support pulse-per-second output
         - ngbe: add an mdio bus driver
         - usbnet: optimize usbnet_bh() by avoiding unnecessary queuing
         - r8152: handle devices with FW with NCM support
         - amd-xgbe: support 10Mbps, 2.5GbE speeds and rx-adaptation
         - virtio-net: support multi buffer XDP
         - virtio/vsock: replace virtio_vsock_pkt with sk_buff
         - tsnep: XDP support

   - Ethernet high-speed switches:
      - nVidia/Mellanox (mlxsw):
         - add support for latency TLV (in FW control messages)
      - Microchip (sparx5):
         - separate explicit and implicit traffic forwarding rules, make
           the implicit rules always active
         - add support for egress DSCP rewrite
         - IS0 VCAP support (Ingress Classification)
         - IS2 VCAP filters (protos, L3 addrs, L4 ports, flags, ToS
           etc.)
         - ES2 VCAP support (Egress Access Control)
         - support for Per-Stream Filtering and Policing (802.1Q,
           8.6.5.1)

   - Ethernet embedded switches:
      - Marvell (mv88e6xxx):
         - add MAB (port auth) offload support
         - enable PTP receive for mv88e6390
      - NXP (ocelot):
         - support MAC Merge layer
         - support for the the vsc7512 internal copper phys
      - Microchip:
         - lan9303: convert to PHYLINK
         - lan966x: support TC flower filter statistics
         - lan937x: PTP support for KSZ9563/KSZ8563 and LAN937x
         - lan937x: support Credit Based Shaper configuration
         - ksz9477: support Energy Efficient Ethernet
      - other:
         - qca8k: convert to regmap read/write API, use bulk operations
         - rswitch: Improve TX timestamp accuracy

   - Intel WiFi (iwlwifi):
      - EHT (Wi-Fi 7) rate reporting
      - STEP equalizer support: transfer some STEP (connection to radio
        on platforms with integrated wifi) related parameters from the
        BIOS to the firmware.

   - Qualcomm 802.11ax WiFi (ath11k):
      - IPQ5018 support
      - Fine Timing Measurement (FTM) responder role support
      - channel 177 support

   - MediaTek WiFi (mt76):
      - per-PHY LED support
      - mt7996: EHT (Wi-Fi 7) support
      - Wireless Ethernet Dispatch (WED) reset support
      - switch to using page pool allocator

   - RealTek WiFi (rtw89):
      - support new version of Bluetooth co-existance

   - Mobile:
      - rmnet: support TX aggregation"

* tag 'net-next-6.3' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next: (1872 commits)
  page_pool: add a comment explaining the fragment counter usage
  net: ethtool: fix __ethtool_dev_mm_supported() implementation
  ethtool: pse-pd: Fix double word in comments
  xsk: add linux/vmalloc.h to xsk.c
  sefltests: netdevsim: wait for devlink instance after netns removal
  selftest: fib_tests: Always cleanup before exit
  net/mlx5e: Align IPsec ASO result memory to be as required by hardware
  net/mlx5e: TC, Set CT miss to the specific ct action instance
  net/mlx5e: Rename CHAIN_TO_REG to MAPPED_OBJ_TO_REG
  net/mlx5: Refactor tc miss handling to a single function
  net/mlx5: Kconfig: Make tc offload depend on tc skb extension
  net/sched: flower: Support hardware miss to tc action
  net/sched: flower: Move filter handle initialization earlier
  net/sched: cls_api: Support hardware miss to tc action
  net/sched: Rename user cookie and act cookie
  sfc: fix builds without CONFIG_RTC_LIB
  sfc: clean up some inconsistent indentings
  net/mlx4_en: Introduce flexible array to silence overflow warning
  net: lan966x: Fix possible deadlock inside PTP
  net/ulp: Remove redundant ->clone() test in inet_clone_ulp().
  ...

