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 Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id C8812C433FE for ; Mon, 22 Nov 2021 09:19:56 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id B2DC26B0073; Mon, 22 Nov 2021 04:19:30 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id ADD4D6B0074; Mon, 22 Nov 2021 04:19:30 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 97EF76B0075; Mon, 22 Nov 2021 04:19:30 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0044.hostedemail.com [216.40.44.44]) by kanga.kvack.org (Postfix) with ESMTP id 8A0F16B0073 for ; Mon, 22 Nov 2021 04:19:30 -0500 (EST) Received: from smtpin05.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay05.hostedemail.com (Postfix) with ESMTP id 44F52180D6F93 for ; Mon, 22 Nov 2021 09:19:20 +0000 (UTC) X-FDA: 78836017890.05.C51317C Received: from mga01.intel.com (mga01.intel.com [192.55.52.88]) by imf08.hostedemail.com (Postfix) with ESMTP id D85E23000255 for ; Mon, 22 Nov 2021 09:19:15 +0000 (UTC) X-IronPort-AV: E=McAfee;i="6200,9189,10175"; a="258571508" X-IronPort-AV: E=Sophos;i="5.87,254,1631602800"; d="scan'208";a="258571508" Received: from orsmga007.jf.intel.com ([10.7.209.58]) by fmsmga101.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 22 Nov 2021 01:19:17 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.87,254,1631602800"; d="scan'208";a="496790995" Received: from chaop.bj.intel.com (HELO localhost) ([10.240.192.101]) by orsmga007.jf.intel.com with ESMTP; 22 Nov 2021 01:19:09 -0800 Date: Mon, 22 Nov 2021 17:18:23 +0800 From: Chao Peng To: Yao Yuan Cc: kvm@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-fsdevel@vger.kernel.org, qemu-devel@nongnu.org, Paolo Bonzini , Jonathan Corbet , Sean Christopherson , Vitaly Kuznetsov , Wanpeng Li , Jim Mattson , Joerg Roedel , Thomas Gleixner , Ingo Molnar , Borislav Petkov , x86@kernel.org, "H . Peter Anvin" , Hugh Dickins , Jeff Layton , "J . Bruce Fields" , Andrew Morton , Yu Zhang , "Kirill A . Shutemov" , luto@kernel.org, john.ji@intel.com, susie.li@intel.com, jun.nakajima@intel.com, dave.hansen@intel.com, ak@linux.intel.com, david@redhat.com Subject: Re: [RFC v2 PATCH 07/13] KVM: Handle page fault for fd based memslot Message-ID: <20211122091823.GB28749@chaop.bj.intel.com> Reply-To: Chao Peng References: <20211119134739.20218-1-chao.p.peng@linux.intel.com> <20211119134739.20218-8-chao.p.peng@linux.intel.com> <20211120015529.w23fg2df3fqs4ov5@sapienza> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20211120015529.w23fg2df3fqs4ov5@sapienza> User-Agent: Mutt/1.9.4 (2018-02-28) X-Stat-Signature: fde1o6bwrekcxgfcwx9fww6grc9s94iy Authentication-Results: imf08.hostedemail.com; dkim=none; spf=none (imf08.hostedemail.com: domain of chao.p.peng@linux.intel.com has no SPF policy when checking 192.55.52.88) smtp.mailfrom=chao.p.peng@linux.intel.com; dmarc=fail reason="No valid SPF, No valid DKIM" header.from=intel.com (policy=none) X-Rspamd-Server: rspam03 X-Rspamd-Queue-Id: D85E23000255 X-HE-Tag: 1637572755-887347 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Sat, Nov 20, 2021 at 09:55:29AM +0800, Yao Yuan wrote: > On Fri, Nov 19, 2021 at 09:47:33PM +0800, Chao Peng wrote: > > Current code assume the private memory is persistent and KVM can check > > with backing store to see if private memory exists at the same address > > by calling get_pfn(alloc=false). > > > > Signed-off-by: Yu Zhang > > Signed-off-by: Chao Peng > > --- > > arch/x86/kvm/mmu/mmu.c | 75 ++++++++++++++++++++++++++++++++++++++++-- > > 1 file changed, 73 insertions(+), 2 deletions(-) > > > > diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c > > index 40377901598b..cd5d1f923694 100644 > > --- a/arch/x86/kvm/mmu/mmu.c > > +++ b/arch/x86/kvm/mmu/mmu.c > > @@ -3277,6 +3277,9 @@ int kvm_mmu_max_mapping_level(struct kvm *kvm, > > if (max_level == PG_LEVEL_4K) > > return PG_LEVEL_4K; > > > > + if (memslot_is_memfd(slot)) > > + return max_level; > > + > > host_level = host_pfn_mapping_level(kvm, gfn, pfn, slot); > > return min(host_level, max_level); > > } > > @@ -4555,6 +4558,65 @@ static bool kvm_arch_setup_async_pf(struct kvm_vcpu *vcpu, gpa_t cr2_or_gpa, > > kvm_vcpu_gfn_to_hva(vcpu, gfn), &arch); > > } > > > > +static bool kvm_faultin_pfn_memfd(struct kvm_vcpu *vcpu, > > + struct kvm_page_fault *fault, int *r) > > +{ int order; > > + kvm_pfn_t pfn; > > + struct kvm_memory_slot *slot = fault->slot; > > + bool priv_gfn = kvm_vcpu_is_private_gfn(vcpu, fault->addr >> PAGE_SHIFT); > > + bool priv_slot_exists = memslot_has_private(slot); > > + bool priv_gfn_exists = false; > > + int mem_convert_type; > > + > > + if (priv_gfn && !priv_slot_exists) { > > + *r = RET_PF_INVALID; > > + return true; > > + } > > + > > + if (priv_slot_exists) { > > + pfn = slot->memfd_ops->get_pfn(slot, slot->priv_file, > > + fault->gfn, false, &order); > > + if (pfn >= 0) > > + priv_gfn_exists = true; > > Need "fault->pfn = pfn" here if actual pfn is returned in > get_pfn(alloc=false) case for private page case. > > > + } > > + > > + if (priv_gfn && !priv_gfn_exists) { > > + mem_convert_type = KVM_EXIT_MEM_MAP_PRIVATE; > > + goto out_convert; > > + } > > + > > + if (!priv_gfn && priv_gfn_exists) { > > + slot->memfd_ops->put_pfn(pfn); > > + mem_convert_type = KVM_EXIT_MEM_MAP_SHARED; > > + goto out_convert; > > + } > > + > > + if (!priv_gfn) { > > + pfn = slot->memfd_ops->get_pfn(slot, slot->file, > > + fault->gfn, true, &order); > > Need "fault->pfn = pfn" here, because he pfn for > share page is getted here only. > > > + if (fault->pfn < 0) { > > + *r = RET_PF_INVALID; > > + return true; > > + } > > + } Right, I actually have "fault->pfn = pfn" here but accidentally deleted in a code factoring. Chao > > + > > + if (slot->flags & KVM_MEM_READONLY) > > + fault->map_writable = false; > > + if (order == 0) > > + fault->max_level = PG_LEVEL_4K; > > + > > + return false; > > + > > +out_convert: > > + vcpu->run->exit_reason = KVM_EXIT_MEMORY_ERROR; > > + vcpu->run->mem.type = mem_convert_type; > > + vcpu->run->mem.u.map.gpa = fault->gfn << PAGE_SHIFT; > > + vcpu->run->mem.u.map.size = PAGE_SIZE; > > + fault->pfn = -1; > > + *r = -1; > > + return true; > > +} > > + > > static bool kvm_faultin_pfn(struct kvm_vcpu *vcpu, struct kvm_page_fault *fault, int *r) > > { > > struct kvm_memory_slot *slot = fault->slot; > > @@ -4596,6 +4658,9 @@ static bool kvm_faultin_pfn(struct kvm_vcpu *vcpu, struct kvm_page_fault *fault, > > } > > } > > > > + if (memslot_is_memfd(slot)) > > + return kvm_faultin_pfn_memfd(vcpu, fault, r); > > + > > async = false; > > fault->pfn = __gfn_to_pfn_memslot(slot, fault->gfn, false, &async, > > fault->write, &fault->map_writable, > > @@ -4660,7 +4725,8 @@ static int direct_page_fault(struct kvm_vcpu *vcpu, struct kvm_page_fault *fault > > else > > write_lock(&vcpu->kvm->mmu_lock); > > > > - if (fault->slot && mmu_notifier_retry_hva(vcpu->kvm, mmu_seq, fault->hva)) > > + if (fault->slot && !memslot_is_memfd(fault->slot) && > > + mmu_notifier_retry_hva(vcpu->kvm, mmu_seq, fault->hva)) > > goto out_unlock; > > r = make_mmu_pages_available(vcpu); > > if (r) > > @@ -4676,7 +4742,12 @@ static int direct_page_fault(struct kvm_vcpu *vcpu, struct kvm_page_fault *fault > > read_unlock(&vcpu->kvm->mmu_lock); > > else > > write_unlock(&vcpu->kvm->mmu_lock); > > - kvm_release_pfn_clean(fault->pfn); > > + > > + if (memslot_is_memfd(fault->slot)) > > + fault->slot->memfd_ops->put_pfn(fault->pfn); > > + else > > + kvm_release_pfn_clean(fault->pfn); > > + > > return r; > > } > > > > -- > > 2.17.1 > >