From patchwork Thu Aug 9 10:52:55 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Zhang, Yi" X-Patchwork-Id: 10560709 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 9685915A6 for ; Thu, 9 Aug 2018 02:14:15 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 7D3C22AC87 for ; Thu, 9 Aug 2018 02:14:15 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 6F9EF2AD81; Thu, 9 Aug 2018 02:14:15 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-1.0 required=2.0 tests=BAYES_00,DATE_IN_FUTURE_06_12, MAILING_LIST_MULTI,RCVD_IN_DNSWL_NONE autolearn=ham version=3.3.1 Received: from ml01.01.org (ml01.01.org [198.145.21.10]) (using TLSv1.2 with cipher DHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id 6E06B2AC87 for ; Thu, 9 Aug 2018 02:14:14 +0000 (UTC) Received: from [127.0.0.1] (localhost [IPv6:::1]) by ml01.01.org (Postfix) with ESMTP id 43021210E2DC5; Wed, 8 Aug 2018 19:14:14 -0700 (PDT) X-Original-To: linux-nvdimm@lists.01.org Delivered-To: linux-nvdimm@lists.01.org Received-SPF: None (no SPF record) identity=mailfrom; client-ip=192.55.52.120; helo=mga04.intel.com; envelope-from=yi.z.zhang@linux.intel.com; receiver=linux-nvdimm@lists.01.org Received: from mga04.intel.com (mga04.intel.com [192.55.52.120]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ml01.01.org (Postfix) with ESMTPS id 65BBB210E2A71 for ; Wed, 8 Aug 2018 19:14:13 -0700 (PDT) X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga002.jf.intel.com ([10.7.209.21]) by fmsmga104.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 08 Aug 2018 19:14:12 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.53,213,1531810800"; d="scan'208";a="81868676" Received: from linux.intel.com ([10.54.29.200]) by orsmga002.jf.intel.com with ESMTP; 08 Aug 2018 19:14:12 -0700 Received: from dazhang1-ssd.sh.intel.com (unknown [10.239.48.78]) by linux.intel.com (Postfix) with ESMTP id 6679A5801BD; Wed, 8 Aug 2018 19:14:10 -0700 (PDT) From: Zhang Yi 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 Subject: [PATCH V3 1/4] kvm: remove redundant reserved page check Date: Thu, 9 Aug 2018 18:52:55 +0800 Message-Id: X-Mailer: git-send-email 2.7.4 In-Reply-To: References: X-BeenThere: linux-nvdimm@lists.01.org X-Mailman-Version: 2.1.27 Precedence: list List-Id: "Linux-nvdimm developer list." List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: linux-mm@kvack.org, yi.z.zhang@intel.com, rkrcmar@redhat.com MIME-Version: 1.0 Errors-To: linux-nvdimm-bounces@lists.01.org Sender: "Linux-nvdimm" X-Virus-Scanned: ClamAV using ClamSMTP PageReserved() is already checked inside kvm_is_reserved_pfn(), remove it from kvm_set_pfn_dirty(). Signed-off-by: Zhang Yi Signed-off-by: Zhang Yu Acked-by: Pankaj Gupta Reviewed-by: David Hildenbrand --- virt/kvm/kvm_main.c | 8 ++------ 1 file changed, 2 insertions(+), 6 deletions(-) diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index 8b47507f..c44c406 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -1690,12 +1690,8 @@ EXPORT_SYMBOL_GPL(kvm_release_pfn_dirty); void kvm_set_pfn_dirty(kvm_pfn_t pfn) { - if (!kvm_is_reserved_pfn(pfn)) { - struct page *page = pfn_to_page(pfn); - - if (!PageReserved(page)) - SetPageDirty(page); - } + if (!kvm_is_reserved_pfn(pfn)) + SetPageDirty(pfn_to_page(pfn)); } EXPORT_SYMBOL_GPL(kvm_set_pfn_dirty); From patchwork Thu Aug 9 10:53:08 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Zhang, Yi" X-Patchwork-Id: 10560717 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id CA42A14E5 for ; Thu, 9 Aug 2018 02:14:35 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id AFEF02AC87 for ; Thu, 9 Aug 2018 02:14:35 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id A3DF62AD81; Thu, 9 Aug 2018 02:14:35 