5 files changed, 336 insertions, 0 deletions

diff --git a/Documentation/virt/kvm/arm/hyp-abi.rst b/Documentation/virt/kvm/arm/hyp-abi.rst
new file mode 100644
index 000000000..412b27644
--- /dev/null
+++ b/Documentation/virt/kvm/arm/hyp-abi.rst
@@ -0,0 +1,78 @@
+.. SPDX-License-Identifier: GPL-2.0
+
+=======================================
+Internal ABI between the kernel and HYP
+=======================================
+
+This file documents the interaction between the Linux kernel and the
+hypervisor layer when running Linux as a hypervisor (for example
+KVM). It doesn't cover the interaction of the kernel with the
+hypervisor when running as a guest (under Xen, KVM or any other
+hypervisor), or any hypervisor-specific interaction when the kernel is
+used as a host.
+
+Note: KVM/arm has been removed from the kernel. The API described
+here is still valid though, as it allows the kernel to kexec when
+booted at HYP. It can also be used by a hypervisor other than KVM
+if necessary.
+
+On arm and arm64 (without VHE), the kernel doesn't run in hypervisor
+mode, but still needs to interact with it, allowing a built-in
+hypervisor to be either installed or torn down.
+
+In order to achieve this, the kernel must be booted at HYP (arm) or
+EL2 (arm64), allowing it to install a set of stubs before dropping to
+SVC/EL1. These stubs are accessible by using a 'hvc #0' instruction,
+and only act on individual CPUs.
+
+Unless specified otherwise, any built-in hypervisor must implement
+these functions (see arch/arm{,64}/include/asm/virt.h):
+
+* ::
+
+    r0/x0 = HVC_SET_VECTORS
+    r1/x1 = vectors
+
+  Set HVBAR/VBAR_EL2 to 'vectors' to enable a hypervisor. 'vectors'
+  must be a physical address, and respect the alignment requirements
+  of the architecture. Only implemented by the initial stubs, not by
+  Linux hypervisors.
+
+* ::
+
+    r0/x0 = HVC_RESET_VECTORS
+
+  Turn HYP/EL2 MMU off, and reset HVBAR/VBAR_EL2 to the initials
+  stubs' exception vector value. This effectively disables an existing
+  hypervisor.
+
+* ::
+
+    r0/x0 = HVC_SOFT_RESTART
+    r1/x1 = restart address
+    x2 = x0's value when entering the next payload (arm64)
+    x3 = x1's value when entering the next payload (arm64)
+    x4 = x2's value when entering the next payload (arm64)
+
+  Mask all exceptions, disable the MMU, clear I+D bits, move the arguments
+  into place (arm64 only), and jump to the restart address while at HYP/EL2.
+  This hypercall is not expected to return to its caller.
+
+* ::
+
+    x0 = HVC_FINALISE_EL2 (arm64 only)
+
+  Finish configuring EL2 depending on the command-line options,
+  including an attempt to upgrade the kernel's exception level from
+  EL1 to EL2 by enabling the VHE mode. This is conditioned by the CPU
+  supporting VHE, the EL2 MMU being off, and VHE not being disabled by
+  any other means (command line option, for example).
+
+Any other value of r0/x0 triggers a hypervisor-specific handling,
+which is not documented here.
+
+The return value of a stub hypercall is held by r0/x0, and is 0 on
+success, and HVC_STUB_ERR on error. A stub hypercall is allowed to
+clobber any of the caller-saved registers (x0-x18 on arm64, r0-r3 and
+ip on arm). It is thus recommended to use a function call to perform
+the hypercall.
diff --git a/Documentation/virt/kvm/arm/hypercalls.rst b/Documentation/virt/kvm/arm/hypercalls.rst
new file mode 100644
index 000000000..3e2308464
--- /dev/null
+++ b/Documentation/virt/kvm/arm/hypercalls.rst
@@ -0,0 +1,138 @@
+.. SPDX-License-Identifier: GPL-2.0
+
+=======================
+ARM Hypercall Interface
+=======================
+
+KVM handles the hypercall services as requested by the guests. New hypercall
+services are regularly made available by the ARM specification or by KVM (as
