diff --git a/.cargo/config b/.cargo/config
new file mode 100644
index 00000000..35049cbc
--- /dev/null
+++ b/.cargo/config
@@ -0,0 +1,2 @@
+[alias]
+xtask = "run --package xtask --"
diff --git a/Cargo.toml b/Cargo.toml
index b81f1ae6..ef83f41f 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -119,7 +119,8 @@ harness = false
 members = [
     "pyo3-macros",
     "pyo3-macros-backend",
-    "examples"
+    "examples",
+    "xtask"
 ]
 
 [package.metadata.docs.rs]
diff --git a/Makefile b/Makefile
index 20e7fa71..229575d0 100644
--- a/Makefile
+++ b/Makefile
@@ -1,6 +1,7 @@
 .PHONY: test test_py publish clippy lint fmt fmt_py fmt_rust
 
 ALL_ADDITIVE_FEATURES = macros multiple-pymethods num-bigint num-complex hashbrown serde indexmap eyre anyhow
+COVERAGE_PACKAGES = --package pyo3 --package pyo3-build-config --package pyo3-macros-backend --package pyo3-macros
 
 list_all_additive_features:
 	@echo $(ALL_ADDITIVE_FEATURES)
@@ -25,6 +26,21 @@ fmt_rust:
 fmt: fmt_rust fmt_py
 	@true
 
+coverage:
+	# cargo llvm-cov clean --workspace
+	# cargo llvm-cov $(COVERAGE_PACKAGES) --no-report
+	# cargo llvm-cov $(COVERAGE_PACKAGES) --no-report --features abi3
+	# cargo llvm-cov $(COVERAGE_PACKAGES) --no-report --features $(ALL_ADDITIVE_FEATURES)
+	# cargo llvm-cov $(COVERAGE_PACKAGES) --no-report --features abi3 $(ALL_ADDITIVE_FEATURES)
+	bash -c "\
+		set -a\
+		source <(cargo llvm-cov show-env)\
+		export TOX_TESTENV_PASSENV=*\
+		make test_py\
+	"
+	cargo llvm-cov $(COVERAGE_PACKAGES) --no-run --summary-only
+
+
 clippy:
 	cargo clippy --features="$(ALL_ADDITIVE_FEATURES)" --all-targets --workspace -- -Dwarnings
 	cargo clippy --features="abi3 $(ALL_ADDITIVE_FEATURES)" --all-targets --workspace -- -Dwarnings
diff --git a/xtask/Cargo.toml b/xtask/Cargo.toml
new file mode 100644
index 00000000..f147d000
--- /dev/null
+++ b/xtask/Cargo.toml
@@ -0,0 +1,8 @@
+[package]
+name = "xtask"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]
+anyhow = "1.0.51"
+clap = { version = "3.0.0-rc.7", features = ["derive"] }
diff --git a/xtask/src/main.rs b/xtask/src/main.rs
new file mode 100644
index 00000000..b077c5cc
--- /dev/null
+++ b/xtask/src/main.rs
@@ -0,0 +1,57 @@
+use anyhow::Result;
+use clap::Parser;
+use std::{collections::HashMap, process::Command};
+
+#[derive(Parser)]
+enum Subcommand {
+    Coverage,
+}
+
+fn main() -> Result<()> {
+    match Subcommand::parse() {
+        Subcommand::Coverage => {
+            run(&mut llvm_cov_command(&["clean", "--workspace"]))?;
+            // FIXME: run (including with various feature combinations)
+            // run(&mut llvm_cov_command(&["--no-report"]))?;
+            let env = get_coverage_env()?;
+            for entry in std::fs::read_dir("pytests")? {
+                let path = entry?.path();
+                if path.is_dir() {
+                    run(Command::new("tox").arg("-c").arg(path).envs(&env))?;
+                }
+            }
+            // FIXME: also run for examples
+            // FIXME: make it possible to generate lcov report too
+            run(&mut llvm_cov_command(&["--no-run", "--summary-only"]))?;
+        }
+    }
+    Ok(())
+}
+
+fn run(command: &mut Command) -> Result<()> {
+    command.spawn()?.wait()?;
+    Ok(())
+}
+
+fn llvm_cov_command(args: &[&str]) -> Command {
+    let mut command = Command::new("cargo");
+    command.args(["llvm-cov", "--package=pyo3"]).args(args);
+    command
+}
+
+fn get_coverage_env() -> Result<HashMap<String, String>> {
+    let mut env = HashMap::new();
+
+    let output = String::from_utf8(llvm_cov_command(&["show-env"]).output()?.stdout)?;
+
+    for line in output.trim().split('\n') {
+        // TODO use split_once on MSRV 1.52
+        let mut iter = line.splitn(2, '=');
+        env.insert(iter.next().unwrap().into(), iter.next().unwrap().trim_matches('"').into());
+    }
+
+    env.insert("TOX_TESTENV_PASSENV".to_owned(), "*".to_owned());
+    env.insert("RUSTUP_TOOLCHAIN".to_owned(), "nightly".to_owned());
+
+    Ok(env)
+}