guest-agent: remove EmitEvent API

The RPC only meaningfully works on TDX (RTMR3 extension), is rarely used,
and cannot be implemented faithfully in the simulator or across TEEs. Apps
that need extra runtime measurements should use native TEE interfaces.
Keep emit_runtime_event for guest boot measurements in dstack-util.

Author: kvinwang

docs/native-tee-interfaces.md

@@ -144,4 +144,4 @@ For configfs-tsm, permissions can be more provider-specific. If your main proces
 
 On TDX, RTMR3 is an append-only runtime measurement register. It is useful when a launcher measures code or configuration first, then hands permission and execution to the measured code.
 
-Use `/EmitEvent` through `/var/run/dstack.sock` when you want dstack's event log and verifier to replay an application runtime measurement. If your application extends RTMR3 directly through native interfaces, your application owns the event-log story for those extensions.
+dstack itself extends RTMR3 during guest boot (compose-hash, key-provider, instance-id, and related runtime events). Applications that need additional runtime measurements should extend RTMR3 through the native TDX / TSM measurement interfaces documented above and own the event-log story for those extensions.

docs/security/security-model.md

@@ -166,7 +166,7 @@ dstack replays an event log only for RTMR3. RTMR0-2 (and MRTD) are not replayed
 
 This is also reflected at the source: the event log shipped alongside an attestation is stripped down to RTMR3 entries before it is embedded. `VersionedAttestation::into_stripped()` keeps only events with `imr == 3` (see `dstack-attest/src/attestation.rs`), and verification only ever replays those runtime events against `rt_mr3` (`verify_tdx_quote_with_events` / `decode_mr_tdx_from_quote`).
 
-The reason boot-time event log entries (RTMR0-2) are dropped is that **nothing downstream consumes them**. Verification recomputes the OS-layer measurements directly from the signed `rt_mr0/1/2` values and compares them to independently reproduced expected measurements, so the corresponding boot event log would be redundant. Keeping it would only bloat the RA-TLS certificate and expose extra detail without adding any verification capability. RTMR3, by contrast, is runtime-extended (compose-hash, key-provider, instance-id, and application-emitted events), so its event log is the only one with a real consumer — the replay that proves what was extended into RTMR3.
+The reason boot-time event log entries (RTMR0-2) are dropped is that **nothing downstream consumes them**. Verification recomputes the OS-layer measurements directly from the signed `rt_mr0/1/2` values and compares them to independently reproduced expected measurements, so the corresponding boot event log would be redundant. Keeping it would only bloat the RA-TLS certificate and expose extra detail without adding any verification capability. RTMR3, by contrast, is runtime-extended (compose-hash, key-provider, instance-id, and other guest boot events), so its event log is the only one with a real consumer — the replay that proves what was extended into RTMR3.
 
 ### Why TDX lite mode does not validate ACPI table contents
 

dstack-attest/src/lib.rs

@@ -24,8 +24,7 @@ mod v1;
 /// Appending to the event log and extending RTMR3 must happen atomically as a
 /// unit: the order of log entries has to match the order of RTMR extensions,
 /// otherwise the RTMR replay performed during quote verification will not
-/// reproduce the measured value. Concurrent callers (e.g. multiple
-/// `emit_event` RPCs hitting the guest-agent at once) would otherwise be able
+/// reproduce the measured value. Concurrent callers would otherwise be able
 /// to interleave their log writes and `extend_rtmr` calls.
 static EMIT_LOCK: LazyLock<Mutex<()>> = LazyLock::new(|| Mutex::new(()));
 

guest-agent-simulator/src/main.rs

@@ -6,7 +6,7 @@ mod simulator;
 
 use std::sync::Arc;
 
-use anyhow::{bail, Context, Result};
+use anyhow::{Context, Result};
 use clap::Parser;
 use dstack_guest_agent::{
     backend::PlatformBackend,
@@ -89,10 +89,6 @@ impl PlatformBackend for SimulatorPlatform {
     fn attest_response(&self, report_data: [u8; 64]) -> Result<AttestResponse> {
         simulator::simulated_attest_response(&self.attestation, report_data, self.patch_report_data)
     }
-
-    fn emit_event(&self, event: &str, _payload: &[u8]) -> Result<()> {
-        bail!("runtime event emission is unavailable in simulator mode: {event}")
-    }
 }
 
 #[rocket::main]
@@ -145,13 +141,6 @@ mod tests {
         SimulatorPlatform::new(fixture, true)
     }
 
