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[2403:580b:97e8:0:82ce:f179:8a79:69f4]) by smtp.gmail.com with ESMTPSA id d9443c01a7336-1f6323e18c7sm62375435ad.177.2024.06.03.04.17.58 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 03 Jun 2024 04:18:00 -0700 (PDT) From: Alistair Francis X-Google-Original-From: Alistair Francis To: qemu-devel@nongnu.org Cc: alistair23@gmail.com, Daniel Henrique Barboza , Joseph Chan , Alistair Francis , qemu-stable Subject: [PULL v2 21/27] target/riscv: prioritize pmp errors in raise_mmu_exception() Date: Mon, 3 Jun 2024 21:16:37 +1000 Message-ID: <20240603111643.258712-22-alistair.francis@wdc.com> X-Mailer: git-send-email 2.45.1 In-Reply-To: <20240603111643.258712-1-alistair.francis@wdc.com> References: <20240603111643.258712-1-alistair.francis@wdc.com> MIME-Version: 1.0 Received-SPF: pass client-ip=2607:f8b0:4864:20::62d; envelope-from=alistair23@gmail.com; helo=mail-pl1-x62d.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, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, FREEMAIL_ENVFROM_END_DIGIT=0.25, FREEMAIL_FROM=0.001, RCVD_IN_DNSWL_NONE=-0.0001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, T_SCC_BODY_TEXT_LINE=-0.01 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+incoming=patchwork.ozlabs.org@nongnu.org Sender: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org From: Daniel Henrique Barboza raise_mmu_exception(), as is today, is prioritizing guest page faults by checking first if virt_enabled && !first_stage, and then considering the regular inst/load/store faults. There's no mention in the spec about guest page fault being a higher priority that PMP faults. In fact, privileged spec section 3.7.1 says: "Attempting to fetch an instruction from a PMP region that does not have execute permissions raises an instruction access-fault exception. Attempting to execute a load or load-reserved instruction which accesses a physical address within a PMP region without read permissions raises a load access-fault exception. Attempting to execute a store, store-conditional, or AMO instruction which accesses a physical address within a PMP region without write permissions raises a store access-fault exception." So, in fact, we're doing it wrong - PMP faults should always be thrown, regardless of also being a first or second stage fault. The way riscv_cpu_tlb_fill() and get_physical_address() work is adequate: a TRANSLATE_PMP_FAIL error is immediately reported and reflected in the 'pmp_violation' flag. What we need is to change raise_mmu_exception() to prioritize it. Reported-by: Joseph Chan Fixes: 82d53adfbb ("target/riscv/cpu_helper.c: Invalid exception on MMU translation stage") Signed-off-by: Daniel Henrique Barboza Reviewed-by: Alistair Francis Message-ID: <20240413105929.7030-1-alexei.filippov@syntacore.com> Cc: qemu-stable Signed-off-by: Alistair Francis --- target/riscv/cpu_helper.c | 22 ++++++++++++---------- 1 file changed, 12 insertions(+), 10 deletions(-) diff --git a/target/riscv/cpu_helper.c b/target/riscv/cpu_helper.c index d71245a8cb..574886a694 100644 --- a/target/riscv/cpu_helper.c +++ b/target/riscv/cpu_helper.c @@ -1177,28 +1177,30 @@ static void raise_mmu_exception(CPURISCVState *env, target_ulong address, switch (access_type) { case MMU_INST_FETCH: - if (env->virt_enabled && !first_stage) { + if (pmp_violation) { + cs->exception_index = RISCV_EXCP_INST_ACCESS_FAULT; + } else if (env->virt_enabled && !first_stage) { cs->exception_index = RISCV_EXCP_INST_GUEST_PAGE_FAULT; } else { - cs->exception_index = pmp_violation ? - RISCV_EXCP_INST_ACCESS_FAULT : RISCV_EXCP_INST_PAGE_FAULT; + cs->exception_index = RISCV_EXCP_INST_PAGE_FAULT; } break; case MMU_DATA_LOAD: - if (two_stage && !first_stage) { + if (pmp_violation) { + cs->exception_index = RISCV_EXCP_LOAD_ACCESS_FAULT; + } else if (two_stage && !first_stage) { cs->exception_index = RISCV_EXCP_LOAD_GUEST_ACCESS_FAULT; } else { - cs->exception_index = pmp_violation ? - RISCV_EXCP_LOAD_ACCESS_FAULT : RISCV_EXCP_LOAD_PAGE_FAULT; + cs->exception_index = RISCV_EXCP_LOAD_PAGE_FAULT; } break; case MMU_DATA_STORE: - if (two_stage && !first_stage) { + if (pmp_violation) { + cs->exception_index = RISCV_EXCP_STORE_AMO_ACCESS_FAULT; + } else if (two_stage && !first_stage) { cs->exception_index = RISCV_EXCP_STORE_GUEST_AMO_ACCESS_FAULT; } else { - cs->exception_index = pmp_violation ? - RISCV_EXCP_STORE_AMO_ACCESS_FAULT : - RISCV_EXCP_STORE_PAGE_FAULT; + cs->exception_index = RISCV_EXCP_STORE_PAGE_FAULT; } break; default: