RISC-V Summit

RISC-V has a lot of optional extensions following different version specifications. When integrating these heterogenous cores in a hybrid architecture SoC, usually it brings a lot of issues for software stacks. For instance, the big core and little core have different version of F extension, or the big core supports V extension while the small core does not.  In such scenario, software stack developers have more concern to support such heterogenous architecture and enable the development and verification far ahead of hardware available. In this proposal, QEMU is modified for such purpose to assist developer to build this hybrid architecture with desired configurations and run software stack on it. With the modifications, a Linux running in AMP way is also shown as an example on this emulation platform. With Linux kernel has per-core capabilities/extensions to be identified (in this proposal, the V and non-V extension is tested), the AMP (relative to SMP) is successfully running with vector and non-vector applications mixed under the normal kernel scheduling.