Transfer Servo IOSurface ports over Mach

Cargo.lock

@@ -2255,6 +2255,7 @@ dependencies = [
  "gpui-component-assets",
  "image",
  "io-surface",
+ "mach2",
  "objc2",
  "objc2-core-foundation",
  "objc2-foundation",
@@ -2268,6 +2269,7 @@ dependencies = [
  "tracing-subscriber",
  "ureq",
  "url",
+ "uuid",
 ]
 
 [[package]]
@@ -2309,6 +2311,7 @@ dependencies = [
  "glow",
  "image",
  "log",
+ "mach2",
  "objc2-io-surface",
  "serde",
  "serde_json",

crates/ely_app/Cargo.toml

@@ -35,10 +35,12 @@ core-foundation = "0.10"
 # version it built against.
 core-video = "0.4"
 io-surface = "0.16"
+mach2 = "0.6"
 objc2 = "0.6"
 objc2-core-foundation = { version = "0.3.2", features = ["CFBase", "CFDictionary", "CFNumber", "CFString"] }
 objc2-foundation = { version = "0.3.1", features = ["NSDictionary", "NSString", "NSValue"] }
 objc2-io-surface = "0.3.2"
+uuid.workspace = true
 
 [dev-dependencies]
 gpui = { workspace = true, features = ["test-support"] }

crates/ely_app/src/services/iosurface_mach.rs

@@ -0,0 +1,233 @@
+use std::{
+    collections::BTreeMap,
+    ffi::CString,
+    mem,
+    time::{Duration, Instant},
+};
+
+use mach2::{
+    bootstrap::{bootstrap_port, bootstrap_register},
+    kern_return::KERN_SUCCESS,
+    mach_port::{mach_port_allocate, mach_port_destroy, mach_port_insert_right},
+    message::{
+        MACH_MSG_PORT_DESCRIPTOR, MACH_MSG_SUCCESS, MACH_MSG_TIMEOUT_NONE, MACH_MSG_TYPE_MAKE_SEND,
+        MACH_RCV_MSG, MACH_RCV_TIMED_OUT, MACH_RCV_TIMEOUT, mach_msg, mach_msg_body_t,
+        mach_msg_header_t, mach_msg_port_descriptor_t, mach_msg_trailer_t,
+    },
+    port::{MACH_PORT_NULL, MACH_PORT_RIGHT_RECEIVE, mach_port_t},
+    traps::mach_task_self,
+};
+use thiserror::Error;
+use uuid::Uuid;
+
+const IOSURFACE_PORT_MESSAGE_ID: i32 = 0x454c_5901;
+const SERVICE_PREFIX: &str = "com.ely.browser.iosurface";
+
+pub(crate) struct IOSurfaceMachReceiver {
+    service_name: String,
+    receive_port: mach_port_t,
+    pending_ports: BTreeMap<u64, mach_port_t>,
+}
+
+#[derive(Debug, Error)]
+pub(crate) enum IOSurfaceMachError {
+    #[error("Mach service name contains an interior nul byte")]
+    InvalidServiceName,
+
+    #[error("mach_port_allocate returned {code}")]
+    AllocatePort { code: i32 },
+
+    #[error("mach_port_insert_right returned {code}")]
+    InsertSendRight { code: i32 },
+
+    #[error("bootstrap_register returned {code}")]
+    RegisterService { code: i32 },
+
+    #[error("mach_msg receive timed out for IOSurface surface {surface_id:#x}")]
+    ReceiveTimedOut { surface_id: u64 },
+
+    #[error("mach_msg receive returned {code}")]
+    Receive { code: i32 },
+
+    #[error("received unexpected Mach message id {message_id}")]
+    UnexpectedMessage { message_id: i32 },
+
+    #[error("received invalid IOSurface Mach message")]
+    InvalidMessage,
+}
+
+impl IOSurfaceMachReceiver {
+    pub(crate) fn new() -> Result<Self, IOSurfaceMachError> {
+        let service_name = unique_service_name();
+        let service_name_c = CString::new(service_name.as_str())
+            .map_err(|_| IOSurfaceMachError::InvalidServiceName)?;
+        let mut receive_port = MACH_PORT_NULL;
+
+        #[expect(unsafe_code)]
+        let task = unsafe { mach_task_self() };
+        #[expect(unsafe_code)]
+        let allocate =
+            unsafe { mach_port_allocate(task, MACH_PORT_RIGHT_RECEIVE, &mut receive_port) };
+        if allocate != KERN_SUCCESS {
+            return Err(IOSurfaceMachError::AllocatePort { code: allocate });
+        }
+
+        #[expect(unsafe_code)]
+        let insert = unsafe {
+            mach_port_insert_right(task, receive_port, receive_port, MACH_MSG_TYPE_MAKE_SEND)
+        };
+        if insert != KERN_SUCCESS {
+            destroy_port(receive_port);
+            return Err(IOSurfaceMachError::InsertSendRight { code: insert });
+        }
+
+        #[expect(unsafe_code)]
+        #[allow(deprecated)]
+        let register = unsafe {
+            bootstrap_register(bootstrap_port, service_name_c.as_ptr() as *mut _, receive_port)
+        };
+        if register != KERN_SUCCESS {
+            destroy_port(receive_port);
+            return Err(IOSurfaceMachError::RegisterService { code: register });
+        }
+
+        Ok(Self { service_name, receive_port, pending_ports: BTreeMap::new() })
