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Wed, 27 Jul 2022 23:15:51 -0700 (PDT) Received: from [192.168.1.18] ([171.50.205.214]) by smtp.gmail.com with ESMTPSA id b12-20020a17090a550c00b001f2fbf2c42esm101361pji.26.2022.07.27.23.15.47 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 27 Jul 2022 23:15:50 -0700 (PDT) Message-ID: <62e5130693cbdbb32355001469f267f63d0311c0.camel@ventanamicro.com> Subject: Re: [PATCH v6 3/5] target/riscv: smstateen check for fcsr From: Mayuresh Chitale To: Weiwei Li , qemu-devel@nongnu.org, qemu-riscv@nongnu.org Cc: alistair.francis@wdc.com Date: Thu, 28 Jul 2022 11:45:42 +0530 In-Reply-To: References: <20220721153136.377578-1-mchitale@ventanamicro.com> <20220721153136.377578-4-mchitale@ventanamicro.com> Content-Type: text/plain; charset="UTF-8" User-Agent: Evolution 3.36.5-0ubuntu1 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Received-SPF: pass client-ip=2607:f8b0:4864:20::535; envelope-from=mchitale@ventanamicro.com; helo=mail-pg1-x535.google.com X-Spam_score_int: -5 X-Spam_score: -0.6 X-Spam_bar: / X-Spam_report: (-0.6 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_SORBS_WEB=1.5, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, T_SCC_BODY_TEXT_LINE=-0.01 autolearn=no autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-riscv@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 28 Jul 2022 06:16:00 -0000 On Mon, 2022-07-25 at 15:23 +0800, Weiwei Li wrote: > > 在 2022/7/24 下午11:49, Mayuresh Chitale 写道: > > On Fri, 2022-07-22 at 09:42 +0800, Weiwei Li wrote: > > > 在 2022/7/21 下午11:31, Mayuresh Chitale 写道: > > > > If smstateen is implemented and sstateen0.fcsr is clear then > > > > the > > > > floating point operations must return illegal instruction > > > > exception. > > > > > > > > Signed-off-by: Mayuresh Chitale > > > > --- > > > > target/riscv/csr.c | 23 ++++++++++++++ > > > > target/riscv/insn_trans/trans_rvf.c.inc | 38 > > > > +++++++++++++++++++++-- > > > > target/riscv/insn_trans/trans_rvzfh.c.inc | 4 +++ > > > > 3 files changed, 63 insertions(+), 2 deletions(-) > > > > > > > > diff --git a/target/riscv/csr.c b/target/riscv/csr.c > > > > index ab06b117f9..a597b6cbc7 100644 > > > > --- a/target/riscv/csr.c > > > > +++ b/target/riscv/csr.c > > > > @@ -96,6 +96,10 @@ static RISCVException fs(CPURISCVState *env, > > > > int > > > > csrno) > > > > !RISCV_CPU(env_cpu(env))->cfg.ext_zfinx) { > > > > return RISCV_EXCP_ILLEGAL_INST; > > > > } > > > > + > > > > + if (!env->debugger && !riscv_cpu_fp_enabled(env)) { > > > > + return smstateen_acc_ok(env, 0, SMSTATEEN0_FCSR); > > > > + } > > > > #endif > > > > return RISCV_EXCP_NONE; > > > > } > > > > @@ -1876,6 +1880,9 @@ static RISCVException > > > > write_mstateen0(CPURISCVState *env, int csrno, > > > > target_ulong new_val) > > > > { > > > > uint64_t wr_mask = SMSTATEEN_STATEN | > > > > SMSTATEEN0_HSENVCFG; > > > > + if (!riscv_has_ext(env, RVF)) { > > > > + wr_mask |= SMSTATEEN0_FCSR; > > > > + } > > > > > > > > return write_mstateen(env, csrno, wr_mask, new_val); > > > > } > > > > @@ -1924,6 +1931,10 @@ static RISCVException > > > > write_mstateen0h(CPURISCVState *env, int csrno, > > > > { > > > > uint64_t wr_mask = SMSTATEEN_STATEN | > > > > SMSTATEEN0_HSENVCFG; > > > > > > > > + if (!riscv_has_ext(env, RVF)) { > > > > + wr_mask |= SMSTATEEN0_FCSR; > > > > + } > > > > + > > > > return write_mstateenh(env, csrno, wr_mask, new_val); > > > > } > > > > > > > > @@ -1973,6 +1984,10 @@ static RISCVException > > > > write_hstateen0(CPURISCVState *env, int csrno, > > > > { > > > > uint64_t wr_mask = SMSTATEEN_STATEN | > > > > SMSTATEEN0_HSENVCFG; > > > > > > > > + if (!riscv_has_ext(env, RVF)) { > > > > + wr_mask |= SMSTATEEN0_FCSR; > > > > + } > > > > + > > > > return write_hstateen(env, csrno, wr_mask, new_val); > > > > } > > > > > > > > @@ -2024,6 +2039,10 @@ static RISCVException > > > > write_hstateen0h(CPURISCVState *env, int csrno, > > > > { > > > > uint64_t wr_mask = SMSTATEEN_STATEN | > > > > SMSTATEEN0_HSENVCFG; > > > > > > > > + if (!riscv_has_ext(env, RVF)) { > > > > + wr_mask |= SMSTATEEN0_FCSR; > > > > + } > > > > + > > > > return write_hstateenh(env, csrno, wr_mask, new_val); > > > > } > > > > > > > > @@ -2083,6 +2102,10 @@ static RISCVException > > > > write_sstateen0(CPURISCVState *env, int csrno, > > > > { > > > > uint64_t wr_mask = SMSTATEEN_STATEN | > > > > SMSTATEEN0_HSENVCFG; > > > > > > > > + if (!riscv_has_ext(env, RVF)) { > > > > + wr_mask |= SMSTATEEN0_FCSR; > > > > + } > > > > + > > > > return write_sstateen(env, csrno, wr_mask, new_val); > > > > } > > > > > > > > diff --git a/target/riscv/insn_trans/trans_rvf.c.inc > > > > b/target/riscv/insn_trans/trans_rvf.c.inc > > > > index a1d3eb52ad..c43c48336b 100644 > > > > --- a/target/riscv/insn_trans/trans_rvf.c.inc > > > > +++ b/target/riscv/insn_trans/trans_rvf.c.inc > > > > @@ -24,9 +24,43 @@ > > > > return false; \ > > > > } while (0) > > > > > > > > +#ifndef CONFIG_USER_ONLY > > > > +#define SMSTATEEN_CHECK(ctx) do {\ > > > > + CPUState *cpu = ctx->cs; \ > > > > + CPURISCVState *env = cpu->env_ptr; \ > > > > + if (ctx->cfg_ptr->ext_smstateen && \ > > > > + (env->priv < PRV_M)) { \ > > > > + uint64_t stateen = env->mstateen[0]; \ > > > > + uint64_t hstateen = env->hstateen[0]; \ > > > > + uint64_t sstateen = env->sstateen[0]; \ > > > > + if (!(stateen & SMSTATEEN_STATEN)) {\ > > > > + hstateen = 0; \ > > > > + sstateen = 0; \ > > > > + } \ > > > > + if (ctx->virt_enabled) { \ > > > > + stateen &= hstateen; \ > > > > + if (!(hstateen & SMSTATEEN_STATEN)) {\ > > > > + sstateen = 0; \ > > > > + } \ > > > > + } \ > > > > + if (env->priv == PRV_U && has_ext(ctx, RVS)) > > > > {\eventually > > > > meaning > > > > + stateen &= sstateen; \ > > > > + } \ > > > > + if (!