From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: 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 732F5210C0CFC for ; Wed, 4 Jul 2018 22:33:27 -0700 (PDT) Subject: Re: [PATCH 3/3] kvm: add a function to check if page is from NVDIMM pmem. References: <359fdf0103b61014bf811d88d4ce36bc793d18f2.1530716899.git.yi.z.zhang@linux.intel.com> <1efab832-8782-38f3-9fd5-7a8b45bde153@redhat.com> From: "Zhang,Yi" Message-ID: Date: Thu, 5 Jul 2018 21:19:30 +0800 MIME-Version: 1.0 In-Reply-To: <1efab832-8782-38f3-9fd5-7a8b45bde153@redhat.com> Content-Language: en-US List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: base64 Errors-To: linux-nvdimm-bounces@lists.01.org Sender: "Linux-nvdimm" To: Paolo Bonzini , kvm@vger.kernel.org, linux-kernel@vger.kernel.org, linux-nvdimm@lists.01.org, dan.j.williams@intel.com, jack@suse.cz, hch@lst.de, yu.c.zhang@intel.com Cc: linux-mm@kvack.org, yi.z.zhang@intel.com, rkrcmar@redhat.com List-ID: CgpPbiAyMDE45bm0MDfmnIgwNOaXpSAyMzoyNSwgUGFvbG8gQm9uemluaSB3cm90ZToKPiBPbiAw NC8wNy8yMDE4IDE3OjMwLCBaaGFuZyBZaSB3cm90ZToKPj4gRm9yIGRldmljZSBzcGVjaWZpYyBt ZW1vcnkgc3BhY2UsIHdoZW4gd2UgbW92ZSB0aGVzZSBhcmVhIG9mIHBmbiB0bwo+PiBtZW1vcnkg em9uZSwgd2Ugd2lsbCBzZXQgdGhlIHBhZ2UgcmVzZXJ2ZWQgZmxhZyBhdCB0aGF0IHRpbWUsIHNv bWUgb2YKPj4gdGhlc2UgcmVzZXJ2ZWQgZm9yIGRldmljZSBtbWlvLCBhbmQgc29tZSBvZiB0aGVz ZSBhcmUgbm90LCBzdWNoIGFzCj4+IE5WRElNTSBwbWVtLgo+Pgo+PiBOb3csIHdlIG1hcCB0aGVz ZSBkZXZfZGF4IG9yIGZzX2RheCBwYWdlcyB0byBrdm0gZm9yIERJTU0vTlZESU1NCj4+IGJhY2tl bmQsIHNpbmNlIHRoZXNlIHBhZ2VzIGFyZSByZXNlcnZlZC4gdGhlIGNoZWNrIG9mCj4+IGt2bV9p c19yZXNlcnZlZF9wZm4oKSBtaXNjb25jZWl2ZXMgdGhvc2UgcGFnZXMgYXMgTU1JTy4gVGhlcmVm b3IsIHdlCj4+IGludHJvZHVjZSAyIHBhZ2UgbWFwIHR5cGVzLCBNRU1PUllfREVWSUNFX0ZTX0RB WC9NRU1PUllfREVWSUNFX0RFVl9EQVgsCj4+IHRvIGluZGVudGlmeSB0aGVzZSBwYWdlcyBhcmUg ZnJvbSBOVkRJTU0gcG1lbS4gYW5kIGxldCBrdm0gdHJlYXQgdGhlc2UKPj4gYXMgbm9ybWFsIHBh Z2VzLgo+Pgo+PiBXaXRob3V0IHRoaXMgcGF0Y2gsIE1hbnkgb3BlcmF0aW9ucyB3aWxsIGJlIG1p c3NlZCBkdWUgdG8gdGhpcwo+PiBtaXN0cmVhdG1lbnQgdG8gcG1lbSBwYWdlcy4gRm9yIGV4YW1w bGUsIGEgcGFnZSBtYXkgbm90IGhhdmUgY2hhbmNlIHRvCj4+IGJlIHVucGlubmVkIGZvciBLVk0g Z3Vlc3QoaW4ga3ZtX3JlbGVhc2VfcGZuX2NsZWFuKTsgbm90IGFibGUgdG8gYmUKPj4gbWFya2Vk IGFzIGRpcnR5L2FjY2Vzc2VkKGluIGt2bV9zZXRfcGZuX2RpcnR5L2FjY2Vzc2VkKSBldGMuCj4+ Cj4+IFNpZ25lZC1vZmYtYnk6IFpoYW5nIFlpIDx5aS56LnpoYW5nQGxpbnV4LmludGVsLmNvbT4K