Enable the uffd feature by default, but filter on OS

Notably, this should get us building and running uffd in Linux CI. It turns out to be a tremendous pain to enable a feature flag for just one crate within a workspace. The situation is [being addressed][1], but in the meantime I believe the best route forward is to just have uffd on by default for Linux. [1]: rust-lang/cargo#5364
bytecodealliance · May 1, 2020 · 8029cf6 · 8029cf6
1 parent 8606d3f
commit 8029cf6
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Showing 13 changed files with 24 additions and 16 deletions.
diff --git a/lucet-runtime/Cargo.toml b/lucet-runtime/Cargo.toml
@@ -49,7 +49,7 @@ assets = [
 ]
 
 [features]
-default-features = []
+default = ["uffd"]
 uffd = ["lucet-runtime-internals/uffd"]
 concurrent_testpoints = []
 

diff --git a/lucet-runtime/lucet-runtime-internals/Cargo.toml b/lucet-runtime/lucet-runtime-internals/Cargo.toml
@@ -28,6 +28,8 @@ rand = "0.7"
 raw-cpuid = "6.0.0"
 thiserror = "1.0.4"
 tracing = "0.1.12"
+
+[target.'cfg(target_os = "linux")'.dependencies]
 userfaultfd = { version = "0.1.0", optional = true }
 
 [dev-dependencies]
@@ -37,8 +39,7 @@ byteorder = "1.2"
 cc = "1.0"
 
 [features]
-default-features = []
-
+default = ["uffd"]
 uffd = ["userfaultfd"]
 concurrent_testpoints = []
 

diff --git a/lucet-runtime/lucet-runtime-internals/src/region.rs b/lucet-runtime/lucet-runtime-internals/src/region.rs
@@ -1,6 +1,6 @@
 pub mod mmap;
 
-#[cfg(feature = "uffd")]
+#[cfg(all(target_os = "linux", feature = "uffd"))]
 pub mod uffd;
 
 use crate::alloc::{Alloc, AllocStrategy, Limits, Slot};

diff --git a/lucet-runtime/src/c_api.rs b/lucet-runtime/src/c_api.rs
@@ -1,4 +1,4 @@
-#[cfg(feature = "uffd")]
+#[cfg(all(target_os = "linux", feature = "uffd"))]
 use crate::UffdRegion;
 use crate::{DlModule, Instance, Limits, MmapRegion, Module, Region};
 use libc::{c_char, c_int, c_void};
@@ -105,7 +105,7 @@ pub unsafe extern "C" fn lucet_uffd_region_create(
     region_out: *mut *mut lucet_region,
 ) -> lucet_error {
     cfg_if::cfg_if! {
-        if #[cfg(feature = "uffd")] {
+        if #[cfg(all(target_os = "linux", feature = "uffd"))] {
             assert_nonnull!(region_out);
             let limits = limits
                 .as_ref()

diff --git a/lucet-runtime/src/lib.rs b/lucet-runtime/src/lib.rs
@@ -386,7 +386,14 @@
 //! `Instance`, reducing startup time. Instance stack pages can also be lazily initialized, reducing
 //! the memory footprint of instances that only use a small portion of their available stack space.
 //!
-//! To use `UffdRegion`, enable the `uffd` Cargo feature, which is off by default.
+//! `UffdRegion` is enabled by default on Linux platforms, but can be disabled by disabling default
+//! features for this crate and `lucet-runtime-internals`:
+//!
+//! ```toml
+//! [dependencies]
+//! lucet-runtime = { version = "0.6.1", default-features = false }
+//! lucet-runtime-internals = { version = "0.6.1", default-features = false }
+//! ```
 
 #![deny(bare_trait_objects)]
 
