diff --git a/hosts/k8s/kubevirt-shoryu/default.nix b/hosts/k8s/kubevirt-shoryu/default.nix
index c7f44166..36b1af50 100644
--- a/hosts/k8s/kubevirt-shoryu/default.nix
+++ b/hosts/k8s/kubevirt-shoryu/default.nix
@@ -50,11 +50,12 @@ in {
       k3sModule
     ];
 
-  # https://kubevirt.io/user-guide/compute/hugepages/
   boot.kernelParams = [
     # disable transparent hugepage(allocate hugepages dynamically)
     "transparent_hugepage=never"
 
+    # https://kubevirt.io/user-guide/compute/hugepages/
+    #
     # pre-allocate hugepages manually(for kubevirt guest vms)
     # NOTE: the hugepages allocated here can not be used for other purposes!
     # so we should left some memory for the host OS
diff --git a/hosts/k8s/kubevirt-shushou/default.nix b/hosts/k8s/kubevirt-shushou/default.nix
index 9c64907c..572afb33 100644
--- a/hosts/k8s/kubevirt-shushou/default.nix
+++ b/hosts/k8s/kubevirt-shushou/default.nix
@@ -44,11 +44,12 @@ in {
       k3sModule
     ];
 
-  # https://kubevirt.io/user-guide/compute/hugepages/
   boot.kernelParams = [
     # disable transparent hugepage(allocate hugepages dynamically)
     "transparent_hugepage=never"
 
+    # https://kubevirt.io/user-guide/compute/hugepages/
+    #
     # pre-allocate hugepages manually(for kubevirt guest vms)
     # NOTE: the hugepages allocated here can not be used for other purposes!
     # so we should left some memory for the host OS
diff --git a/hosts/k8s/kubevirt-youko/default.nix b/hosts/k8s/kubevirt-youko/default.nix
index e28bfe44..08ec2228 100644
--- a/hosts/k8s/kubevirt-youko/default.nix
+++ b/hosts/k8s/kubevirt-youko/default.nix
@@ -44,15 +44,23 @@ in {
       k3sModule
     ];
 
-  # https://kubevirt.io/user-guide/compute/hugepages/
   boot.kernelParams = [
     # disable transparent hugepage(allocate hugepages dynamically)
     "transparent_hugepage=never"
 
+    # https://kubevirt.io/user-guide/compute/hugepages/
+    #
     # pre-allocate hugepages manually(for kubevirt guest vms)
     # NOTE: the hugepages allocated here can not be used for other purposes!
     # so we should left some memory for the host OS
     "hugepagesz=1G"
     "hugepages=16"
+
+    # https://kubevirt.io/user-guide/compute/host-devices/
+    #
+    # PCI passthrough
+    # "amd_iommu=on" # enable IOMMU
+    # "iommu=pt" # use passthrough mode
+    # "pcie_acs_override=downstream" # enable ACS override
   ];
 }