Makefile: add system-vm target and GUI=true option

Makefile

@@ -4,6 +4,7 @@ GIT_AUTHOR := $(shell git log -1 --format=%an)
 GIT_PUBKEY := $(shell git log -1 --format=%GK)
 GIT_TIMESTAMP := $(shell git log -1 --format=%cd --date=iso)
 EFI := false
+GUI := false
 ,:=,
 export
 
@@ -51,6 +52,32 @@ out/dev-shell.digest: Containerfile | out
 shell: out/dev-shell.digest
 	docker run -it $(shell cat $<) /bin/sh
 
+.PHONY: system-vm
+system-vm:
+	qemu-system-x86_64 \
+		-m 4G \
+		-machine q35,kernel-irqchip=split \
+		-usb \
+		-device sdhci-pci \
+		-device sd-card,drive=external \
+		-drive id=external,if=none,format=raw,file=out/sdcard.img \
+		-device usb-storage,drive=usbdrive \
+		-device intel-iommu,intremap=on \
+		-netdev user,id=net0 \
+		-device e1000,netdev=net0 \
+		-chardev socket,path=out/qga.sock,server=on,wait=off,id=qga0 \
+		-device virtio-serial \
+		-device virtserialport,chardev=qga0,name=org.qemu.guest_agent.0 \
+		$(if $(filter $(EFI),true) ,\
+			-bios /usr/share/ovmf/OVMF.fd \
+			-drive id=boot$(,)if=virtio$(,)format=raw$(,)file=out/airgap.iso \
+		,\
+			-drive id=usbdrive,if=none,format=raw,file=out/airgap.iso \
+			-boot order=c \
+		) \
+		$(if (,$(wildcard /dev/kvm)),-cpu host --accel kvm,) \
+		$(if $(filter $(GUI),true),,-nographic)
+
 .PHONY: vm
 vm: out/dev-shell.digest out/airgap.iso out/sdcard.img
 	docker run -it -v ./out:/out $(shell cat $<) sh -c "\