+    }
+
+    pub(crate) fn service_name(&self) -> &str {
+        self.service_name.as_str()
+    }
+
+    pub(crate) fn receive_port_for_surface(
+        &mut self,
+        surface_id: u64,
+        timeout: Duration,
+    ) -> Result<mach_port_t, IOSurfaceMachError> {
+        if let Some(port) = self.pending_ports.remove(&surface_id) {
+            return Ok(port);
+        }
+
+        let deadline = Instant::now() + timeout;
+        loop {
+            let remaining = deadline.saturating_duration_since(Instant::now());
+            if remaining.is_zero() {
+                return Err(IOSurfaceMachError::ReceiveTimedOut { surface_id });
+            }
+            let Some(received) = self.receive_one(remaining)? else {
+                return Err(IOSurfaceMachError::ReceiveTimedOut { surface_id });
+            };
+            if received.surface_id == surface_id {
+                return Ok(received.mach_port);
+            }
+            self.pending_ports.insert(received.surface_id, received.mach_port);
+        }
+    }
+
+    fn receive_one(
+        &self,
+        timeout: Duration,
+    ) -> Result<Option<ReceivedSurfacePort>, IOSurfaceMachError> {
+        #[expect(unsafe_code)]
+        let mut received_message: ReceivedIOSurfacePortMessage = unsafe { mem::zeroed() };
+        let timeout_ms = timeout_millis(timeout);
+        #[expect(unsafe_code)]
+        let result = unsafe {
+            mach_msg(
+                &mut received_message.message.header,
+                MACH_RCV_MSG | MACH_RCV_TIMEOUT,
+                0,
+                mem::size_of::<ReceivedIOSurfacePortMessage>() as u32,
+                self.receive_port,
+                timeout_ms,
+                MACH_PORT_NULL,
+            )
+        };
+
+        if result == MACH_RCV_TIMED_OUT {
+            return Ok(None);
+        }
+        if result != MACH_MSG_SUCCESS {
+            return Err(IOSurfaceMachError::Receive { code: result });
+        }
+        let message = &mut received_message.message;
+        if message.header.msgh_id != IOSURFACE_PORT_MESSAGE_ID {
+            destroy_message(message);
+            return Err(IOSurfaceMachError::UnexpectedMessage {
+                message_id: message.header.msgh_id,
+            });
+        }
+        if message.body.msgh_descriptor_count != 1
+            || message.surface_port.type_ != MACH_MSG_PORT_DESCRIPTOR as u8
+            || message.surface_port.name == MACH_PORT_NULL
+        {
+            destroy_message(message);
+            return Err(IOSurfaceMachError::InvalidMessage);
+        }
+
+        Ok(Some(ReceivedSurfacePort {
+            surface_id: message.surface_id,
+            mach_port: message.surface_port.name,
+        }))
+    }
+}
+
+impl Drop for IOSurfaceMachReceiver {
+    fn drop(&mut self) {
+        for port in std::mem::take(&mut self.pending_ports).into_values() {
+            deallocate_port(port);
+        }
+        destroy_port(self.receive_port);
+    }
+}
+
+struct ReceivedSurfacePort {
+    surface_id: u64,
+    mach_port: mach_port_t,
+}
+
+#[repr(C)]
+struct IOSurfacePortMessage {
+    header: mach_msg_header_t,
+    body: mach_msg_body_t,
+    surface_port: mach_msg_port_descriptor_t,
+    surface_id: u64,
+}
+
+#[repr(C)]
+struct ReceivedIOSurfacePortMessage {
+    message: IOSurfacePortMessage,
+    _trailer: mach_msg_trailer_t,
+}
+
+fn unique_service_name() -> String {
+    format!("{SERVICE_PREFIX}.{}", Uuid::now_v7().as_simple())
+}
+
+fn timeout_millis(timeout: Duration) -> u32 {
+    u32::try_from(timeout.as_millis()).unwrap_or(u32::MAX).max(MACH_MSG_TIMEOUT_NONE + 1)
+}
+
+fn destroy_message(message: &mut IOSurfacePortMessage) {
+    #[expect(unsafe_code)]
+    unsafe {
+        mach2::message::mach_msg_destroy(&mut message.header);
+    }
+}
+
+fn destroy_port(port: mach_port_t) {
+    #[expect(unsafe_code)]
+    let task = unsafe { mach_task_self() };
+    #[expect(unsafe_code)]
+    unsafe {
+        let _ = mach_port_destroy(task, port);
+    }
+}
+
+fn deallocate_port(port: mach_port_t) {
+    #[expect(unsafe_code)]
+    let task = unsafe { mach_task_self() };
+    #[expect(unsafe_code)]
+    unsafe {
+        let _ = mach2::mach_port::mach_port_deallocate(task, port);
+    }
+}

