On 2026-02-06 11:01, Sébastien Michelland wrote:
> trans_rvv.c.inc checks for the RVV extension through the function
> require_rvv. However, at least under CONFIG_USER_ONLY, the RVV extension
> status in DisasContex->mstatus_vs is always set to DIRTY, therefore
> treating RVV instructions as legal even when the extension is not
> present, e.g. with -cpu=rv32,v=false.
>
> This bug manifests rarely because vset{i}vl{i} perform extra checks that
> do fail without RVV, thus raising SIGILL, and with no vtype set nearly
> all other RVV instructions still pass require_rvv but fail the vill check.
> Only instructions that don't depend on type (whole-register load/stores,
> such as vs*r.v) would show the bug by being executed when v=false.
>
> This patch sets mstatus_vs to DISABLED when RVV is not present (checked
> with the minimalistic Zve32x), meaning require_rvv now fails as intended.
>
> Signed-off-by: Sébastien Michelland <[email protected]>
> ---
> Thanks Max for your patience with this patch.
Reviewed-by: Max Chou <[email protected]>
rnax
