Re: [PATCH v2 1/3] target/riscv: Do not allow MXL_RV32 for TARGET_RISCV64

[Alistair Francis]

On Tue, Oct 17, 2023 at 12:14 PM LIU Zhiwei
<zhiwei_liu@linux.alibaba.com> wrote:
>
>
> On 2023/10/16 9:51, Alistair Francis wrote:
> > On Sun, Oct 15, 2023 at 4:05 AM Daniel Henrique Barboza
> > <dbarboza@ventanamicro.com> wrote:
> >>
> >>
> >> On 10/14/23 00:35, Akihiko Odaki wrote:
> >>> TARGET_RISCV64 does not have riscv-32bit-cpu.xml so it shouldn't accept
> >>> MXL_RV32.
> >>>
> >>> Signed-off-by: Akihiko Odaki <akihiko.odaki@daynix.com>
> >>> ---
> >> Reviewed-by: Daniel Henrique Barboza <dbarboza@ventanamicro.com>
> >>
> >>
> >>>    target/riscv/tcg/tcg-cpu.c | 3 ++-
> >>>    1 file changed, 2 insertions(+), 1 deletion(-)
> >>>
> >>> diff --git a/target/riscv/tcg/tcg-cpu.c b/target/riscv/tcg/tcg-cpu.c
> >>> index a28918ab30..e0cbc56320 100644
> >>> --- a/target/riscv/tcg/tcg-cpu.c
> >>> +++ b/target/riscv/tcg/tcg-cpu.c
> >>> @@ -161,10 +161,11 @@ static void riscv_cpu_validate_misa_mxl(RISCVCPU 
> >>> *cpu, Error **errp)
> >>>        case MXL_RV128:
> >>>            cc->gdb_core_xml_file = "riscv-64bit-cpu.xml";
> >>>            break;
> >>> -#endif
> >>> +#elif defined(TARGET_RISCV32)
> >>>        case MXL_RV32:
> >>>            cc->gdb_core_xml_file = "riscv-32bit-cpu.xml";
> >>>            break;
> >>> +#endif
> > This isn't the right fix. The idea is that riscv64-softmmu can run
> > 32-bit CPUs, so we instead should include riscv-32bit-cpu.xml
>
> Agree. I'd like to go on the work. The question is that we don't have
> 64-bit OpenSBI which supports booting 32-bit Linux.
> So even we have implemented the SXLEN 32bit, we may not have the
> software to test it.

Ah! So I was first talking around just a full 32-bit CPU.

So for example:
    qemu-system-riscv64 -machine opentitan

So we are using qemu-system-riscv64 to run a 32-bit only CPU.

Then we can think about SXLEN

>
> Do you support the SXL upstreaming with no testing?

No, it should be tested

Alistair

>
> Thanks,
> Zhiwei
>
> >
> > Alistair
> >
> >>>        default:
> >>>            g_assert_not_reached();
> >>>        }