+vendor services) if they make sense from a virtualization point of view.
+
+This means that a guest booted on two different versions of KVM can observe
+two different "firmware" revisions. This could cause issues if a given guest
+is tied to a particular version of a hypercall service, or if a migration
+causes a different version to be exposed out of the blue to an unsuspecting
+guest.
+
+In order to remedy this situation, KVM exposes a set of "firmware
+pseudo-registers" that can be manipulated using the GET/SET_ONE_REG
+interface. These registers can be saved/restored by userspace, and set
+to a convenient value as required.
+
+The following registers are defined:
+
+* KVM_REG_ARM_PSCI_VERSION:
+
+  KVM implements the PSCI (Power State Coordination Interface)
+  specification in order to provide services such as CPU on/off, reset
+  and power-off to the guest.
+
+  - Only valid if the vcpu has the KVM_ARM_VCPU_PSCI_0_2 feature set
+    (and thus has already been initialized)
+  - Returns the current PSCI version on GET_ONE_REG (defaulting to the
+    highest PSCI version implemented by KVM and compatible with v0.2)
+  - Allows any PSCI version implemented by KVM and compatible with
+    v0.2 to be set with SET_ONE_REG
+  - Affects the whole VM (even if the register view is per-vcpu)
+
+* KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_1:
+    Holds the state of the firmware support to mitigate CVE-2017-5715, as
+    offered by KVM to the guest via a HVC call. The workaround is described
+    under SMCCC_ARCH_WORKAROUND_1 in [1].
+
+  Accepted values are:
+
+    KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_1_NOT_AVAIL:
+      KVM does not offer
+      firmware support for the workaround. The mitigation status for the
+      guest is unknown.
+    KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_1_AVAIL:
+      The workaround HVC call is
+      available to the guest and required for the mitigation.
+    KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_1_NOT_REQUIRED:
+      The workaround HVC call
+      is available to the guest, but it is not needed on this VCPU.
+
+* KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2:
+    Holds the state of the firmware support to mitigate CVE-2018-3639, as
+    offered by KVM to the guest via a HVC call. The workaround is described
+    under SMCCC_ARCH_WORKAROUND_2 in [1]_.
+
+  Accepted values are:
+
+    KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2_NOT_AVAIL:
+      A workaround is not
+      available. KVM does not offer firmware support for the workaround.
+    KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2_UNKNOWN:
+      The workaround state is
+      unknown. KVM does not offer firmware support for the workaround.
+    KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2_AVAIL:
+      The workaround is available,
+      and can be disabled by a vCPU. If
+      KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2_ENABLED is set, it is active for
+      this vCPU.
+    KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2_NOT_REQUIRED:
+      The workaround is always active on this vCPU or it is not needed.
+
+
+Bitmap Feature Firmware Registers
+---------------------------------
+
+Contrary to the above registers, the following registers exposes the
+hypercall services in the form of a feature-bitmap to the userspace. This
+bitmap is translated to the services that are available to the guest.
+There is a register defined per service call owner and can be accessed via
+GET/SET_ONE_REG interface.
+
+By default, these registers are set with the upper limit of the features
+that are supported. This way userspace can discover all the usable
+hypercall services via GET_ONE_REG. The user-space can write-back the
+desired bitmap back via SET_ONE_REG. The features for the registers that
