A milder policy than banning Qualcomm would be something like a mandate that foreign chipmakers must manufacture a certain percentage of sold chips (need not be latest node) at designated "reliable" fabs like SMIC, under penalty of heavy fines or tariffs.
That way, foreign chipmakers at least have the option of complying, incurring minimal changes in costs and revenue (assuming SMIC's services are competitively priced). At the same time, this would funnel money into developing local semiconductor industries, while siphoning business away from TSMC and Samsung.
This can be generalized into a policy that would require foreign companies to source some high-tech parts and services locally in exchange for access to Chinese markets. One benefit to this is that this can be enforced for domestic companies as well, framing it as a matter of national security to minimize disruptions in supply chains.
That way, foreign chipmakers at least have the option of complying, incurring minimal changes in costs and revenue (assuming SMIC's services are competitively priced). At the same time, this would funnel money into developing local semiconductor industries, while siphoning business away from TSMC and Samsung.
This can be generalized into a policy that would require foreign companies to source some high-tech parts and services locally in exchange for access to Chinese markets. One benefit to this is that this can be enforced for domestic companies as well, framing it as a matter of national security to minimize disruptions in supply chains.