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Optimize serialization of function calls #444

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b14634a
Serialize FunctionCall into &[u8] instead of Vec<u8>, avoiding unnece…
ludfjig Apr 29, 2025
56bf4a2
Remove need for buffer validation by slightly modifying function sign…
ludfjig Apr 29, 2025
24586f5
Remove direct dependency on flatbuffers in hyperlight-host and hyperl…
ludfjig Apr 29, 2025
9d05679
Add benchmark for guest call with large parameters
ludfjig Apr 30, 2025
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1 change: 0 additions & 1 deletion Cargo.lock
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160 changes: 63 additions & 97 deletions src/hyperlight_common/src/flatbuffer_wrappers/function_call.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -18,7 +18,7 @@ use alloc::string::{String, ToString};
use alloc::vec::Vec;

use anyhow::{bail, Error, Result};
use flatbuffers::{size_prefixed_root, WIPOffset};
use flatbuffers::{size_prefixed_root, FlatBufferBuilder, WIPOffset};
#[cfg(feature = "tracing")]
use tracing::{instrument, Span};

Expand All @@ -41,7 +41,6 @@ pub enum FunctionCallType {
}

/// `Functioncall` represents a call to a function in the guest or host.
#[derive(Clone)]
pub struct FunctionCall {
/// The function name
pub function_name: String,
Expand Down Expand Up @@ -72,91 +71,29 @@ impl FunctionCall {
pub fn function_call_type(&self) -> FunctionCallType {
self.function_call_type.clone()
}
}

#[cfg_attr(feature = "tracing", instrument(err(Debug), skip_all, parent = Span::current(), level= "Trace"))]
pub fn validate_guest_function_call_buffer(function_call_buffer: &[u8]) -> Result<()> {
let guest_function_call_fb = size_prefixed_root::<FbFunctionCall>(function_call_buffer)
.map_err(|e| anyhow::anyhow!("Error reading function call buffer: {:?}", e))?;
match guest_function_call_fb.function_call_type() {
FbFunctionCallType::guest => Ok(()),
other => {
bail!("Invalid function call type: {:?}", other);
}
}
}

#[cfg_attr(feature = "tracing", instrument(err(Debug), skip_all, parent = Span::current(), level= "Trace"))]
pub fn validate_host_function_call_buffer(function_call_buffer: &[u8]) -> Result<()> {
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Maybe I missed it, but where was this function called?
If it wasn't used at all, I am curious how the compiler hasn't warned us.

let host_function_call_fb = size_prefixed_root::<FbFunctionCall>(function_call_buffer)
.map_err(|e| anyhow::anyhow!("Error reading function call buffer: {:?}", e))?;
match host_function_call_fb.function_call_type() {
FbFunctionCallType::host => Ok(()),
other => {
bail!("Invalid function call type: {:?}", other);
}
}
}
/// Encodes self into the given builder and returns the encoded data.
pub fn encode<'a>(&self, builder: &'a mut FlatBufferBuilder) -> &'a [u8] {
let function_name = builder.create_string(&self.function_name);

impl TryFrom<&[u8]> for FunctionCall {
type Error = Error;
#[cfg_attr(feature = "tracing", instrument(err(Debug), skip_all, parent = Span::current(), level= "Trace"))]
fn try_from(value: &[u8]) -> Result<Self> {
let function_call_fb = size_prefixed_root::<FbFunctionCall>(value)
.map_err(|e| anyhow::anyhow!("Error reading function call buffer: {:?}", e))?;
let function_name = function_call_fb.function_name();
let function_call_type = match function_call_fb.function_call_type() {
FbFunctionCallType::guest => FunctionCallType::Guest,
FbFunctionCallType::host => FunctionCallType::Host,
other => {
bail!("Invalid function call type: {:?}", other);
}
};
let expected_return_type = function_call_fb.expected_return_type().try_into()?;

let parameters = function_call_fb
.parameters()
.map(|v| {
v.iter()
.map(|p| p.try_into())
.collect::<Result<Vec<ParameterValue>>>()
})
.transpose()?;

