fix: netvm start edge case handling

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

@@ -61,10 +61,11 @@ function cmd_start(){
         [ ! -f "${LOCKFILE}" ] || { echo "Error: Netvm already running"; exit 1; }
 	local net_args=""
 	while read line; do
+		[ -n "$line" ] || break
 		echo "Preparing PCI network device: $line"
 		bus=$(echo $line | awk '{ print $1 }')
 		id=$(echo $line | awk '{ print $4 }' | tr ':' ' ')
-		echo "$id" > /sys/bus/pci/drivers/vfio-pci/new_id || :
+		echo "$id" > /sys/bus/pci/drivers/vfio-pci/new_id 2>&1 || :
 		net_args="$net_args -device vfio-pci,host=${bus}"
 	done <<< "$(lspci | grep 0200 )"
 	if [[ -n "$net_args" ]]; then
@@ -80,14 +81,15 @@ function cmd_start(){
                 -net none \
                 -cdrom /guest.img \
                 -boot order=d \
-                -chardev socket,path=/var/run/netvm_qga.sock,server=on,wait=off,id=qga0 \
+                -chardev socket,path=${QGA_SOCKET},server=on,wait=off,id=qga0 \
 		$net_args \
 		-device qemu-xhci \
                 -device virtio-serial \
                 -device virtserialport,chardev=qga0,name=org.qemu.guest_agent.0 &
         pid=$!
 	echo "$pid" > "${LOCKFILE}"
-        until qemu_ga guest-ping; do
+        until [ -S "${QGA_SOCKET}" ]; do sleep 1; done
+        until qemu_ga guest-ping "{}"; do
 		ps -p $pid >/dev/null || {
 			echo "Error: netvm exited unexpectedly";
 			exit 1;
@@ -95,6 +97,7 @@ function cmd_start(){
 		}
                 sleep 1
         done
+	echo "NetVM is booted"
 }
 
 function cmd_stop(){