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-1.0 required=2.0 tests=BAYES_00,DATE_IN_FUTURE_06_12, MAILING_LIST_MULTI,RCVD_IN_DNSWL_NONE autolearn=ham version=3.3.1 Received: from ml01.01.org (ml01.01.org [198.145.21.10]) (using TLSv1.2 with cipher DHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id 5BD0E2AC87 for ; Thu, 9 Aug 2018 02:14:35 +0000 (UTC) Received: from [127.0.0.1] (localhost [IPv6:::1]) by ml01.01.org (Postfix) with ESMTP id 5C662210E2DC7; Wed, 8 Aug 2018 19:14:35 -0700 (PDT) X-Original-To: linux-nvdimm@lists.01.org Delivered-To: linux-nvdimm@lists.01.org Received-SPF: None (no SPF record) identity=mailfrom; client-ip=134.134.136.20; helo=mga02.intel.com; envelope-from=yi.z.zhang@linux.intel.com; receiver=linux-nvdimm@lists.01.org Received: from mga02.intel.com (mga02.intel.com [134.134.136.20]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ml01.01.org (Postfix) with ESMTPS id DF267210E2DC3 for ; Wed, 8 Aug 2018 19:14:33 -0700 (PDT) X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga003.fm.intel.com ([10.253.24.29]) by orsmga101.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 08 Aug 2018 19:14:33 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.53,213,1531810800"; d="scan'208";a="71346413" Received: from linux.intel.com ([10.54.29.200]) by FMSMGA003.fm.intel.com with ESMTP; 08 Aug 2018 19:14:30 -0700 Received: from dazhang1-ssd.sh.intel.com (unknown [10.239.48.78]) by linux.intel.com (Postfix) with ESMTP id 5A5425801BD; Wed, 8 Aug 2018 19:14:28 -0700 (PDT) From: Zhang Yi 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 Subject: [PATCH V3 2/4] mm: introduce memory type MEMORY_DEVICE_DEV_DAX Date: Thu, 9 Aug 2018 18:53:08 +0800 Message-Id: <01aaca83694c3b0093fcb2f48af1dff0b147a4b2.1533811181.git.yi.z.zhang@linux.intel.com> X-Mailer: git-send-email 2.7.4 In-Reply-To: References: X-BeenThere: linux-nvdimm@lists.01.org X-Mailman-Version: 2.1.27 Precedence: list List-Id: "Linux-nvdimm developer list." List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: linux-mm@kvack.org, yi.z.zhang@intel.com, rkrcmar@redhat.com MIME-Version: 1.0 Errors-To: linux-nvdimm-bounces@lists.01.org Sender: "Linux-nvdimm" X-Virus-Scanned: ClamAV using ClamSMTP Currently, NVDIMM pages will be marked 'PageReserved'. However, unlike other reserved PFNs, pages on NVDIMM shall still behave like normal ones in many cases, i.e. when used as backend memory of KVM guest. This patch introduces a new memory type, MEMORY_DEVICE_DEV_DAX. And set this flag while dax driver hotplug the device memory. Signed-off-by: Zhang Yi Signed-off-by: Zhang Yu Reviewed-by: Jan Kara --- drivers/dax/pmem.c | 1 + include/linux/memremap.h | 8 ++++++++ 2 files changed, 9 insertions(+) diff --git a/drivers/dax/pmem.c b/drivers/dax/pmem.c index fd49b24..fb3f363 100644 --- a/drivers/dax/pmem.c +++ b/drivers/dax/pmem.c @@ -111,6 +111,7 @@ static int dax_pmem_probe(struct device *dev) return rc; dax_pmem->pgmap.ref = &dax_pmem->ref; + dax_pmem->pgmap.type = MEMORY_DEVICE_DEV_DAX; addr = devm_memremap_pages(dev, &dax_pmem->pgmap); if (IS_ERR(addr)) return PTR_ERR(addr); diff --git a/include/linux/memremap.h b/include/linux/memremap.h index f91f9e7..cd07ca8 100644 --- a/include/linux/memremap.h +++ b/include/linux/memremap.h @@ -53,11 +53,19 @@ struct vmem_altmap { * wakeup event whenever a page is unpinned and becomes idle. This * wakeup is used to coordinate physical address space management (ex: * fs truncate/hole punch) vs pinned pages (ex: device dma). + * + * MEMORY_DEVICE_DEV_DAX: + * Device memory that support raw access to persistent memory. Without need + * of an intervening filesystem, it could be directed mapped via an mmap + * capable character device. Together