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 X-Spam-Level: X-Spam-Status: No, score=-6.8 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 30B8CCA9EA0 for ; Tue, 22 Oct 2019 17:14:23 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id E000120684 for ; Tue, 22 Oct 2019 17:14:22 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="NNwUX6Cg" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org E000120684 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 9826E6B0008; Tue, 22 Oct 2019 13:14:22 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 95BA36B000A; Tue, 22 Oct 2019 13:14:22 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 7FB5A6B000C; Tue, 22 Oct 2019 13:14:22 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0247.hostedemail.com [216.40.44.247]) by kanga.kvack.org (Postfix) with ESMTP id 5C5C36B0008 for ; Tue, 22 Oct 2019 13:14:22 -0400 (EDT) Received: from smtpin30.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay01.hostedemail.com (Postfix) with SMTP id E0F3A180AD817 for ; Tue, 22 Oct 2019 17:14:21 +0000 (UTC) X-FDA: 76072069122.30.salt93_432a55ad54928 X-HE-Tag: salt93_432a55ad54928 X-Filterd-Recvd-Size: 8346 Received: from us-smtp-delivery-1.mimecast.com (us-smtp-1.mimecast.com [205.139.110.61]) by imf28.hostedemail.com (Postfix) with ESMTP for ; Tue, 22 Oct 2019 17:14:21 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1571764460; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=RJLxUYZkphEfv5+PiNRBYPJsBqxuoPsQs816P7mVHAI=; b=NNwUX6CgFZ70V4w5Uk1yxnzjKqOFuMgWexwXGUZe/MyItZUaXvIcibPpFUHdHmANpuoeuk Ow/yjaidrdMb+gMXg5czxi0pwKK2G0bG8QdhbppX713R1eDQZXlR6jSuY37vilF7KNpwHK olVgle/K15j/ou/AMSDrj+RcgQeRHiE= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-196-LQ7sslTiPc68PqWCypqf4g-1; Tue, 22 Oct 2019 13:14:18 -0400 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.phx2.redhat.com [10.5.11.14]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id C3CE880183D; Tue, 22 Oct 2019 17:14:13 +0000 (UTC) Received: from t460s.redhat.com (ovpn-116-248.ams2.redhat.com [10.36.116.248]) by smtp.corp.redhat.com (Postfix) with ESMTP id 83D8F5ED21; Tue, 22 Oct 2019 17:13:53 +0000 (UTC) From: David Hildenbrand To: linux-kernel@vger.kernel.org Cc: linux-mm@kvack.org, David Hildenbrand , Michal Hocko , Andrew Morton , kvm-ppc@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, kvm@vger.kernel.org, linux-hyperv@vger.kernel.org, devel@driverdev.osuosl.org, xen-devel@lists.xenproject.org, x86@kernel.org, Alexander Duyck , Alexander Duyck , Alex Williamson , Allison Randal , Andy Lutomirski , "Aneesh Kumar K.V" , Anshuman Khandual , Anthony Yznaga , Ben Chan , Benjamin Herrenschmidt , Borislav Petkov , Boris Ostrovsky , Christophe Leroy , Cornelia Huck , Dan Carpenter , Dan Williams , Dave Hansen , Fabio Estevam , Greg Kroah-Hartman , Haiyang Zhang , "H. Peter Anvin" , Ingo Molnar , "Isaac J. Manjarres" , Jeremy Sowden , Jim Mattson , Joerg Roedel , Johannes Weiner , Juergen Gross , KarimAllah Ahmed , Kate Stewart , Kees Cook , "K. Y. Srinivasan" , Madhumitha Prabakaran , Matt Sickler , Mel Gorman , Michael Ellerman , Michal Hocko , Mike Rapoport , Mike Rapoport , Nicholas Piggin , Nishka Dasgupta , Oscar Salvador , Paolo Bonzini , Paul Mackerras , Paul Mackerras , Pavel Tatashin , Pavel Tatashin , Peter Zijlstra , Qian Cai , =?UTF-8?q?Radim=20Kr=C4=8Dm=C3=A1=C5=99?= , Rob Springer , Sasha Levin , Sean Christopherson , =?UTF-8?q?Simon=20Sandstr=C3=B6m?