On Tue, Sep 14, 2021 at 10:10 AM Richard Henderson <
[email protected]> wrote:

> On 9/13/21 6:37 PM, [email protected] wrote:
> > From: Frank Chang <[email protected]>
> >
> > When V=1, both vsstauts.FS and HS-level sstatus.FS are in effect.
> > Modifying the floating-point state when V=1 causes both fields to
> > be set to 3 (Dirty).
> >
> > However, it's possible that HS-level sstatus.FS is Clean and VS-level
> > vsstatus.FS is Dirty at the time mark_fs_dirty() is called when V=1.
> > We can't early return for this case because we still need to set
> > sstatus.FS to Dirty according to spec.
> >
> > Signed-off-by: Frank Chang <[email protected]>
> > Reviewed-by: Vincent Chen <[email protected]>
> > Tested-by: Vincent Chen <[email protected]>
> > ---
> >   target/riscv/translate.c | 19 ++++++++++---------
> >   1 file changed, 10 insertions(+), 9 deletions(-)
> >
> > diff --git a/target/riscv/translate.c b/target/riscv/translate.c
> > index e356fc6c46c..0096b098738 100644
> > --- a/target/riscv/translate.c
> > +++ b/target/riscv/translate.c
> > @@ -280,26 +280,27 @@ static void gen_jal(DisasContext *ctx, int rd,
> target_ulong imm)
> >   static void mark_fs_dirty(DisasContext *ctx)
> >   {
> >       TCGv tmp;
> > -    target_ulong sd;
> > +    target_ulong sd = is_32bit(ctx) ? MSTATUS32_SD : MSTATUS64_SD;
> > +
> > +    if (ctx->virt_enabled) {
> > +        tmp = tcg_temp_new();
> > +        tcg_gen_ld_tl(tmp, cpu_env, offsetof(CPURISCVState,
> mstatus_hs));
> > +        tcg_gen_ori_tl(tmp, tmp, MSTATUS_FS | sd);
> > +        tcg_gen_st_tl(tmp, cpu_env, offsetof(CPURISCVState,
> mstatus_hs));
> > +        tcg_temp_free(tmp);
> > +    }
> >
> >       if (ctx->mstatus_fs == MSTATUS_FS) {
> >           return;
> >       }
>
> You should introduce a ctx->mstatus_hs field to track the code that you
> moved.  Otherwise
> you'll be setting this dirty bit for every fp insn.
>
>
Thanks, Richard, I was struggling with whether to introduce a new field
in DisasContext.
I will update my patch.

Regards,
Frank Chang


>
> r~
>

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