From patchwork Thu Jan 18 07:52:40 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Michael Tokarev X-Patchwork-Id: 1887759 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@legolas.ozlabs.org Authentication-Results: legolas.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=nongnu.org (client-ip=209.51.188.17; helo=lists.gnu.org; envelope-from=qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org; receiver=patchwork.ozlabs.org) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-ECDSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by legolas.ozlabs.org (Postfix) with ESMTPS id 4TFw7f1s3Sz23f8 for ; Thu, 18 Jan 2024 18:57:02 +1100 (AEDT) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1rQNEh-0000vo-0t; Thu, 18 Jan 2024 02:54:51 -0500 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 1rQNEf-0000us-S1; Thu, 18 Jan 2024 02:54:49 -0500 Received: from isrv.corpit.ru ([86.62.121.231]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1rQNEe-0007Oy-AI; Thu, 18 Jan 2024 02:54:49 -0500 Received: from tsrv.corpit.ru (tsrv.tls.msk.ru [192.168.177.2]) by isrv.corpit.ru (Postfix) with ESMTP id A082845037; Thu, 18 Jan 2024 10:54:35 +0300 (MSK) Received: from tls.msk.ru (mjt.wg.tls.msk.ru [192.168.177.130]) by tsrv.corpit.ru (Postfix) with SMTP id CC44C661A0; Thu, 18 Jan 2024 10:54:05 +0300 (MSK) Received: (nullmailer pid 2381667 invoked by uid 1000); Thu, 18 Jan 2024 07:54:04 -0000 From: Michael Tokarev To: qemu-devel@nongnu.org Cc: qemu-stable@nongnu.org, Max Erenberg , Michael Tokarev Subject: [Stable-8.2.1 13/38] edu: fix DMA range upper bound check Date: Thu, 18 Jan 2024 10:52:40 +0300 Message-Id: <20240118075404.2381519-13-mjt@tls.msk.ru> X-Mailer: git-send-email 2.39.2 In-Reply-To: References: MIME-Version: 1.0 Received-SPF: pass client-ip=86.62.121.231; envelope-from=mjt@tls.msk.ru; helo=isrv.corpit.ru X-Spam_score_int: -68 X-Spam_score: -6.9 X-Spam_bar: ------ X-Spam_report: (-6.9 / 5.0 requ) BAYES_00=-1.9, RCVD_IN_DNSWL_HI=-5, 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: Max Erenberg The edu_check_range function checks that start <= end1 < end2, where end1 is the upper bound (exclusive) of the guest-supplied DMA range and end2 is the upper bound (exclusive) of the device's allowed DMA range. When the guest tries to transfer exactly DMA_SIZE (4096) bytes, end1 will be equal to end2, so the check fails and QEMU aborts with this puzzling error message (newlines added for formatting): qemu: hardware error: EDU: DMA range 0x0000000000040000-0x0000000000040fff out of bounds (0x0000000000040000-0x0000000000040fff)! By checking end1 <= end2 instead, guests will be allowed to transfer exactly 4096 bytes. It is not necessary to explicitly check for start <= end1 because the previous two checks (within(addr, start, end2) and end1 > addr) imply start < end1. Fixes: b30934cb52a7 ("hw: misc, add educational driver", 2015-01-21) Signed-off-by: Max Erenberg Signed-off-by: Michael Tokarev (cherry picked from commit 2c5107e1b455d4a157124f021826ead4e04b4aea) Signed-off-by: Michael Tokarev diff --git a/hw/misc/edu.c b/hw/misc/edu.c index a1f8bc77e7..e64a246d3f 100644 --- a/hw/misc/edu.c +++ b/hw/misc/edu.c @@ -115,7 +115,7 @@ static void edu_check_range(uint64_t addr, uint64_t size1, uint64_t start, uint64_t end2 = start + size2; if (within(addr, start, end2) && - end1 > addr && within(end1, start, end2)) { + end1 > addr && end1 <= end2) { return; }