Pj4gU2lnbmVkLW9mZi1ieTogWmhhbmcgWXUgPHl1LmMuemhhbmdAbGludXguaW50ZWwuY29tPgo+ PiAtLS0KPj4gIHZpcnQva3ZtL2t2bV9tYWluLmMgfCAxNyArKysrKysrKysrKysrKystLQo+PiAg MSBmaWxlIGNoYW5nZWQsIDE1IGluc2VydGlvbnMoKyksIDIgZGVsZXRpb25zKC0pCj4+Cj4+IGRp ZmYgLS1naXQgYS92aXJ0L2t2bS9rdm1fbWFpbi5jIGIvdmlydC9rdm0va3ZtX21haW4uYwo+PiBp bmRleCBhZmIyZTZlLi4xMzY1ZDE4IDEwMDY0NAo+PiAtLS0gYS92aXJ0L2t2bS9rdm1fbWFpbi5j Cj4+ICsrKyBiL3ZpcnQva3ZtL2t2bV9tYWluLmMKPj4gQEAgLTE0MCwxMCArMTQwLDIzIEBAIF9f d2VhayB2b2lkIGt2bV9hcmNoX21tdV9ub3RpZmllcl9pbnZhbGlkYXRlX3JhbmdlKHN0cnVjdCBr dm0gKmt2bSwKPj4gIHsKPj4gIH0KPj4gIAo+PiArc3RhdGljIGJvb2wga3ZtX2lzX25kX3Bmbihr dm1fcGZuX3QgcGZuKQo+PiArewo+PiArCXN0cnVjdCBwYWdlICpwYWdlID0gcGZuX3RvX3BhZ2Uo cGZuKTsKPj4gKwo+PiArCXJldHVybiBpc196b25lX2RldmljZV9wYWdlKHBhZ2UpICYmCj4+ICsJ CSgocGFnZS0+cGdtYXAtPnR5cGUgPT0gTUVNT1JZX0RFVklDRV9GU19EQVgpIHx8Cj4+ICsJCSAo cGFnZS0+cGdtYXAtPnR5cGUgPT0gTUVNT1JZX0RFVklDRV9ERVZfREFYKSk7Cj4+ICt9Cj4gSWYg dGhlIG1tIHBlb3BsZSBhZ3JlZSwgSSdkIHByZWZlciBzb21ldGhpbmcgdGhhdCB0YWtlcyBhIHN0 cnVjdCBwYWdlICoKPiBhbmQgaXMgZXhwb3J0ZWQgYnkgaW5jbHVkZS9saW51eC9tbS5oLiAgVGhl biBLVk0gY2FuIGp1c3QgZG8gc29tZXRoaW5nIGxpa2UKPgo+IAlzdHJ1Y3QgcGFnZSAqcGFnZTsK PiAJaWYgKCFwZm5fdmFsaWQocGZuKSkKPiAJCXJldHVybiB0cnVlOwo+Cj4gCXBhZ2UgPSBwZm5f dG9fcGFnZShwZm4pOwo+IAlyZXR1cm4gUGFnZVJlc2VydmVkKHBhZ2UpICYmICFpc19kYXhfcGFn ZShwYWdlKTsKPgo+IFRoYW5rcywKPgo+IFBhb2xvClllYWgsIHRoYXQgY291bGQgYmUgbXVjaCBi ZXR0ZXIuIFRoYW5rcyBmb3IgeW91ciBjb21tZW50cyBQYW9sby4KCkhpIEthcmEsIERvIHUgaGF2 ZSBBbnkgb3BpbmlvbnMvaWRlYXMgdG8gYWRkIHN1Y2ggZGVmaW5pdGlvbiBpbiBtbT8KClJlZ2Fy ZHMsCllpCl9fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fCkxp bnV4LW52ZGltbSBtYWlsaW5nIGxpc3QKTGludXgtbnZkaW1tQGxpc3RzLjAxLm9yZwpodHRwczov L2xpc3RzLjAxLm9yZy9tYWlsbWFuL2xpc3RpbmZvL2xpbnV4LW52ZGltbQo= 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=-0.8 required=3.0 tests=DATE_IN_FUTURE_06_12, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS 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 1F101C6778A for ; Thu, 5 Jul 2018 05:33:34 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id CF4882401D for ; Thu, 5 Jul 2018 05:33:33 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org CF4882401D Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linux.intel.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 S1753297AbeGEFda (ORCPT ); Thu, 5 Jul 2018 01:33:30 -0400 Received: from mga02.intel.com ([134.134.136.20]:19525 "EHLO mga02.