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: 10676565 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 C8CC8175A for ; Fri, 9 Nov 2018 20:40:31 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id B96372F214 for ; Fri, 9 Nov 2018 20:40:31 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id AC7502F235; Fri, 9 Nov 2018 20:40:31 +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=-2.7 required=2.0 tests=BAYES_00,DKIM_ADSP_CUSTOM_MED, DKIM_INVALID,DKIM_SIGNED,MAILING_LIST_MULTI,RCVD_IN_DNSWL_NONE autolearn=ham version=3.3.1 Received: from ml01.01.org (ml01.01.org [198.145.21.10]) (using TLSv1.2 with cipher DHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id 5C9682F214 for ; Fri, 9 Nov 2018 20:40:31 +0000 (UTC) Received: from [127.0.0.1] (localhost [IPv6:::1]) by ml01.01.org (Postfix) with ESMTP id 76E9E21CB74B7; Fri, 9 Nov 2018 12:40:28 -0800 (PST) X-Original-To: linux-nvdimm@lists.01.org Delivered-To: linux-nvdimm@lists.01.org Received-SPF: Pass (sender SPF authorized) identity=mailfrom; client-ip=2607:f8b0:4864:20::74a; helo=mail-qk1-x74a.google.com; envelope-from=3hpdlwwqkdoeeukrjrrjoh.frpolqxa-qyglppolvwv.de.ruj@flex--brho.bounces.google.com; receiver=linux-nvdimm@lists.01.org Received: from mail-qk1-x74a.google.com (mail-qk1-x74a.google.com [IPv6:2607:f8b0:4864:20::74a]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by ml01.01.org (Postfix) with ESMTPS id F40D321A00AE6 for ; Fri, 9 Nov 2018 12:39:32 -0800 (PST) Received: by mail-qk1-x74a.google.com with SMTP id 67so5817296qkj.18 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=LVnjZ+XFupS3fhdM1vleCdijGnKiZiNP4MatovbrCTUO9npAIYge9mQTuJGei12Q3i p65qLgMZu4TULf1H32oxpUsc5OGc9OAPrnGVi0qy5+A5j6gaTXDzgWpO1KpMOBcKbdQk Fyvbc7/nW9gpqppLLsMwA9ePvGHzEUu9HW15z7IXNgj+J6nAGapKcSoDHomCfv+8kWTN Sc9N9ZLS0KXv+Y4H7nOFL3lLbIqFPYdxhgaQGqUIekQxSBm6gwTggyZmjde/i5Zeq46o kSRUwLATkDI8oU3I3o2VUU+uUgp1+/vAIZDTCEBiQPPTBj3btAOM7RRTN4jR9qLvDcYC iOFQ== X-Gm-Message-State: AGRZ1gKVj34zG+Q5KDWZdVDJYOPTlp0Cm8l/1BgpP/eoTAHmud0cI/Zi eJt7n/XlavicdkTDCXufE9IGg3S+ 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 X-BeenThere: linux-nvdimm@lists.01.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: "Linux-nvdimm developer list." List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: kvm@vger.kernel.org, yu.c.zhang@intel.com, linux-nvdimm@lists.01.org, x86@kernel.org, linux-kernel@vger.kernel.org, "H. Peter Anvin" , yi.z.zhang@intel.com Errors-To: linux-nvdimm-bounces@lists.01.org Sender: "Linux-nvdimm" 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;