Add ubpf support via UBPF_jll

Author: jpsamaroo

Manifest.toml

@@ -8,10 +8,12 @@ GPUCompiler = "61eb1bfa-7361-4325-ad38-22787b887f55"
 InteractiveUtils = "b77e0a4c-d291-57a0-90e8-8db25a27a240"
 LLVM = "929cbde3-209d-540e-8aea-75f648917ca0"
 Libdl = "8f399da3-3557-5675-b5ff-fb832c97cbdb"
+UBPF_jll = "502467ad-4a4a-57e4-9860-6b433130b33f"
 
 [compat]
-GPUCompiler = "0.9"
+GPUCompiler = "0.9.1"
 LLVM = "3.4"
+UBF_jll = "0.0.2"
 julia = "1.6"
 
 [extras]

Project.toml

@@ -5,7 +5,11 @@ using InteractiveUtils
 using Libdl
 using GPUCompiler
 
-# Host API
+# ubpf VM
+using UBPF_jll
+include("ubpf.jl")
+
+# Common API
 module API
 include("common.jl")
 include("libbpf.jl")

src/BPFnative.jl

@@ -0,0 +1,75 @@
+export ubpfcall, ubpfverify, ubpfloadelf
+
+struct ebpf_inst
+    opcode::UInt8
+    dst_src::UInt8
+    offset::Int16
+    imm::Int32
+end
+const ubpf_jit_fn = Ptr{Cvoid}
+const ext_func = Ptr{Cvoid}
+Base.@kwdef struct ubpf_vm
+    insts::Ptr{ebpf_inst}
+    num_insts::UInt16
+    jitted::ubpf_jit_fn = C_NULL
+    jitted_size::Csize_t = 0
+    ext_funcs::Ptr{ext_func} = C_NULL
+    ext_func_names::Ptr{Cstring} = C_NULL
+    bounds_check_enabled::Bool = true
+end
+ubpf_vm(exe::Vector{ebpf_inst}; kwargs...) =
+    ubpf_vm(pointer(exe), length(exe); kwargs...)
+ubpf_vm(exe::Vector{UInt8}; kwargs...) =
+    ubpf_vm(reinterpret(Ptr{ebpf_inst}, pointer(exe)),
+            div(length(exe),sizeof(ebpf_inst));
+            kwargs...)
+
+ubpfcall(exe::Vector{UInt8}, mem::Vector{UInt8}; kwargs...) =
+    ubpfcall(collect(reinterpret(ebpf_inst, exe)), mem; kwargs...)
+function ubpfcall(exe::Vector{ebpf_inst}, mem::Vector{UInt8}; kwargs...)
+    GC.@preserve exe mem begin
+        vm = ubpf_vm(exe; kwargs...)
+        if ubpfverify(vm) == 0
+            unsafe_ubpfcall(vm, mem)
+        else
+            error("BPF verification failed")
+        end
+    end
+end
+function ubpfverify(vm::ubpf_vm)
+    vm_ref = Ref(vm)
+    GC.@preserve vm_ref begin
+        ccall((:ubpf_verify, libubpf), Cint, (Ptr{ubpf_vm},), vm_ref)
+    end
+end
+function unsafe_ubpfcall(vm::ubpf_vm, mem::Union{<:Ptr,<:Integer}, mem_len::Integer)
+    vm_ref = Ref(vm)
+    mem = sizeof(mem) < sizeof(Ptr{Cvoid}) ? UInt(mem) : mem
+    GC.@preserve vm_ref mem begin
+        ccall((:ubpf_exec, libubpf), UInt64,
+              (Ptr{ubpf_vm}, Ptr{Cvoid}, Csize_t),
+              vm_ref, reinterpret(Ptr{Cvoid}, mem), mem_len)
+    end
+end
+function unsafe_ubpfcall(vm::ubpf_vm, mem::Vector{UInt8})
+    vm_ref = Ref(vm)
+    GC.@preserve vm_ref mem begin
+        ccall((:ubpf_exec, libubpf), UInt64,
+              (Ptr{ubpf_vm}, Ptr{Cvoid}, Csize_t),
+              vm_ref, mem, length(mem))
+    end
+end
+function ubpfloadelf(vm::ubpf_vm, exe::Vector{UInt8})
+    vm_ref = Ref(vm)
+    errmsg = Ref{Cstring}()
+    ret = GC.@preserve vm_ref errmsg begin
+        ccall((:ubpf_load_elf, BPFnative.libubpf), Cint,
+              (Ptr{BPFnative.ubpf_vm}, Ptr{UInt8}, Csize_t, Ptr{Cstring}),
+              vm_ref, pointer(exe), length(exe), errmsg)
+    end
+    if ret != 0
+        error(unsafe_string(errmsg[]))
+    end
+    vm_ref[]
+end
+ubpfloadelf(path::String) = ubpfloadelf(read(path))

src/ubpf.jl

@@ -21,6 +21,33 @@ end
 
 using InteractiveUtils
 
+if !isdefined(BPFnative, :libubpf)
+    @warn "ubpf unavailable; skipping interpreter tests"
+end
+function ubpftest(fn, Targs, arg)
+    exe = bpffunction(fn, Targs; btf=false, name="kernel")
+    vm = BPFnative.ubpf_vm(;insts=C_NULL, num_insts=0)
+    vm = ubpfloadelf(vm, exe)
+    if ubpfverify(vm) != 0
+        error("eBPF verifier error during test")
+    end
+    if arg === nothing
+        BPFnative.unsafe_ubpfcall(vm, C_NULL, 0)
+    else
+        BPFnative.unsafe_ubpfcall(vm, arg, sizeof(arg))
+    end
+end
+macro ubpftest(call)
+    if isdefined(BPFnative, :libubpf)
+        @assert Meta.isexpr(call, :call) "@ubpftest expects a call"
+        @assert length(call.args) <= 2 "Too many call arguments, 1 expected"
+        fn = call.args[1]
+        arg = get(call.args, 2, nothing)
+        Targ = arg !== nothing ? Base.to_tuple_type(typeof.((arg,))) : Tuple{}
+        :(ubpftest($(esc(fn)), $Targ, $arg))
+    end
+end
+
 @testset "codegen" begin
     map_types = (UInt8, UInt16, UInt32, UInt64,
                  Int8,  Int16,  Int32,  Int64)
@@ -32,6 +59,27 @@ using InteractiveUtils
         @test occursin(".section\tlicense,", asm)
         @test occursin("_license,@object", asm)
         @test occursin(".asciz\t\"abc\"", asm)
+        @test @ubpftest(kernel(0)) == 0
+    end
+    @testset "verifier errors" begin
+        @testset "loop" begin
+            function kernel(x)
+                while true end
+                0
+            end
+            @test_throws ErrorException @ubpftest(kernel(0))
+        end
+    end
+    @info "uBPF error messages during testing are OK"
+    @testset "runtime errors" begin
+        @testset "out-of-bounds load" begin
+            kernel(x) = unsafe_load(Ptr{UInt8}(1))
+            @test @ubpftest(kernel(0)) == typemax(UInt)
+        end
+    end
+    @testset "argument usage" begin
+        kernel(x) = x+1
+        @test @ubpftest(kernel(1)) == 2
     end
     @testset "map helpers" begin
         function kernel(x)