(stateen & SMSTATEEN0_FCSR)) { \ > > > > + return false; \ > > > > + } \ > > > > + } \ > > > > +} while (0) > > > > > > It's better to add a space before '\'. > > > > ok. will modify in the next version. > > > > +#else > > > > +#define SMSTATEEN_CHECK(ctx) > > > > +#endif > > > > + > > > > #define REQUIRE_ZFINX_OR_F(ctx) do {\ > > > > - if (!ctx->cfg_ptr->ext_zfinx) { \ > > > > - REQUIRE_EXT(ctx, RVF); \ > > > > + if (!has_ext(ctx, RVF)) { \ > > > > + SMSTATEEN_CHECK(ctx); \ > > > > + if (!ctx->cfg_ptr->ext_zfinx) { \ > > > > + return false; \ > > > > + } \ > > > > } \ > > > > } while (0) > > > > > > SMSTATEEN_CHECK is for CSR. and REQUIRE_ZFINX_OR_F is for > > > Extension. > > > I think It's better to separate them. By the way, if we want the > > > smallest modification > > > for current code, adding it to REQUIRE_FPU seems better. > > > > Actually REQUIRE_FPU is checking for mstatus.fs but as per > > smstateen > > spec we need to check for misa.f which is done in > > REQUIRE_ZFINX_OR_F. > > OK. It's acceptable to me even though I prefer separating them. > > However, I find another question in SMSTATEEN_CHECK: when access is > disallowed by Xstateen.FCSR, > > it's always return false which will trigger illegal instruction > exception finally. > > However, this exception is triggered by accessing fcsr CSR which may > trigger illegal instruction trap and virtual > instruction trap in different situation. > > "For convenience, when the stateen CSRs are implemented and misa.F = > 0, then if bit 1 of a > controlling stateen0 CSR is zero, all floating-point instructions > cause an illegal instruction trap (or virtual > instruction trap, if relevant), as though they all access fcsr, > regardless of whether they really do." > > And stateen.fcsr is only work when zfinx is enabled, so it's better > to SMSTATEEN_CHECK(ctx) after check for > > "!ctx->cfg_ptr->ext_zfinx" Actually the spec refers only to misa.F and not zfinx and regarding the fcsr its : "as though they all access fcsr, regardless of whether they really do" > Regards, > Weiwei Li > > > Regards, > > > Weiwei Li > > > > > > > > > > > diff --git a/target/riscv/insn_trans/trans_rvzfh.c.inc > > > > b/target/riscv/insn_trans/trans_rvzfh.c.inc > > > > index 5d07150cd0..b165ea9d58 100644 > > > > --- a/target/riscv/insn_trans/trans_rvzfh.c.inc > > > > +++ b/target/riscv/insn_trans/trans_rvzfh.c.inc > > > > @@ -17,24 +17,28 @@ > > > > */ > > > > > > > > #define REQUIRE_ZFH(ctx) do { \ > > > > + SMSTATEEN_CHECK(ctx); \ > > > > if (!ctx->cfg_ptr->ext_zfh) { \ > > > > return false; \ > > > > } \ > > > > } while (0) > > > > > > > > #define REQUIRE_ZHINX_OR_ZFH(ctx) do { \ > > > > + SMSTATEEN_CHECK(ctx); \ > > > > if (!ctx->cfg_ptr->ext_zhinx && !ctx->cfg_ptr->ext_zfh) { > > > > \ > > > > return false; \ > > > > } \ > > > > } while (0) > > > > > > > > #define REQUIRE_ZFH_OR_ZFHMIN(ctx) do { \ > > > > + SMSTATEEN_CHECK(ctx); \ > > > > if (!(ctx->cfg_ptr->ext_zfh || ctx->cfg_ptr->ext_zfhmin)) > > > > { \ > > > > return false; \ > > > > } \ > > > > } while (0) > > > > > > > > #define REQUIRE_ZFH_OR_ZFHMIN_OR_ZHINX_OR_ZHINXMIN(ctx) do { > > > > \ > > > > + SMSTATEEN_CHECK(ctx); \ > > > > if (!(ctx->cfg_ptr->ext_zfh || ctx->cfg_ptr->ext_zfhmin > > > > || \ > > > > ctx->cfg_ptr->ext_zhinx || ctx->cfg_ptr- > > > > >ext_zhinxmin)) > > > > { \ > > > > return > > > > false; \