Enable kvm in docker images if available

ci/run-docker.sh

@@ -8,10 +8,14 @@ run() {
     # use -f so we can use ci/ as build context
     docker build -t libc -f ci/docker/$1/Dockerfile ci/
     mkdir -p target
+    if [ -w /dev/kvm ]; then
+      kvm="--volume /dev/kvm:/dev/kvm"
+    fi
     docker run \
       --user `id -u`:`id -g` \
       --rm \
       --volume $HOME/.cargo:/cargo \
+      $kvm \
       --env CARGO_HOME=/cargo \
       --volume `rustc --print sysroot`:/rust:ro \
       --volume `pwd`:/checkout:ro \

ci/run.sh

@@ -111,7 +111,11 @@ case "$TARGET" in
     # https://issues.jenkins-ci.org/browse/JENKINS-26930?focusedCommentId=230791&page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel#comment-230791
     export SHELL=/bin/dash
     arch=$(echo $TARGET | cut -d- -f1)
-    emulator @$arch -no-window -no-accel &
+    accel="-no-accel"
+    if emulator -accel-check; then
+      accel=""
+    fi
+    emulator @$arch -no-window $accel &
     adb wait-for-device
     adb push $CARGO_TARGET_DIR/$TARGET/debug/libc-test /data/local/tmp/libc-test
     adb shell /data/local/tmp/libc-test 2>&1 | tee /tmp/out