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[189.68.153.170]) by smtp.gmail.com with ESMTPSA id s11sm5587021otq.69.2022.01.26.12.14.47 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 26 Jan 2022 12:14:48 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=vgs4ZRYoFMEPHstEvbl7Jw7UVg0M4T8VJNHyCHZmMaQ=; b=jfvxmjk8jy1SRAMiNma+ZrOPabR6eNepIdAj5NxM5rZScxtsQUxuICUjoEg59GtTfo s/w82zoWak3tbEKRYN/oQ6EIao8kFArplxnLUJRj4YPqnDyTh7DaDjQzwKhNnipc7k5r V8M4Ne1n60Uuggd2sql8V2g1HugzkHGDmagMU/+UASKZCa4Zqj5wy83Lm7uNT/yv8NXa S0ZMGT3KPr+D5vplcl7poqsHhqXEldWUZOT0fGy4PXZLf3IcEG/yJ+rb7UxAKUBqPdyU VaShVSH9/MzDTBMg6v3vhZl/fdvkYOoGIotWpJLY/+okW/mT0No1ei1LCVBeF8sjyAk4 CznA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=vgs4ZRYoFMEPHstEvbl7Jw7UVg0M4T8VJNHyCHZmMaQ=; b=oCdnzykL22GO+amjH0EnTUdiPc4N3VmYCk5cAHJhsat6AKeUMaEcE43EE17Me1ACNV dZRtXjWB+JseWeSj6EQzaMvfLiGuUwG6drDnmEayZJLoEKMO9R+g43zm0gWi3mycYaSW cxcYTySHrFJwPWU6U3mUs/E3bKzeBGLRLYhlcSmvLr2OgbEGZ6REDC0ykGu2+LNfVYEe f3POCvb72egWQGZbmd95VUcQVHw15/9k3wy6nwuz/qrzd2YgUZLolZjCsfhUscoZLuv+ dmu/qQORwud4UD7fjf/cIgNMbM70CUpjBh38eR8JQexwknH40u1apy37EMuDPDl5s362 HPEQ== X-Gm-Message-State: AOAM532ksuJSlzxVkLXxQj/gvZiRKgdhm77NNyszu/h8fn9GT4QJV5SA lco315ODH75KjG/kF0bijbcKT76EvHw= X-Google-Smtp-Source: ABdhPJzheed6FQpLe/nTUgSuhIdo5L+N3jRE79Fy7prL71YOoi5ja6WjIxclvX89qkoVrdufvuuNVw== X-Received: by 2002:a05:6808:ecc:: with SMTP id q12mr4985886oiv.118.1643228089090; Wed, 26 Jan 2022 12:14:49 -0800 (PST) From: Daniel Henrique Barboza To: qemu-devel@nongnu.org Subject: [PATCH v2 1/2] ppc/pnv: use a do-while() loop in pnv_phb3_translate_tve() Date: Wed, 26 Jan 2022 17:14:37 -0300 Message-Id: <20220126201438.822457-2-danielhb413@gmail.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20220126201438.822457-1-danielhb413@gmail.com> References: <20220126201438.822457-1-danielhb413@gmail.com> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-Host-Lookup-Failed: Reverse DNS lookup failed for 2607:f8b0:4864:20::230 (failed) Received-SPF: pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) client-ip=209.51.188.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Received-SPF: pass client-ip=2607:f8b0:4864:20::230; envelope-from=danielhb413@gmail.com; helo=mail-oi1-x230.google.com X-Spam_score_int: -10 X-Spam_score: -1.1 X-Spam_bar: - X-Spam_report: (-1.1 / 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, PDS_HP_HELO_NORDNS=0.001, RCVD_IN_DNSWL_NONE=-0.0001, RDNS_NONE=0.793, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=no 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: , Cc: "Matheus K . Ferst" , Daniel Henrique Barboza , qemu-ppc@nongnu.org, clg@kaod.org, david@gibson.dropbear.id.au Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: "Qemu-devel" X-ZohoMail-DKIM: fail (Header signature does not verify) X-ZM-MESSAGEID: 1643228319698100001 Content-Type: text/plain; charset="utf-8" The 'taddr' variable is left unintialized, being set only inside the "while ((lev--) >=3D 0)" loop where we get the TCE address. The 'lev' var is an int32_t that is being initiliazed by the GETFIELD() macro, which returns an uint64_t. For a human reader this means that 'lev' will always be positive or zero. But some compilers may beg to differ. 'lev' being an int32_t can in theory be set as negative, and the "while ((lev--) >=3D 0)" loop might never be reached, and 'taddr' will be left unitialized. This can cause phb3_error() to use 'taddr' uninitialized down below: if ((is_write & !(tce & 2)) || ((!is_write) && !(tce & 1))) { phb3_error(phb, "TCE access fault at 0x%"PRIx64, taddr); A quick way of fixing it is to use a do/while() loop. This will keep the same semanting as the existing while() loop does and the compiler will understand that 'taddr' will be initialized at least once. Suggested-by: Matheus K. Ferst Resolves: https://gitlab.com/qemu-project/qemu/-/issues/573 Signed-off-by: Daniel Henrique Barboza --- hw/pci-host/pnv_phb3.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/hw/pci-host/pnv_phb3.c b/hw/pci-host/pnv_phb3.c index 7fb35dc031..39a6184419 100644 --- a/hw/pci-host/pnv_phb3.c +++ b/hw/pci-host/pnv_phb3.c @@ -792,7 +792,7 @@ static void pnv_phb3_translate_tve(PnvPhb3DMASpace *ds,= hwaddr addr, sh =3D tbl_shift * lev + tce_shift; =20 /* TODO: Multi-level untested */ - while ((lev--) >=3D 0) { + do { /* Grab the TCE address */ taddr =3D base | (((addr >> sh) & ((1ul << tbl_shift) - 1)) <<= 3); if (dma_memory_read(&address_space_memory, taddr, &tce, @@ -813,7 +813,7 @@ static void pnv_phb3_translate_tve(PnvPhb3DMASpace *ds,= hwaddr addr, } sh -=3D tbl_shift; base =3D tce & ~0xfffull; - } + } while ((lev--) >=3D 0); =20 /* We exit the loop with TCE being the final TCE */ tce_mask =3D ~((1ull << tce_shift) - 1); --=20 2.34.1