with the type MEMORY_DEVICE_FS_DAX, + * we could distinguish the persistent memory pages from normal ZONE_DEVICE + * pages. */ enum memory_type { MEMORY_DEVICE_PRIVATE = 1, MEMORY_DEVICE_PUBLIC, MEMORY_DEVICE_FS_DAX, + MEMORY_DEVICE_DEV_DAX, }; /* From patchwork Thu Aug 9 10:53:21 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Zhang, Yi" X-Patchwork-Id: 10560723 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id E3A8315A6 for ; Thu, 9 Aug 2018 02:14:40 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id CA5D02AC87 for ; Thu, 9 Aug 2018 02:14:40 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id BC60E2AD81; Thu, 9 Aug 2018 02:14:40 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-1.0 required=2.0 tests=BAYES_00,DATE_IN_FUTURE_06_12, MAILING_LIST_MULTI,RCVD_IN_DNSWL_NONE autolearn=ham version=3.3.1 Received: from ml01.01.org (ml01.01.org [198.145.21.10]) (using TLSv1.2 with cipher DHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id 7014A2AC87 for ; Thu, 9 Aug 2018 02:14:40 +0000 (UTC) Received: from [127.0.0.1] (localhost [IPv6:::1]) by ml01.01.org (Postfix) with ESMTP id 71E27210E2DCA; Wed, 8 Aug 2018 19:14:40 -0700 (PDT) X-Original-To: linux-nvdimm@lists.01.org Delivered-To: linux-nvdimm@lists.01.org Received-SPF: None (no SPF record) identity=mailfrom; client-ip=134.134.136.100; helo=mga07.intel.com; envelope-from=yi.z.zhang@linux.intel.com; receiver=linux-nvdimm@lists.01.org Received: from mga07.intel.com (mga07.intel.com [134.134.136.100]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ml01.01.org (Postfix) with ESMTPS id CEA2D210E2DC3 for ; Wed, 8 Aug 2018 19:14:38 -0700 (PDT) X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga002.fm.intel.com ([10.253.24.26]) by orsmga105.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 08 Aug 2018 19:14:38 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.53,213,1531810800"; d="scan'208";a="74999559" Received: from linux.intel.com ([10.54.29.200]) by fmsmga002.fm.intel.com with ESMTP; 08 Aug 2018 19:14:38 -0700 Received: from dazhang1-ssd.sh.intel.com (unknown [10.239.48.78]) by linux.intel.com (Postfix) with ESMTP id E129B5801BD; Wed, 8 Aug 2018 19:14:35 -0700 (PDT) From: Zhang Yi 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 Subject: [PATCH V3 3/4] mm: add a function to differentiate the pages is from DAX device memory Date: Thu, 9 Aug 2018 18:53:21 +0800 Message-Id: <2b7856596e519130946c834d5d61b00b7f592770.1533811181.git.yi.z.zhang@linux.intel.com> X-Mailer: git-send-email 2.7.4 In-Reply-To: References: X-BeenThere: linux-nvdimm@lists.01.org X-Mailman-Version: 2.1.27 Precedence: list List-Id: "Linux-nvdimm developer list." List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: linux-mm@kvack.org, yi.z.zhang@intel.com, rkrcmar@redhat.com MIME-Version: 1.0 Errors-To: linux-nvdimm-bounces@lists.01.org Sender: "Linux-nvdimm" X-Virus-Scanned: ClamAV using ClamSMTP DAX driver hotplug the device memory and move it to memory zone, these pages will be marked reserved flag, however, some other kernel componet will misconceive these pages are reserved mmio (ex: we map these dev_dax or fs_dax pages to kvm for DIMM/NVDIMM backend). Together with the type MEMORY_DEVICE_FS_DAX, we can use is_dax_page() to differentiate the pages is DAX device memory or not. Signed-off-by: Zhang Yi Signed-off-by: Zhang Yu --- include/linux/mm.h | 12 ++++++++++++ 1 file changed, 12 insertions(+) diff --git a/include/linux/mm.h b/include/linux/mm.h index 68a5121..de5cbc3 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -889,6 +889,13 @@ static inline bool is_device_public_page(const struct page *page) page->pgmap->type == MEMORY_DEVICE_PUBLIC; } +static inline bool