From nobody Mon Nov 3 06:05:05 2025 Delivered-To: importer@patchew.org Received-SPF: pass (zoho.com: domain of gnu.org designates 208.118.235.17 as permitted sender) client-ip=208.118.235.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Authentication-Results: mx.zohomail.com; spf=pass (zoho.com: domain of gnu.org designates 208.118.235.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org; dmarc=fail(p=none dis=none) header.from=linaro.org Return-Path: Received: from lists.gnu.org (lists.gnu.org [208.118.235.17]) by mx.zohomail.com with SMTPS id 1528737980917807.7339618062686; Mon, 11 Jun 2018 10:26:20 -0700 (PDT) Received: from localhost ([::1]:50416 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1fSQa8-0008K9-7o for importer@patchew.org; Mon, 11 Jun 2018 13:26:16 -0400 Received: from eggs.gnu.org ([2001:4830:134:3::10]:56077) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1fSQYa-00079F-Oi for qemu-devel@nongnu.org; Mon, 11 Jun 2018 13:24:41 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1fSQYa-0000m9-09 for qemu-devel@nongnu.org; Mon, 11 Jun 2018 13:24:40 -0400 Received: from orth.archaic.org.uk ([2001:8b0:1d0::2]:42702) by eggs.gnu.org with esmtps (TLS1.0:RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1fSQYZ-0000kf-PF for qemu-devel@nongnu.org; Mon, 11 Jun 2018 13:24:39 -0400 Received: from pm215 by orth.archaic.org.uk with local (Exim 4.89) (envelope-from ) id 1fSQKc-0007Ep-1Y; Mon, 11 Jun 2018 18:10:14 +0100 From: Peter Maydell To: qemu-devel@nongnu.org Date: Mon, 11 Jun 2018 18:10:06 +0100 Message-Id: <20180611171007.4165-3-peter.maydell@linaro.org> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20180611171007.4165-1-peter.maydell@linaro.org> References: <20180611171007.4165-1-peter.maydell@linaro.org> X-detected-operating-system: by eggs.gnu.org: Genre and OS details not recognized. X-Received-From: 2001:8b0:1d0::2 Subject: [Qemu-devel] [PATCH 2/3] exec.c: Don't accidentally sign-extend 4-byte loads in subpage_read() X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Paolo Bonzini , Richard Henderson , patches@linaro.org Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: "Qemu-devel" X-ZohoMail: RSF_0 Z_629925259 SPT_0 Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" In subpage_read() we perform a load of the data into a local buffer which we then access using ldub_p(), lduw_p(), ldl_p() or ldq_p() depending on its size, storing the result into the uint64_t *data. Since ldl_p() returns an 'int', this means that for the 4-byte case we will sign-extend the data, whereas for 1 and 2 byte reads we zero-extend it. This ought not to matter since the caller will likely ignore values in the high bytes of the data, but add a cast so that we're consistent. Signed-off-by: Peter Maydell Reviewed-by: Richard Henderson --- exec.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/exec.c b/exec.c index 9cbba6adcd3..90b47cde7b1 100644 --- a/exec.c +++ b/exec.c @@ -2747,7 +2747,7 @@ static MemTxResult subpage_read(void *opaque, hwaddr = addr, uint64_t *data, *data =3D lduw_p(buf); return MEMTX_OK; case 4: - *data =3D ldl_p(buf); + *data =3D (uint32_t)ldl_p(buf); return MEMTX_OK; case 8: *data =3D ldq_p(buf); --=20 2.17.1