Ok(Self {
function_name: function_name.to_string(),
parameters,
function_call_type,
expected_return_type,
})
}
}

impl TryFrom<FunctionCall> for Vec<u8> {
type Error = Error;
#[cfg_attr(feature = "tracing", instrument(err(Debug), skip_all, parent = Span::current(), level= "Trace"))]
fn try_from(value: FunctionCall) -> Result<Vec<u8>> {
let mut builder = flatbuffers::FlatBufferBuilder::new();
let function_name = builder.create_string(&value.function_name);

let function_call_type = match value.function_call_type {
let function_call_type = match self.function_call_type {
FunctionCallType::Guest => FbFunctionCallType::guest,
FunctionCallType::Host => FbFunctionCallType::host,
};

let expected_return_type = value.expected_return_type.into();
let expected_return_type = self.expected_return_type.into();

let parameters = match &value.parameters {
let parameters = match &self.parameters {
Some(p) => {
let num_items = p.len();
let mut parameters: Vec<WIPOffset<Parameter>> = Vec::with_capacity(num_items);

for param in p {
match param {
ParameterValue::Int(i) => {
let hlint = hlint::create(&mut builder, &hlintArgs { value: *i });
let hlint = hlint::create(builder, &hlintArgs { value: *i });
let parameter = Parameter::create(
&mut builder,
builder,
&ParameterArgs {
value_type: FbParameterValue::hlint,
value: Some(hlint.as_union_value()),
Expand All @@ -165,9 +102,9 @@ impl TryFrom<FunctionCall> for Vec<u8> {
parameters.push(parameter);
}
ParameterValue::UInt(ui) => {
let hluint = hluint::create(&mut builder, &hluintArgs { value: *ui });
let hluint = hluint::create(builder, &hluintArgs { value: *ui });
let parameter = Parameter::create(
&mut builder,
builder,
&ParameterArgs {
value_type: FbParameterValue::hluint,
value: Some(hluint.as_union_value()),
Expand All @@ -176,9 +113,9 @@ impl TryFrom<FunctionCall> for Vec<u8> {
parameters.push(parameter);
}
ParameterValue::Long(l) => {
let hllong = hllong::create(&mut builder, &hllongArgs { value: *l });
let hllong = hllong::create(builder, &hllongArgs { value: *l });
let parameter = Parameter::create(
&mut builder,
builder,
&ParameterArgs {
value_type: FbParameterValue::hllong,
value: Some(hllong.as_union_value()),
Expand All @@ -187,10 +124,9 @@ impl TryFrom<FunctionCall> for Vec<u8> {
parameters.push(parameter);
}
ParameterValue::ULong(ul) => {
let hlulong =
hlulong::create(&mut builder, &hlulongArgs { value: *ul });
let hlulong = hlulong::create(builder, &hlulongArgs { value: *ul });
let parameter = Parameter::create(
&mut builder,
builder,
&ParameterArgs {
value_type: FbParameterValue::hlulong,
value: Some(hlulong.as_union_value()),
Expand All @@ -199,9 +135,9 @@ impl TryFrom<FunctionCall> for Vec<u8> {
parameters.push(parameter);
}
ParameterValue::Float(f) => {
let hlfloat = hlfloat::create(&mut builder, &hlfloatArgs { value: *f });
let hlfloat = hlfloat::create(builder, &hlfloatArgs { value: *f });
let parameter = Parameter::create(
&mut builder,
builder,
&ParameterArgs {
value_type: FbParameterValue::hlfloat,
value: Some(hlfloat.as_union_value()),
Expand All @@ -210,10 +146,9 @@ impl TryFrom<FunctionCall> for Vec<u8> {
parameters.push(parameter);
}
ParameterValue::Double(d) => {
let hldouble =
hldouble::create(&mut builder, &hldoubleArgs { value: *d });
let hldouble = hldouble::create(builder, &hldoubleArgs { value: *d });
let parameter = Parameter::create(
&mut builder,
builder,
&ParameterArgs {
value_type: FbParameterValue::hldouble,
value: Some(hldouble.as_union_value()),
Expand All @@ -223,9 +158,9 @@ impl TryFrom<FunctionCall> for Vec<u8> {
}
ParameterValue::Bool(b) => {
let hlbool: WIPOffset<hlbool<'_>> =
hlbool::create(&mut builder, &hlboolArgs { value: *b });
hlbool::create(builder, &hlboolArgs { value: *b });
let parameter = Parameter::create(
&mut builder,
builder,
&ParameterArgs {
value_type: FbParameterValue::hlbool,
value: Some(hlbool.as_union_value()),
Expand All @@ -236,10 +171,10 @@ impl TryFrom<FunctionCall> for Vec<u8> {
ParameterValue::String(s) => {
let hlstring = {
let val = builder.create_string(s.as_str());
hlstring::create(&mut builder, &hlstringArgs { value: Some(val) })
hlstring::create(builder, &hlstringArgs { value: Some(val) })
};
let parameter = Parameter::create(
&mut builder,
builder,
&ParameterArgs {
value_type: FbParameterValue::hlstring,
value: Some(hlstring.as_union_value()),
Expand All @@ -251,13 +186,13 @@ impl TryFrom<FunctionCall> for Vec<u8> {
let vec_bytes = builder.create_vector(v);

