From patchwork Fri Jan 10 19:03:10 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Joao Martins X-Patchwork-Id: 11328257 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 5C84C930 for ; Fri, 10 Jan 2020 19:05:45 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 31EDC208E4 for ; Fri, 10 Jan 2020 19:05:45 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=oracle.com header.i=@oracle.com header.b="Bzn/J7UT" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728724AbgAJTFl (ORCPT ); Fri, 10 Jan 2020 14:05:41 -0500 Received: from userp2120.oracle.com ([156.151.31.85]:55314 "EHLO userp2120.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728562AbgAJTFl (ORCPT ); Fri, 10 Jan 2020 14:05:41 -0500 Received: from pps.filterd (userp2120.oracle.com [127.0.0.1]) by userp2120.oracle.com (8.16.0.27/8.16.0.27) with SMTP id 00AJ44Ed111312; Fri, 10 Jan 2020 19:05:16 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=oracle.com; h=from : to : cc : subject : date : message-id : in-reply-to : references; s=corp-2019-08-05; bh=AOtZE2Ew8hycb3SG+EnQmNQT+PxozxfzEjsUQMh/A/s=; b=Bzn/J7UT1T61gmZkCk5vbEUQl1TX7zikcJc7drBa47visSSlDYUrXXYCwC2IDFAR4i7t 58SVag0bRztRmzfWIYStozEQPsR/ZS2dbeSOMtWcyvB9NIjDDqiqquffapV9/J0QYRTO KaO7RCvWsQGtypBGMmqXw+OZA8QLWNfxxqxyzDWJmGFWQABgp/2Y20Zeu7HMImLxfn1B Zmuw+GnvpjZlKfSP9b0cI/t76wg/m/Thl2aktuoRCDM2Vjt2IptsxQ7XNh3yX0HtRf/o k9dcm9Cn1AEgHDg6QuoYJsLCakcfFqfzmdYObBpBzFRYlix+mW8pQrQwe5XkDfBCsnpQ jw== Received: from userp3020.oracle.com (userp3020.oracle.com [156.151.31.79]) by userp2120.oracle.com with ESMTP id 2xakbrbyrr-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Fri, 10 Jan 2020 19:05:16 +0000 Received: from pps.filterd (userp3020.oracle.com [127.0.0.1]) by userp3020.oracle.com (8.16.0.27/8.16.0.27) with SMTP id 00AJ4RxF038537; Fri, 10 Jan 2020 19:05:16 GMT Received: from userv0121.oracle.com (userv0121.oracle.com [156.151.31.72]) by userp3020.oracle.com with ESMTP id 2xekkvjm94-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Fri, 10 Jan 2020 19:05:15 +0000 Received: from abhmp0013.oracle.com (abhmp0013.oracle.com [141.146.116.19]) by userv0121.oracle.com (8.14.4/8.13.8) with ESMTP id 00AJ5Ec4006978; Fri, 10 Jan 2020 19:05:14 GMT Received: from paddy.uk.oracle.com (/10.175.192.165) by default (Oracle Beehive Gateway v4.0) with ESMTP ; Fri, 10 Jan 2020 11:05:14 -0800 From: Joao Martins To: linux-nvdimm@lists.01.org Cc: Dan Williams , Vishal Verma , Dave Jiang , Ira Weiny , Alex Williamson , Cornelia Huck , kvm@vger.kernel.org, Andrew Morton , linux-mm@kvack.org, linux-kernel@vger.kernel.org, Thomas Gleixner , Ingo Molnar , Borislav Petkov , "H . Peter Anvin" , x86@kernel.org, Liran Alon , Nikita Leshenko , Barret Rhoden , Boris Ostrovsky , Matthew Wilcox , Konrad Rzeszutek Wilk Subject: [PATCH RFC 07/10] device-dax: Add support for PFN_SPECIAL flags Date: Fri, 10 Jan 2020 19:03:10 +0000 Message-Id: <20200110190313.17144-8-joao.m.martins@oracle.com> X-Mailer: git-send-email 2.11.0 In-Reply-To: <20200110190313.17144-1-joao.m.martins@oracle.com> References: <20200110190313.17144-1-joao.m.martins@oracle.com> X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9496 signatures=668685 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 suspectscore=1 malwarescore=0 phishscore=0 bulkscore=0 spamscore=0 mlxscore=0 mlxlogscore=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1911140001 definitions=main-2001100154 X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9496 signatures=668685 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 priorityscore=1501 malwarescore=0 suspectscore=1 phishscore=0 bulkscore=0 spamscore=0 clxscore=1015 lowpriorityscore=0 mlxscore=0 impostorscore=0 mlxlogscore=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1911140001 definitions=main-2001100154 Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org Right now we assume there's