-    #[test]
-    fn simulator_rejects_runtime_event_emission() {
-        let platform = load_fixture_platform();
-        let err = platform.emit_event("test.event", b"payload").unwrap_err();
-        assert!(err.to_string().contains("unavailable in simulator mode"));
-    }
-
     #[test]
     fn simulator_provides_certificate_attestation() {
         let platform = load_fixture_platform();

guest-agent/rpc/proto/agent_rpc.proto

@@ -50,9 +50,6 @@ service DstackGuest {
   // Returns a dstack-defined attestation format that supports different attestation modes across platforms.
   rpc Attest(RawQuoteArgs) returns (AttestResponse) {}
 
-  // Emit an event. This extends the event to RTMR3 on TDX platform.
-  rpc EmitEvent(EmitEventArgs) returns (google.protobuf.Empty) {}
-
   // Get app info
   rpc Info(google.protobuf.Empty) returns (AppInfo) {}
 
@@ -205,13 +202,6 @@ message GetQuoteResponse {
   bytes attestation = 5;
 }
 
-message EmitEventArgs {
-  // The event name
-  string event = 1;
-  // The event data
-  bytes payload = 2;
-}
-
 // The request to derive a key
 message AppInfo {
   // App ID

guest-agent/src/backend.rs

@@ -3,7 +3,6 @@
 // SPDX-License-Identifier: Apache-2.0
 
 use anyhow::{Context, Result};
-use dstack_attest::emit_runtime_event;
 use dstack_guest_agent_rpc::{AttestResponse, GetQuoteResponse};
 use ra_tls::attestation::Attestation;
 use ra_tls::attestation::{QuoteContentType, VersionedAttestation};
@@ -13,7 +12,6 @@ pub trait PlatformBackend: Send + Sync {
     fn certificate_attestation(&self, pubkey: &[u8]) -> Result<VersionedAttestation>;
     fn quote_response(&self, report_data: [u8; 64], vm_config: &str) -> Result<GetQuoteResponse>;
     fn attest_response(&self, report_data: [u8; 64]) -> Result<AttestResponse>;
-    fn emit_event(&self, event: &str, payload: &[u8]) -> Result<()>;
 }
 
 #[derive(Debug, Default)]
@@ -62,8 +60,4 @@ impl PlatformBackend for RealPlatform {
             attestation: attestation.into_versioned().to_bytes()?,
         })
     }
-
-    fn emit_event(&self, event: &str, payload: &[u8]) -> Result<()> {
-        emit_runtime_event(event, payload)
-    }
 }

guest-agent/src/rpc_service.rs

@@ -11,10 +11,10 @@ use dstack_guest_agent_rpc::{
     dstack_guest_server::{DstackGuestRpc, DstackGuestServer},
     tappd_server::{TappdRpc, TappdServer},
     worker_server::{WorkerRpc, WorkerServer},
-    AppInfo, AttestResponse, DeriveK256KeyResponse, DeriveKeyArgs, EmitEventArgs,
-    GetAttestationForAppKeyRequest, GetKeyArgs, GetKeyResponse, GetQuoteResponse, GetTlsKeyArgs,
-    GetTlsKeyResponse, RawQuoteArgs, SignRequest, SignResponse, TdxQuoteArgs, TdxQuoteResponse,
-    VerifyRequest, VerifyResponse, WorkerVersion,
+    AppInfo, AttestResponse, DeriveK256KeyResponse, DeriveKeyArgs, GetAttestationForAppKeyRequest,
+    GetKeyArgs, GetKeyResponse, GetQuoteResponse, GetTlsKeyArgs, GetTlsKeyResponse, RawQuoteArgs,
+    SignRequest, SignResponse, TdxQuoteArgs, TdxQuoteResponse, VerifyRequest, VerifyResponse,
+    WorkerVersion,
 };
 use dstack_types::{AppKeys, SysConfig};
 use ed25519_dalek::ed25519::signature::hazmat::{PrehashSigner, PrehashVerifier};
@@ -179,10 +179,6 @@ impl AppState {
     fn attest_response(&self, report_data: [u8; 64]) -> Result<AttestResponse> {
         self.inner.platform.attest_response(report_data)
     }
-
-    fn emit_event(&self, event: &str, payload: &[u8]) -> Result<()> {
-        self.inner.platform.emit_event(event, payload)
-    }
 }
 
 pub struct InternalRpcHandler {
@@ -328,10 +324,6 @@ impl DstackGuestRpc for InternalRpcHandler {
         self.state.quote_response(report_data)
     }
 
