Re: qemu support for rv64imafd/rv64imafdc

[Billa Surendra]

Thanks for the info. 

On Thu, 11 Feb, 2021, 1:58 am Palmer Dabbelt, <palmer@dabbelt.com> wrote:

On Wed, 10 Feb 2021 02:10:35 PST (-0800), billa.iitmadras@gmail.com wrote:
> Does riscv qemu support  both kernel image generated with RV64IMAFD
> extensions and Image generated with RV64IMAFDC ?. If the answer is yes, how
> is it supporting both ?. Please reply to my question if anyone knows.

You can use CPU properties to enable/disable various ISA subsets.  Something like

    qemu-system-riscv64 -cpu rv64,c=off

would turn C off.  The other supported ISA subsets can be enabled/disabled in a
similar fashion, including everything you listed.  There's no known reason
RV64G (ie, non-C) kernels wouldn't work but they're not widely used so you may
run into some long-tail issues.  You need C for EFI, but most people aren't
using that on RISC-V yet.