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 9A5346B000A for ; Mon, 13 Aug 2018 05:48:23 -0400 (EDT) Received: by mail-pl0-f71.google.com with SMTP id z3-v6so10652600plb.16 for ; Mon, 13 Aug 2018 02:48:23 -0700 (PDT) Received: from mga02.intel.com (mga02.intel.com. [134.134.136.20]) by mx.google.com with ESMTPS id a5-v6si15055100pgd.400.2018.08.13.02.48.22 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Mon, 13 Aug 2018 02:48:22 -0700 (PDT) Subject: Re: [PATCH V3 4/4] kvm: add a check if pfn is from NVDIMM pmem. References: <0cc6cba7020f80168695fba731b8fd72fd649dc8.1533811181.git.yi.z.zhang@linux.intel.com> <2130082365.883434.1533803526182.JavaMail.zimbra@redhat.com> From: "Zhang,Yi" Message-ID: <083b8170-a9ba-beee-7578-6d33e70a8b6e@linux.intel.com> Date: Tue, 14 Aug 2018 01:32:05 +0800 MIME-Version: 1.0 In-Reply-To: <2130082365.883434.1533803526182.JavaMail.zimbra@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: Pankaj Gupta Cc: kvm@vger.kernel.org, linux-kernel@vger.kernel.org, linux-nvdimm@lists.01.org, pbonzini@redhat.com, dan j williams , jack@suse.cz, hch@lst.de, yu c zhang , linux-mm@kvack.org, rkrcmar@redhat.com, yi z zhang On 2018a1'08ae??09ae?JPY 16:32, Pankaj Gupta 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 > s/indentify/identify & remove '.' Thanks Pankaj, :-) > >> 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; >> } >> -- >> 2.7.4 >> >>