Hardware Hacker: Walling Off China From RISC-V Ain't Such A Great Idea, Mr President

Continued pressure by US lawmakers to restrict China's access to RISC-V has been called into question.

Ahead of the annual RISC-V Summit in Silicon Valley's Santa Clara, taking place this week, Andrew 'bunnie' Huang - a noted hardware hacker, electronics biz owner, and author - said attempts by politicians to somehow stop China from using RISC-V was destined to backfire on American companies. He urged the Biden administration to instead take action to promote rather than stifle innovation in that part of the chip sector.

Huang's warning, made in an open letter on his blog and sent to the White House, US Dept of Commerce, and members of Congress came in response to a group of bipartisan lawmakers calling on the White House to address, in their minds', the national security risks posed by the People's Republic of China (PRC) using RISC-V. These lawmakers are unhappy that China is getting its hands so easily on what they see as American-controlled technology.

Developed in 2010 by researchers at the University of California, Berkeley, in the US, RISC-V has risen to prominence thanks, in no small part, to its open nature. It's a royalty-free instruction set architecture (ISA) that specifies a base set of CPU instructions, with various optional extensions available to extend its functionality.

Chip designers around the world, from the USA and Europe to India, China, and Japan, are free to create processors and other components that are compatible with it, and have done so and are expected to keep doing so. A good deal of RISC-V designs and software are open source, though that openness is not required: you can make a RISC-V-compatible processor yourself, using the open ISA, and keep the blueprints private, if you so wished.

RISC-V International is the Swiss organization that steers development of the ISA, and it does not design CPU cores. The body even relocated its address to Switzerland from the US in 2019 in an attempt to avoid America and others from restricting access to the project.

Despite that move, and RISC-V's global open nature, US politicians see the thing as American, or something that America can control access to. No matter where RISC-V International says it is incorporated, exports of RISC-V stuff into China should be restricted, according to the Congressfolk.

Perhaps the politicians think they'll be able to cut off Beijing's access to the bits of the RISC-V specification that were made by US persons, or RISC-V chips that were designed or made on American soil, or just put up a firewall between themselves and China on RISC-V. It's not entirely clear.

"While the benefits of open-source collaboration on RISC-V promise to be significant for advancement and development of the US semiconductor industry, it can only be realized when contributors are working with the sole aim of improving the technology, and not aiding the technological goals and geopolitical interests of the PRC," the group of 18 Congressfolk wrote in their letter [PDF] to Commerce Secretary Gina Raimondo last week.

Following several rounds of US sanctions leveled against China's semiconductor industry, several chipmakers and hyperscalers, including Alibaba, Tencent, and Baidu have accelerated development of homegrown RISC-V silicon in an effort to insulate the nation's supply chain from further disruption by trade sanctions brought by the US.

[Speaking of Baidu and homegrown chips, the cloud giant has ordered a bunch of AI accelerators from Huawei that are supposed to be an alternative to Nvidia's A100 GPU – ed.]

The lawmakers suggested the White House had the authority under the Export Control Reform Act of 2018 "to require US persons engaging with the [People's Republic of China] on RISC-V technology, or other instruction set architecture, to first receive an export control license from the Department of Commerce."

A chilling effect

One of Huang's biggest fears is that the risk of violating US export controls [PDF], which includes civil penalties of up to $250,000 and criminal penalties of 20 years in prison, and a maximum $1 million fine, could have a chilling effect on contributions to RISC-V development.

"The restrictions are so onerous that I feel even the specter of being potentially held liable, even if it's very unlikely… will give people pause to engage with the ecosystem," Huang told The Register.

This, he says, could lead to companies and institutions deciding against contributing to or adopting RISC-V, and licensing technologies instead from places like Arm. That would leave the RISC-V world poorer: less innovation and contributions from Americans at least, less encouragement and motivation for others to use it, less reason for people to develop it. The ISA would become a renegade architecture, an always-distant competitor of Arm and x86. That would leave America, for one, without a strong third-choice ISA.