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753075AbeGEFd2 (ORCPT ); Thu, 5 Jul 2018 01:33:28 -0400 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga002.fm.intel.com ([10.253.24.26]) by orsmga101.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 04 Jul 2018 22:33:27 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.51,310,1526367600"; d="scan'208";a="64286405" Received: from dazhang1-z97x.sh.intel.com (HELO [10.239.13.115]) ([10.239.13.115]) by fmsmga002.fm.intel.com with ESMTP; 04 Jul 2018 22:33:25 -0700 Subject: Re: [PATCH 3/3] kvm: add a function to check if page is from NVDIMM pmem. To: Paolo Bonzini , kvm@vger.kernel.org, linux-kernel@vger.kernel.org, linux-nvdimm@lists.01.org, dan.j.williams@intel.com, jack@suse.cz, hch@lst.de, yu.c.zhang@intel.com Cc: linux-mm@kvack.org, rkrcmar@redhat.com, yi.z.zhang@intel.com References: <359fdf0103b61014bf811d88d4ce36bc793d18f2.1530716899.git.yi.z.zhang@linux.intel.com> <1efab832-8782-38f3-9fd5-7a8b45bde153@redhat.com> From: "Zhang,Yi" Message-ID: Date: Thu, 5 Jul 2018 21:19:30 +0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.2.1 MIME-Version: 1.0 In-Reply-To: <1efab832-8782-38f3-9fd5-7a8b45bde153@redhat.com> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit Content-Language: en-US Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2018年07月04日 23:25, Paolo Bonzini wrote: > On 04/07/2018 17:30, 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. >> >> Signed-off-by: Zhang Yi >> Signed-off-by: Zhang Yu >> --- >> virt/kvm/kvm_main.c | 17 +++++++++++++++-- >> 1 file changed, 15 insertions(+), 2 deletions(-) >> >> diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c >> index afb2e6e..1365d18 100644 >> --- a/virt/kvm/kvm_main.c >> +++ b/virt/kvm/kvm_main.c >> @@ -140,10 +140,23 @@ __weak void kvm_arch_mmu_notifier_invalidate_range(struct kvm *kvm, >> { >> } >> >> +static bool kvm_is_nd_pfn(kvm_pfn_t pfn) >> +{ >> + struct page *page = pfn_to_page(pfn); >> + >> + return is_zone_device_page(page) && >> + ((page->pgmap->type == MEMORY_DEVICE_FS_DAX) || >> + (page->pgmap->type == MEMORY_DEVICE_DEV_DAX)); >> +} > If the mm people agree, I'd prefer something that takes a struct page * > and is exported by include/linux/mm.h. Then KVM can just do something like > > struct page *page; > if (!pfn_valid(pfn)) > return