qemu support for rv64imafd/rv64imafdc

qemu support for rv64imafd/rv64imafdc

[Billa Surendra]

[-- Attachment #1: Type: text/plain, Size: 250 bytes --]

Dear all,

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.

Thanks in advance
Billa

[-- Attachment #2: Type: text/html, Size: 361 bytes --]

Re: qemu support for rv64imafd/rv64imafdc

[Palmer Dabbelt]

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.

Re: qemu support for rv64imafd/rv64imafdc

[Billa Surendra]

[-- Attachment #1: Type: text/plain, Size: 887 bytes --]

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.
>

[-- Attachment #2: Type: text/html, Size: 1297 bytes --]