diff --git a/ci.sh b/ci.sh
index 67cbed4f826..a29fc3deca5 100755
--- a/ci.sh
+++ b/ci.sh
@@ -54,8 +54,8 @@ function run_tests {
   unset RUSTC MIRI
   rm -rf .cargo
 
-  # Ensure that our benchmarks all work, on the host at least.
-  if [ -z "${MIRI_TEST_TARGET+exists}" ]; then
+  # Ensure that our benchmarks all work, but only on Linux hosts.
+  if [ -z "${MIRI_TEST_TARGET+exists}" ] && [ "$HOST_TARGET" = x86_64-unknown-linux-gnu ] ; then
     for BENCH in $(ls "bench-cargo-miri"); do
       cargo miri run --manifest-path bench-cargo-miri/$BENCH/Cargo.toml
     done
diff --git a/miri b/miri
index 956b8cca75b..0295fc3ab3a 100755
--- a/miri
+++ b/miri
@@ -90,13 +90,13 @@ bench)
     # Make sure we have an up-to-date Miri installed
     "$0" install
     # Run the requested benchmarks
-    if [ -z "$@" ]; then
+    if [ -z "${1+exists}" ]; then
         BENCHES=( $(ls "$MIRIDIR/bench-cargo-miri" ) )
     else
         BENCHES=("$@")
     fi
     for BENCH in "${BENCHES[@]}"; do
-        hyperfine -w 1 -m 5 --shell=none "cargo +$TOOLCHAIN miri run --manifest-path bench-cargo-miri/$BENCH/Cargo.toml"
+        hyperfine -w 1 -m 5 --shell=none "cargo +$TOOLCHAIN miri run --manifest-path $MIRIDIR/bench-cargo-miri/$BENCH/Cargo.toml"
     done
     exit 0
     ;;