From patchwork Wed Nov 14 21:51:54 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Barret Rhoden X-Patchwork-Id: 10683307 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 9736114D6 for ; Wed, 14 Nov 2018 22:57:26 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 7FD932BF8B for ; Wed, 14 Nov 2018 22:57:26 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 729102BFAA; Wed, 14 Nov 2018 22:57:26 +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=-15.5 required=2.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,RCVD_IN_DNSWL_HI, USER_IN_DEF_DKIM_WL autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 5B5B02BF8B for ; Wed, 14 Nov 2018 22:57:25 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727128AbeKOJCi (ORCPT ); Thu, 15 Nov 2018 04:02:38 -0500 Received: from mail-vk1-f201.google.com ([209.85.221.201]:47020 "EHLO mail-vk1-f201.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725895AbeKOJCi (ORCPT ); Thu, 15 Nov 2018 04:02:38 -0500 Received: by mail-vk1-f201.google.com with SMTP id p22so2900537vkd.13 for ; Wed, 14 Nov 2018 14:57:23 -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=TjNbpFDEmROOYDgX+JBtXjmBSAKa/KDKnxWS9mQYdnM=; b=taFjDK0teNWIgkT/L+183FUK7Rjv5BiYjc2vj9n0IhdJavI+1kbRzaJU2Yiiu0h737 Wh0YUHhy9yDVHl+9c4GqoLinKZL/hiYqZIJgsfeS1QhSZjd36eM3bD78H/Q8sGHJ+vLm I7/MEgB1fNMShiA10dPq+M3pt1sOc2JWuVUnU9G7dxuXUvzheuRMYLSs/jlRC6c7hyFE APQR91LYXzb4ENO5mM4jbgKl9V7Yus/mOvA2PBY5nGoYkqPxnKIh+QLY4Uv0+ZDJUDRJ lfa4l23S3nN7B/tI6vj3q9nyARf3QBI5df/wHX2XKckqMBtglSEKQIibBZ0wwNQznCwd GYjA== 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=TjNbpFDEmROOYDgX+JBtXjmBSAKa/KDKnxWS9mQYdnM=; b=dOrpd/xBOZ/5fZEFEaoSnTakgIRB+QuCjpd3O5R0ISqHQNGugAylA7htV0xnq1LrlR FGFN4RGi1AjxSNR1zd3GJrL7TBoOnXj1I+/TZfYygXpn20Q3wA7rINWUviGyJKU2aNZA T4zXhbMYlWNG0O4YzgOdO2W29xPbs2lETuT5aT69O40+AyQYk3mGMbHm9QtNPPBsYsCm 3hfg8Q0gAISh0UCeEyDgmuviuE1TND0EO4uT6Ilp2oodS+w/+2V4Oo0Zhb4R4SSb6Gw6 Oq3iG9eM2bJMjTPm53dEYbnfHqO4IxicXoMfjtXjfdpt2rYNCitLLvl4qxOfBMTxhcAn JhZw== X-Gm-Message-State: AGRZ1gJH8SLe72/eNPVeL8WxZwsAxZ7acnjOMGcP60BhlQmZYTp1+OXb pMEZO840xDbvjY/m8H2z9kDbI+qm X-Google-Smtp-Source: AJdET5fxjUluLcn0PMYFFDQMUPhJJ6f6///VYVv7kfdG0gbmeQPMhsaCe6AtiBa2pml32koG0VHN598e X-Received: by 2002:ab0:72d6:: with SMTP id g22mr3170146uap.14.1542232387447; Wed, 14 Nov 2018 13:53:07 -0800 (PST) Date: Wed, 14 Nov 2018 16:51:54 -0500 In-Reply-To: <20181114215155.259978-1-brho@google.com> Message-Id: <20181114215155.259978-3-brho@google.com> Mime-Version: 1.0 References: <20181109203921.178363-1-brho@google.com> <20181114215155.259978-1-brho@google.com> X-Mailer: git-send-email 2.19.1.1215.g8438c0b245-goog Subject: [PATCH v2 2/3] kvm: Use huge pages for DAX-backed files From: Barret Rhoden To: Dan Williams , Dave Jiang , Ross Zwisler , Vishal Verma , Paolo Bonzini , " =?utf-8?b?UmFkaW0gS3LEjW3DocWZ?= " , Thomas Gleixner , Ingo Molnar , Borislav Petkov Cc: linux-nvdimm@lists.01.org, linux-kernel@vger.kernel.org, "H. Peter Anvin" , x86@kernel.org, kvm@vger.kernel.org, yu.c.zhang@intel.com, yi.z.zhang@intel.com Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP 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 --- - removed map_shift local variable arch/x86/kvm/mmu.c | 33 +++++++++++++++++++++++++++++++-- 1 file changed, 31 insertions(+), 2 deletions(-) diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c index cf5f572f2305..6914989d1e3d 100644 --- a/arch/x86/kvm/mmu.c +++ b/arch/x86/kvm/mmu.c @@ -3152,6 +3152,35 @@ static int kvm_handle_bad_page(struct kvm_vcpu *vcpu, gfn_t gfn, kvm_pfn_t pfn) return -EFAULT; } +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. + */ + switch (dev_pagemap_mapping_shift(hva, current->mm)) { + case PMD_SHIFT: + case PUD_SIZE: + return true; + } + return false; +} + static void transparent_hugepage_adjust(struct kvm_vcpu *vcpu, gfn_t *gfnp, kvm_pfn_t *pfnp, int *levelp) @@ -3168,7 +3197,7 @@ static void transparent_hugepage_adjust(struct kvm_vcpu *vcpu, */ if (!is_error_noslot_pfn(pfn) && !kvm_is_reserved_pfn(pfn) && level == PT_PAGE_TABLE_LEVEL && - PageTransCompoundMap(pfn_to_page(pfn)) && + pfn_is_huge_mapped(vcpu->kvm, gfn, pfn) && !mmu_gfn_lpage_is_disallowed(vcpu, gfn, PT_DIRECTORY_LEVEL)) { unsigned long mask; /* @@ -5678,7 +5707,7 @@ static bool kvm_mmu_zap_collapsible_spte(struct kvm *kvm, */ if (sp->role.direct && !kvm_is_reserved_pfn(pfn) && - PageTransCompoundMap(pfn_to_page(pfn))) { + pfn_is_huge_mapped(kvm, sp->gfn, pfn)) { pte_list_remove(rmap_head, sptep); need_tlb_flush = 1; goto restart;