Why RISC-V doesn't (yet) support KVM

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2021-05-20 20:30:04

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By Jonathan Corbet May 20, 2021 The RISC-V CPU architecture has been gaining prominence for some years; its relatively open nature makes it an attractive platform on which a number of companies have built products. Linux supports RISC-V well, but there is one gaping hole: there is no support for virtualization with KVM, despite the fact that a high-quality implementation exists. A recent attempt to add that support is shining some light on a part of the ecosystem that, it seems, does not work quite as well as one would like.

Linux supports a number of virtualization mechanisms, but KVM is generally seen as the native solution. It provides a standard interface across systems, but much of KVM is necessarily architecture-specific, since the mechanisms for supporting virtualization vary from one processor to the next. Thus, architectures that support KVM generally have a kvm directory nestled in with the rest of the architecture-specific code.