cloud-hypervisor: Use correct console on aarch64

Similarly to qemu, cloud-hypervisor also emulates a serial device that gets
mapped to ttyAMA0 on aarch64, adjust kernel command line accordingly.

Signed-off-by: Santtu Lakkala <[email protected]>

Author: slakkala

lib/runners/cloud-hypervisor.nix

@@ -4,7 +4,7 @@
 }:
 
 let
-  inherit (pkgs) lib;
+  inherit (pkgs) lib system;
   inherit (microvmConfig) vcpu mem balloonMem user interfaces volumes shares socket devices hugepageMem graphics storeDisk storeOnDisk kernel initrdPath;
   inherit (microvmConfig.cloud-hypervisor) extraArgs;
 
@@ -13,6 +13,13 @@ let
     aarch64-linux = "${kernel.out}/${pkgs.stdenv.hostPlatform.linux-kernel.target}";
   }.${pkgs.system};
 
+  kernelConsole =
+    if system == "x86_64-linux"
+    then "earlyprintk=ttyS0 console=ttyS0"
+    else if system == "aarch64-linux"
+    then "console=ttyAMA0"
+    else "";
+
   # balloon
   useBallooning = balloonMem > 0;