Re: [PATCH 2/2] target/riscv: Allow UXL to be 3 in mstatus on rv128

[Daniel Henrique Barboza <daniel.barboza@oss.qualcomm.com>]

On 7/29/2026 5:39 AM, frederic.petrot@univ-grenoble-alpes.fr wrote:
> From: Frédéric Pétrot <frederic.petrot@univ-grenoble-alpes.fr>
> 
> Valid UXL field values for mstatus were restricted to fix a
> reported issue, but this inadvertently broke the experimental
> rv128 support where a value of 3 validly represents 128-bit
> execution.
> 
> Update the mstatus write logic to permit UXL=3 when running on
> an rv128 CPU.
> 
> Fixes: dcd028517749 ("target/riscv: Apply UXL WARL handling to vsstatus")
> Signed-off-by: Frédéric Pétrot <frederic.petrot@univ-grenoble-alpes.fr>
> ---

Reviewed-by: Daniel Henrique Barboza <daniel.barboza@oss.qualcomm.com>

>   target/riscv/tcg/csr.c | 4 ++--
>   1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/target/riscv/tcg/csr.c b/target/riscv/tcg/csr.c
> index d834b77714..5eeb9f0e0f 100644
> --- a/target/riscv/tcg/csr.c
> +++ b/target/riscv/tcg/csr.c
> @@ -2014,8 +2014,8 @@ static uint64_t riscv_write_uxl(CPURISCVState *env, uint64_t val,
>       RISCVMXL xl = riscv_cpu_mxl(env);
>       uint64_t uxl = get_field(val, field);
>   
> -    if (uxl == MXL_RV128) {
> -        uxl = xl == MXL_RV128 ? MXL_RV64 : xl;
> +    if (xl != MXL_RV128 && uxl == MXL_RV128) {
> +        uxl = xl;
>           val = set_field(val, field, uxl);
>       }
>