crates/ely_app/src/services/mod.rs

@@ -2,6 +2,8 @@ pub mod download_checksums;
 pub mod download_files;
 pub mod http_downloads;
 #[cfg(target_os = "macos")]
+pub(crate) mod iosurface_mach;
+#[cfg(target_os = "macos")]
 pub(crate) mod iosurface_metal;
 pub mod plugin_package_store;
 pub mod plugin_packages;

crates/ely_app/src/services/servo_live.rs

@@ -2,6 +2,7 @@ use std::{
     io::{self, BufRead, BufReader, Read, Write},
     path::PathBuf,
     process::{Child, ChildStdin, ChildStdout, Stdio},
+    time::Duration,
 };
 
 /// Environment variable that lets the user pick the rendering context
@@ -18,13 +19,16 @@ use thiserror::Error;
 mod wire;
 
 use super::servo_sidecar_command::{
-    SidecarCommandError, default_sidecar_command, rendering_context_from_env,
+    SidecarCommandError, SidecarRenderingContext, default_sidecar_command,
+    rendering_context_from_env,
 };
 use wire::{
     LiveFrameReport, LiveRequest, LiveResponse, LiveSurfaceHandle, log_frame_perf,
     log_iosurface_current, log_iosurface_handle,
 };
 
+#[cfg(target_os = "macos")]
+use super::iosurface_mach::{IOSurfaceMachError, IOSurfaceMachReceiver};
 #[cfg(target_os = "macos")]
 use super::iosurface_metal::IOSurfaceCache;
 #[cfg(target_os = "macos")]
@@ -39,6 +43,8 @@ pub(crate) struct ServoLiveClient {
     /// software-path tabs never trigger construction.
     #[cfg(target_os = "macos")]
     iosurface_cache: IOSurfaceCache,
+    #[cfg(target_os = "macos")]
+    iosurface_receiver: Option<IOSurfaceMachReceiver>,
 }
 
 impl ServoLiveClient {
@@ -48,9 +54,18 @@ impl ServoLiveClient {
             return Err(ServoLiveError::SidecarBinaryUnavailable { path: path.to_path_buf() });
         }
 
