diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index c78c928b4..a6fa9ce87 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -19,7 +19,6 @@ on:
 # Keep this in sync with the other *.yml files
 env:
   CI_REQ_DOTNET_SDK_VER: 5.0.300
-  COVERAGE_FILENAME: coverage.info
   CI_NODE_MIN_VER: 12.0.0
   RUSTFLAGS: -D warnings
   MACOSX_DEPLOYMENT_TARGET: 10.12
@@ -57,7 +56,7 @@ jobs:
       - uses: actions/upload-artifact@v2
         with:
           name: coverage.info
-          path: src/csharp/Intel/Iced.UnitTests/${{env.COVERAGE_FILENAME}}
+          path: src/csharp/Intel/Iced.UnitTests/coverage.info
           if-no-files-found: error
 
       - name: Upload coverage report
@@ -65,6 +64,7 @@ jobs:
         shell: bash
         continue-on-error: true
         run: |
+          # https://docs.codecov.com/docs/codecov-uploader
           curl https://keybase.io/codecovsecurity/pgp_keys.asc | gpg --no-default-keyring --keyring trustedkeys.gpg --import
           curl -Os https://uploader.codecov.io/latest/linux/codecov
           curl -Os https://uploader.codecov.io/latest/linux/codecov.SHA256SUM
@@ -72,7 +72,7 @@ jobs:
           gpgv codecov.SHA256SUM.sig codecov.SHA256SUM
           shasum -a 256 -c codecov.SHA256SUM
           chmod +x codecov
-          ./codecov -t ${{secrets.CODECOV_TOKEN}} -f "src/csharp/Intel/Iced.UnitTests/${{env.COVERAGE_FILENAME}}"
+          ./codecov -t "${{secrets.CODECOV_TOKEN}}" -f "src/csharp/Intel/Iced.UnitTests/coverage.info"
 
   #############################################################################
   #############################################################################
@@ -96,9 +96,36 @@ jobs:
         with:
           dotnet-version: ${{env.CI_REQ_DOTNET_SDK_VER}}
 
+      - name: Install kcov
+        shell: bash
+        run: |
+          sudo apt update
+          sudo apt install kcov
+
       - name: Build and test
         shell: bash
-        run: ./build/build-rust --no-set-rustflags --no-tests --test-current --test-msrv --test-no_std
+        run: ./build/build-rust --no-set-rustflags --no-tests --test-current --test-msrv --test-no_std --coverage
+
+      - uses: actions/upload-artifact@v2
+        with:
+          name: rust-coverage
+          path: cov-out/rust/merged/
+          if-no-files-found: error
+
+      - name: Upload coverage report
+        if: github.ref == 'refs/heads/master'
+        shell: bash
+        continue-on-error: true
+        run: |
+          # https://docs.codecov.com/docs/codecov-uploader
+          curl https://keybase.io/codecovsecurity/pgp_keys.asc | gpg --no-default-keyring --keyring trustedkeys.gpg --import
+          curl -Os https://uploader.codecov.io/latest/linux/codecov
+          curl -Os https://uploader.codecov.io/latest/linux/codecov.SHA256SUM
+          curl -Os https://uploader.codecov.io/latest/linux/codecov.SHA256SUM.sig
+          gpgv codecov.SHA256SUM.sig codecov.SHA256SUM
+          shasum -a 256 -c codecov.SHA256SUM
+          chmod +x codecov
+          ./codecov -t "${{secrets.CODECOV_TOKEN}}" -f "cov-out/rust/merged/kcov-merged/cobertura.xml"
 
   #############################################################################
   #############################################################################
diff --git a/.github/workflows/release.yml b/.github/workflows/release.yml
index a3a016078..628ae7dc7 100644
--- a/.github/workflows/release.yml
+++ b/.github/workflows/release.yml
@@ -7,7 +7,6 @@ on:
 # Keep this in sync with the other *.yml files
 env:
   CI_REQ_DOTNET_SDK_VER: 5.0.300
-  COVERAGE_FILENAME: coverage.info
   CI_NODE_MIN_VER: 12.0.0
   RUSTFLAGS: -D warnings
   MACOSX_DEPLOYMENT_TARGET: 10.12
@@ -48,13 +47,6 @@ jobs:
           path: src/csharp/Intel/Iced/bin/Release/*.*nupkg
           if-no-files-found: error
 
