At the time that Huawei was placed on the US government's Entity List last week, Huawei is thought to have built enough supplied of key components to last up to 12 months. The report comes via the Nikkei Asian Review that says Huawei told suppliers that it wanted to build up a year's worth of inventory to help cushion the impact of the US-China trade war.
https://www.notebookcheck.net/Huawei-has-stockpiled-up-to-a-12-month-supply-of-parts-as-a-buffer-against-a-potential-ban.421922.0.html