gonna be a PFN_DEV|PFN_MAP which means it will have a struct page backing the PFN but that is not placed in normal system RAM zones. Add support for PFN_DEV|PFN_SPECIAL only and therefore the underlying vma won't have a struct page. For device dax, this means not assuming callers will pass a dev_pagemap, and avoid returning SIGBUS for the lack of PFN_MAP region pfn flag and finally not setting struct page index/mapping on fault. Signed-off-by: Joao Martins --- drivers/dax/bus.c | 3 ++- drivers/dax/device.c | 40 ++++++++++++++++++++++------------------ 2 files changed, 24 insertions(+), 19 deletions(-) diff --git a/drivers/dax/bus.c b/drivers/dax/bus.c index 46e46047a1f7..96ca3ac85278 100644 --- a/drivers/dax/bus.c +++ b/drivers/dax/bus.c @@ -414,7 +414,8 @@ struct dev_dax *__devm_create_dev_dax(struct dax_region *dax_region, int id, if (!dev_dax) return ERR_PTR(-ENOMEM); - memcpy(&dev_dax->pgmap, pgmap, sizeof(*pgmap)); + if (pgmap) + memcpy(&dev_dax->pgmap, pgmap, sizeof(*pgmap)); /* * No 'host' or dax_operations since there is no access to this diff --git a/drivers/dax/device.c b/drivers/dax/device.c index 113a554de3ee..aa38f5ff180a 100644 --- a/drivers/dax/device.c +++ b/drivers/dax/device.c @@ -14,6 +14,12 @@ #include "dax-private.h" #include "bus.h" +static int dax_is_pfn_special(struct dev_dax *dev_dax) +{ + return (dev_dax->region->pfn_flags & + (PFN_DEV|PFN_SPECIAL)) == (PFN_DEV|PFN_SPECIAL); +} + static int dax_is_pfn_dev(struct dev_dax *dev_dax) { return (dev_dax->region->pfn_flags & (PFN_DEV|PFN_MAP)) == PFN_DEV; @@ -104,6 +110,7 @@ static vm_fault_t __dev_dax_pte_fault(struct dev_dax *dev_dax, struct dax_region *dax_region; phys_addr_t phys; unsigned int fault_size = PAGE_SIZE; + int rc; if (check_vma(dev_dax, vmf->vma, __func__)) return VM_FAULT_SIGBUS; @@ -126,7 +133,12 @@ static vm_fault_t __dev_dax_pte_fault(struct dev_dax *dev_dax, *pfn = phys_to_pfn_t(phys, dax_region->pfn_flags); - return vmf_insert_mixed(vmf->vma, vmf->address, *pfn); + if (dax_is_pfn_special(dev_dax)) + rc = vmf_insert_pfn(vmf->vma, vmf->address, pfn_t_to_pfn(*pfn)); + else + rc = vmf_insert_mixed(vmf->vma, vmf->address, *pfn); + + return rc; } static vm_fault_t __dev_dax_pmd_fault(struct dev_dax *dev_dax, @@ -149,12 +161,6 @@ static vm_fault_t __dev_dax_pmd_fault(struct dev_dax *dev_dax, return VM_FAULT_SIGBUS; } - /* dax pmd mappings require pfn_t_devmap() */ - if (!dax_is_pfn_map(dev_dax)) { - dev_dbg(dev, "region lacks devmap flags\n"); - return VM_FAULT_SIGBUS; - } - if (fault_size < dax_region->align) return VM_FAULT_SIGBUS; else if (fault_size > dax_region->align) @@ -199,12 +205,6 @@ static vm_fault_t __dev_dax_pud_fault(struct dev_dax *dev_dax, return VM_FAULT_SIGBUS; } - /* dax pud mappings require pfn_t_devmap() */ - if (!dax_is_pfn_map(dev_dax)) { - dev_dbg(dev, "region lacks devmap flags\n"); - return VM_FAULT_SIGBUS; - } - if (fault_size < dax_region->align) return VM_FAULT_SIGBUS; else if (fault_size > dax_region->align) @@ -266,7 +266,7 @@ static vm_fault_t dev_dax_huge_fault(struct vm_fault *vmf, rc = VM_FAULT_SIGBUS; } - if (rc == VM_FAULT_NOPAGE) { + if (dax_is_pfn_map(dev_dax) && (rc == VM_FAULT_NOPAGE)) { unsigned long i; pgoff_t pgoff; @@ -344,6 +344,8 @@ static int dax_mmap(struct file *filp, struct vm_area_struct *vma) vma->vm_ops = &dax_vm_ops; vma->vm_flags |= VM_HUGEPAGE; + if (dax_is_pfn_special(dev_dax)) + vma->vm_flags |= VM_PFNMAP; return 0; } @@ -450,10 +452,12 @@ int dev_dax_probe(struct device *dev) return -EBUSY; } - dev_dax->pgmap.type = MEMORY_DEVICE_DEVDAX; - addr = devm_memremap_pages(dev, &dev_dax->pgmap); - if (IS_ERR(addr)) - return PTR_ERR(addr); + if (dax_is_pfn_map(dev_dax)) { + dev_dax->pgmap.type = MEMORY_DEVICE_DEVDAX; + addr = devm_memremap_pages(dev, &dev_dax->pgmap); + if (IS_ERR(addr)) + return PTR_ERR(addr); + } inode = dax_inode(dax_dev); cdev = inode->i_cdev;