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[201.1.57.208]) by smtp.gmail.com with ESMTPSA id n67-20020aca4046000000b00325cda1ff94sm917146oia.19.2022.05.05.11.50.04 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 05 May 2022 11:50:07 -0700 (PDT) From: Daniel Henrique Barboza To: qemu-devel@nongnu.org Cc: qemu-ppc@nongnu.org, danielhb413@gmail.com, peter.maydell@linaro.org, richard.henderson@linaro.org, =?utf-8?q?Philippe_Mathieu-Daud=C3=A9?= , David Gibson Subject: [PULL 01/30] target/ppc: initialize 'val' union in kvm_get_one_spr() Date: Thu, 5 May 2022 15:49:09 -0300 Message-Id: <20220505184938.351866-2-danielhb413@gmail.com> X-Mailer: git-send-email 2.32.0 In-Reply-To: <20220505184938.351866-1-danielhb413@gmail.com> References: <20220505184938.351866-1-danielhb413@gmail.com> MIME-Version: 1.0 Received-SPF: pass client-ip=2607:f8b0:4864:20::22f; envelope-from=danielhb413@gmail.com; helo=mail-oi1-x22f.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+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" Valgrind isn't convinced that we are initializing the values we assign to env->spr[spr] because it doesn't understand that the 'val' union is being written by the kvm_vcpu_ioctl() that follows (via struct kvm_one_reg). This results in Valgrind complaining about uninitialized values every time we use env->spr in a conditional, like this instance: ==707578== Thread 1: ==707578== Conditional jump or move depends on uninitialised value(s) ==707578== at 0xA10A40: hreg_compute_hflags_value (helper_regs.c:106) ==707578== by 0xA10C9F: hreg_compute_hflags (helper_regs.c:173) ==707578== by 0xA110F7: hreg_store_msr (helper_regs.c:262) ==707578== by 0xA051A3: ppc_cpu_reset (cpu_init.c:7168) ==707578== by 0xD4730F: device_transitional_reset (qdev.c:799) ==707578== by 0xD4A11B: resettable_phase_hold (resettable.c:182) ==707578== by 0xD49A77: resettable_assert_reset (resettable.c:60) ==707578== by 0xD4994B: resettable_reset (resettable.c:45) ==707578== by 0xD458BB: device_cold_reset (qdev.c:296) ==707578== by 0x48FBC7: cpu_reset (cpu-common.c:114) ==707578== by 0x97B5EB: spapr_reset_vcpu (spapr_cpu_core.c:38) ==707578== by 0x97BABB: spapr_cpu_core_reset (spapr_cpu_core.c:209) ==707578== Uninitialised value was created by a stack allocation ==707578== at 0xB11F08: kvm_get_one_spr (kvm.c:543) Initializing 'val' has no impact in the logic and makes Valgrind output more bearable. Reviewed-by: Philippe Mathieu-Daudé Signed-off-by: Daniel Henrique Barboza Reviewed-by: David Gibson Message-Id: <20220331001717.616938-2-danielhb413@gmail.com> Signed-off-by: Daniel Henrique Barboza --- target/ppc/kvm.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/target/ppc/kvm.c b/target/ppc/kvm.c index a3c31b4e48..01baea467f 100644 --- a/target/ppc/kvm.c +++ b/target/ppc/kvm.c @@ -542,10 +542,11 @@ static void kvm_get_one_spr(CPUState *cs, uint64_t id, int spr) { PowerPCCPU *cpu = POWERPC_CPU(cs); CPUPPCState *env = &cpu->env; + /* Init 'val' to avoid "uninitialised value" Valgrind warnings */ union { uint32_t u32; uint64_t u64; - } val; + } val = { }; struct kvm_one_reg reg = { .id = id, .addr = (uintptr_t) &val,