From 2b423e82a420cafd406e32334fffa61ad0ef8555 Mon Sep 17 00:00:00 2001
From: Malte Voos <git@mal.tc>
Date: Tue, 13 Oct 2026 12:43:24 +0200
Subject: opportunistic KVM accel

---
 server.nix | 16 +++++++++++-----
 1 file changed, 11 insertions(+), 5 deletions(-)

diff --git a/server.nix b/server.nix
index 78f9e29..f4aeb82 100644
--- a/server.nix
+++ b/server.nix
@@ -134,11 +134,17 @@ writeShellApplication {
   runtimeInputs = [ qemu ];
 
   text = ''
-    rm -f ./reMder.qcow2
-    qemu-img create -b ${diskImage} -F qcow2 -f qcow2 ./reMder.qcow2
-
-    qemu-system-arm \
-        -machine virt \
+    # check if we're on an aarch64 system with support for aarch32 at EL1
+    if echo quit | qemu-system-aarch64 -machine virt -accel kvm -cpu host,aarch64=off \
+         -display none -nodefaults -S -monitor stdio >/dev/null 2>&1; then
+      qemu="qemu-system-aarch64"
+      accel_opts=(-accel kvm -cpu "host,aarch64=off")
+    else
+      qemu="qemu-system-arm"
+      accel_opts=()
+    fi
+
+    exec "$qemu" -machine virt "''${accel_opts[@]}" \
         -m 2048 \
         -kernel ${kernel}/zImage \
         -snapshot \
-- 
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