@@ -410,7 +417,7 @@ pub use lucet_runtime_internals::instance::{
 pub use lucet_runtime_internals::lucet_hostcalls;
 pub use lucet_runtime_internals::module::{DlModule, Module};
 pub use lucet_runtime_internals::region::mmap::MmapRegion;
-#[cfg(feature = "uffd")]
+#[cfg(all(target_os = "linux", feature = "uffd"))]
 pub use lucet_runtime_internals::region::uffd::UffdRegion;
 pub use lucet_runtime_internals::region::{InstanceBuilder, Region, RegionCreate};
 pub use lucet_runtime_internals::val::{UntypedRetVal, Val};

diff --git a/lucet-runtime/tests/entrypoint.rs b/lucet-runtime/tests/entrypoint.rs
@@ -1,7 +1,7 @@
 use lucet_runtime_tests::entrypoint_tests;
 
 cfg_if::cfg_if! {
-    if #[cfg(feature = "uffd")] {
+    if #[cfg(all(target_os = "linux", feature = "uffd"))] {
         entrypoint_tests!(
             mmap => lucet_runtime::MmapRegion,
             uffd => lucet_runtime::UffdRegion

diff --git a/lucet-runtime/tests/globals.rs b/lucet-runtime/tests/globals.rs
@@ -1,7 +1,7 @@
 use lucet_runtime_tests::globals_tests;
 
 cfg_if::cfg_if! {
-    if #[cfg(feature = "uffd")] {
+    if #[cfg(all(target_os = "linux", feature = "uffd"))] {
         globals_tests!(
             mmap => lucet_runtime::MmapRegion,
             uffd => lucet_runtime::UffdRegion

diff --git a/lucet-runtime/tests/guest_fault.rs b/lucet-runtime/tests/guest_fault.rs
@@ -3,7 +3,7 @@ use lucet_runtime_tests::{guest_fault_common_defs, guest_fault_tests};
 guest_fault_common_defs!();
 
 cfg_if::cfg_if! {
-    if #[cfg(feature = "uffd")] {
+    if #[cfg(all(target_os = "linux", feature = "uffd"))] {
         guest_fault_tests!(
             mmap => lucet_runtime::MmapRegion,
             uffd => lucet_runtime::UffdRegion

diff --git a/lucet-runtime/tests/host.rs b/lucet-runtime/tests/host.rs
@@ -1,7 +1,7 @@
 use lucet_runtime_tests::host_tests;
 
 cfg_if::cfg_if! {
-    if #[cfg(feature = "uffd")] {
+    if #[cfg(all(target_os = "linux", feature = "uffd"))] {
         host_tests!(
             mmap => lucet_runtime::MmapRegion,
             uffd => lucet_runtime::UffdRegion

diff --git a/lucet-runtime/tests/memory.rs b/lucet-runtime/tests/memory.rs
@@ -1,7 +1,7 @@
 use lucet_runtime_tests::memory_tests;
 
 cfg_if::cfg_if! {
-    if #[cfg(feature = "uffd")] {
+    if #[cfg(all(target_os = "linux", feature = "uffd"))] {
         memory_tests!(
             mmap => lucet_runtime::MmapRegion,
             uffd => lucet_runtime::UffdRegion

diff --git a/lucet-runtime/tests/stack.rs b/lucet-runtime/tests/stack.rs
@@ -1,7 +1,7 @@
 use lucet_runtime_tests::stack_tests;
 
 cfg_if::cfg_if! {
-    if #[cfg(feature = "uffd")] {
+    if #[cfg(all(target_os = "linux", feature = "uffd"))] {
         stack_tests!(
             mmap => lucet_runtime::MmapRegion,
             uffd => lucet_runtime::UffdRegion

diff --git a/lucet-runtime/tests/start.rs b/lucet-runtime/tests/start.rs
@@ -1,7 +1,7 @@
 use lucet_runtime_tests::start_tests;
 
 cfg_if::cfg_if! {
-    if #[cfg(feature = "uffd")] {
+    if #[cfg(all(target_os = "linux", feature = "uffd"))] {
         start_tests!(
             mmap => lucet_runtime::MmapRegion,
             uffd => lucet_runtime::UffdRegion

diff --git a/lucet-runtime/tests/strcmp.rs b/lucet-runtime/tests/strcmp.rs
@@ -1,7 +1,7 @@
 use lucet_runtime_tests::strcmp_tests;
 
 cfg_if::cfg_if! {
-    if #[cfg(feature = "uffd")] {
+    if #[cfg(all(target_os = "linux", feature = "uffd"))] {
         strcmp_tests!(
             mmap => lucet_runtime::MmapRegion,
             uffd => lucet_runtime::UffdRegion