Zhaoxin 7-Series x86 CPUs Mitigated For Spectre V2 + SWAPGS

When it comes to the Zhaoxin x86-compatible processors coming out of VIA's joint venture in Shanghai, their forthcoming 7-series (KX-7000) has hardware mitigations in place for some CPU vulnerabilities.

We haven't heard much about these Chinese x86 CPUs with regards to speculative execution vulnerabilities but it appears the pre-7-Series is vulnerable to Spectre Variant Two and at least SWAPGS. But with their 7-series, hardware mitigations appear to be in place.

This patch by a Zhaoxin engineer from Wednesday confirms that the Family 7 processors are not affected by SWAPGS and thus whitelisted from software mitigations.

Additionally, a separate patch whitelists the new Zhaoxin CPUs from Spectre V2 mitigations.

These are the first whitelists we're seeing for any Zhaoxin CPUs within the Linux kernel when it comes to these CPU vulnerabilities.

The Zhaoxin 7-series are said to be 7nm x86 CPUs featuring DDR5 memory, PCI Express 4.0, and other improvements to make them more competitive against today's Intel and AMD CPUs. Having Spectre V2 + SWAPGS hardware mitigations in place would be another boost for its performance.

In other Zhaoxin/Centaur Linux CPU news, Intel recently reworked the KVM code within x86/cpu to allow those CPUs to make use of the Intel KVM driver code for virtualization. That code should be moving forward with Linux 5.6 along with these whitelist patches.