+        let rendering_context = rendering_context_from_env();
         let mut command = command_target.command();
         command.arg("live").arg("--profile-data-dir").arg(profile_data_dir);
-        command.arg("--rendering-context").arg(rendering_context_from_env().cli_arg());
+        command.arg("--rendering-context").arg(rendering_context.cli_arg());
+        #[cfg(target_os = "macos")]
+        let iosurface_receiver = if rendering_context == SidecarRenderingContext::Hardware {
+            let receiver = IOSurfaceMachReceiver::new()?;
+            command.arg("--iosurface-mach-service").arg(receiver.service_name());
+            Some(receiver)
+        } else {
+            None
+        };
         let mut child = command
             .stdin(Stdio::piped())
             .stdout(Stdio::piped())
@@ -67,6 +82,8 @@ impl ServoLiveClient {
             stdout: BufReader::new(stdout),
             #[cfg(target_os = "macos")]
             iosurface_cache: IOSurfaceCache::new(),
+            #[cfg(target_os = "macos")]
+            iosurface_receiver,
         })
     }
 
@@ -195,7 +212,13 @@ impl ServoLiveClient {
         &mut self,
         handle: &LiveSurfaceHandle,
     ) -> Result<(), ServoLiveError> {
-        match self.iosurface_cache.import(handle.mach_port_name, handle.surface_id) {
+        let mach_port_name = match self.iosurface_receiver.as_mut() {
+            Some(receiver) => {
+                receiver.receive_port_for_surface(handle.surface_id, Duration::from_secs(1))?
+            }
+            None => handle.mach_port_name,
+        };
+        match self.iosurface_cache.import(mach_port_name, handle.surface_id) {
             Ok(()) => tracing::info!(
                 target: "ely::servo::iosurface",
                 surface_id = handle.surface_id,
@@ -212,7 +235,7 @@ impl ServoLiveClient {
                 );
                 return Err(ServoLiveError::IOSurfaceImportFailed {
                     surface_id: handle.surface_id,
-                    mach_port_name: handle.mach_port_name,
+                    mach_port_name,
                     message: error.to_string(),
                 });
             }
@@ -438,6 +461,10 @@ pub(crate) enum ServoLiveError {
     #[error("servo live IOSurface {surface_id:#x} was selected before its pixel buffer import")]
     IOSurfacePixelBufferMissing { surface_id: u64 },
 
+    #[cfg(target_os = "macos")]
+    #[error(transparent)]
+    IOSurfaceMach(#[from] IOSurfaceMachError),
+
     #[error(transparent)]
     Json(#[from] serde_json::Error),
 

crates/ely_servo_host/Cargo.toml

@@ -14,6 +14,7 @@ hardware-render = [
     "dep:glow",
     "dep:image",
     "dep:log",
+    "dep:mach2",
     "dep:surfman",
     "dep:objc2-io-surface",
 ]
@@ -39,6 +40,7 @@ thiserror.workspace = true
 url = { workspace = true, optional = true }
 
 [target.'cfg(target_os = "macos")'.dependencies]
+mach2 = { version = "0.6", optional = true }
 objc2-io-surface = { version = "0.3.2", optional = true }
 
 [lints]

crates/ely_servo_host/src/bin/ely_servo_sidecar.rs

@@ -14,6 +14,9 @@ use thiserror::Error;
 
