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author | 2023-02-21 18:24:12 -0800 | |
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committer | 2023-02-21 18:24:12 -0800 | |
commit | 5b7c4cabbb65f5c469464da6c5f614cbd7f730f2 (patch) | |
tree | cc5c2d0a898769fd59549594fedb3ee6f84e59a0 /Documentation/powerpc/vas-api.rst | |
download | linux-5b7c4cabbb65f5c469464da6c5f614cbd7f730f2.tar.gz linux-5b7c4cabbb65f5c469464da6c5f614cbd7f730f2.zip |
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().
...
Diffstat (limited to 'Documentation/powerpc/vas-api.rst')
-rw-r--r-- | Documentation/powerpc/vas-api.rst | 305 |
1 files changed, 305 insertions, 0 deletions
diff --git a/Documentation/powerpc/vas-api.rst b/Documentation/powerpc/vas-api.rst new file mode 100644 index 000000000..bdb50fed9 --- /dev/null +++ b/Documentation/powerpc/vas-api.rst @@ -0,0 +1,305 @@ +.. SPDX-License-Identifier: GPL-2.0 +.. _VAS-API: + +=================================================== +Virtual Accelerator Switchboard (VAS) userspace API +=================================================== + +Introduction +============ + +Power9 processor introduced Virtual Accelerator Switchboard (VAS) which +allows both userspace and kernel communicate to co-processor +(hardware accelerator) referred to as the Nest Accelerator (NX). The NX +unit comprises of one or more hardware engines or co-processor types +such as 842 compression, GZIP compression and encryption. On power9, +userspace applications will have access to only GZIP Compression engine +which supports ZLIB and GZIP compression algorithms in the hardware. + +To communicate with NX, kernel has to establish a channel or window and +then requests can be submitted directly without kernel involvement. +Requests to the GZIP engine must be formatted as a co-processor Request +Block (CRB) and these CRBs must be submitted to the NX using COPY/PASTE +instructions to paste the CRB to hardware address that is associated with +the engine's request queue. + +The GZIP engine provides two priority levels of requests: Normal and +High. Only Normal requests are supported from userspace right now. + +This document explains userspace API that is used to interact with +kernel to setup channel / window which can be used to send compression +requests directly to NX accelerator. + + +Overview +======== + +Application access to the GZIP engine is provided through +/dev/crypto/nx-gzip device node implemented by the VAS/NX device driver. +An application must open the /dev/crypto/nx-gzip device to obtain a file +descriptor (fd). Then should issue VAS_TX_WIN_OPEN ioctl with this fd to +establish connection to the engine. It means send window is opened on GZIP +engine for this process. Once a connection is established, the application +should use the mmap() system call to map the hardware address of engine's +request queue into the application's virtual address space. + +The application can then submit one or more requests to the engine by +using copy/paste instructions and pasting the CRBs to the virtual address +(aka paste_address) returned by mmap(). User space can close the +established connection or send window by closing the file descriptior +(close(fd)) or upon the process exit. + +Note that applications can send several requests with the same window or +can establish multiple windows, but one window for each file descriptor. + +Following sections provide additional details and references about the +individual steps. + +NX-GZIP Device Node +=================== + +There is one /dev/crypto/nx-gzip node in the system and it provides +access to all GZIP engines in the system. The only valid operations on +/dev/crypto/nx-gzip are: + + * open() the device for read and write. + * issue VAS_TX_WIN_OPEN ioctl + * mmap() the engine's request queue into application's virtual + address space (i.e. get a paste_address for the co-processor + engine). + * close the device node. + +Other file operations on this device node are undefined. + +Note that the copy and paste operations go directly to the hardware and +do not go through this device. Refer COPY/PASTE document for more +details. + +Although a system may have several instances of the NX co-processor +engines (typically, one per P9 chip) there is just one +/dev/crypto/nx-gzip device node in the system. When the nx-gzip device +node is opened, Kernel opens send window on a suitable instance of NX +accelerator. It finds CPU on which the user process is executing and +determine the NX instance for the corresponding chip on which this CPU +belongs. + +Applications may chose a specific instance of the NX co-processor using +the vas_id field in the VAS_TX_WIN_OPEN ioctl as detailed below. + +A userspace library libnxz is available here but still in development: + + https://github.com/abalib/power-gzip + +Applications that use inflate / deflate calls can link with libnxz +instead of libz and use NX GZIP compression without any modification. + +Open /dev/crypto/nx-gzip +======================== + +The nx-gzip device should be opened for read and write. No special +privileges are needed to open the device. Each window corresponds to one +file descriptor. So if the userspace process needs multiple windows, +several open calls have to be issued. + +See open(2) system call man pages for other details such as return values, +error codes and restrictions. + +VAS_TX_WIN_OPEN ioctl +===================== + +Applications should use the VAS_TX_WIN_OPEN ioctl as follows to establish +a connection with NX co-processor engine: + + :: + + struct vas_tx_win_open_attr { + __u32 version; + __s16 vas_id; /* specific instance of vas or -1 + for default */ + __u16 reserved1; + __u64 flags; /* For future use */ + __u64 reserved2[6]; + }; + + version: + The version field must be currently set to 1. + vas_id: + If '-1' is passed, kernel will make a best-effort attempt + to assign an optimal instance of NX for the process. To + select the specific VAS