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([2a01:e0a:e17:9700:16d2:7456:6634:9626]) by smtp.gmail.com with ESMTPSA id d2e1a72fcca58-71e77371193sm4859580b3a.21.2024.10.17.07.52.56 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 17 Oct 2024 07:53:02 -0700 (PDT) From: =?utf-8?b?Q2zDqW1lbnQgTMOpZ2Vy?= To: qemu-riscv@nongnu.org, Palmer Dabbelt , Alistair Francis , Bin Meng Cc: =?utf-8?b?Q2zDqW1lbnQgTMOpZ2Vy?= , Weiwei Li , Daniel Henrique Barboza , Liu Zhiwei , Ved Shanbhogue , Atish Patra , qemu-devel@nongnu.org Subject: [PATCH v4 3/9] target/riscv: Implement Ssdbltrp sret, mret and mnret behavior Date: Thu, 17 Oct 2024 16:52:14 +0200 Message-ID: <20241017145226.365825-4-cleger@rivosinc.com> X-Mailer: git-send-email 2.45.2 In-Reply-To: <20241017145226.365825-1-cleger@rivosinc.com> References: <20241017145226.365825-1-cleger@rivosinc.com> MIME-Version: 1.0 Received-SPF: pass client-ip=2607:f8b0:4864:20::429; envelope-from=cleger@rivosinc.com; helo=mail-pf1-x429.google.com X-Spam_score_int: -18 X-Spam_score: -1.9 X-Spam_bar: - X-Spam_report: (-1.9 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org When the Ssdbltrp extension is enabled, SSTATUS.SDT field is cleared when executing sret. When executing mret/mnret, SSTATUS.SDT is cleared when returning to U, VS or VU and VSSTATUS.SDT is cleared when returning to VU from HS. Signed-off-by: Clément Léger Reviewed-by: Alistair Francis --- target/riscv/op_helper.c | 35 ++++++++++++++++++++++++++++++++++- 1 file changed, 34 insertions(+), 1 deletion(-) diff --git a/target/riscv/op_helper.c b/target/riscv/op_helper.c index 180886f32a..dabc74de39 100644 --- a/target/riscv/op_helper.c +++ b/target/riscv/op_helper.c @@ -287,6 +287,18 @@ target_ulong helper_sret(CPURISCVState *env) get_field(mstatus, MSTATUS_SPIE)); mstatus = set_field(mstatus, MSTATUS_SPIE, 1); mstatus = set_field(mstatus, MSTATUS_SPP, PRV_U); + + if (riscv_cpu_cfg(env)->ext_ssdbltrp) { + if (riscv_has_ext(env, RVH)) { + target_ulong prev_vu = get_field(env->hstatus, HSTATUS_SPV) && + prev_priv == PRV_U; + /* Returning to VU from HS, vsstatus.sdt = 0 */ + if (!env->virt_enabled && prev_vu) { + env->vsstatus = set_field(env->vsstatus, MSTATUS_SDT, 0); + } + } + mstatus = set_field(mstatus, MSTATUS_SDT, 0); + } if (env->priv_ver >= PRIV_VERSION_1_12_0) { mstatus = set_field(mstatus, MSTATUS_MPRV, 0); } @@ -297,7 +309,6 @@ target_ulong helper_sret(CPURISCVState *env) target_ulong hstatus = env->hstatus; prev_virt = get_field(hstatus, HSTATUS_SPV); - hstatus = set_field(hstatus, HSTATUS_SPV, 0); env->hstatus = hstatus; @@ -328,6 +339,22 @@ static void check_ret_from_m_mode(CPURISCVState *env, target_ulong retpc, riscv_raise_exception(env, RISCV_EXCP_INST_ACCESS_FAULT, GETPC()); } } +static target_ulong ssdbltrp_mxret(CPURISCVState *env, target_ulong mstatus, + target_ulong prev_priv, + target_ulong prev_virt) +{ + /* If returning to U, VS or VU, sstatus.sdt = 0 */ + if (prev_priv == PRV_U || (prev_virt && + (prev_priv == PRV_S || prev_priv == PRV_U))) { + mstatus = set_field(mstatus, MSTATUS_SDT, 0); + /* If returning to VU, vsstatus.sdt = 0 */ + if (prev_virt && prev_priv == PRV_U) { + env->vsstatus = set_field(env->vsstatus, MSTATUS_SDT, 0); + } + } + + return mstatus; +} target_ulong helper_mret(CPURISCVState *env) { @@ -345,6 +372,9 @@ target_ulong helper_mret(CPURISCVState *env) mstatus = set_field(mstatus, MSTATUS_MPP, riscv_has_ext(env, RVU) ? PRV_U : PRV_M); mstatus = set_field(mstatus, MSTATUS_MPV, 0); + if (riscv_cpu_cfg(env)->ext_ssdbltrp) { + mstatus = ssdbltrp_mxret(env, mstatus, prev_priv, prev_virt); + } if ((env->priv_ver >= PRIV_VERSION_1_12_0) && (prev_priv != PRV_M)) { mstatus = set_field(mstatus, MSTATUS_MPRV, 0); } @@ -378,6 +408,9 @@ target_ulong helper_mnret(CPURISCVState *env) if (prev_priv < PRV_M) { env->mstatus = set_field(env->mstatus, MSTATUS_MPRV, false); } + if (riscv_cpu_cfg(env)->ext_ssdbltrp) { + env->mstatus = ssdbltrp_mxret(env, env->mstatus, prev_priv, prev_virt); + } if (riscv_has_ext(env, RVH) && prev_virt) { riscv_cpu_swap_hypervisor_regs(env);