-      - uses: actions/upload-artifact@v2
-        if: startsWith(matrix.os, 'ubuntu-')
-        with:
-          name: coverage.info
-          path: src/csharp/Intel/Iced.UnitTests/${{env.COVERAGE_FILENAME}}
-          if-no-files-found: error
-
   #############################################################################
   #############################################################################
   #############################################################################
@@ -554,10 +546,6 @@ jobs:
       - name: Verify downloads
         shell: bash
         run: |
-          if [ ! -f "/tmp/artifacts/coverage.info/$COVERAGE_FILENAME" ]; then
-            echo "Missing coverage"
-            exit 1
-          fi
           if [ -z "$(ls -A /tmp/artifacts/nupkg/Iced.*.nupkg)" ]; then
             echo "Missing nupkg files"
             exit 1
diff --git a/.gitignore b/.gitignore
index 1d74e2196..d342cdbab 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1 +1,3 @@
 .vscode/
+coverage.info
+/cov-out/
diff --git a/build/build-rust b/build/build-rust
index 6e19a1968..fba6a1ca8 100755
--- a/build/build-rust
+++ b/build/build-rust
@@ -17,6 +17,13 @@ test_features=y
 test_current=y
 test_msrv=y
 test_code_asm=y
+test_cov=n
+
+kcov=kcov
+cov_out=$root_dir/cov-out
+cov_out_rust=$cov_out/rust
+cov_out_rust_tmp=$cov_out_rust/tmp
+cov_out_rust_merged=$cov_out_rust/merged
 
 # Minimum supported Rust version
 msrv="1.48.0"
@@ -44,22 +51,31 @@ test_valid_invalid_instructions() {
 
 	# The C# code needs a formatter so add masm feature
 	dotnet build -c:$configuration -p:IcedFeatureFlags="DECODER ENCODER OPCODE_INFO INSTR_INFO MASM" "$root_dir/src/csharp/Intel/IcedFuzzer/IcedFuzzer/IcedFuzzer.csproj"
+	if [ "$test_cov" = "y" ]; then
+		release_flag=
+		fzgt_output_dir=debug
+	else
+		release_flag="--release"
+		fzgt_output_dir=release
+	fi
+	cargo build --color always $release_flag --manifest-path "$root_dir/src/rust/iced-x86-fzgt/Cargo.toml"
+	fzgt_exe="$root_dir/src/rust/iced-x86-fzgt/target/$fzgt_output_dir/iced-x86-fzgt"
 	for bitness in 16 32 64; do
 		echo "==== ${bitness}-bit: Generating valid/invalid files ===="
 		dotnet run -c:$configuration --no-build -p "$root_dir/src/csharp/Intel/IcedFuzzer/IcedFuzzer/IcedFuzzer.csproj" -- -$bitness -oil "$invalid_file" -ovlc "$valid_file"
 		echo "==== ${bitness}-bit: Testing valid instructions ===="
-		cargo run --color always --release --manifest-path "$root_dir/src/rust/iced-x86-fzgt/Cargo.toml" -- -b $bitness -f "$valid_file"
+		cov_test "test_valid_$bitness" "$fzgt_exe" -b $bitness -f "$valid_file"
 		echo "==== ${bitness}-bit: Testing invalid instructions ===="
-		cargo run --color always --release --manifest-path "$root_dir/src/rust/iced-x86-fzgt/Cargo.toml" -- -b $bitness -f "$invalid_file" --invalid
+		cov_test "test_invalid_$bitness" "$fzgt_exe" -b $bitness -f "$invalid_file" --invalid
 	done
 