let hlvecbytes = hlvecbytes::create(
&mut builder,
builder,
&hlvecbytesArgs {
value: Some(vec_bytes),
},
);
let parameter = Parameter::create(
&mut builder,
builder,
&ParameterArgs {
value_type: FbParameterValue::hlvecbytes,
value: Some(hlvecbytes.as_union_value()),
Expand All @@ -279,7 +214,7 @@ impl TryFrom<FunctionCall> for Vec<u8> {
};

let function_call = FbFunctionCall::create(
&mut builder,
builder,
&FbFunctionCallArgs {
function_name: Some(function_name),
parameters,
Expand All @@ -288,9 +223,40 @@ impl TryFrom<FunctionCall> for Vec<u8> {
},
);
builder.finish_size_prefixed(function_call, None);
let res = builder.finished_data().to_vec();
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This to_vec is the clone I was able to avoid, which is the most important part of this PR

builder.finished_data()
}
}

impl TryFrom<&[u8]> for FunctionCall {
type Error = Error;
#[cfg_attr(feature = "tracing", instrument(err(Debug), skip_all, parent = Span::current(), level= "Trace"))]
fn try_from(value: &[u8]) -> Result<Self> {
let function_call_fb = size_prefixed_root::<FbFunctionCall>(value)
.map_err(|e| anyhow::anyhow!("Error reading function call buffer: {:?}", e))?;
let function_name = function_call_fb.function_name();
let function_call_type = match function_call_fb.function_call_type() {
FbFunctionCallType::guest => FunctionCallType::Guest,
FbFunctionCallType::host => FunctionCallType::Host,
other => {
bail!("Invalid function call type: {:?}", other);
}
};
let expected_return_type = function_call_fb.expected_return_type().try_into()?;
let parameters = function_call_fb
.parameters()
.map(|v| {
v.iter()
.map(|p| p.try_into())
.collect::<Result<Vec<ParameterValue>>>()
})
.transpose()?;

Ok(res)
Ok(Self {
function_name: function_name.to_string(),
parameters,
function_call_type,
expected_return_type,
})
}
}

