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From: Alistair Francis <alistair23@gmail.com>
To: Richard Henderson <richard.henderson@linaro.org>
Cc: "open list:RISC-V" <qemu-riscv@nongnu.org>,
	Palmer Dabbelt <palmer@dabbelt.com>,
	Bin Meng <bmeng.cn@gmail.com>,
	Alistair Francis <alistair.francis@wdc.com>,
	"qemu-devel@nongnu.org Developers" <qemu-devel@nongnu.org>
Subject: Re: [PATCH v1 4/8] target/riscv: Remove the hardcoded MSTATUS_SD macro
Date: Wed, 7 Apr 2021 13:11:03 -0400	[thread overview]
Message-ID: <CAKmqyKMabQjq0Rwp_kNQLrW-SB5rnZ9yc0Sr9qg=2KhN1cq7xw@mail.gmail.com> (raw)
In-Reply-To: <81cbeace-c357-1ef3-1a1c-f1b266e66a98@linaro.org>

On Mon, Apr 5, 2021 at 11:10 AM Richard Henderson
<richard.henderson@linaro.org> wrote:
>
> On 4/2/21 1:02 PM, Alistair Francis wrote:
> > @@ -369,6 +369,9 @@ static void gen_jal(DisasContext *ctx, int rd, target_ulong imm)
> >   static void mark_fs_dirty(DisasContext *ctx)
> >   {
> >       TCGv tmp;
> > +    CPUState *cpu = ctx->cs;
> > +    CPURISCVState *env = cpu->env_ptr;
> > +
> >       if (ctx->mstatus_fs == MSTATUS_FS) {
> >           return;
> >       }
> > @@ -377,12 +380,24 @@ static void mark_fs_dirty(DisasContext *ctx)
> >
> >       tmp = tcg_temp_new();
> >       tcg_gen_ld_tl(tmp, cpu_env, offsetof(CPURISCVState, mstatus));
> > -    tcg_gen_ori_tl(tmp, tmp, MSTATUS_FS | MSTATUS_SD);
> > +    if (riscv_cpu_is_32bit(env)) {
>
> This is less than ideal, and will be incorrect long term.
> You should check ctx->misa instead.
>
> Eventually you'll need to change riscv_tr_init_disas_context to not just copy
> ctx->misa from env.  At present we flush all translation blocks when misa
> changes, which works.  But you won't want to do that when the hypervisor is
> 64-bit and the guest is 32-bit.
>
> Anyway, I think it would be a good idea to create a helper local to translate,
> akin to has_ext().
>
> > +        tcg_gen_ori_tl(tmp, tmp, MSTATUS_FS | MSTATUS32_SD);
> > +    } else {
> > +#if defined(TARGET_RISCV64)
> > +        tcg_gen_ori_tl(tmp, tmp, MSTATUS_FS | MSTATUS64_SD);
> > +#endif
>
> The ifdefs are ugly.  I presume there's some sort of compiler warning here?
> Does it go away if you cast to target_ulong?
>
> How about
>
>      target_ulong sd = is_32bit(ctx) ? MSTATUS32_SD : MSTATUS64_SD;
>      tcg_gen_ori_tl(tmp, tmp, MSTATUS_FS | sd);
>

That works, thanks!

Alistair

>
> r~


  reply	other threads:[~2021-04-07 17:14 UTC|newest]

Thread overview: 24+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-04-02 20:02 [PATCH v1 0/8] RISC-V: Steps towards running 32-bit guests on Alistair Francis
2021-04-02 20:02 ` [PATCH v1 1/8] target/riscv: Remove the hardcoded RVXLEN macro Alistair Francis
2021-04-05 14:48   ` Richard Henderson
2021-04-12  9:10   ` Bin Meng
2021-04-02 20:02 ` [PATCH v1 2/8] target/riscv: Remove the hardcoded SSTATUS_SD macro Alistair Francis
2021-04-05 14:49   ` Richard Henderson
2021-04-12  9:10   ` Bin Meng
2021-04-02 20:02 ` [PATCH v1 3/8] target/riscv: Remove the hardcoded HGATP_MODE macro Alistair Francis
2021-04-05 14:54   ` Richard Henderson
2021-04-02 20:02 ` [PATCH v1 4/8] target/riscv: Remove the hardcoded MSTATUS_SD macro Alistair Francis
2021-04-05 15:10   ` Richard Henderson
2021-04-07 17:11     ` Alistair Francis [this message]
2021-04-08 15:20     ` Alistair Francis
2021-04-08 18:51       ` Richard Henderson
2021-04-02 20:02 ` [PATCH v1 5/8] target/riscv: Remove the hardcoded SATP_MODE macro Alistair Francis
2021-04-05 15:14   ` Richard Henderson
2021-04-02 20:02 ` [PATCH v1 6/8] target/riscv: Remove the unused HSTATUS_WPRI macro Alistair Francis
2021-04-05 15:15   ` Richard Henderson
2021-04-12  9:10   ` Bin Meng
2021-04-02 20:02 ` [PATCH v1 7/8] target/riscv: Remove an unused CASE_OP_32_64 macro Alistair Francis
2021-04-05 15:15   ` Richard Henderson
2021-04-12  9:10   ` Bin Meng
2021-04-02 20:03 ` [PATCH v1 8/8] target/riscv: Include RV32 instructions in RV64 build Alistair Francis
2021-04-06 14:57   ` Richard Henderson

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