From nobody Thu Dec 18 22:18:35 2025 Delivered-To: importer@patchew.org Authentication-Results: mx.zohomail.com; dkim=pass; spf=pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org; dmarc=pass(p=none dis=none) header.from=gmail.com ARC-Seal: i=1; a=rsa-sha256; t=1744704275; cv=none; d=zohomail.com; s=zohoarc; b=Eva73vgQ2qaBBtFEYdpbEhY5h+y+RNPCtkz8xwIYUmFnOYTK6ap7I1LXZS0l2RYYPFvOHYYOOvEfQ4J6Gjl0t/R5dDOGbxsJa87BDfQbPcRHyBCc7Ao1YBAG7HJ+uRNmFSYXWzWLWBNA4zcsZNBVwslFspRynDyUpybkYth0p3U= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=zohomail.com; s=zohoarc; t=1744704275; h=Content-Transfer-Encoding:Cc:Cc:Date:Date:From:From:In-Reply-To:List-Subscribe:List-Post:List-Id:List-Archive:List-Help:List-Unsubscribe:MIME-Version:Message-ID:References:Sender:Subject:Subject:To:To:Message-Id:Reply-To; bh=fVdc1YwIRV2GyTbuh3vK0eXda9+aM0GBapiUKLD+4mY=; b=mUXx4TohdSkhW0xTKgW3HzK5/ntP60H86za68EV3QPSQc/viXKgzbF1ZedU/FIMROP70OCzaAJNHHnnYjZaplgritU4j/jafnPonZO6r9HnhA7nix6M+qlXlg4BcCNFYKQH7PBUAKC85cI8GhsMxqdAI93j+jM6ONN/cuCd8se4= ARC-Authentication-Results: i=1; mx.zohomail.com; dkim=pass; spf=pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org; dmarc=pass header.from= (p=none dis=none) Return-Path: Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) by mx.zohomail.com with SMTPS id 1744704275223235.71099099910816; Tue, 15 Apr 2025 01:04:35 -0700 (PDT) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1u4bGK-0007Ua-IT; Tue, 15 Apr 2025 04:03:21 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1u4bGA-0007TJ-OM; Tue, 15 Apr 2025 04:03:11 -0400 Received: from mail-pg1-x532.google.com ([2607:f8b0:4864:20::532]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.90_1) (envelope-from ) id 1u4bG8-0000ak-Cz; Tue, 15 Apr 2025 04:03:10 -0400 Received: by mail-pg1-x532.google.com with SMTP id 41be03b00d2f7-aee79a0f192so3469369a12.3; Tue, 15 Apr 2025 01:03:07 -0700 (PDT) Received: from station.lan ([155.69.190.63]) by smtp.gmail.com with ESMTPSA id 98e67ed59e1d1-306dd12b5c5sm12640745a91.24.2025.04.15.01.03.04 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 15 Apr 2025 01:03:05 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1744704186; x=1745308986; darn=nongnu.org; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=fVdc1YwIRV2GyTbuh3vK0eXda9+aM0GBapiUKLD+4mY=; b=aG8Wmks5KYKe7NPNYAphLjxk6TQMQHopa9Z3bsRR4OojtWbU8zkQufdNooaT8bvyOn TgohpT/pRjVoIEvXPi/plPy7FFRUA8jhezNY4hOaweRaAWekoXEbzqb1glRyoGh8VJOG hQ4wVl4KhiZ0aMLHv3KnYIuBmsxUFSBLK9Tr/eUdh8qX6cnVt0LAz2Hd4Ow2f3oO59wc kvmmfuKrs1S5ao0zRYGkj3Gd7NoFWYl6VrzvFsKjM4eYeDDykISfMAPEmLGf3eieTEaP 85/jkPYsawAvaDOl3ZzJ4klR78OK+clqv55AUyEQ2gTWsH/4P3QT9JDUDJ/XcBeanmsD wdbw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1744704186; x=1745308986; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=fVdc1YwIRV2GyTbuh3vK0eXda9+aM0GBapiUKLD+4mY=; b=nlAHsXZt90thy1tvRFxerQ905gnu+l1Yu5J3PJ7LCbxmeE2YDdJBsOmg06g/omDyqt ISRTg6p0yjCdNdi5+X/hM0vFGB4qbhmBL2//IpasgDvALNBzoYfsYBFLpjnw3KB3wtwm y+vxU6bp0P3F3ZmA86qcyghs/7GujSzT7VtQt/IjRXk5Rwd2/Du0XfQrBMPJwMK+Tvrb wY6Qx0Y5EvSCq7XW4t+ZdHnPPXil0IR/P/UVlgdOrJNiQ8VvwLf5mv64tPET7Ndgxy+f 5PidU2BOYg9sS0CuqPj6lJbgK1QU61B5hPYVoQkap/ISi/GE35MLe+5FXy1BqJgvHmCo +/EQ== X-Forwarded-Encrypted: i=1; AJvYcCVbDJcuKuv6G6yKqg4dlRyDRgBdJJUDSKfM6MLY9iYT3yNVeasXrOfPrU8+fF5iKvD0Nttekqt+e15FE+E=@nongnu.org X-Gm-Message-State: AOJu0YxdPgUEqRzj9wQH+pzoz89Lnm8g2bDvuyJyvYnlH7u3oBBNIvFL