From nobody Tue Oct 28 12:17:38 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 Return-Path: Received: from lists.gnu.org (208.118.235.17 [208.118.235.17]) by mx.zohomail.com with SMTPS id 1514484634062312.84703141005957; Thu, 28 Dec 2017 10:10:34 -0800 (PST) Received: from localhost ([::1]:60589 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1eUcdK-0000qg-KU for importer@patchew.org; Thu, 28 Dec 2017 13:10:22 -0500 Received: from eggs.gnu.org ([2001:4830:134:3::10]:54601) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1eUcbR-000843-0i for qemu-devel@nongnu.org; Thu, 28 Dec 2017 13:08:26 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1eUcbQ-00013U-2m for qemu-devel@nongnu.org; Thu, 28 Dec 2017 13:08:24 -0500 Received: from mav.lukeshu.com ([2001:19f0:5c00:8069:5400:ff:fe26:6a86]:41956) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1eUcbP-00012p-Vb for qemu-devel@nongnu.org; Thu, 28 Dec 2017 13:08:24 -0500 Received: from build64-par (unknown [IPv6:2601:803:202:9275:da50:e6ff:fe00:4a5b]) by mav.lukeshu.com (Postfix) with ESMTPSA id 350F480508; Thu, 28 Dec 2017 13:08:19 -0500 (EST) From: Luke Shumaker To: qemu-devel@nongnu.org Date: Thu, 28 Dec 2017 13:08:09 -0500 Message-Id: <20171228180814.9749-7-lukeshu@lukeshu.com> X-Mailer: git-send-email 2.15.1 In-Reply-To: <20171228180814.9749-1-lukeshu@lukeshu.com> References: <20171228180814.9749-1-lukeshu@lukeshu.com> X-detected-operating-system: by eggs.gnu.org: Genre and OS details not recognized. X-Received-From: 2001:19f0:5c00:8069:5400:ff:fe26:6a86 Subject: [Qemu-devel] [PATCH 06/10] linux-user: init_guest_commpage: Add a comment about size check 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: Luke Shumaker , Riku Voipio , Laurent Vivier 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" From: Luke Shumaker Signed-off-by: Luke Shumaker Reviewed-by: Peter Maydell --- linux-user/elfload.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/linux-user/elfload.c b/linux-user/elfload.c index 22f2632dfa..b560f5d6fe 100644 --- a/linux-user/elfload.c +++ b/linux-user/elfload.c @@ -374,6 +374,11 @@ static int init_guest_commpage(unsigned long guest_bas= e, =20 /* If the commpage lies within the already allocated guest space, * then there is no way we can allocate it. + * + * You may be thinking that that this check is redundant because + * we already validated the guest size against MAX_RESERVED_VA; + * but if qemu_host_page_mask is unusually large, then + * test_page_addr may be lower. */ if (test_page_addr >=3D guest_base && test_page_addr < (guest_base + guest_size)) { --=20 2.15.1