is_dax_page(const struct page *page) +{ + return is_zone_device_page(page) && + (page->pgmap->type == MEMORY_DEVICE_FS_DAX || + page->pgmap->type == MEMORY_DEVICE_DEV_DAX); +} + #else /* CONFIG_DEV_PAGEMAP_OPS */ static inline void dev_pagemap_get_ops(void) { @@ -912,6 +919,11 @@ static inline bool is_device_public_page(const struct page *page) { return false; } + +static inline bool is_dax_page(const struct page *page) +{ + return false; +} #endif /* CONFIG_DEV_PAGEMAP_OPS */ static inline void get_page(struct page *page) From patchwork Thu Aug 9 10:53:30 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Zhang, Yi" X-Patchwork-Id: 10560729 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 87655157B for ; Thu, 9 Aug 2018 02:15:05 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 6B6C72AC87 for ; Thu, 9 Aug 2018 02:15:05 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 5C5832AD81; Thu, 9 Aug 2018 02:15:05 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-1.0 required=2.0 tests=BAYES_00,DATE_IN_FUTURE_06_12, MAILING_LIST_MULTI,RCVD_IN_DNSWL_NONE autolearn=ham version=3.3.1 Received: from ml01.01.org (ml01.01.org [198.145.21.10]) (using TLSv1.2 with cipher DHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id 8C7AA2AC87 for ; Thu, 9 Aug 2018 02:15:03 +0000 (UTC) Received: from [127.0.0.1] (localhost [IPv6:::1]) by ml01.01.org (Postfix) with ESMTP id 8C2EC210E2DC9; Wed, 8 Aug 2018 19:15:03 -0700 (PDT) X-Original-To: linux-nvdimm@lists.01.org Delivered-To: linux-nvdimm@lists.01.org Received-SPF: None (no SPF record) identity=mailfrom; client-ip=134.134.136.126; helo=mga18.intel.com; envelope-from=yi.z.zhang@linux.intel.com; receiver=linux-nvdimm@lists.01.org Received: from mga18.intel.com (mga18.intel.com [134.134.136.126]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ml01.01.org (Postfix) with ESMTPS id E4998210E2DC0 for ; Wed, 8 Aug 2018 19:15:01 -0700 (PDT) X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga002.jf.intel.com ([10.7.209.21]) by orsmga106.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 08 Aug 2018 19:15:01 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.53,213,1531810800"; d="scan'208";a="81868743" Received: from linux.intel.com ([10.54.29.200]) by orsmga002.jf.intel.com with ESMTP; 08 Aug 2018 19:14:47 -0700 Received: from dazhang1-ssd.sh.intel.com (unknown [10.239.48.78]) by linux.intel.com (Postfix) with ESMTP id 876E95801BD; Wed, 8 Aug 2018 19:14:45 -0700 (PDT) From: Zhang Yi 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 Subject: [PATCH V3 4/4] kvm: add a check if pfn is from NVDIMM pmem. Date: Thu, 9 Aug 2018 18:53:30 +0800 Message-Id: <0cc6cba7020f80168695fba731b8fd72fd649dc8.1533811181.git.yi.z.zhang@linux.intel.com> X-Mailer: git-send-email 2.7.4 In-Reply-To: References: X-BeenThere: linux-nvdimm@lists.01.org X-Mailman-Version: 2.1.27 Precedence: list List-Id: "Linux-nvdimm developer list." List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: linux-mm@kvack.org, yi.z.zhang@intel.com, rkrcmar@redhat.com MIME-Version: 1.0 Errors-To: linux-nvdimm-bounces@lists.01.org Sender: "Linux-nvdimm" X-Virus-Scanned: ClamAV using ClamSMTP 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 Signed-off-by: Zhang Yi --- virt/kvm/kvm_main.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index c44c406..969b6ca 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -147,8 +147,12 @@ __weak void kvm_arch_mmu_notifier_invalidate_range(struct kvm *kvm, bool kvm_is_reserved_pfn(kvm_pfn_t pfn) { - if (pfn_valid(pfn)) - return PageReserved(pfn_to_page(pfn)); + struct page *page; + + if (pfn_valid(pfn)) { + page = pfn_to_page(pfn); + return PageReserved(page) && !is_dax_page(page); + } return true; }