Expand All @@ -303,7 +269,8 @@ mod tests {

#[test]
fn read_from_flatbuffer() -> Result<()> {
let test_data: Vec<u8> = FunctionCall::new(
let mut builder = FlatBufferBuilder::new();
let test_data = FunctionCall::new(
"PrintTwelveArgs".to_string(),
Some(vec![
ParameterValue::String("1".to_string()),
Expand All @@ -322,10 +289,9 @@ mod tests {
FunctionCallType::Guest,
ReturnType::Int,
)
.try_into()
.unwrap();
.encode(&mut builder);

let function_call = FunctionCall::try_from(test_data.as_slice())?;
let function_call = FunctionCall::try_from(test_data)?;
assert_eq!(function_call.function_name, "PrintTwelveArgs");
assert!(function_call.parameters.is_some());
let parameters = function_call.parameters.unwrap();
Expand Down
3 changes: 3 additions & 0 deletions src/hyperlight_common/src/lib.rs
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Expand Up @@ -36,3 +36,6 @@ pub mod flatbuffer_wrappers;
mod flatbuffers;
/// cbindgen:ignore
pub mod mem;

extern crate flatbuffers as fb;
pub use fb::FlatBufferBuilder;
2 changes: 1 addition & 1 deletion src/hyperlight_guest/src/guest_function_call.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -93,7 +93,7 @@ fn internal_dispatch_function() -> Result<()> {
set_error(e.kind.clone(), e.message.as_str());
})?;

push_shared_output_data(result_vec)
push_shared_output_data(&result_vec)
}

// This is implemented as a separate function to make sure that epilogue in the internal_dispatch_function is called before the halt()
Expand Down
8 changes: 3 additions & 5 deletions src/hyperlight_guest/src/host_function_call.rs
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Expand Up @@ -26,6 +26,7 @@ use hyperlight_common::flatbuffer_wrappers::function_types::{
use hyperlight_common::flatbuffer_wrappers::guest_error::ErrorCode;
use hyperlight_common::flatbuffer_wrappers::util::get_flatbuffer_result;
use hyperlight_common::mem::RunMode;
use hyperlight_common::FlatBufferBuilder;

use crate::error::{HyperlightGuestError, Result};
use crate::host_error::check_for_host_error;
Expand Down Expand Up @@ -73,11 +74,8 @@ pub fn call_host_function(

validate_host_function_call(&host_function_call)?;

let host_function_call_buffer: Vec<u8> = host_function_call
.try_into()
.expect("Unable to serialize host function call");

push_shared_output_data(host_function_call_buffer)?;
let mut builder = FlatBufferBuilder::new();
push_shared_output_data(host_function_call.encode(&mut builder))?;

outb(OutBAction::CallFunction as u16, 0);

Expand Down
2 changes: 1 addition & 1 deletion src/hyperlight_guest/src/logging.rs
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Expand Up @@ -44,7 +44,7 @@ fn write_log_data(
.try_into()
.expect("Failed to convert GuestLogData to bytes");

push_shared_output_data(bytes).expect("Unable to push log data to shared output data");
push_shared_output_data(&bytes).expect("Unable to push log data to shared output data");
}

pub fn log_message(
Expand Down
3 changes: 1 addition & 2 deletions src/hyperlight_guest/src/shared_output_data.rs
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Expand Up @@ -16,15 +16,14 @@ limitations under the License.

use alloc::format;
use alloc::string::ToString;
use alloc::vec::Vec;
use core::slice::from_raw_parts_mut;

use hyperlight_common::flatbuffer_wrappers::guest_error::ErrorCode;

use crate::error::{HyperlightGuestError, Result};
use crate::P_PEB;

pub fn push_shared_output_data(data: Vec<u8>) -> Result<()> {
pub fn push_shared_output_data(data: &[u8]) -> Result<()> {
let peb_ptr = unsafe { P_PEB.unwrap() };
let shared_buffer_size = unsafe { (*peb_ptr).outputdata.outputDataSize as usize };
let odb = unsafe {
Expand Down
1 change: 0 additions & 1 deletion src/hyperlight_host/Cargo.toml
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Expand Up @@ -26,7 +26,6 @@ rand = { version = "0.9" }
cfg-if = { version = "1.0.0" }
libc = { version = "0.2.172" }
paste = "1.0"
flatbuffers = "25.2.10"
page_size = "0.6.0"
termcolor = "1.2.0"
bitflags = "2.9.0"
Expand Down
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