= , Stefano Stabellini , Stephen Hemminger , Thomas Gleixner , Todd Poynor , Vandana BN , Vitaly Kuznetsov , Vlastimil Babka , Wanpeng Li , YueHaibing Subject: [PATCH RFC v1 03/12] KVM: x86/mmu: Prepare kvm_is_mmio_pfn() for PG_reserved changes Date: Tue, 22 Oct 2019 19:12:30 +0200 Message-Id: <20191022171239.21487-4-david@redhat.com> In-Reply-To: <20191022171239.21487-1-david@redhat.com> References: <20191022171239.21487-1-david@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.14 X-MC-Unique: LQ7sslTiPc68PqWCypqf4g-1 X-Mimecast-Spam-Score: 0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable 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: Right now, ZONE_DEVICE memory is always set PG_reserved. We want to change that. KVM has this weird use case that you can map anything from /dev/mem into the guest. pfn_valid() is not a reliable check whether the memmap was initialized and can be touched. pfn_to_online_page() makes sure that we have an initialized memmap - however, there is no reliable and fast check to detect memmaps that were initialized and are ZONE_DEVICE. Let's rewrite kvm_is_mmio_pfn() so we really only touch initialized memmaps that are guaranteed to not contain garbage. Make sure that RAM without a memmap is still not detected as MMIO and that ZONE_DEVICE that is not UC/UC-/WC is not detected as MMIO. Cc: Paolo Bonzini Cc: "Radim Kr=C4=8Dm=C3=A1=C5=99" Cc: Sean Christopherson Cc: Vitaly Kuznetsov Cc: Wanpeng Li Cc: Jim Mattson Cc: Joerg Roedel Cc: Thomas Gleixner Cc: Ingo Molnar Cc: Borislav Petkov Cc: "H. Peter Anvin" Cc: KarimAllah Ahmed Cc: Michal Hocko Cc: Dan Williams Signed-off-by: David Hildenbrand --- arch/x86/kvm/mmu.c | 30 ++++++++++++++++++------------ 1 file changed, 18 insertions(+), 12 deletions(-) diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c index 24c23c66b226..795869ffd4bb 100644 --- a/arch/x86/kvm/mmu.c +++ b/arch/x86/kvm/mmu.c @@ -2962,20 +2962,26 @@ static bool mmu_need_write_protect(struct kvm_vcpu = *vcpu, gfn_t gfn, =20 static bool kvm_is_mmio_pfn(kvm_pfn_t pfn) { +=09struct page *page =3D pfn_to_online_page(pfn); + +=09/* +=09 * Online pages consist of pages managed by the buddy. Especially, +=09 * ZONE_DEVICE pages are never online. Online pages that are reserved +=09 * indicate the zero page and MMIO pages. +=09 */ +=09if (page) +=09=09return !is_zero_pfn(pfn) && PageReserved(pfn_to_page(pfn)); + +=09/* +=09 * Anything with a valid memmap could be ZONE_DEVICE - or the +=09 * memmap could be uninitialized. Treat only UC/UC-/WC pages as MMIO. +=09 */ =09if (pfn_valid(pfn)) -=09=09return !is_zero_pfn(pfn) && PageReserved(pfn_to_page(pfn)) && -=09=09=09/* -=09=09=09 * Some reserved pages, such as those from NVDIMM -=09=09=09 * DAX devices, are not for MMIO, and can be mapped -=09=09=09 * with cached memory type for better performance. -=09=09=09 * However, the above check misconceives those pages -=09=09=09 * as MMIO, and results in KVM mapping them with UC -=09=09=09 * memory type, which would hurt the performance. -=09=09=09 * Therefore, we check the host memory type in addition -=09=09=09 * and only treat UC/UC-/WC pages as MMIO. -=09=09=09 */ -=09=09=09(!pat_enabled() || pat_pfn_immune_to_uc_mtrr(pfn)); +=09=09return !pat_enabled() || pat_pfn_immune_to_uc_mtrr(pfn); =20 +=09/* +=09 * Any RAM that has no memmap (e.g., mapped via /dev/mem) is not MMIO. +=09 */ =09return !e820__mapped_raw_any(pfn_to_hpa(pfn), =09=09=09=09 pfn_to_hpa(pfn + 1) - 1, =09=09=09=09 E820_TYPE_RAM); --=20 2.21.0