Adds a script for KVM perf issue mitigation on 6.x kernel (#155)

Signed-off-by: Simon Davies <[email protected]>

Author: simongdavies

src/hyperlight_host/scripts/apply-kvm-perf-mitigation.sh

@@ -0,0 +1,14 @@
+#!/bin/bash
+set -Eeuo pipefail  
+kernel_version=$(uname -r)
+if [[ "$kernel_version" == 6.* ]]; then
+  if [[ $(cat /sys/devices/system/cpu/vulnerabilities/itlb_multihit) == "Not affected" ]]; then
+    KVM_VENDOR_MOD=$(lsmod |grep -P "^kvm_(amd|intel)" | awk '{print $1}')
+    sudo modprobe -r $KVM_VENDOR_MOD kvm
+    sudo modprobe kvm nx_huge_pages=never
+    sudo modprobe $KVM_VENDOR_MOD
+  fi
+  if [ -f /sys/fs/cgroup/cgroup.controllers ]; then
+    sudo mount -o remount,favordynmods /sys/fs/cgroup
+  fi
+fi