eyD0gJnKRxsYY2u43lHoxEOybV7halORlOzACwW8odvPXmUdy68jRvBKDLus X-Gm-Gg: ASbGncugY1QEZdAIIv4jTaLTDmXX8t/T0fnw1996pPS0yE4LxMHh8urxSSoR7pQ1FD1 C5T9JNL1MT/brKgzZPBC9SZlKcP/rKXv45/MuZ7stEDWf2B/K1D+Hzj+bIuFd6x+uosa+iBL5u3 6bXbzl8OpOiNxLqM8uqqAsbpg8NbWby+1YEJgTQOegKOiKJnRrckTUtb4VUrCiCaiRmmZPFAya9 Lo5sf2Q9ZLYf/yMbGqyG8kr5Go4mWQejwypU86OkUyA4CEUz54+5L2N63/VCFeaTKYCBACIL3uk JbzHWqFZHG/WEEPDhZtKFS9TuBrmon/w31wl2geD X-Google-Smtp-Source: AGHT+IEM6SnnT4U83vT5Oyz6uNGi46RbIwqHKC2BsaBiibjfZPH1Ry1tWzRNVnR00RGIqksYWev95g== X-Received: by 2002:a17:90b:2551:b0:2ff:7ad4:77af with SMTP id 98e67ed59e1d1-3082378e72cmr23084739a91.20.1744704186243; Tue, 15 Apr 2025 01:03:06 -0700 (PDT) From: Ziqiao Kong To: qemu-devel@nongnu.org Cc: ziqiaokong@gmail.com, qemu-trivial@nongnu.org, alistair.francis@wdc.com, richard.henderson@linaro.org, philmd@linaro.org, pbonzini@redhat.com Subject: [PATCH v3 1/1] target/riscv: fix endless translation loop on big endian systems Date: Tue, 15 Apr 2025 16:02:54 +0800 Message-Id: <20250415080254.3667878-2-ziqiaokong@gmail.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20250415080254.3667878-1-ziqiaokong@gmail.com> References: <20250415080254.3667878-1-ziqiaokong@gmail.com> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable 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::532; envelope-from=ziqiaokong@gmail.com; helo=mail-pg1-x532.google.com X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 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_FROM=0.001, 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+importer=patchew.org@nongnu.org Sender: qemu-devel-bounces+importer=patchew.org@nongnu.org X-ZohoMail-DKIM: pass (identity @gmail.com) X-ZM-MESSAGEID: 1744704277859019100 Content-Type: text/plain; charset="utf-8" On big endian systems, pte and updated_pte hold big endian host data while pte_pa points to little endian target data. This means the branch at cpu_helper.c:1669 will be always satisfied and restart translation, causing an endless translation loop. The correctness of this patch can be deduced by: old_pte will hold value either from cpu_to_le32/64(pte) or=20 cpu_to_le32/64(updated_pte), both of wich is litte endian. After that,=20 an in-place conversion by le32/64_to_cpu(old_pte) ensures that old_pte=20 now is in native endian, same with pte. Therefore, the endianness of the both side of if (old_pte !=3D pte) is correct.=20 Signed-off-by: Ziqiao Kong Reviewed-by: Alistair Francis Reviewed-by: Richard Henderson --- target/riscv/cpu_helper.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/target/riscv/cpu_helper.c b/target/riscv/cpu_helper.c index 6c4391d96b..3233b66e7e 100644 --- a/target/riscv/cpu_helper.c +++ b/target/riscv/cpu_helper.c @@ -1662,9 +1662,11 @@ static int get_physical_address(CPURISCVState *env, = hwaddr *physical, target_ulong *pte_pa =3D qemu_map_ram_ptr(mr->ram_block, addr1= ); target_ulong old_pte; if (riscv_cpu_sxl(env) =3D=3D MXL_RV32) { - old_pte =3D qatomic_cmpxchg((uint32_t *)pte_pa, pte, updat= ed_pte); + old_pte =3D qatomic_cmpxchg((uint32_t *)pte_pa, cpu_to_le3= 2(pte), cpu_to_le32(updated_pte)); + old_pte =3D le32_to_cpu(old_pte); } else { - old_pte =3D qatomic_cmpxchg(pte_pa, pte, updated_pte); + old_pte =3D qatomic_cmpxchg(pte_pa, cpu_to_le64(pte), cpu_= to_le64(updated_pte)); + old_pte =3D le64_to_cpu(old_pte); } if (old_pte !=3D pte) { goto restart; --=20 2.34.1