From patchwork Thu Dec 12 18:22:38 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Barret Rhoden X-Patchwork-Id: 11289011 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 4317E14B7 for ; Thu, 12 Dec 2019 18:23:06 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 20FE922527 for ; Thu, 12 Dec 2019 18:23:06 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="Ba0ZrxLu" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730168AbfLLSXC (ORCPT ); Thu, 12 Dec 2019 13:23:02 -0500 Received: from mail-pj1-f74.google.com ([209.85.216.74]:43686 "EHLO mail-pj1-f74.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730210AbfLLSXB (ORCPT ); Thu, 12 Dec 2019 13:23:01 -0500 Received: by mail-pj1-f74.google.com with SMTP id b23so1581356pjz.10 for ; Thu, 12 Dec 2019 10:23:01 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=date:in-reply-to:message-id:mime-version:references:subject:from:to :cc; bh=QJzS5cf1va+nrqwiPMy+1/CZ1shjgAqUeBFnOuHAc2s=; b=Ba0ZrxLur6jY5/yOkxJ3TztRuqj4f0wSiJ88PrOZrz6TKvyfeg1L/B0CGclVQMSKMS fKntKcN+MxF41ny/fjJJQzA/TxZnRfVwqE4Abw4zWB1eEXysAMU83K8rIwXbt5IfGWXL rTV7A36Z09p7odDbSD00a4mbTY0Lvu0IyNj4tT49mjw31Q5L9IhFdG8cXyX4r40FjVEo hjq3LR16hnJ3NKy94C2uwvo9okl0CTJT0ZPXdKG5OjVbxKPM8y7IX0CWAy14neVt1hO7 4Os1UMSWnkdTVnbXe37U4lvvoG1ujSbhU8yfBrGa1meSA02y74bsiSjr7iBssE0ojlWA XmTg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=QJzS5cf1va+nrqwiPMy+1/CZ1shjgAqUeBFnOuHAc2s=; b=Z3dUoHwY35ohFoQ6bbxPx6sZZ6yPOna6lAKc8GmW3ZPd2uWx3UkeThRBHx4p6Tp8DP kd8CC3VH2qt+/HloW0TBaqc1pW5EANYS+br3v3Vo56qIMmkrSbgrt+tB13kGOv4WafuQ tytvOOVV7HT6Q51rT4uLSOQE6rsvnOTkTxHOyy6JHpGI4xXnJAw5izgmggghTAl+46mH 2O4DryzwMbO67bPP/38kswas0bfAKTYeDDGudsWNH0FfbCvEdDQPfrH1uT5yPnR5+uHz 7VLkH0/b6Aqw+n0dvjcyZWBdN8496CY6BukaXsComI5SJrQTaA5Zm5hr6namcy/8Wmm2 0wZg== X-Gm-Message-State: APjAAAVvuSzsPJKbHwLz1aVLvWiWMnWAP4CdQERVjMbjrujWATeJ8tAo V+QqfTRtz2qU3VbAZr7An/w1jQj8 X-Google-Smtp-Source: APXvYqx3OSYyAEpeU1hpMzeLCwi0nWCUbjiyweJI73Oot2AiHdC93XItct57lFn8p5M9ukNOGXwyBoTV X-Received: by 2002:a65:5a4d:: with SMTP id z13mr11986210pgs.21.1576174981140; Thu, 12 Dec 2019 10:23:01 -0800 (PST) Date: Thu, 12 Dec 2019 13:22:38 -0500 In-Reply-To: <20191212182238.46535-1-brho@google.com> Message-Id: <20191212182238.46535-3-brho@google.com> Mime-Version: 1.0 References: <20191212182238.46535-1-brho@google.com> X-Mailer: git-send-email 2.24.1.735.g03f4e72817-goog Subject: [PATCH v5 2/2] kvm: Use huge pages for DAX-backed files From: Barret Rhoden To: Paolo Bonzini , Dan Williams , David Hildenbrand , Dave Jiang , Alexander Duyck , Sean Christopherson Cc: linux-nvdimm@lists.01.org, x86@kernel.org, kvm@vger.kernel.org, linux-kernel@vger.kernel.org, jason.zeng@intel.com Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org This change allows KVM to map DAX-backed files made of huge pages with huge mappings in the EPT/TDP. DAX pages are not PageTransCompound. The existing check is trying to determine if the mapping for the pfn is a huge mapping or not. For non-DAX maps, e.g. hugetlbfs, that means checking PageTransCompound. For DAX, we can check the page table itself. Note that KVM already faulted in the page (or huge page) in the host's page table, and we hold the KVM mmu spinlock. We grabbed that lock in kvm_mmu_notifier_invalidate_range_end, before checking the mmu seq. Signed-off-by: Barret Rhoden --- arch/x86/kvm/mmu/mmu.c | 31 +++++++++++++++++++++++++++---- 1 file changed, 27 insertions(+), 4 deletions(-) diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c index 7269130ea5e2..ea8f6951398b 100644 --- a/arch/x86/kvm/mmu/mmu.c +++ b/arch/x86/kvm/mmu/mmu.c @@ -3328,6 +3328,30 @@ static void direct_pte_prefetch(struct kvm_vcpu *vcpu, u64 *sptep) __direct_pte_prefetch(vcpu, sp, sptep); } +static bool pfn_is_huge_mapped(struct kvm *kvm, gfn_t gfn, kvm_pfn_t pfn) +{ + struct page *page = pfn_to_page(pfn); + unsigned long hva; + + if (!is_zone_device_page(page)) + return PageTransCompoundMap(page); + + /* + * DAX pages do not use compound pages. The page should have already + * been mapped into the host-side page table during try_async_pf(), so + * we can check the page tables directly. + */ + hva = gfn_to_hva(kvm, gfn); + if (kvm_is_error_hva(hva)) + return false; + + /* + * Our caller grabbed the KVM mmu_lock with a successful + * mmu_notifier_retry, so we're safe to walk the page table. + */ + return dev_pagemap_mapping_shift(hva, current->mm) > PAGE_SHIFT; +} + static void transparent_hugepage_adjust(struct kvm_vcpu *vcpu, gfn_t gfn, kvm_pfn_t *pfnp, int *levelp) @@ -3342,8 +3366,8 @@ static void transparent_hugepage_adjust(struct kvm_vcpu *vcpu, * here. */ if (!is_error_noslot_pfn(pfn) && !kvm_is_reserved_pfn(pfn) && - !kvm_is_zone_device_pfn(pfn) && level == PT_PAGE_TABLE_LEVEL && - PageTransCompoundMap(pfn_to_page(pfn))) { + level == PT_PAGE_TABLE_LEVEL && + pfn_is_huge_mapped(vcpu->kvm, gfn, pfn)) { unsigned long mask; /* @@ -5957,8 +5981,7 @@ static bool kvm_mmu_zap_collapsible_spte(struct kvm *kvm, * mapping if the indirect sp has level = 1. */ if (sp->role.direct && !kvm_is_reserved_pfn(pfn) && - !kvm_is_zone_device_pfn(pfn) && - PageTransCompoundMap(pfn_to_page(pfn))) { + pfn_is_huge_mapped(kvm, sp->gfn, pfn)) { pte_list_remove(rmap_head, sptep); if (kvm_available_flush_tlb_with_range())