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Add new syscall instruction to interpreter and jitter #621

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merged 9 commits into from
Nov 6, 2024
Merged

Add new syscall instruction to interpreter and jitter #621

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ef31de0
Modify interpreter and jit
LucasSte Oct 18, 2024
2c0ab11
Revamp execution tests
LucasSte Oct 20, 2024
857b45d
Add invalid syscall test
LucasSte Oct 20, 2024
68efd2c
Fix imports
LucasSte Oct 20, 2024
db59e7d
Use debug_assert
LucasSte Oct 22, 2024
d0bf95c
Remove unregistered syscall test
LucasSte Oct 24, 2024
ec78387
Gate call imm in sbpf v2
LucasSte Nov 4, 2024
fe35891
Reorganize tests
LucasSte Nov 4, 2024
09d73c1
Remove unused parameters from macro
LucasSte Nov 4, 2024
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74 changes: 36 additions & 38 deletions src/interpreter.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -16,6 +16,7 @@ use crate::{
ebpf::{self, STACK_PTR_REG},
elf::Executable,
error::{EbpfError, ProgramResult},
program::BuiltinFunction,
vm::{Config, ContextObject, EbpfVm},
};

Expand Down Expand Up @@ -526,55 +527,44 @@ impl<'a, 'b, C: ContextObject> Interpreter<'a, 'b, C> {

// Do not delegate the check to the verifier, since self.registered functions can be
// changed after the program has been verified.
ebpf::CALL_IMM
| ebpf::SYSCALL if insn.opc == ebpf::CALL_IMM || self.executable.get_sbpf_version().static_syscalls() => {
let mut resolved = false;
let (external, internal) = if self.executable.get_sbpf_version().static_syscalls() {
(insn.src == 0, insn.src != 0)
} else {
(true, true)
};

if external {
if let Some((_function_name, function)) = self.executable.get_loader().get_function_registry(self.executable.get_sbpf_version()).lookup_by_key(insn.imm as u32) {
resolved = true;

self.vm.due_insn_count = self.vm.previous_instruction_meter - self.vm.due_insn_count;
self.vm.registers[0..6].copy_from_slice(&self.reg[0..6]);
self.vm.invoke_function(function);
self.vm.due_insn_count = 0;
self.reg[0] = match &self.vm.program_result {
ProgramResult::Ok(value) => *value,
ProgramResult::Err(_err) => return false,
};
}
}

if internal && !resolved {
if let Some((_function_name, target_pc)) =
ebpf::CALL_IMM => {
if let (false, Some((_, function))) =
(self.executable.get_sbpf_version().static_syscalls(),
self.executable.get_loader().get_function_registry(self.executable.get_sbpf_version()).lookup_by_key(insn.imm as u32)) {
// SBPFv1 syscall
self.reg[0] = match self.dispatch_syscall(function) {
ProgramResult::Ok(value) => *value,
ProgramResult::Err(_err) => return false,
};
} else if let Some((_, target_pc)) =
self.executable
.get_function_registry()
.lookup_by_key(
self
.executable
.get_sbpf_version()
.calculate_call_imm_target_pc(self.reg[11] as usize, insn.imm)
)
{
resolved = true;

// make BPF to BPF call
if !self.push_frame(config) {
return false;
}
check_pc!(self, next_pc, target_pc as u64);
) {
// make BPF to BPF call
if !self.push_frame(config) {
return false;
}
}

if !resolved {
check_pc!(self, next_pc, target_pc as u64);
} else {
throw_error!(self, EbpfError::UnsupportedInstruction);
}
}
ebpf::SYSCALL if self.executable.get_sbpf_version().static_syscalls() => {
if let Some((_, function)) = self.executable.get_loader().get_function_registry(self.executable.get_sbpf_version()).lookup_by_key(insn.imm as u32) {
// SBPFv2 syscall
self.reg[0] = match self.dispatch_syscall(function) {
ProgramResult::Ok(value) => *value,
ProgramResult::Err(_err) => return false,
};
} else {
debug_assert!(false, "Invalid syscall should have been detected in the verifier.");
}
},
ebpf::RETURN
| ebpf::EXIT => {
if (insn.opc == ebpf::EXIT && self.executable.get_sbpf_version().static_syscalls())
Expand Down Expand Up @@ -609,4 +599,12 @@ impl<'a, 'b, C: ContextObject> Interpreter<'a, 'b, C> {
self.reg[11] = next_pc;
true
}

fn dispatch_syscall(&mut self, function: BuiltinFunction<C>) -> &ProgramResult {
self.vm.due_insn_count = self.vm.previous_instruction_meter - self.vm.due_insn_count;
self.vm.registers[0..6].copy_from_slice(&self.reg[0..6]);
self.vm.invoke_function(function);
self.vm.due_insn_count = 0;
&self.vm.program_result
}
}
71 changes: 35 additions & 36 deletions src/jit.rs
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -31,6 +31,7 @@ use crate::{
allocate_pages, free_pages, get_system_page_size, protect_pages, round_to_page_size,
},
memory_region::{AccessType, MemoryMapping},
program::BuiltinFunction,
vm::{get_runtime_environment_key, Config, ContextObject, EbpfVm},
x86::*,
};
Expand Down Expand Up @@ -705,48 +706,36 @@ impl<'a, C: ContextObject> JitCompiler<'a, C> {
ebpf::JSLT_REG => self.emit_conditional_branch_reg(0x8c, false, src, dst, target_pc),
ebpf::JSLE_IMM => self.emit_conditional_branch_imm(0x8e, false, insn.imm, dst, target_pc),
ebpf::JSLE_REG => self.emit_conditional_branch_reg(0x8e, false, src, dst, target_pc),
ebpf::CALL_IMM | ebpf::SYSCALL
if insn.opc == ebpf::CALL_IMM || self.executable.get_sbpf_version().static_syscalls() => {
ebpf::CALL_IMM => {
// For JIT, external functions MUST be registered at compile time.

