From patchwork Thu Mar 17 16:51:59 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Ross Lagerwall X-Patchwork-Id: 8613311 Return-Path: X-Original-To: patchwork-xen-devel@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork2.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.136]) by patchwork2.web.kernel.org (Postfix) with ESMTP id 05702C0553 for ; Thu, 17 Mar 2016 16:54:45 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 39E6E20218 for ; Thu, 17 Mar 2016 16:54:44 +0000 (UTC) Received: from lists.xenproject.org (lists.xenproject.org [192.237.175.120]) (using TLSv1.2 with cipher AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 5A48B201ED for ; Thu, 17 Mar 2016 16:54:43 +0000 (UTC) Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.84_2) (envelope-from ) id 1agb9c-0001rL-Jq; Thu, 17 Mar 2016 16:52:08 +0000 Received: from mail6.bemta5.messagelabs.com ([195.245.231.135]) by lists.xenproject.org with esmtp (Exim 4.84_2) (envelope-from ) id 1agb9b-0001r7-7f for xen-devel@lists.xenproject.org; Thu, 17 Mar 2016 16:52:07 +0000 Received: from [85.158.139.211] by server-17.bemta-5.messagelabs.com id 34/59-15848-6B0EAE65; Thu, 17 Mar 2016 16:52:06 +0000 X-Env-Sender: prvs=87711cbd2=ross.lagerwall@citrix.com X-Msg-Ref: server-15.tower-206.messagelabs.com!1458233524!21415516!1 X-Originating-IP: [66.165.176.89] X-SpamReason: No, hits=0.0 required=7.0 tests=sa_preprocessor: VHJ1c3RlZCBJUDogNjYuMTY1LjE3Ni44OSA9PiAyMDMwMDc=\n, received_headers: No Received headers X-StarScan-Received: X-StarScan-Version: 8.11; banners=-,-,- X-VirusChecked: Checked Received: (qmail 3810 invoked from network); 17 Mar 2016 16:52:05 -0000 Received: from smtp.citrix.com (HELO SMTP.CITRIX.COM) (66.165.176.89) by server-15.tower-206.messagelabs.com with RC4-SHA encrypted SMTP; 17 Mar 2016 16:52:05 -0000 X-IronPort-AV: E=Sophos;i="5.24,350,1454976000"; d="scan'208";a="339998887" From: Ross Lagerwall To: Date: Thu, 17 Mar 2016 16:51:59 +0000 Message-ID: <1458233520-18821-1-git-send-email-ross.lagerwall@citrix.com> X-Mailer: git-send-email 2.4.3 MIME-Version: 1.0 X-DLP: MIA1 Cc: Ross Lagerwall , Boris Ostrovsky , David Vrabel Subject: [Xen-devel] [PATCH 1/2] xen: Fix page <-> pfn conversion on 32 bit systems X-BeenThere: xen-devel@lists.xen.org X-Mailman-Version: 2.1.18 Precedence: list List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Errors-To: xen-devel-bounces@lists.xen.org Sender: "Xen-devel" X-Spam-Status: No, score=-1.9 required=5.0 tests=BAYES_00, UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP The xen functions to convert between pages and pfns fail due to an overflow on systems where a physical address may not fit in an unsigned long (e.g. x86 32 bit PAE systems). Rework the conversion to avoid overflow. This should also result in simpler object code. This bug manifested itself as disk corruption with Linux 4.4 when using blkfront in a Xen HVM x86 32 bit guest with more than 4 GiB of memory. Signed-off-by: Ross Lagerwall --- include/xen/page.h | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/include/xen/page.h b/include/xen/page.h index 96294ac..9dc46cb 100644 --- a/include/xen/page.h +++ b/include/xen/page.h @@ -15,9 +15,9 @@ */ #define xen_pfn_to_page(xen_pfn) \ - ((pfn_to_page(((unsigned long)(xen_pfn) << XEN_PAGE_SHIFT) >> PAGE_SHIFT))) + (pfn_to_page((unsigned long)(xen_pfn) >> (PAGE_SHIFT - XEN_PAGE_SHIFT))) #define page_to_xen_pfn(page) \ - (((page_to_pfn(page)) << PAGE_SHIFT) >> XEN_PAGE_SHIFT) + ((page_to_pfn(page)) << (PAGE_SHIFT - XEN_PAGE_SHIFT)) #define XEN_PFN_PER_PAGE (PAGE_SIZE / XEN_PAGE_SIZE)