feat: add hot plugging for usb devices

src/host/rootfs/usr/local/bin/netvm

@@ -4,6 +4,7 @@ set -eu
 COMMAND=($@)
 LOCKFILE=/var/run/netvm.pid
 QGA_SOCK_PATH=/var/run/netvm_qga.sock
+QMP_SOCK_PATH=/var/run/netvm_qmp.sock
 QGA_SOCK_FDS=false
 
 qga_connect() {
@@ -107,9 +108,10 @@ function cmd_start(){
 		-net none \
 		-cdrom /guest.img \
 		-boot order=d \
-		-chardev socket,path=/var/run/netvm_qga.sock,server=on,wait=off,id=qga0 \
+		-chardev socket,path=${QGA_SOCK_PATH},server=on,wait=off,id=qga0 \
+		-qmp unix:${QMP_SOCK_PATH},server,nowait \
 		$net_args \
-		-device qemu-xhci \
+		-device qemu-xhci,id=usb \
 		-device virtio-serial \
 		-device virtserialport,chardev=qga0,name=org.qemu.guest_agent.0 \
 	>/dev/null 2>&1 &!
@@ -237,6 +239,20 @@ function cmd_run(){
 	done
 }
 
+function cmd_attach() {
+	local id="${COMMAND[1]}"
+	IFS=":" read vendorid_hex productid_hex <<< "$id"
+
+	vendorid=$(printf "%d\n" "0x$vendorid_hex")
+	productid=$(printf "%d\n" "0x$productid_hex")
+	echo $productid
+	echo $vendorid
+	(
+		echo '{"execute":"qmp_capabilities"}'
+		echo '{"execute":"device_add","arguments":{"driver":"usb-host","bus":"usb.0","vendorid":'$vendorid',"productid":'$productid'}}'
+	) | socat - UNIX-CONNECT:/var/run/netvm_qmp.sock 
+}
+
 cmd_usage() {
 	cat <<-_EOF
 	netvm
@@ -252,6 +268,8 @@ cmd_usage() {
 	      Start interactive network vm in the foreground
 	  netvm status
 	      Get hostname and uptime from running network vm
+      	  netvm attach <vendorid:deviceid>
+	      Hot-plug a USB device to network VM
 	  netvm push <local-path> <remote-path>
 	      Push a local file to the network VM
 	  netvm pull <remote-path> <local-path>