+are untouched, probably because userspace isn't aware of them, will be
+exposed as is to the guest.
+
+Note that KVM will not allow the userspace to configure the registers
+anymore once any of the vCPUs has run at least once. Instead, it will
+return a -EBUSY.
+
+The pseudo-firmware bitmap register are as follows:
+
+* KVM_REG_ARM_STD_BMAP:
+    Controls the bitmap of the ARM Standard Secure Service Calls.
+
+  The following bits are accepted:
+
+    Bit-0: KVM_REG_ARM_STD_BIT_TRNG_V1_0:
+      The bit represents the services offered under v1.0 of ARM True Random
+      Number Generator (TRNG) specification, ARM DEN0098.
+
+* KVM_REG_ARM_STD_HYP_BMAP:
+    Controls the bitmap of the ARM Standard Hypervisor Service Calls.
+
+  The following bits are accepted:
+
+    Bit-0: KVM_REG_ARM_STD_HYP_BIT_PV_TIME:
+      The bit represents the Paravirtualized Time service as represented by
+      ARM DEN0057A.
+
+* KVM_REG_ARM_VENDOR_HYP_BMAP:
+    Controls the bitmap of the Vendor specific Hypervisor Service Calls.
+
+  The following bits are accepted:
+
+    Bit-0: KVM_REG_ARM_VENDOR_HYP_BIT_FUNC_FEAT
+      The bit represents the ARM_SMCCC_VENDOR_HYP_KVM_FEATURES_FUNC_ID
+      and ARM_SMCCC_VENDOR_HYP_CALL_UID_FUNC_ID function-ids.
+
+    Bit-1: KVM_REG_ARM_VENDOR_HYP_BIT_PTP:
+      The bit represents the Precision Time Protocol KVM service.
+
+Errors:
+
+    =======  =============================================================
+    -ENOENT   Unknown register accessed.
+    -EBUSY    Attempt a 'write' to the register after the VM has started.
+    -EINVAL   Invalid bitmap written to the register.
+    =======  =============================================================
+
+.. [1] https://developer.arm.com/-/media/developer/pdf/ARM_DEN_0070A_Firmware_interfaces_for_mitigating_CVE-2017-5715.pdf
diff --git a/Documentation/virt/kvm/arm/index.rst b/Documentation/virt/kvm/arm/index.rst
new file mode 100644
index 000000000..e84848432
--- /dev/null
+++ b/Documentation/virt/kvm/arm/index.rst
@@ -0,0 +1,13 @@
+.. SPDX-License-Identifier: GPL-2.0
+
+===
+ARM
+===
+
+.. toctree::
+   :maxdepth: 2
+
+   hyp-abi
+   hypercalls
+   pvtime
+   ptp_kvm
diff --git a/Documentation/virt/kvm/arm/ptp_kvm.rst b/Documentation/virt/kvm/arm/ptp_kvm.rst
new file mode 100644
index 000000000..aecdc80dd
--- /dev/null
+++ b/Documentation/virt/kvm/arm/ptp_kvm.rst
@@ -0,0 +1,25 @@
+.. SPDX-License-Identifier: GPL-2.0
+
+PTP_KVM support for arm/arm64
+=============================
+
+PTP_KVM is used for high precision time sync between host and guests.
+It relies on transferring the wall clock and counter value from the
+host to the guest using a KVM-specific hypercall.
+
+* ARM_SMCCC_VENDOR_HYP_KVM_PTP_FUNC_ID: 0x86000001
+
+This hypercall uses the SMC32/HVC32 calling convention:
+
+ARM_SMCCC_VENDOR_HYP_KVM_PTP_FUNC_ID
+    ==============    ========    =====================================
+    Function ID:      (uint32)    0x86000001
+    Arguments:        (uint32)    KVM_PTP_VIRT_COUNTER(0)
+                                  KVM_PTP_PHYS_COUNTER(1)
+    Return Values:    (int32)     NOT_SUPPORTED(-1) on error, or
+                      (uint32)    Upper 32 bits of wall clock time (r0)
+                      (uint32)    Lower 32 bits of wall clock time (r1)
+                      (uint32)    Upper 32 bits of counter (r2)
+                      (uint32)    Lower 32 bits of counter (r3)
+    Endianness:                   No Restrictions.
+    ==============    ========    =====================================
diff --git a/Documentation/virt/kvm/arm/pvtime.rst b/Documentation/virt/kvm/arm/pvtime.rst
new file mode 100644
index 000000000..e88b34e58
--- /dev/null
+++ b/Documentation/virt/kvm/arm/pvtime.rst
@@ -0,0 +1,82 @@
+.. SPDX-License-Identifier: GPL-2.0
+
+Paravirtualized time support for arm64