While lawmakers argue restrictions are necessary to stop Chinese manufacturers building more advanced RISC-V chips, Huang insists such action would slow American progress in developing, furthering, and adopting this technology itself and ultimately could have the opposite effect intended by lawmakers.

In fact, Huang argues that US efforts to stifle China's chip industry have largely motivated the Middle Kingdom to try and end its reliance on Western technologies. Rather than spend money on US-developed chips, Chinese outfits are putting that money toward building their own, he noted.

"There's a general lack of understanding about what open source is by lawmakers and policy makers," he said.

"The thing that stands out to me is they could have done this with a call for a ban on CPUs with a certain number of execution units, out of order, depths, reorder, cache size — you can use whatever criteria you want… but instead they focus on architecture."

There's precedent for this. As part of its recent IPO filing, Arm revealed that it was restricted from selling its highest-end Neoverse cores in China. Meanwhile, the Biden Administration recently restricted the export of AI accelerators exceeding certain performance levels, and preemptively ordered Nvidia to cease shipments of most datacenter GPUs to China ahead of the November deadline.

• Arm grabs a slice of Raspberry Pi to sweeten relationship with IoT devs
• Google formally gets to work on Android on RISC-V
• RISC-V champ SiFive confirms it's laying off 1 in 5 workers
• Hot fuzz: Cascade finds dozens of RISC-V chip bugs using random data storm

Rather than putting limits on RISC-V, Huang suggests the President take steps toward investing in domestic development of the architecture.

"The US has strong precedents for companies navigating the boundaries of open standards," he wrote in his letter, pointing to Intel and AMD, which have gained market dominance on the back of proprietary implementations of the x86 computer standard. "What the US needs is an American answer to Arm's monopoly, and that answer comes from investing in US companies that embrace RISC-V."

Huang is also encouraging those involved in the RISC-V ecosystem to make their opinions known to lawmakers, whether they agree with him or not.

"President Biden, I urge you: have faith in American innovation," he finished his letter with. "Have faith in American values. Do not place any restrictions on the sharing of RISC-V technology. We can work together to build more US chip maker success stories, while embracing the American value of freedom of expression."

A growing concern

Huang isn't the only one raising the alarm about efforts to restrict access to RISC-V. In a statement to The Register, Santa Clara, California-based SiFive compared banning RISC-V to telling people they can't work on the internet.

"Open standards like Linux, Ethernet, Wi-Fi, and now RISC-V, are critical to technology innovation and growth. There seems to be confusion with the RISC-V open standard and the actual technology products which are well controlled by relevant export laws already," the biz told us.

"Telling US companies to stop working on this important technology would be an enormous setback for the US. The US is the leader and RISC-V was invented here."

SiFive made some of its RISC-V CPU core designs and other semiconductor blueprints openly available; one wonders what will happen if someone in China grabs that code from GitHub and uses it to make a microcontroller or a system-on-chip, and the US lawmakers get their way? A spokesperson for SiFive told us it stopped supporting those open-source CPU core designs in 2021, and has left them online in archive form.

As a side note, RISC-V in China is one of the topics SiFive will be discussing during one of two keynotes at this week's RISC-V Summit, though the biz won't have a booth at the shindig. Earlier this year, SiFive chief architect Krste Asanović – one of the founders of the RISC-V ISA – stepped down as chairman of RISC-V International, and the biz last month announced double-decimation layoffs amid a company-wide restructuring.

Speaking of RISC-V International, the governing body has also weighed in on potential regulation. Early last month, its CEO Calista Redmond defended the value of open standards amid an initial call to restrict access to RISC-V.

"Contemplating actions by governments for an unprecedented restriction in open standards will have the consequence of diminished access to the global marketplace of products, solutions, talent," she wrote. "Bifurcating on the standards level would lead to a world of incompatible solutions that duplicate effort and close off markets."

As we reported at the time, Redmond noted that the specifications published by RISC-V International don't contain any more information than is available for proprietary architectures. The key difference is that chipmakers are able to use these documents to make RISC-V-compatible components without licensing them from a controlling company.

By contrast, companies like Arm require chipmakers to either license cores or obtain an architectural license to develop compatible cores of their own. ®