 #[path = "ely_servo_sidecar/args.rs"]
 mod args;
+#[cfg(all(feature = "hardware-render", target_os = "macos"))]
+#[path = "ely_servo_sidecar/iosurface_mach.rs"]
+mod iosurface_mach;
 #[path = "ely_servo_sidecar/live.rs"]
 mod live;
 #[path = "ely_servo_sidecar/live_output.rs"]

crates/ely_servo_host/src/bin/ely_servo_sidecar/args.rs

@@ -15,6 +15,7 @@ pub(super) enum SidecarCommand {
 
 pub(super) struct LiveArgs {
     pub(super) profile_data_dir: PathBuf,
+    pub(super) iosurface_mach_service: Option<String>,
     /// Rendering context the host's webviews are built against.
     /// Defaults to [`RenderingContextKind::Software`], which keeps
     /// the binary's behaviour bit-identical to pre-flag builds.
@@ -137,6 +138,7 @@ fn parse_command(
 fn parse_live_args(args: impl IntoIterator<Item = String>) -> Result<LiveArgs, SidecarArgsError> {
     let mut args = args.into_iter();
     let mut profile_data_dir = None;
+    let mut iosurface_mach_service = None;
     let mut rendering_context_kind = RenderingContextKind::default();
 
     while let Some(name) = args.next() {
@@ -155,6 +157,10 @@ fn parse_live_args(args: impl IntoIterator<Item = String>) -> Result<LiveArgs, S
                     _ => return Err(SidecarArgsError::InvalidRenderingContext { value }),
                 };
             }
+            "--iosurface-mach-service" => {
+                iosurface_mach_service =
+                    Some(next_argument(&mut args, "--iosurface-mach-service")?);
+            }
             _ => return Err(SidecarArgsError::UnknownArgument { value: name }),
         }
     }
@@ -162,6 +168,7 @@ fn parse_live_args(args: impl IntoIterator<Item = String>) -> Result<LiveArgs, S
     Ok(LiveArgs {
         profile_data_dir: profile_data_dir
             .ok_or(SidecarArgsError::MissingRequiredArgument { name: "--profile-data-dir" })?,
+        iosurface_mach_service,
         rendering_context_kind,
     })
 }

crates/ely_servo_host/src/bin/ely_servo_sidecar/args_tests.rs

@@ -159,6 +159,13 @@ fn live_accepts_explicit_hardware_rendering_context() -> Result<(), SidecarArgsE
     Ok(())
 }
 
+#[test]
+fn live_accepts_iosurface_mach_service_name() -> Result<(), SidecarArgsError> {
+    let args = parse_live(&["--iosurface-mach-service", "com.ely.test.iosurface"])?;
+    assert_eq!(args.iosurface_mach_service.as_deref(), Some("com.ely.test.iosurface"));
+    Ok(())
+}
+
 #[test]
 fn live_rejects_unknown_rendering_context_value() {
     assert!(matches!(