instance, refer + "Discovery of available VAS engines" section below. + + flags, reserved1 and reserved2[6] fields are for future extension + and must be set to 0. + + The attributes attr for the VAS_TX_WIN_OPEN ioctl are defined as + follows:: + + #define VAS_MAGIC 'v' + #define VAS_TX_WIN_OPEN _IOW(VAS_MAGIC, 1, + struct vas_tx_win_open_attr) + + struct vas_tx_win_open_attr attr; + rc = ioctl(fd, VAS_TX_WIN_OPEN, &attr); + + The VAS_TX_WIN_OPEN ioctl returns 0 on success. On errors, it + returns -1 and sets the errno variable to indicate the error. + + Error conditions: + + ====== ================================================ + EINVAL fd does not refer to a valid VAS device. + EINVAL Invalid vas ID + EINVAL version is not set with proper value + EEXIST Window is already opened for the given fd + ENOMEM Memory is not available to allocate window + ENOSPC System has too many active windows (connections) + opened + EINVAL reserved fields are not set to 0. + ====== ================================================ + + See the ioctl(2) man page for more details, error codes and + restrictions. + +mmap() NX-GZIP device +===================== + +The mmap() system call for a NX-GZIP device fd returns a paste_address +that the application can use to copy/paste its CRB to the hardware engines. + + :: + + paste_addr = mmap(addr, size, prot, flags, fd, offset); + + Only restrictions on mmap for a NX-GZIP device fd are: + + * size should be PAGE_SIZE + * offset parameter should be 0ULL + + Refer to mmap(2) man page for additional details/restrictions. + In addition to the error conditions listed on the mmap(2) man + page, can also fail with one of the following error codes: + + ====== ============================================= + EINVAL fd is not associated with an open window + (i.e mmap() does not follow a successful call + to the VAS_TX_WIN_OPEN ioctl). + EINVAL offset field is not 0ULL. + ====== ============================================= + +Discovery of available VAS engines +================================== + +Each available VAS instance in the system will have a device tree node +like /proc/device-tree/vas@* or /proc/device-tree/xscom@*/vas@*. +Determine the chip or VAS instance and use the corresponding ibm,vas-id +property value in this node to select specific VAS instance. + +Copy/Paste operations +===================== + +Applications should use the copy and paste instructions to send CRB to NX. +Refer section 4.4 in PowerISA for Copy/Paste instructions: +https://openpowerfoundation.org/?resource_lib=power-isa-version-3-0 + +CRB Specification and use NX +============================ + +Applications should format requests to the co-processor using the +co-processor Request Block (CRBs). Refer NX-GZIP user's manual for the format +of CRB and use NX from userspace such as sending requests and checking +request status. + +NX Fault handling +================= + +Applications send requests to NX and wait for the status by polling on +co-processor Status Block (CSB) flags. NX updates status in CSB after each +request is processed. Refer NX-GZIP user's manual for the format of CSB and +status flags. + +In case if NX encounters translation error (called NX page fault) on CSB +address or any request buffer, raises an interrupt on the CPU to handle the +fault. Page fault can happen if an application passes invalid addresses or +request buffers are not in memory. The operating system handles the fault by +updating CSB with the following data:: + + csb.flags = CSB_V; + csb.cc = CSB_CC_FAULT_ADDRESS; + csb.ce = CSB_CE_TERMINATION; + csb.address = fault_address; + +When an application receives translation error, it can touch or access +the page that has a fault address so that this page will be in memory. Then +the application can resend this request to NX. + +If the OS can not update CSB due to invalid CSB address, sends SEGV signal +to the process who opened the send window on which the original request was +issued. This signal returns with the following siginfo struct:: + + siginfo.si_signo = SIGSEGV; + siginfo.si_errno = EFAULT; + siginfo.si_code = SEGV_MAPERR; + siginfo.si_addr = CSB adress; + +In the case of multi-thread applications, NX send windows can be shared +across all threads. For example, a child thread can open a send window, +but other threads can send requests to NX using this window. These +requests will be successful even in the case of OS handling faults as long +as CSB address is valid. If the NX request contains an invalid CSB address, +the signal will be sent to the child thread that opened the window. But if +the thread is exited without closing the window and the request is issued +using this window. the signal will be issued to the thread group leader +(tgid). It is up to the application whether to ignore or handle these +signals. + +NX-GZIP User's Manual: +https://github.com/libnxz/power-gzip/blob/master/doc/power_nx_gzip_um.pdf + +Simple example +============== + + :: + + int use_nx_gzip() + { + int rc, fd; + void *addr; + struct vas_setup_attr txattr; + + fd = open("/dev/crypto/nx-gzip", O_RDWR); + if (fd < 0) { + fprintf(stderr, "open nx-gzip failed\n"); + return -1; + } + memset(&txattr, 0, sizeof(txattr)); + txattr.version = 1; + txattr.vas_id = -1 + rc = ioctl(fd, VAS_TX_WIN_OPEN, + (unsigned long)&txattr); + if (rc < 0) { + fprintf(stderr, "ioctl() n %d, error %d\n", + rc, errno); + return rc; + } + addr = mmap(NULL, 4096, PROT_READ|PROT_WRITE, + MAP_SHARED, fd, 0ULL); + if (addr == MAP_FAILED) { + fprintf(stderr, "mmap() failed, errno %d\n", + errno); + return -errno; + } + do { + //Format CRB request with compression or + //uncompression + // Refer tests for vas_copy/vas_paste + vas_copy((&crb, 0, 1); + vas_paste(addr, 0, 1); + // Poll on csb.flags with timeout + // csb address is listed in CRB + } while (true) + close(fd) or window can be closed upon process exit + } + + Refer https://github.com/libnxz/power-gzip for tests or more + use cases. |