-    async fn emit_event(self, request: EmitEventArgs) -> Result<()> {
-        self.state.emit_event(&request.event, &request.payload)
-    }
-
     async fn info(self) -> Result<AppInfo> {
         get_info(&self.state, false).await
     }
@@ -858,10 +850,6 @@ pNs85uhOZE8z2jr8Pg==
                     attestation: VersionedAttestation::V1 { attestation }.to_bytes()?,
                 })
             }
-
-            fn emit_event(&self, _event: &str, _payload: &[u8]) -> Result<()> {
-                Ok(())
-            }
         }
 
         let inner = AppStateInner {

sdk/curl/api.md

@@ -174,34 +174,7 @@ curl --unix-socket /var/run/dstack.sock http://dstack/Info
 }
 ```
 
-### 5. Emit Event
-
-Emit an event to be extended to RTMR3 on TDX platform. This API requires dstack OS 0.5.0 or later.
-
-**Endpoint:** `/EmitEvent`
-
-**Request Parameters:**
-
-| Field | Type | Description | Example |
-|-------|------|-------------|----------|
-| `event` | string | The event name | `"custom-event"` |
-| `payload` | string | Hex-encoded payload data | `"deadbeef"` |
-
-**Example:**
-```bash
-curl --unix-socket /var/run/dstack.sock -X POST \
-  http://dstack/EmitEvent \
-  -H 'Content-Type: application/json' \
-  -d '{
-    "event": "custom-event",
-    "payload": "deadbeef"
-  }'
-```
-
-**Response:**
-Empty response with HTTP 200 status code on success.
-
-### 6. Sign (not yet released)
+### 5. Sign (not yet released)
 
 Signs a payload.
 
@@ -238,7 +211,7 @@ curl --unix-socket /var/run/dstack.sock -X POST \
 }
 ```
 
-### 7. Verify (not yet released)
+### 6. Verify (not yet released)
 
 Verifies a signature.
 
@@ -273,7 +246,7 @@ curl --unix-socket /var/run/dstack.sock -X POST \
 }
 ```
 
-### 8. Attest
+### 7. Attest
 
 Generates a versioned attestation with the given report data. Returns a dstack-defined attestation format that supports different attestation modes across platforms.
 You can submit the returned `attestation` directly to the verifier `/verify` endpoint.

sdk/go/README.md

@@ -168,37 +168,6 @@ tlsKey2, _ := client.GetTlsKey(ctx, dstack.TlsKeyOptions{})
 // tlsKey1.Key != tlsKey2.Key (always different!)
 ```
 
-### Event Logging
-
-> [!NOTE]
-> This feature isn't available in the simulator. We recommend sticking with `report_data` for most cases since it's simpler and safer to use. If you're not super familiar with SGX/TDX attestation quotes, it's best to avoid adding data directly into quotes as it could cause verification issues.
-
-Extend RTMR3 with custom events for audit trails:
-
-```go
-// Emit custom events (requires dstack OS 0.5.0+)
-eventData := map[string]interface{}{
-	"action":    "transfer",
-	"amount":    1000,
-	"timestamp": time.Now().Unix(),
-}
-eventPayload, _ := json.Marshal(eventData)
-
-err := client.EmitEvent(ctx, "user-action", eventPayload)
-if err != nil {
-	log.Fatal(err)
-}
-
-// Events are automatically included in subsequent quotes
-quote, err := client.GetQuote(ctx, []byte("audit-data"))
-if err != nil {
-	log.Fatal(err)
-}
-
-var events []interface{}
-json.Unmarshal([]byte(quote.EventLog), &events)
-```
-
 ## Optional blockchain helpers (build tags)
 
 By default, the Go SDK builds a **core profile** (attestation, key derivation, info, signing, env encryption).
@@ -655,18 +624,6 @@ cert2, _ := client.GetTlsKey(ctx, dstack.TlsKeyOptions{})
 // cert1.Key != cert2.Key (always different)
 ```
 
-##### `EmitEvent(ctx context.Context, event string, payload []byte) error`
-
-Extends RTMR3 with a custom event for audit logging.
-
-**Parameters:**
-- `event`: Event identifier string
-- `payload`: Event data
-
-**Requirements:**
-- dstack OS version 0.5.0 or later
-- Events are permanently recorded in TEE measurements
-
 ##### `IsReachable(ctx context.Context) bool`
 
 Tests connectivity to the dstack service.

sdk/go/dstack/client.go

@@ -697,21 +697,6 @@ func (c *DstackClient) IsReachable(ctx context.Context) bool {
 	return err == nil
 }
 
-// EmitEvent sends an event to be extended to RTMR3 on TDX platform.
-// The event will be extended to RTMR3 with the provided name and payload.
-//
-// Requires dstack OS 0.5.0 or later.
-func (c *DstackClient) EmitEvent(ctx context.Context, event string, payload []byte) error {
-	if event == "" {
-		return fmt.Errorf("event name cannot be empty")
-	}
-	_, err := c.sendRPCRequest(ctx, "/EmitEvent", map[string]interface{}{
-		"event":   event,
-		"payload": hex.EncodeToString(payload),
-	})
-	return err
-}
-
 // Legacy methods for backward compatibility with warnings
 
 // DeriveKey is deprecated. Use GetKey instead.