From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pl0-f71.google.com (mail-pl0-f71.google.com [209.85.160.71]) by kanga.kvack.org (Postfix) with ESMTP id D9D506B0003 for ; Fri, 20 Jul 2018 02:25:38 -0400 (EDT) Received: by mail-pl0-f71.google.com with SMTP id e93-v6so6577172plb.5 for ; Thu, 19 Jul 2018 23:25:38 -0700 (PDT) Received: from mga12.intel.com (mga12.intel.com. [192.55.52.136]) by mx.google.com with ESMTPS id h23-v6si1077338pgl.373.2018.07.19.23.25.37 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 19 Jul 2018 23:25:37 -0700 (PDT) Subject: Re: [PATCH V2 0/4] Fix kvm misconceives NVDIMM pages as reserved mmio References: From: "Zhang,Yi" Message-ID: Date: Fri, 20 Jul 2018 22:11:30 +0800 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit Content-Language: en-US Sender: owner-linux-mm@kvack.org List-ID: To: kvm@vger.kernel.org, linux-kernel@vger.kernel.org, linux-nvdimm@lists.01.org, pbonzini@redhat.com, dan.j.williams@intel.com, jack@suse.cz, hch@lst.de, yu.c.zhang@intel.com, dave.jiang@intel.com Cc: linux-mm@kvack.org, rkrcmar@redhat.com, yi.z.zhang@intel.com Added Jiang,Dave, Ping for further review, comments. Thanks All Regards Yi. On 2018a1'07ae??11ae?JPY 01:01, Zhang Yi wrote: > For device specific memory space, when we move these area of pfn to > memory zone, we will set the page reserved flag at that time, some of > these reserved for device mmio, and some of these are not, such as > NVDIMM pmem. > > Now, we map these dev_dax or fs_dax pages to kvm for DIMM/NVDIMM > backend, since these pages are reserved. the check of > kvm_is_reserved_pfn() misconceives those pages as MMIO. Therefor, we > introduce 2 page map types, MEMORY_DEVICE_FS_DAX/MEMORY_DEVICE_DEV_DAX, > to indentify these pages are from NVDIMM pmem. and let kvm treat these > as normal pages. > > Without this patch, Many operations will be missed due to this > mistreatment to pmem pages. For example, a page may not have chance to > be unpinned for KVM guest(in kvm_release_pfn_clean); not able to be > marked as dirty/accessed(in kvm_set_pfn_dirty/accessed) etc. > > V1: > https://lkml.org/lkml/2018/7/4/91 > > V2: > *Add documentation for MEMORY_DEVICE_DEV_DAX memory type in comment block > *Add is_dax_page() in mm.h to differentiate the pages is from DAX device. > *Remove the function kvm_is_nd_pfn(). > > Zhang Yi (4): > kvm: remove redundant reserved page check > mm: introduce memory type MEMORY_DEVICE_DEV_DAX > mm: add a function to differentiate the pages is from DAX device > memory > kvm: add a check if pfn is from NVDIMM pmem. > > drivers/dax/pmem.c | 1 + > include/linux/memremap.h | 9 +++++++++ > include/linux/mm.h | 12 ++++++++++++ > virt/kvm/kvm_main.c | 16 ++++++++-------- > 4 files changed, 30 insertions(+), 8 deletions(-) >