From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-ed1-f70.google.com (mail-ed1-f70.google.com [209.85.208.70]) by kanga.kvack.org (Postfix) with ESMTP id DF7896B0269 for ; Thu, 9 Aug 2018 05:02:10 -0400 (EDT) Received: by mail-ed1-f70.google.com with SMTP id z20-v6so1874380edq.10 for ; Thu, 09 Aug 2018 02:02:10 -0700 (PDT) Received: from mx1.suse.de (mx2.suse.de. [195.135.220.15]) by mx.google.com with ESMTPS id b5-v6si969794edq.130.2018.08.09.02.02.09 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 09 Aug 2018 02:02:09 -0700 (PDT) Date: Thu, 9 Aug 2018 11:02:08 +0200 From: Jan Kara Subject: Re: [PATCH V3 0/4] Fix kvm misconceives NVDIMM pages as reserved mmio Message-ID: <20180809090208.GD5069@quack2.suse.cz> References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Sender: owner-linux-mm@kvack.org List-ID: To: Zhang Yi Cc: 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, linux-mm@kvack.org, rkrcmar@redhat.com, yi.z.zhang@intel.com On Thu 09-08-18 18:52:48, 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: > https://lkml.org/lkml/2018/7/10/135 > > V3: > [PATCH V3 1/4] Needs Comments. > [PATCH V3 2/4] Update the description of MEMORY_DEVICE_DEV_DAX: Jan > [PATCH V3 3/4] Acked-by: Jan in V2 Hum, but it is not the the patch... Honza -- Jan Kara SUSE Labs, CR