true; > > page = pfn_to_page(pfn); > return PageReserved(page) && !is_dax_page(page); > > Thanks, > > Paolo Yeah, that could be much better. Thanks for your comments Paolo. Hi Kara, Do u have Any opinions/ideas to add such definition in mm? Regards, Yi From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Zhang,Yi" Subject: Re: [PATCH 3/3] kvm: add a function to check if page is from NVDIMM pmem. Date: Thu, 5 Jul 2018 21:19:30 +0800 Message-ID: References: <359fdf0103b61014bf811d88d4ce36bc793d18f2.1530716899.git.yi.z.zhang@linux.intel.com> <1efab832-8782-38f3-9fd5-7a8b45bde153@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: base64 Cc: linux-mm-Bw31MaZKKs3YtjvyW6yDsg@public.gmane.org, yi.z.zhang-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org, rkrcmar-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org To: Paolo Bonzini , kvm-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-nvdimm-hn68Rpc1hR1g9hUCZPvPmw@public.gmane.org, dan.j.williams-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org, jack-AlSwsSmVLrQ@public.gmane.org, hch-jcswGhMUV9g@public.gmane.org, yu.c.zhang-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org Return-path: In-Reply-To: <1efab832-8782-38f3-9fd5-7a8b45bde153-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org> Content-Language: en-US List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: linux-nvdimm-bounces-hn68Rpc1hR1g9hUCZPvPmw@public.gmane.org Sender: "Linux-nvdimm" List-Id: kvm.vger.kernel.org CgpPbiAyMDE45bm0MDfmnIgwNOaXpSAyMzoyNSwgUGFvbG8gQm9uemluaSB3cm90ZToKPiBPbiAw NC8wNy8yMDE4IDE3OjMwLCBaaGFuZyBZaSB3cm90ZToKPj4gRm9yIGRldmljZSBzcGVjaWZpYyBt ZW1vcnkgc3BhY2UsIHdoZW4gd2UgbW92ZSB0aGVzZSBhcmVhIG9mIHBmbiB0bwo+PiBtZW1vcnkg em9uZSwgd2Ugd2lsbCBzZXQgdGhlIHBhZ2UgcmVzZXJ2ZWQgZmxhZyBhdCB0aGF0IHRpbWUsIHNv bWUgb2YKPj4gdGhlc2UgcmVzZXJ2ZWQgZm9yIGRldmljZSBtbWlvLCBhbmQgc29tZSBvZiB0aGVz ZSBhcmUgbm90LCBzdWNoIGFzCj4+IE5WRElNTSBwbWVtLgo+Pgo+PiBOb3csIHdlIG1hcCB0aGVz ZSBkZXZfZGF4IG9yIGZzX2RheCBwYWdlcyB0byBrdm0gZm9yIERJTU0vTlZESU1NCj4+IGJhY2tl bmQsIHNpbmNlIHRoZXNlIHBhZ2VzIGFyZSByZXNlcnZlZC4gdGhlIGNoZWNrIG9mCj4+IGt2bV9p c19yZXNlcnZlZF9wZm4oKSBtaXNjb25jZWl2ZXMgdGhvc2UgcGFnZXMgYXMgTU1JTy4gVGhlcmVm b3IsIHdlCj4+IGludHJvZHVjZSAyIHBhZ2UgbWFwIHR5cGVzLCBNRU1PUllfREVWSUNFX0ZTX0RB WC9NRU1PUllfREVWSUNFX0RFVl9EQVgsCj4+IHRvIGluZGVudGlmeSB0aGVzZSBwYWdlcyBhcmUg