systemvm: Fix VR bootstrapping/connection state in KVM (#3524)

Enable qemu-guest-agent / add start qemu-guest-agent back.
Improve hotplug kernel module loading and verbosity.

Author: Sven Vogel

systemvm/debian/opt/cloud/bin/setup/bootstrap.sh

@@ -85,12 +85,18 @@ config_guest() {
           sed -i "s/%/ /g" $CMDLINE
           ;;
      kvm)
-          # Configure hot-plug
-          modprobe acpiphp || true
-          modprobe pci_hotplug || true
+          # Configure kvm hotplug support
+          if grep -E 'CONFIG_HOTPLUG_PCI=y|CONFIG_HOTPLUG_PCI_ACPI=y' /boot/config-`uname -r`; then
+            log_it "acpiphp and pci_hotplug module already compiled in"
+          else
+            modprobe acpiphp 2> /dev/null && log_it "acpiphp module loaded" || true
+            modprobe pci_hotplug 2> /dev/null && log_it "pci_hotplug module loaded" || true
+          fi
+
           sed -i -e "/^s0:2345:respawn.*/d" /etc/inittab
           sed -i -e "/6:23:respawn/a\s0:2345:respawn:/sbin/getty -L 115200 ttyS0 vt102" /etc/inittab
-          systemctl enable --now qemu-guest-agent
+          systemctl enable qemu-guest-agent
+          systemctl start qemu-guest-agent
 
           # Wait for $CMDLINE file to be written by the qemu-guest-agent
           for i in {1..60}; do