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=-8.5 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_SANE_1 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 B1DA4C0650E for ; Thu, 4 Jul 2019 05:50:59 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 89C6921882 for ; Thu, 4 Jul 2019 05:50:59 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 89C6921882 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:42970 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.86_2) (envelope-from ) id 1hiue2-00035t-Fs for qemu-devel@archiver.kernel.org; Thu, 04 Jul 2019 01:50:58 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:36232) by lists.gnu.org with esmtp (Exim 4.86_2) (envelope-from ) id 1hiuZI-0001aX-Mm for qemu-devel@nongnu.org; Thu, 04 Jul 2019 01:46:06 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1hiuZG-0000cv-Fy for qemu-devel@nongnu.org; Thu, 04 Jul 2019 01:46:04 -0400 Received: from mx1.redhat.com ([209.132.183.28]:41082) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1hiuZE-0000Xd-Do for qemu-devel@nongnu.org; Thu, 04 Jul 2019 01:46:02 -0400 Received: from smtp.corp.redhat.com (int-mx05.intmail.prod.int.phx2.redhat.com [10.5.11.15]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 3E26181DE0; Thu, 4 Jul 2019 05:45:56 +0000 (UTC) Received: from [10.72.12.202] (ovpn-12-202.pek2.redhat.com [10.72.12.202]) by smtp.corp.redhat.com (Postfix) with ESMTP id A88A71758A; Thu, 4 Jul 2019 05:45:43 +0000 (UTC) To: Peter Xu , qemu-devel@nongnu.org References: <20190624091811.30412-1-peterx@redhat.com> <20190624091811.30412-3-peterx@redhat.com> From: Jason Wang Message-ID: Date: Thu, 4 Jul 2019 13:45:41 +0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.7.2 MIME-Version: 1.0 In-Reply-To: <20190624091811.30412-3-peterx@redhat.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US X-Scanned-By: MIMEDefang 2.79 on 10.5.11.15 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.25]); Thu, 04 Jul 2019 05:45:56 +0000 (UTC) Content-Transfer-Encoding: quoted-printable X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 209.132.183.28 Subject: Re: [Qemu-devel] [PATCH v2 2/2] intel_iommu: Fix unexpected unmaps during global unmap X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Paolo Bonzini , Yan Zhao , Auger Eric , "Michael S . Tsirkin" Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On 2019/6/24 =E4=B8=8B=E5=8D=885:18, Peter Xu wrote: > This is an replacement work of Yan Zhao's patch: > > https://www.mail-archive.com/qemu-devel@nongnu.org/msg625340.html > > vtd_address_space_unmap() will do proper page mask alignment to make > sure each IOTLB message will have correct masks for notification > messages (2^N-1), but sometimes it can be expanded to even supercede > the registered range. I wonder under what circumstance that could we meet this? Thanks > That could lead to unexpected UNMAP of already > mapped regions in some other notifiers. > > Instead of doing mindless expension of the start address and address > mask, we split the range into smaller ones and guarantee that each > small range will have correct masks (2^N-1) and at the same time we > should also try our best to generate as less IOTLB messages as > possible. > > Reported-by: Yan Zhao > Signed-off-by: Peter Xu > --- > hw/i386/intel_iommu.c | 67 ++++++++++++++++++++++++++----------------= - > 1 file changed, 41 insertions(+), 26 deletions(-) > > diff --git a/hw/i386/intel_iommu.c b/hw/i386/intel_iommu.c > index 719ce19ab3..de86f53b4e 100644 > --- a/hw/i386/intel_iommu.c > +++ b/hw/i386/intel_iommu.c > @@ -3363,11 +3363,28 @@ VTDAddressSpace *vtd_find_add_as(IntelIOMMUStat= e *s, PCIBus *bus, int devfn) > return vtd_dev_as; > } > =20 > +static uint64_t get_naturally_aligned_size(uint64_t start, > + uint64_t size, int gaw) > +{ > + uint64_t max_mask =3D 1ULL << gaw; > + uint64_t alignment =3D start ? start & -start : max_mask; > + > + alignment =3D MIN(alignment, max_mask); > + size =3D MIN(size, max_mask); > + > + if (alignment <=3D size) { > + /* Increase the alignment of start */ > + return alignment; > + } else { > + /* Find the largest page mask from size */ > + return 1ULL << (63 - clz64(size)); > + } > +} > + > /* Unmap the whole range in the notifier's scope. */ > static void vtd_address_space_unmap(VTDAddressSpace *as, IOMMUNotifie= r *n) > { > - IOMMUTLBEntry entry; > - hwaddr size; > + hwaddr size, remain; > hwaddr start =3D n->start; > hwaddr end =3D n->end; > IntelIOMMUState *s =3D as->iommu_state; > @@ -3388,39 +3405,37 @@ static void vtd_address_space_unmap(VTDAddressS= pace *as, IOMMUNotifier *n) > } > =20 > assert(start <=3D end); > - size =3D end - start; > + size =3D remain =3D end - start + 1; > =20 > - if (ctpop64(size) !=3D 1) { > - /* > - * This size cannot format a correct mask. Let's enlarge it to > - * suite the minimum available mask. > - */ > - int n =3D 64 - clz64(size); > - if (n > s->aw_bits) { > - /* should not happen, but in case it happens, limit it */ > - n =3D s->aw_bits; > - } > - size =3D 1ULL << n; > + while (remain >=3D VTD_PAGE_SIZE) { > + IOMMUTLBEntry entry; > + uint64_t mask =3D get_naturally_aligned_size(start, remain, s-= >aw_bits); > + > + assert(mask); > + > + entry.iova =3D start; > + entry.addr_mask =3D mask - 1; > + entry.target_as =3D &address_space_memory; > + entry.perm =3D IOMMU_NONE; > + /* This field is meaningless for unmap */ > + entry.translated_addr =3D 0; > + > + memory_region_notify_one(n, &entry); > + > + start +=3D mask; > + remain -=3D mask; > } > =20 > - entry.target_as =3D &address_space_memory; > - /* Adjust iova for the size */ > - entry.iova =3D n->start & ~(size - 1); > - /* This field is meaningless for unmap */ > - entry.translated_addr =3D 0; > - entry.perm =3D IOMMU_NONE; > - entry.addr_mask =3D size - 1; > + assert(!remain); > =20 > trace_vtd_as_unmap_whole(pci_bus_num(as->bus), > VTD_PCI_SLOT(as->devfn), > VTD_PCI_FUNC(as->devfn), > - entry.iova, size); > + n->start, size); > =20 > - map.iova =3D entry.iova; > - map.size =3D entry.addr_mask; > + map.iova =3D n->start; > + map.size =3D size; > iova_tree_remove(as->iova_tree, &map); > - > - memory_region_notify_one(n, &entry); > } > =20 > static void vtd_address_space_unmap_all(IntelIOMMUState *s)