crates/ely_servo_host/src/bin/ely_servo_sidecar/iosurface_mach.rs

@@ -0,0 +1,133 @@
+use std::{ffi::CString, mem, time::Duration};
+
+use mach2::{
+    bootstrap::{bootstrap_look_up, bootstrap_port},
+    kern_return::KERN_SUCCESS,
+    mach_port::mach_port_deallocate,
+    message::{
+        MACH_MSG_SUCCESS, MACH_MSG_TYPE_COPY_SEND, MACH_MSG_TYPE_MOVE_SEND, MACH_MSGH_BITS,
+        MACH_MSGH_BITS_COMPLEX, MACH_SEND_MSG, MACH_SEND_TIMEOUT, mach_msg, mach_msg_body_t,
+        mach_msg_header_t, mach_msg_port_descriptor_t,
+    },
+    port::{MACH_PORT_NULL, mach_port_t},
+    traps::mach_task_self,
+};
+use thiserror::Error;
+
+use super::live_protocol::{LiveOutcome, LiveSidecarError};
+
+const IOSURFACE_PORT_MESSAGE_ID: i32 = 0x454c_5901;
+const SEND_TIMEOUT: Duration = Duration::from_secs(1);
+
+pub(super) struct IOSurfaceMachSender {
+    send_port: mach_port_t,
+}
+
+#[derive(Debug, Error)]
+pub(super) enum IOSurfaceMachError {
+    #[error("Mach service name contains an interior nul byte")]
+    InvalidServiceName,
+
+    #[error("bootstrap_look_up returned {code}")]
+    LookupService { code: i32 },
+
+    #[error("mach_msg send returned {code}")]
+    Send { code: i32 },
+}
+
+impl IOSurfaceMachSender {
+    pub(super) fn connect(service_name: &str) -> Result<Self, IOSurfaceMachError> {
+        let service_name =
+            CString::new(service_name).map_err(|_| IOSurfaceMachError::InvalidServiceName)?;
+        let mut send_port = MACH_PORT_NULL;
+        #[expect(unsafe_code)]
+        let result =
+            unsafe { bootstrap_look_up(bootstrap_port, service_name.as_ptr(), &mut send_port) };
+        if result != KERN_SUCCESS {
+            return Err(IOSurfaceMachError::LookupService { code: result });
+        }
+        Ok(Self { send_port })
+    }
+
+    pub(super) fn send_surface_port(
+        &mut self,
+        surface_id: u64,
+        mach_port: mach_port_t,
+    ) -> Result<(), IOSurfaceMachError> {
+        let mut message = IOSurfacePortMessage {
+            header: mach_msg_header_t {
+                msgh_bits: MACH_MSGH_BITS(MACH_MSG_TYPE_COPY_SEND, 0) | MACH_MSGH_BITS_COMPLEX,
+                msgh_size: mem::size_of::<IOSurfacePortMessage>() as u32,
+                msgh_remote_port: self.send_port,
+                msgh_local_port: MACH_PORT_NULL,
+                msgh_voucher_port: MACH_PORT_NULL,
+                msgh_id: IOSURFACE_PORT_MESSAGE_ID,
+            },
+            body: mach_msg_body_t { msgh_descriptor_count: 1 },
+            surface_port: mach_msg_port_descriptor_t::new(mach_port, MACH_MSG_TYPE_MOVE_SEND),
+            surface_id,
+        };
+        #[expect(unsafe_code)]
+        let result = unsafe {
+            mach_msg(
+                &mut message.header,
+                MACH_SEND_MSG | MACH_SEND_TIMEOUT,
+                message.header.msgh_size,
+                0,
+                MACH_PORT_NULL,
+                timeout_millis(SEND_TIMEOUT),
+                MACH_PORT_NULL,
+            )
+        };
+        if result != MACH_MSG_SUCCESS {
+            destroy_message(&mut message);
+            return Err(IOSurfaceMachError::Send { code: result });
+        }
+        Ok(())
+    }
+}
+
+impl Drop for IOSurfaceMachSender {
+    fn drop(&mut self) {
+        #[expect(unsafe_code)]
+        let task = unsafe { mach_task_self() };
+        #[expect(unsafe_code)]
+        unsafe {
+            let _ = mach_port_deallocate(task, self.send_port);
+        }
+    }
+}
+
+pub(super) fn send_surface_port_if_needed(
+    sender: Option<&mut IOSurfaceMachSender>,
+    outcome: &mut Result<LiveOutcome, LiveSidecarError>,
+) {
+    let (Some(sender), Ok(live_outcome)) = (sender, outcome.as_ref()) else {
+        return;
+    };
+    let Some(handle) = live_outcome.response.surface_handle else {
+        return;
+    };
+    if let Err(error) = sender.send_surface_port(handle.surface_id, handle.mach_port_name) {
+        *outcome = Err(LiveSidecarError::IOSurfaceMach(error));
+    }
+}
+
+#[repr(C)]
+struct IOSurfacePortMessage {
+    header: mach_msg_header_t,
+    body: mach_msg_body_t,
+    surface_port: mach_msg_port_descriptor_t,
+    surface_id: u64,
+}
+
+fn timeout_millis(timeout: Duration) -> u32 {
+    u32::try_from(timeout.as_millis()).unwrap_or(u32::MAX).max(1)
+}
+
+fn destroy_message(message: &mut IOSurfacePortMessage) {
+    #[expect(unsafe_code)]
+    unsafe {
+        mach2::message::mach_msg_destroy(&mut message.header);
+    }
+}

