Change guest tracing to use flatbuffers serialization

Signed-off-by: Doru Blânzeanu <[email protected]>

Author: dblnz

Cargo.lock

@@ -34,9 +34,8 @@ pub fn halt() {
             unsafe {
                 asm!("hlt",
                     in("r8") OutBAction::TraceBatch as u64,
-                    in("r9") tbi.guest_start_tsc,
-                    in("r10") tbi.spans_ptr,
-                    in("r11") tbi.events_ptr,
+                    in("r9") tbi.serialized_data.as_ptr() as u64,
+                    in("r10") tbi.serialized_data.len() as u64,
                     options(nostack)
                 )
             };
@@ -134,9 +133,8 @@ pub(crate) unsafe fn out32(port: u16, val: u32) {
                     in("dx") port,
                     in("eax") val,
                     in("r8") OutBAction::TraceBatch as u64,
-                    in("r9") tbi.guest_start_tsc,
-                    in("r10") tbi.spans_ptr,
-                    in("r11") tbi.events_ptr,
+                    in("r9") tbi.serialized_data.as_ptr() as u64,
+                    in("r10") tbi.serialized_data.len() as u64,
                     options(preserves_flags, nomem, nostack)
                 )
             };

src/hyperlight_guest/src/exit.rs

@@ -10,7 +10,6 @@ readme.workspace = true
 description = """Provides the tracing functionality for the hyperlight guest."""
 
 [dependencies]
-heapless = { version = "0.9.1", features = ["serde"] }
 hyperlight-common = { workspace = true, default-features = false }
 spin = "0.10.0"
 tracing = { version = "0.1.41", default-features = false, features = ["attributes"] }

src/hyperlight_guest_tracing/Cargo.toml

@@ -15,7 +15,6 @@ limitations under the License.
 */
 
 #![no_std]
-use heapless as hl;
 
 /// Expose invariant TSC module
 pub mod invariant_tsc;
@@ -42,102 +41,6 @@ pub use trace::{
     set_start_tsc,
 };
 
-/// Maximum number of spans that the guest can store
-const MAX_NO_OF_SPANS: usize = 10;
-/// Maximum number of events that the guest can store
-const MAX_NO_OF_EVENTS: usize = 10;
-/// Maximum length a name can have in a span/event
-const MAX_NAME_LENGTH: usize = 64;
-/// Maximum length the target can have in a span/event
-const MAX_TARGET_LENGTH: usize = 64;
-/// Maximum length key of a Field can have
-const MAX_FIELD_KEY_LENGTH: usize = 32;
-/// Maximum length value of a Field can have
-const MAX_FIELD_VALUE_LENGTH: usize = 96;
-/// Maximum number of fields a span/event can have
-const MAX_NO_OF_FIELDS: usize = 8;
-
-/// Alias for the complicated heapless::Vec type for Spans
-pub type Spans = hl::Vec<
-    GuestSpan<
-        MAX_NAME_LENGTH,
-        MAX_TARGET_LENGTH,
-        MAX_FIELD_KEY_LENGTH,
-        MAX_FIELD_VALUE_LENGTH,
-        MAX_NO_OF_FIELDS,
-    >,
-    MAX_NO_OF_SPANS,
->;
-
-/// Alias for the complicated heapless::Vec type for Events
-pub type Events = hl::Vec<
-    GuestEvent<MAX_NAME_LENGTH, MAX_FIELD_KEY_LENGTH, MAX_FIELD_VALUE_LENGTH, MAX_NO_OF_FIELDS>,
-    MAX_NO_OF_EVENTS,
->;
-
-/// The trace level assigned to a span/event
-#[derive(Debug, Copy, Clone)]
-pub enum TraceLevel {
-    Error,
-    Warn,
-    Info,
-    Debug,
-    Trace,
-}
-
-impl From<tracing::Level> for TraceLevel {
-    fn from(value: tracing::Level) -> Self {
-        match value {
-            tracing::Level::ERROR => Self::Error,
-            tracing::Level::WARN => Self::Warn,
-            tracing::Level::INFO => Self::Info,
-            tracing::Level::DEBUG => Self::Debug,
-            tracing::Level::TRACE => Self::Trace,
-        }
-    }
-}
-impl From<TraceLevel> for tracing::Level {
-    fn from(value: TraceLevel) -> Self {
-        match value {
-            TraceLevel::Error => Self::ERROR,
-            TraceLevel::Warn => Self::WARN,
-            TraceLevel::Info => Self::INFO,
-            TraceLevel::Debug => Self::DEBUG,
-            TraceLevel::Trace => Self::TRACE,
-        }
-    }
-}
-
-/// The structure in which a guest stores Span information
-pub struct GuestSpan<
-    const N: usize,
-    const T: usize,
-    const FK: usize,
-    const FV: usize,
-    const F: usize,
-> {
-    pub id: u64,
-    pub parent_id: Option<u64>,
-    pub level: TraceLevel,
-    /// Span name
-    pub name: hl::String<N>,
-    /// Filename
-    pub target: hl::String<T>,
-    pub start_tsc: u64,
-    pub end_tsc: Option<u64>,
-    pub fields: hl::Vec<(hl::String<FK>, hl::String<FV>), F>,
-}
-
-/// The structure in which a guest stores Event information
-pub struct GuestEvent<const N: usize, const FK: usize, const FV: usize, const F: usize> {
-    pub parent_id: u64,
-    pub level: TraceLevel,
-    pub name: hl::String<N>,
-    /// Event name
-    pub tsc: u64,
-    pub fields: hl::Vec<(hl::String<FK>, hl::String<FV>), F>,
-}
-
 /// This module is gated because some of these types are also used on the host, but we want
 /// only the guest to allocate and allow the functionality intended for the guest.
 #[cfg(feature = "trace")]