eBPF Offload to Hardware: cls_bpf and XDP Motivation - Avoiding - - PowerPoint PPT Presentation

▶

Aug 19, 2023 416 likes •671 views

eBPF Offload to Hardware: cls_bpf and XDP Motivation - Avoiding Whack-a-mole Motivation - Why eBPF? Target architecture (NFP based NIC) RX Path Flow of eBPF Packet The Flow Processing Core (Fully Programmable) Mapping eBPF -> NFP

SLIDE 1

eBPF Offload to Hardware: cls_bpf and XDP

SLIDE 2

Motivation - Avoiding Whack-a-mole

SLIDE 3

Motivation - Why eBPF?

SLIDE 4

Target architecture (NFP based NIC)

RX Path

SLIDE 5

Flow of eBPF Packet

SLIDE 6

The Flow Processing Core (Fully Programmable)

SLIDE 7

Mapping eBPF -> NFP

SLIDE 8

Programming Model

SLIDE 9

Kernel basics (before)

user space kernel space

BPF syscall

program
type (sk filter, kprobe, cls, xdp)
license
...

verifier

fd host JIT

tc TC

cls_bpf modification

XDP ctrl

fd verification fd driver

RX TX XDP BPF prog

SLIDE 10

Kernel basics (flow no offload)

user space kernel space

BPF syscall

program
type (sk filter, kprobe, cls, xdp)
license
...

verifier

fd host JIT

tc TC

cls_bpf modification

XDP ctrl

fd fd driver

RX TX XDP BPF prog s k b

verification

SLIDE 11

Kernel basics (after)

user space kernel space

BPF syscall

program
type (sk filter, kprobe, cls, xdp)
license
...

verifier

fd host JIT

tc TC

cls_bpf modification

XDP ctrl

ffload
bject

fd, skip_* flags verification fd, skip_* flags driver

RX TX XDP

ndo setup tc

HW JIT / translator

stats & maps

BPF prog

SLIDE 12

Kernel basics (after)

user space kernel space

BPF syscall

program
type (sk filter, kprobe, cls, xdp)
license
...

verifier

fd host JIT

tc TC

cls_bpf modification

XDP ctrl

ffload
bject

fd, skip_* flags fd, skip_* flags driver

RX TX XDP

ndo setup tc

HW JIT / translator

stats & maps

BPF prog

verification

SLIDE 13

Kernel basics (flow with offload)

user space kernel space

BPF syscall

program
type (sk filter, kprobe, cls, xdp)
license
...

verifier

fd host JIT

tc TC

cls_bpf modification

XDP ctrl

ffload
bject

fd, skip_* flags fd, skip_* flags driver

RX TX XDP

ndo setup tc

HW JIT / translator

stats & maps

BPF prog

fallback

stats metadata

verification

SLIDE 14

Translation and loading

user space kernel space

BPF syscall

program
type (sk filter, kprobe, cls, xdp)
license
...

verifier

fd host JIT

tc TC

cls_bpf modification

XDP ctrl

ffload
bject

fd, skip_* flags fd, skip_* flags driver

RX TX XDP

ndo setup tc

HW JIT / translator

stats & maps

BPF prog (1) Check HW capabilities and image parameters

verification

SLIDE 15

Translation and loading

user space kernel space

BPF syscall

program
type (sk filter, kprobe, cls, xdp)
license
...

verifier

fd host JIT

tc TC

cls_bpf modification

XDP ctrl

ffload
bject

fd, skip_* flags fd, skip_* flags driver

RX TX XDP

ndo setup tc

HW JIT / translator

stats & maps

BPF prog (1) Check HW capabilities and image parameters (2) Re-run the verifier

verification

SLIDE 16

Translation and loading

user space kernel space

BPF syscall

program
type (sk filter, kprobe, cls, xdp)
license
...

verifier

fd host JIT

tc TC

cls_bpf modification

XDP ctrl

ffload
bject

fd, skip_* flags fd, skip_* flags driver

RX TX XDP

ndo setup tc

HW JIT / translator

stats & maps

BPF prog (1) Check HW capabilities and image parameters (2) Re-run the verifier (3) Collect state/analyze

verification

SLIDE 17

Translation and loading

user space kernel space

BPF syscall

program
type (sk filter, kprobe, cls, xdp)
license
...

verifier

fd host JIT

tc TC

cls_bpf modification

XDP ctrl

ffload
bject

fd, skip_* flags fd, skip_* flags driver

RX TX XDP

ndo setup tc

HW JIT / translator

stats & maps

BPF prog (1) Check HW capabilities and image parameters (2) Re-run the verifier (3) Collect state/analyze (4) Optimize (5) JIT/generate image (6) Load image

verification

SLIDE 18

Quick peek at the device path

device driver

RX TX XDP

ndo setup tc

HW JIT / translator

stats & maps kernel space

core core core core core core core Memory stats maps Data path core

packet data m descriptor ring bits in descriptors metadata in prepend

MAC0 MAC1 MAC2 MAC3

SLIDE 19

Operations and actions (done or near/mid term)

device driver

RX TX XDP

ndo setup tc

HW JIT / translator

stats & maps kernel space

core core core core core core core Memory stats maps core

packet data m descriptor ring bits in descriptors metadata in prepend

MAC0 MAC1 MAC2 MAC3 Data Path

SLIDE 20

Map plans and ideas

Use of map by offloaded program Map location Mechanism needed Read only Host + device copy update interception Read/write Device only update/read interception lock out map in kernel space Read + statistics gather update/read interception

use verifier to check access types;
add hooks in map code;
add netdevice for binding the map to the device;
read + statistics require further investigation;
nly allow read/write offload for skip-sw programs.

SLIDE 21

Optimizations and verifier future work

SLIDE 22

Demo Links to eBPF Webinar Start of Webinar: https://www.youtube.com/watch?v=apU5sg0Ui5U Start of Demo: https://youtu.be/apU5sg0Ui5U?t=2003 Also Check out: http://open-nfp.org/the-classroom/

SLIDE 23

Summary

SLIDE 24

Kernel basics (after)

user space kernel space

BPF syscall

program
type (sk filter, kprobe, cls, xdp)
license
...

verifier

fd host JIT

tc TC

cls_bpf

driver

modification

RX path TX path XDP XDP ctrl

ndo setup tc

ffload
bject

fd, skip_* flags

HW JIT / translator

translation verification fd, skip_* flags

BPF prog