ZnJvbSBOVkRJTU0gcG1lbS4gYW5kIGxldCBrdm0gdHJlYXQgdGhlc2UKPj4gYXMgbm9ybWFsIHBh Z2VzLgo+Pgo+PiBXaXRob3V0IHRoaXMgcGF0Y2gsIE1hbnkgb3BlcmF0aW9ucyB3aWxsIGJlIG1p c3NlZCBkdWUgdG8gdGhpcwo+PiBtaXN0cmVhdG1lbnQgdG8gcG1lbSBwYWdlcy4gRm9yIGV4YW1w bGUsIGEgcGFnZSBtYXkgbm90IGhhdmUgY2hhbmNlIHRvCj4+IGJlIHVucGlubmVkIGZvciBLVk0g Z3Vlc3QoaW4ga3ZtX3JlbGVhc2VfcGZuX2NsZWFuKTsgbm90IGFibGUgdG8gYmUKPj4gbWFya2Vk IGFzIGRpcnR5L2FjY2Vzc2VkKGluIGt2bV9zZXRfcGZuX2RpcnR5L2FjY2Vzc2VkKSBldGMuCj4+ Cj4+IFNpZ25lZC1vZmYtYnk6IFpoYW5nIFlpIDx5aS56LnpoYW5nQGxpbnV4LmludGVsLmNvbT4K Pj4gU2lnbmVkLW9mZi1ieTogWmhhbmcgWXUgPHl1LmMuemhhbmdAbGludXguaW50ZWwuY29tPgo+ PiAtLS0KPj4gIHZpcnQva3ZtL2t2bV9tYWluLmMgfCAxNyArKysrKysrKysrKysrKystLQo+PiAg MSBmaWxlIGNoYW5nZWQsIDE1IGluc2VydGlvbnMoKyksIDIgZGVsZXRpb25zKC0pCj4+Cj4+IGRp ZmYgLS1naXQgYS92aXJ0L2t2bS9rdm1fbWFpbi5jIGIvdmlydC9rdm0va3ZtX21haW4uYwo+PiBp bmRleCBhZmIyZTZlLi4xMzY1ZDE4IDEwMDY0NAo+PiAtLS0gYS92aXJ0L2t2bS9rdm1fbWFpbi5j Cj4+ICsrKyBiL3ZpcnQva3ZtL2t2bV9tYWluLmMKPj4gQEAgLTE0MCwxMCArMTQwLDIzIEBAIF9f d2VhayB2b2lkIGt2bV9hcmNoX21tdV9ub3RpZmllcl9pbnZhbGlkYXRlX3JhbmdlKHN0cnVjdCBr dm0gKmt2bSwKPj4gIHsKPj4gIH0KPj4gIAo+PiArc3RhdGljIGJvb2wga3ZtX2lzX25kX3Bmbihr dm1fcGZuX3QgcGZuKQo+PiArewo+PiArCXN0cnVjdCBwYWdlICpwYWdlID0gcGZuX3RvX3BhZ2Uo cGZuKTsKPj4gKwo+PiArCXJldHVybiBpc196b25lX2RldmljZV9wYWdlKHBhZ2UpICYmCj4+ICsJ CSgocGFnZS0+cGdtYXAtPnR5cGUgPT0gTUVNT1JZX0RFVklDRV9GU19EQVgpIHx8Cj4+ICsJCSAo cGFnZS0+cGdtYXAtPnR5cGUgPT0gTUVNT1JZX0RFVklDRV9ERVZfREFYKSk7Cj4+ICt9Cj4gSWYg dGhlIG1tIHBlb3BsZSBhZ3JlZSwgSSdkIHByZWZlciBzb21ldGhpbmcgdGhhdCB0YWtlcyBhIHN0 cnVjdCBwYWdlICoKPiBhbmQgaXMgZXhwb3J0ZWQgYnkgaW5jbHVkZS9saW51eC9tbS5oLiAgVGhl biBLVk0gY2FuIGp1c3QgZG8gc29tZXRoaW5nIGxpa2UKPgo+IAlzdHJ1Y3QgcGFnZSAqcGFnZTsK PiAJaWYgKCFwZm5fdmFsaWQocGZuKSkKPiAJCXJldHVybiB0cnVlOwo+Cj4gCXBhZ2UgPSBwZm5f dG9fcGFnZShwZm4pOwo+IAlyZXR1cm4gUGFnZVJlc2VydmVkKHBhZ2UpICYmICFpc19kYXhfcGFn ZShwYWdlKTsKPgo+IFRoYW5rcywKPgo+IFBhb2xvClllYWgsIHRoYXQgY291bGQgYmUgbXVjaCBi ZXR0ZXIuIFRoYW5rcyBmb3IgeW91ciBjb21tZW50cyBQYW9sby4KCkhpIEthcmEsIERvIHUgaGF2 ZSBBbnkgb3BpbmlvbnMvaWRlYXMgdG8gYWRkIHN1Y2ggZGVmaW5pdGlvbiBpbiBtbT8KClJlZ2Fy ZHMsCllpCl9fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fCkxp bnV4LW52ZGltbSBtYWlsaW5nIGxpc3QKTGludXgtbnZkaW1tQGxpc3RzLjAxLm9yZwpodHRwczov L2xpc3RzLjAxLm9yZy9tYWlsbWFuL2xpc3RpbmZvL2xpbnV4LW52ZGltbQo= 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 05A2C6B0005 for ; Thu, 5 Jul 2018 