From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.8 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_PASS,UNPARSEABLE_RELAY autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id E4714C64EBC for ; Thu, 4 Oct 2018 17:19:07 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 925F92087D for ; Thu, 4 Oct 2018 17:19:07 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=oracle.com header.i=@oracle.com header.b="sU4W6leU" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 925F92087D Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=oracle.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727690AbeJEANR (ORCPT ); Thu, 4 Oct 2018 20:13:17 -0400 Received: from aserp2120.oracle.com ([141.146.126.78]:55788 "EHLO aserp2120.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727523AbeJEANQ (ORCPT ); Thu, 4 Oct 2018 20:13:16 -0400 Received: from pps.filterd (aserp2120.oracle.com [127.0.0.1]) by aserp2120.oracle.com (8.16.0.22/8.16.0.22) with SMTP id w94H9LKq060287; Thu, 4 Oct 2018 17:19:00 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=oracle.com; h=subject : from : to : cc : references : message-id : date : mime-version : in-reply-to : content-type : content-transfer-encoding; s=corp-2018-07-02; bh=SUMThIHP/J89j9ROreiDoGFd6p7qScujQjvcnDLFO1c=; b=sU4W6leULgVnIUmF+KMk6TFVeDyv521THxcuo+2fBZvHpPJBmmfJxPNHvAtfGidR/8QA QJktvf0S4P1lFSXa/JOfTom5Vrh3rSYJBL109TRWcDVaGic5pG632luNnjeSQc0fIOav djAL7QzZ1RLal4jlBM6XW4yjkdgsc1xKVbjCgSauwMZTSbeDgGskkjbl5sHsQtZ6pBm0 GUUqkYmUPcPNLI9tpcLE88GgQWtJmkR8n6uoLXx5Kke9jH2JJ4kDrE0w9zdNlSCj5vbO F7TX9bI85yid6KESKOYLHPk7qBbVGK5ovUDouIVeZqe3iRrPe2/cqb7zcC9T9iPwNDxF 1g== Received: from aserv0021.oracle.com (aserv0021.oracle.com [141.146.126.233]) by aserp2120.oracle.com with ESMTP id 2mt1bqdq1v-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Thu, 04 Oct 2018 17:19:00 +0000 Received: from userv0122.oracle.com (userv0122.oracle.com [156.151.31.75]) by aserv0021.oracle.com (8.14.4/8.14.4) with ESMTP id w94HIx3s019701 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Thu, 4 Oct 2018 17:19:00 GMT Received: from abhmp0017.oracle.com (abhmp0017.oracle.com [141.146.116.23]) by userv0122.oracle.com (8.14.4/8.14.4) with ESMTP id w94HIxcY011599; Thu, 4 Oct 2018 17:18:59 GMT Received: from anastasis.us.oracle.com (/10.152.36.80) by default (Oracle Beehive Gateway v4.0) with ESMTP ; Thu, 04 Oct 2018 17:18:59 +0000 Subject: [PATCH 1/1] drivers/char/mem.c: Disable encryption bit in page tables for, MMIO access From: James Puthukattukaran To: "Lendacky, Thomas" , "Singh, Brijesh" Cc: gregkh@linuxfoundation.org, Linux Kernel Mailing List References: <671c6651-71b3-0e0d-8e87-191ca14fed50@oracle.com> Message-ID: Date: Thu, 4 Oct 2018 13:18:58 -0400 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.6.0 MIME-Version: 1.0 In-Reply-To: <671c6651-71b3-0e0d-8e87-191ca14fed50@oracle.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit X-Proofpoint-Virus-Version: vendor=nai engine=5900 definitions=9036 signatures=668706 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 suspectscore=0 malwarescore=0 phishscore=0 bulkscore=0 spamscore=0 mlxscore=0 mlxlogscore=891 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1807170000 definitions=main-1810040159 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Attempting to mmap to a memory mapped IO space returns -1s because the memory encryption bit is set for these pages. According to the AMD spec, this bit should not be set for non-DRAM space. The patch checks if this is an memory IO region being accessed and decrypts accordingly. Signed-off-by: James Puthukattukaran --- drivers/char/mem.c | 27 +++++++++++++++++++++++++++ 1 file changed, 27 insertions(+) diff --git a/drivers/char/mem.c b/drivers/char/mem.c index ffeb60d..beaa374 100644 --- a/drivers/char/mem.c +++ b/drivers/char/mem.c @@ -355,10 +355,30 @@ static inline int private_mapping_ok(struct vm_area_struct *vma) #endif }; +static int check_flags(struct resource *res, void *arg) +{ + int *mmio = arg; + *mmio = (!((res->flags & IORESOURCE_SYSTEM_RAM) == + IORESOURCE_SYSTEM_RAM) && (res->desc == IORES_DESC_NONE)); + return *mmio; +} + +static void check_iomem_region(phys_addr_t addr, size_t size, + int *mmio) +{ + u64 start, end; + + start = (u64)addr; + end = start + size - 1; + *mmio = 0; + walk_mem_res(start, end, mmio, check_flags); +} + static int mmap_mem(struct file *file, struct vm_area_struct *vma) { size_t size = vma->vm_end - vma->vm_start; phys_addr_t offset = (phys_addr_t)vma->vm_pgoff << PAGE_SHIFT; + int mmio; /* Does it even fit in phys_addr_t? */ if (offset >> PAGE_SHIFT != vma->vm_pgoff) @@ -387,6 +407,13 @@ static int mmap_mem(struct file *file, struct vm_area_struct *vma) vma->vm_ops = &mmap_mem_ops; + if (mem_encrypt_active()) { + check_iomem_region(vma->vm_pgoff, size, &mmio); + if (mmio) + vma->vm_page_prot = + pgprot_decrypted(vma->vm_page_prot); + } + /* Remap-pfn-range will mark the range VM_IO */ if (remap_pfn_range(vma, vma->vm_start,