From patchwork Fri Nov 9 20:39:21 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Barret Rhoden X-Patchwork-Id: 10676559 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 66FB215E9 for ; Fri, 9 Nov 2018 20:39:46 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 595E92F214 for ; Fri, 9 Nov 2018 20:39:46 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 4DB012F235; Fri, 9 Nov 2018 20:39:46 +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 E522F2F214 for ; Fri, 9 Nov 2018 20:39:45 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728457AbeKJGVq (ORCPT ); Sat, 10 Nov 2018 01:21:46 -0500 Received: from mail-qk1-f202.google.com ([209.85.222.202]:33618 "EHLO mail-qk1-f202.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728352AbeKJGVp (ORCPT ); Sat, 10 Nov 2018 01:21:45 -0500 Received: by mail-qk1-f202.google.com with SMTP id 80so5938908qkd.0 for ; Fri, 09 Nov 2018 12:39:32 -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=fRNmz9gb6VrAwP0ad3suXpCd45/0Nzbx55I8Ob0Nxw8=; b=lHERq8Q4HYqaAxGtbFCNPXNjW/o1OBADouxj8g1FuxzZEueE/zn25nbHwssVZKcRXG 6in38OCNmSPHkwrlLMmZ7KPYCQzv5PF5b/5fVyQyPWOm1AmcfC9vyl9B84T8qrWcRyGx rWcomYRaHpJbbDn5GcKH54UwEMPYm2jTOIOoY5MkflAJv+Y8A3WuHbpPqigTK53wK+9X qWApRbCyNX+1F9am8vCrTSM22C4LklypAScWEKX0NkqbT8kxmO/gFh0Z91D1HO83XQgd gKdWYYRDdTugkpaPxi9VubaNIfdDbdiq2uleU3bzzB39RwmZ69nr8VsSMos+QHwPHTYp F6Xg== 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=fRNmz9gb6VrAwP0ad3suXpCd45/0Nzbx55I8Ob0Nxw8=; b=De0Aoz/wHMMiaHz5m7yw4uQ506W8Y1I+p1fQTymRB160Zy6IaI4ZxizEhZ0A4Dqkg3 QnzeXQDNxsCfqJj6Yic02kNFjAu3cFJ01VQ6d3jrJKA8dtigedQm+JgCJryqM/uDDsdN CyCRLjIWY8lrflJO6Mguxaqsv9+HY9csbSIHLlr2sr6S4hHolKJQSzyGsNlqIEmey+ft EqvxhZXmSELR20+fDhwMv0Nf0ZPe+5z26LSvdEYybAb2pLExaZUVxbNuu9/j/WTfa+wS gAfVG58FI5dm4lgC+mXBGf2Yxg5tdwsL4BNSVZL1lhlU++2OE4DnT5iRE1IWxYJbhE/J yDAQ== X-Gm-Message-State: AGRZ1gJPbYnMdrRZ31F4BlP4/h0k8tkyN+gu1g5vS3ShvcyQrU8QbyAv +cRk62Q9tFAP1AHYHBrzrYDFJ4Jm X-Google-Smtp-Source: AJdET5c72sXqRFS23DYfcp7KtuzEUK5qHEqYsH1dZDbfT6cQJniU25zASApUpTizlH/1a4frDMn1gl7p X-Received: by 2002:ac8:fe6:: with SMTP id f35mr4922088qtk.5.1541795972066; Fri, 09 Nov 2018 12:39:32 -0800 (PST) Date: Fri, 9 Nov 2018 15:39:21 -0500 In-Reply-To: <20181109203921.178363-1-brho@google.com> Message-Id: <20181109203921.178363-3-brho@google.com> Mime-Version: 1.0 References: <20181109203921.178363-1-brho@google.com> X-Mailer: git-send-email 2.19.1.930.g4563a0d9d0-goog Subject: [PATCH 2/2] 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 (grabbed before checking the mmu seq). Signed-off-by: Barret Rhoden --- arch/x86/kvm/mmu.c | 34 ++++++++++++++++++++++++++++++++-- 1 file changed, 32 insertions(+), 2 deletions(-) diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c index cf5f572f2305..2df8c459dc6a 100644 --- a/arch/x86/kvm/mmu.c +++ b/arch/x86/kvm/mmu.c @@ -3152,6 +3152,36 @@ 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, map_shift; + + 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. + */ + map_shift = dev_pagemap_mapping_shift(hva, current->mm); + switch (map_shift) { + 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 +3198,7 @@ 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 +5708,7 @@ 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;