01:33:29 -0400 (EDT) Received: by mail-pl0-f71.google.com with SMTP id 70-v6so1260149plc.1 for ; Wed, 04 Jul 2018 22:33:28 -0700 (PDT) Received: from mga14.intel.com (mga14.intel.com. [192.55.52.115]) by mx.google.com with ESMTPS id e17-v6si4531536pgv.160.2018.07.04.22.33.27 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 04 Jul 2018 22:33:27 -0700 (PDT) Subject: Re: [PATCH 3/3] kvm: add a function to check if page is from NVDIMM pmem. References: <359fdf0103b61014bf811d88d4ce36bc793d18f2.1530716899.git.yi.z.zhang@linux.intel.com> <1efab832-8782-38f3-9fd5-7a8b45bde153@redhat.com> From: "Zhang,Yi" Message-ID: Date: Thu, 5 Jul 2018 21:19:30 +0800 MIME-Version: 1.0 In-Reply-To: <1efab832-8782-38f3-9fd5-7a8b45bde153@redhat.com> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit Content-Language: en-US Sender: owner-linux-mm@kvack.org List-ID: To: Paolo Bonzini , kvm@vger.kernel.org, linux-kernel@vger.kernel.org, linux-nvdimm@lists.01.org, dan.j.williams@intel.com, jack@suse.cz, hch@lst.de, yu.c.zhang@intel.com Cc: linux-mm@kvack.org, rkrcmar@redhat.com, yi.z.zhang@intel.com On 2018a1'07ae??04ae?JPY 23:25, Paolo Bonzini wrote: > On 04/07/2018 17:30, 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. >> >> Signed-off-by: Zhang Yi >> Signed-off-by: Zhang Yu >> --- >> virt/kvm/kvm_main.c | 17 +++++++++++++++-- >> 1 file changed, 15 insertions(+), 2 deletions(-) >> >> diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c >> index afb2e6e..1365d18 100644 >> --- a/virt/kvm/kvm_main.c >> +++ b/virt/kvm/kvm_main.c >> @@ -140,10 +140,23 @@ __weak void kvm_arch_mmu_notifier_invalidate_range(struct kvm *kvm, >> { >> } >> >> +static bool kvm_is_nd_pfn(kvm_pfn_t pfn) >> +{ >> + struct page *page = pfn_to_page(pfn); >> + >> + return is_zone_device_page(page) && >> + ((page->pgmap->type == MEMORY_DEVICE_FS_DAX) || >> + (page->pgmap->type == MEMORY_DEVICE_DEV_DAX)); >> +} > If the mm people agree, I'd prefer something that takes a struct page * > and is exported by include/linux/mm.h. Then KVM can just do something like > > struct page *page; > if (!pfn_valid(pfn)) > return true; > > page = pfn_to_page(pfn); > return PageReserved(page) && !is_dax_page(page); > > Thanks, > > Paolo Yeah, that could be much better. Thanks for your comments Paolo. Hi Kara, Do u have Any opinions/ideas to add such definition in mm? Regards, Yi