let mut resolved = false;
let (external, internal) = if self.executable.get_sbpf_version().static_syscalls() {
(insn.src == 0, insn.src != 0)
} else {
(true, true)
};

if external {
if let Some((_function_name, function)) = self.executable.get_loader().get_function_registry(self.executable.get_sbpf_version()).lookup_by_key(insn.imm as u32) {
self.emit_validate_and_profile_instruction_count(false, Some(0));
self.emit_ins(X86Instruction::load_immediate(OperandSize::S64, REGISTER_SCRATCH, function as usize as i64));
self.emit_ins(X86Instruction::call_immediate(self.relative_to_anchor(ANCHOR_EXTERNAL_FUNCTION_CALL, 5)));
self.emit_undo_profile_instruction_count(0);
resolved = true;
}
}

if internal {
if let Some((_function_name, target_pc)) =
if let (false, Some((_, function))) =
(self.executable.get_sbpf_version().static_syscalls(),
self.executable.get_loader().get_function_registry(self.executable.get_sbpf_version()).lookup_by_key(insn.imm as u32)) {
// SBPFv1 syscall
self.emit_syscall_dispatch(function);
} else if let Some((_function_name, target_pc)) =
self.executable
.get_function_registry()
.lookup_by_key(
self
.executable
.get_sbpf_version()
.calculate_call_imm_target_pc(self.pc, insn.imm)
)
{
self.emit_internal_call(Value::Constant64(target_pc as i64, true));
resolved = true;
}
}

if !resolved {
) {
// BPF to BPF call
self.emit_internal_call(Value::Constant64(target_pc as i64, true));
} else {
self.emit_ins(X86Instruction::load_immediate(OperandSize::S64, REGISTER_SCRATCH, self.pc as i64));
self.emit_ins(X86Instruction::jump_immediate(self.relative_to_anchor(ANCHOR_CALL_UNSUPPORTED_INSTRUCTION, 5)));
}
},
ebpf::SYSCALL if self.executable.get_sbpf_version().static_syscalls() => {
if let Some((_, function)) = self.executable.get_loader().get_function_registry(self.executable.get_sbpf_version()).lookup_by_key(insn.imm as u32) {
self.emit_syscall_dispatch(function);
} else {
debug_assert!(false, "Invalid syscall should have been detected in the verifier.")
}
},
ebpf::CALL_REG => {
let target_pc = if self.executable.get_sbpf_version().callx_uses_src_reg() {
src
Expand Down Expand Up @@ -1144,6 +1133,14 @@ impl<'a, C: ContextObject> JitCompiler<'a, C> {
}
}

#[inline]
fn emit_syscall_dispatch(&mut self, function: BuiltinFunction<C>) {
self.emit_validate_and_profile_instruction_count(false, Some(0));
self.emit_ins(X86Instruction::load_immediate(OperandSize::S64, REGISTER_SCRATCH, function as usize as i64));
self.emit_ins(X86Instruction::call_immediate(self.relative_to_anchor(ANCHOR_EXTERNAL_FUNCTION_CALL, 5)));
self.emit_undo_profile_instruction_count(0);
}

#[inline]
fn emit_address_translation(&mut self, dst: Option<u8>, vm_addr: Value, len: u64, value: Option<Value>) {
debug_assert_ne!(dst.is_some(), value.is_some());
Expand Down Expand Up @@ -1705,7 +1702,7 @@ impl<'a, C: ContextObject> JitCompiler<'a, C> {
mod tests {
use super::*;
use crate::{
program::{BuiltinFunction, BuiltinProgram, FunctionRegistry, SBPFVersion},
program::{BuiltinProgram, FunctionRegistry, SBPFVersion},
syscalls,
vm::TestContextObject,
};
Expand Down Expand Up @@ -1752,12 +1749,10 @@ mod tests {

fn create_mockup_executable(config: Config, program: &[u8]) -> Executable<TestContextObject> {
let sbpf_version = *config.enabled_sbpf_versions.end();
let mut function_registry =
FunctionRegistry::<BuiltinFunction<TestContextObject>>::default();
function_registry
.register_function_hashed(*b"gather_bytes", syscalls::SyscallGatherBytes::vm)
let mut loader = BuiltinProgram::new_loader_with_dense_registration(config);
loader
.register_function("gather_bytes", 1, syscalls::SyscallGatherBytes::vm)
.unwrap();
let loader = BuiltinProgram::new_loader(config, function_registry);
let mut function_registry = FunctionRegistry::default();
function_registry
.register_function(8, *b"function_foo", 8)
Expand Down Expand Up @@ -1844,6 +1839,10 @@ mod tests {
opcode = 0x85;
(0x88, 0x91020CDD)
}
0x95 => {
// Put a valid syscall
(0, 1)
}
0xD4 | 0xDC => (0x88, 16),
_ => (0x88, 0xFFFFFFFF),
};
Expand Down
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