bench: add bzImage loader benchmark

Signed-off-by: Alexandra Iordache <aghecen@amazon.com>

Author: Alexandra Iordache

benches/main.rs

@@ -4,6 +4,7 @@
 // found in the LICENSE-BSD-3-Clause file.
 //
 // SPDX-License-Identifier: Apache-2.0 AND BSD-3-Clause
+
 extern crate criterion;
 extern crate linux_loader;
 extern crate vm_memory;
@@ -20,12 +21,37 @@ mod aarch64;
 #[cfg(target_arch = "aarch64")]
 use aarch64::*;
 
+pub fn criterion_benchmark_nop(_: &mut Criterion) {}
+
 criterion_group! {
     name = benches;
     config = Criterion::default().sample_size(500);
     targets = criterion_benchmark
 }
 
+#[cfg(all(any(target_arch = "x86", target_arch = "x86_64"), feature = "bzimage"))]
+// Explicit (arch, feature) tuple required as clippy complains about
+// `criterion_benchmark_bzimage` missing on aarch64.
+criterion_group! {
+    name = benches_bzimage;
+    // Only ~125 runs fit in 5 seconds. Either extend the duration, or reduce
+    // the number of iterations.
+    config = Criterion::default().sample_size(100);
+    targets = criterion_benchmark_bzimage
+}
+
+// NOP because the `criterion_main!` macro doesn't support cfg(feature)
+// macro expansions.
+#[cfg(any(target_arch = "aarch64", not(feature = "bzimage")))]
+criterion_group! {
+    name = benches_bzimage;
+    // Sample size must be >= 10.
+    // https://github.com/bheisler/criterion.rs/blob/0.3.0/src/lib.rs#L757
+    config = Criterion::default().sample_size(10);
+    targets = criterion_benchmark_nop
+}
+
 criterion_main! {
-    benches
+    benches,
+    benches_bzimage
 }

benches/x86_64/mod.rs

@@ -12,6 +12,8 @@ extern crate vm_memory;
 
 use linux_loader::configurator::pvh::PvhBootConfigurator;
 use linux_loader::configurator::{BootConfigurator, BootParams};
+#[cfg(feature = "bzimage")]
+use linux_loader::loader::bzimage::BzImage;
 use linux_loader::loader::elf::start_info::{hvm_memmap_table_entry, hvm_start_info};
 use linux_loader::loader::elf::Elf;
 use linux_loader::loader::KernelLoader;
@@ -65,6 +67,15 @@ fn build_pvh_boot_params() -> BootParams {
     boot_params
 }
 
+#[cfg(feature = "bzimage")]
+fn create_bzimage() -> Vec<u8> {
+    include_bytes!(concat!(
+        env!("CARGO_MANIFEST_DIR"),
+        "/src/loader/x86_64/bzimage/bzimage"
+    ))
+    .to_vec()
+}
+
 pub fn criterion_benchmark(c: &mut Criterion) {
     let guest_mem = create_guest_memory();
 
@@ -93,3 +104,21 @@ pub fn criterion_benchmark(c: &mut Criterion) {
         })
     });
 }
+
+#[cfg(feature = "bzimage")]
+pub fn criterion_benchmark_bzimage(c: &mut Criterion) {
+    let guest_mem = create_guest_memory();
+    let bzimage = create_bzimage();
+
+    c.bench_function("load_bzimage", |b| {
+        b.iter(|| {
+            black_box(BzImage::load(
+                &guest_mem,
+                None,
+                &mut Cursor::new(&bzimage),
+                None,
+            ))
+            .unwrap();
+        })
+    });
+}