From 557ed94d1d628fc3e83cd7f3b052d0f9d36c2c07 Mon Sep 17 00:00:00 2001
From: Simon Davies <simongdavies@users.noreply.github.com>
Date: Wed, 11 Jun 2025 21:03:35 +0100
Subject: [PATCH] Changes to allow hyperlight-host to build with
 x86_64-unknown-linux-musl target

Signed-off-by: Simon Davies <simongdavies@users.noreply.github.com>
---
 Justfile                                      |  7 ++++++-
 rust-toolchain.toml                           |  2 +-
 .../src/hypervisor/hyperv_linux.rs            | 13 ++++++++++++
 src/hyperlight_host/src/hypervisor/kvm.rs     | 13 ++++++++++++
 src/hyperlight_host/src/seccomp/guest.rs      | 20 ++++++++++++++++++-
 5 files changed, 52 insertions(+), 3 deletions(-)

diff --git a/Justfile b/Justfile
index b14448166..59c095c52 100644
--- a/Justfile
+++ b/Justfile
@@ -24,7 +24,12 @@ alias cg := build-and-move-c-guests
 
 # build host library
 build target=default-target:
-    cargo build --profile={{ if target == "debug" { "dev" } else { target } }}
+    cargo build --profile={{ if target == "debug" { "dev" } else { target } }} 
+
+# build host library
+build-with-musl-libc target=default-target:
+    cargo build --profile={{ if target == "debug" { "dev" } else { target } }} --target x86_64-unknown-linux-musl
+
 
 # build testing guest binaries
 guests: build-and-move-rust-guests build-and-move-c-guests
diff --git a/rust-toolchain.toml b/rust-toolchain.toml
index 779844372..5432e53da 100644
--- a/rust-toolchain.toml
+++ b/rust-toolchain.toml
@@ -2,4 +2,4 @@
 channel = "1.85"
 # Target used for guest binaries. This is an additive list of targets in addition to host platform.
 # Will install the target if not already installed when building guest binaries.
-targets = ["x86_64-unknown-none"]
\ No newline at end of file
+targets = ["x86_64-unknown-none", "x86_64-unknown-linux-musl"]
diff --git a/src/hyperlight_host/src/hypervisor/hyperv_linux.rs b/src/hyperlight_host/src/hypervisor/hyperv_linux.rs
index a35ffe703..e7f34d171 100644
--- a/src/hyperlight_host/src/hypervisor/hyperv_linux.rs
+++ b/src/hyperlight_host/src/hypervisor/hyperv_linux.rs
@@ -405,6 +405,19 @@ impl HypervLinuxDriver {
             interrupt_handle: Arc::new(LinuxInterruptHandle {
                 running: AtomicU64::new(0),
                 cancel_requested: AtomicBool::new(false),
+                #[cfg(all(
+                    target_arch = "x86_64",
+                    target_vendor = "unknown",
+                    target_os = "linux",
+                    target_env = "musl"
+                ))]
+                tid: AtomicU64::new(unsafe { libc::pthread_self() as u64 }),
+                #[cfg(not(all(
+                    target_arch = "x86_64",
+                    target_vendor = "unknown",
+                    target_os = "linux",
+                    target_env = "musl"
+                )))]
                 tid: AtomicU64::new(unsafe { libc::pthread_self() }),
                 retry_delay: config.get_interrupt_retry_delay(),
                 sig_rt_min_offset: config.get_interrupt_vcpu_sigrtmin_offset(),
diff --git a/src/hyperlight_host/src/hypervisor/kvm.rs b/src/hyperlight_host/src/hypervisor/kvm.rs
index 03f03aeaa..5fb772764 100644
--- a/src/hyperlight_host/src/hypervisor/kvm.rs
+++ b/src/hyperlight_host/src/hypervisor/kvm.rs
@@ -360,6 +360,19 @@ impl KVMDriver {
             interrupt_handle: Arc::new(LinuxInterruptHandle {
                 running: AtomicU64::new(0),
                 cancel_requested: AtomicBool::new(false),
+                #[cfg(all(
+                    target_arch = "x86_64",
+                    target_vendor = "unknown",
+                    target_os = "linux",
+                    target_env = "musl"
+                ))]
+                tid: AtomicU64::new(unsafe { libc::pthread_self() as u64 }),
+                #[cfg(not(all(
+                    target_arch = "x86_64",
+                    target_vendor = "unknown",
+                    target_os = "linux",
+                    target_env = "musl"
+                )))]
                 tid: AtomicU64::new(unsafe { libc::pthread_self() }),
                 retry_delay: config.get_interrupt_retry_delay(),
                 dropped: AtomicBool::new(false),
diff --git a/src/hyperlight_host/src/seccomp/guest.rs b/src/hyperlight_host/src/seccomp/guest.rs
index c036cbc03..cd4801d89 100644
--- a/src/hyperlight_host/src/seccomp/guest.rs
+++ b/src/hyperlight_host/src/seccomp/guest.rs
@@ -49,7 +49,25 @@ fn syscalls_allowlist() -> Result<Vec<(i64, Vec<SeccompRule>)>> {
         // because we don't currently support registering parameterized syscalls.
         (
             libc::SYS_ioctl,
-            or![and![Cond::new(1, ArgLen::Dword, Eq, libc::TCGETS)?]],
+            or![and![Cond::new(
+                1,
+                ArgLen::Dword,
+                Eq,
+                #[cfg(all(
+                    target_arch = "x86_64",
+                    target_vendor = "unknown",
+                    target_os = "linux",
+                    target_env = "musl"
+                ))]
+                libc::TCGETS.try_into()?,
+                #[cfg(not(all(
+                    target_arch = "x86_64",
+                    target_vendor = "unknown",
+                    target_os = "linux",
+                    target_env = "musl"
+                )))]
+                libc::TCGETS,
+            )?]],
         ),
         // `futex` is needed for some tests that run in parallel (`simple_test_parallel`,
         // and `callback_test_parallel`).