crates/ely_servo_host/src/bin/ely_servo_sidecar/live.rs

@@ -14,6 +14,8 @@ use ely_servo_host::{
 };
 
 use super::args::LiveArgs;
+#[cfg(all(feature = "hardware-render", target_os = "macos"))]
+use super::iosurface_mach::{IOSurfaceMachSender, send_surface_port_if_needed};
 use super::live_output::{populate_surface_fields, write_outcome};
 pub(super) use super::live_protocol::LiveSidecarError;
 use super::live_protocol::{
@@ -28,14 +30,19 @@ const LIVE_FRAME_WAIT_TIMEOUT: Duration = Duration::from_millis(250);
 const LIVE_FRAME_WAIT_INTERVAL: Duration = Duration::from_millis(2);
 
 pub(super) fn run_live(args: LiveArgs) -> Result<(), LiveSidecarError> {
-    fs::create_dir_all(&args.profile_data_dir)?;
-    let rendering_context_kind = args.rendering_context_kind;
+    let LiveArgs { profile_data_dir, iosurface_mach_service, rendering_context_kind } = args;
+    fs::create_dir_all(&profile_data_dir)?;
     let context_label = rendering_context_label(rendering_context_kind);
     let mut host = SoftwareServoHost::new_with_config_dir_and_kind(
         ServoSurfaceSize::new(1, 1),
-        Some(args.profile_data_dir),
+        Some(profile_data_dir),
         rendering_context_kind,
     )?;
+    #[cfg(all(feature = "hardware-render", target_os = "macos"))]
+    let mut iosurface_mach_sender =
+        iosurface_mach_service.as_deref().map(IOSurfaceMachSender::connect).transpose()?;
+    #[cfg(not(all(feature = "hardware-render", target_os = "macos")))]
+    let _ = iosurface_mach_service;
     let mut sessions = HashMap::new();
     let mut perf =
         FramePerfAggregator::new(context_label, FramePerfAggregator::DEFAULT_WINDOW_SIZE);
@@ -56,7 +63,7 @@ pub(super) fn run_live(args: LiveArgs) -> Result<(), LiveSidecarError> {
         // matching stop is the `stdout.flush()` inside
         // `write_outcome`.
         let frame_started_at = Instant::now();
-        let outcome = match serde_json::from_str::<LiveRequest>(&line) {
+        let mut outcome = match serde_json::from_str::<LiveRequest>(&line) {
             Ok(request) => handle_request(
                 &mut host,
                 &mut sessions,
@@ -66,6 +73,8 @@ pub(super) fn run_live(args: LiveArgs) -> Result<(), LiveSidecarError> {
             ),
             Err(error) => Err(LiveSidecarError::Json(error)),
         };
+        #[cfg(all(feature = "hardware-render", target_os = "macos"))]
+        send_surface_port_if_needed(iosurface_mach_sender.as_mut(), &mut outcome);
         write_outcome(&mut stdout, &mut perf, &mut pending_summary, outcome, frame_started_at)?;
     }
 

crates/ely_servo_host/src/bin/ely_servo_sidecar/live_protocol.rs

@@ -9,6 +9,8 @@ use ely_servo_host::{
 use serde::{Deserialize, Serialize};
 use thiserror::Error;
 
+#[cfg(all(feature = "hardware-render", target_os = "macos"))]
+use super::iosurface_mach::IOSurfaceMachError;
 use super::perf::FramePerfSummary;
 
 #[derive(Deserialize)]
@@ -242,6 +244,10 @@ pub(super) enum LiveSidecarError {
 
     #[error(transparent)]
     Json(#[from] serde_json::Error),
+
+    #[cfg(all(feature = "hardware-render", target_os = "macos"))]
+    #[error(transparent)]
+    IOSurfaceMach(#[from] IOSurfaceMachError),
 }
 
 #[cfg(test)]