 	for bitness in 16 32 64; do
 		echo "==== ${bitness}-bit (AMD): Generating valid/invalid files ===="
 		dotnet run -c:$configuration --no-build -p "$root_dir/src/csharp/Intel/IcedFuzzer/IcedFuzzer/IcedFuzzer.csproj" -- -$bitness -oil "$invalid_file" -ovlc "$valid_file" --amd
 		echo "==== ${bitness}-bit (AMD): Testing valid instructions ===="
-		cargo run --color always --release --manifest-path "$root_dir/src/rust/iced-x86-fzgt/Cargo.toml" -- -b $bitness -f "$valid_file" --amd
+		cov_test "test_amd_valid_$bitness" "$fzgt_exe" -b $bitness -f "$valid_file" --amd
 		echo "==== ${bitness}-bit (AMD): Testing invalid instructions ===="
-		cargo run --color always --release --manifest-path "$root_dir/src/rust/iced-x86-fzgt/Cargo.toml" -- -b $bitness -f "$invalid_file" --invalid --amd
+		cov_test "test_amd_invalid_$bitness" "$fzgt_exe" -b $bitness -f "$invalid_file" --invalid --amd
 	done
 
 	rm "$valid_file"
@@ -164,6 +180,33 @@ build_features() {
 	cd "$curr_dir"
 }
 
+cov_test() {
+	cov_test_dir=$1
+	shift
+	if [ "$test_cov" = "y" ]; then
+		$kcov --verify --exclude-pattern=/tests/,/test/,/test_utils/ --include-pattern=/iced-x86/ "$cov_out_rust_tmp/$cov_test_dir" "$@"
+	else
+		"$@"
+	fi
+}
+
+cargo_test_cov() {
+	cov_test_dir=$1
+	shift
+	if [ "$test_cov" = "y" ]; then
+		test_exe=$(cargo test --color always --no-run --message-format=json "$@" | grep -- '"name":"iced-x86"' | tail -1 | sed -e 's/.*"executable":"\([^"]\+\)".*/\1/')
+		if [ ! -x "$test_exe" ]; then
+			echo "Couldn't get the test executable name, got '$test_exe'"
+			echo "json output:"
+			cargo test --color always --no-run --message-format=json "$@"
+			exit 1
+		fi
+		cov_test "$cov_test_dir" "$test_exe"
+	else
+		cargo test --color always "$@"
+	fi
+}
+
 build_test_current_version() {
 	new_func "Build, test (current version)"
 	curr_dir=$(pwd)
@@ -194,10 +237,10 @@ build_test_current_version() {
 	# Make sure the two read-mem methods behave the same
 	# Also test serde code. It needs encoder to also test 'db x,y,z', see serde tests
 	echo "==== TEST DEBUG: std decoder encoder serde __internal_flip ===="
-	cargo test --color always --tests --no-default-features --features "std decoder encoder serde __internal_flip"
+	cargo_test_cov test_internal_flip --tests --no-default-features --features "std decoder encoder serde __internal_flip"
 
 	echo "==== TEST DEBUG ===="
-	cargo test --color always --tests --features "serde $test_code_asm_feat mvex"
+	cargo_test_cov test_debug --tests --features "serde $test_code_asm_feat mvex"
 
 	echo "==== BUILD RELEASE wasm32-unknown-unknown ===="
 	cargo check --color always --target wasm32-unknown-unknown --release --features "serde code_asm mvex"
@@ -269,6 +312,7 @@ while [ "$#" -gt 0 ]; do
 	--test-features) test_features=y ;;
 	--test-current) test_current=y ;;
 	--test-msrv) test_msrv=y ;;
+	--coverage) test_cov=y ;;
 
 	--no-set-rustflags) set_rustflags=n ;;
 	*) echo "Unknown arg: $1"; exit 1 ;;
@@ -289,6 +333,13 @@ fi
 echo "rustup show"
 rustup show
 
+if [ "$test_cov" = "y" ]; then
+	mkdir -p "$cov_out"
+	rm -rf "$cov_out_rust" "$cov_out_rust_merged"
+	mkdir -p "$cov_out_rust_tmp"
+	kcov --version
+fi
+
 if [ "$test_code_asm" = "y" ]; then
 	test_code_asm_feat="code_asm"
 else
@@ -318,3 +369,7 @@ fi
 if [ "$test_msrv" = "y" ]; then
 	build_test_msrv
 fi
+
+if [ "$test_cov" = "y" ]; then
+	$kcov --merge "$cov_out_rust_merged" "$cov_out_rust_tmp/"*
+fi
\ No newline at end of file