+======================================
+
+Arm specification DEN0057/A defines a standard for paravirtualised time
+support for AArch64 guests:
+
+https://developer.arm.com/docs/den0057/a
+
+KVM/arm64 implements the stolen time part of this specification by providing
+some hypervisor service calls to support a paravirtualized guest obtaining a
+view of the amount of time stolen from its execution.
+
+Two new SMCCC compatible hypercalls are defined:
+
+* PV_TIME_FEATURES: 0xC5000020
+* PV_TIME_ST:       0xC5000021
+
+These are only available in the SMC64/HVC64 calling convention as
+paravirtualized time is not available to 32 bit Arm guests. The existence of
+the PV_TIME_FEATURES hypercall should be probed using the SMCCC 1.1
+ARCH_FEATURES mechanism before calling it.
+
+PV_TIME_FEATURES
+
+    ============= ========    =================================================
+    Function ID:  (uint32)    0xC5000020
+    PV_call_id:   (uint32)    The function to query for support.
+                              Currently only PV_TIME_ST is supported.
+    Return value: (int64)     NOT_SUPPORTED (-1) or SUCCESS (0) if the relevant
+                              PV-time feature is supported by the hypervisor.
+    ============= ========    =================================================
+
+PV_TIME_ST
+
+    ============= ========    ==============================================
+    Function ID:  (uint32)    0xC5000021
+    Return value: (int64)     IPA of the stolen time data structure for this
+                              VCPU. On failure:
+                              NOT_SUPPORTED (-1)
+    ============= ========    ==============================================
+
+The IPA returned by PV_TIME_ST should be mapped by the guest as normal memory
+with inner and outer write back caching attributes, in the inner shareable
+domain. A total of 16 bytes from the IPA returned are guaranteed to be
+meaningfully filled by the hypervisor (see structure below).
+
+PV_TIME_ST returns the structure for the calling VCPU.
+
+Stolen Time
+-----------
+
+The structure pointed to by the PV_TIME_ST hypercall is as follows:
+
++-------------+-------------+-------------+----------------------------+
+| Field       | Byte Length | Byte Offset | Description                |
++=============+=============+=============+============================+
+| Revision    |      4      |      0      | Must be 0 for version 1.0  |
++-------------+-------------+-------------+----------------------------+
+| Attributes  |      4      |      4      | Must be 0                  |
++-------------+-------------+-------------+----------------------------+
+| Stolen time |      8      |      8      | Stolen time in unsigned    |
+|             |             |             | nanoseconds indicating how |
+|             |             |             | much time this VCPU thread |
+|             |             |             | was involuntarily not      |
+|             |             |             | running on a physical CPU. |
++-------------+-------------+-------------+----------------------------+
+
+All values in the structure are stored little-endian.
+
+The structure will be updated by the hypervisor prior to scheduling a VCPU. It
+will be present within a reserved region of the normal memory given to the
+guest. The guest should not attempt to write into this memory. There is a
+structure per VCPU of the guest.
+
+It is advisable that one or more 64k pages are set aside for the purpose of
+these structures and not used for other purposes, this enables the guest to map
+the region using 64k pages and avoids conflicting attributes with other memory.
+
+For the user space interface see
+:ref:`Documentation/virt/kvm/devices/vcpu.rst <kvm_arm_vcpu_pvtime_ctrl>`.
\ No newline at end of file