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=-8.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, USER_AGENT_MUTT 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 8791FC43613 for ; Mon, 24 Jun 2019 08:31:26 +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 9ABA22089F for ; Mon, 24 Jun 2019 08:31:25 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 9ABA22089F Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=intel.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:48756 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.86_2) (envelope-from ) id 1hfKNo-0001WX-Ui for qemu-devel@archiver.kernel.org; Mon, 24 Jun 2019 04:31:24 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:39612) by lists.gnu.org with esmtp (Exim 4.86_2) (envelope-from ) id 1hfKMq-00014l-EF for qemu-devel@nongnu.org; Mon, 24 Jun 2019 04:30:25 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1hfKMp-0001es-1T for qemu-devel@nongnu.org; Mon, 24 Jun 2019 04:30:24 -0400 Received: from mga18.intel.com ([134.134.136.126]:1121) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1hfKMo-0001ab-OE for qemu-devel@nongnu.org; Mon, 24 Jun 2019 04:30:22 -0400 X-Amp-Result: UNKNOWN X-Amp-Original-Verdict: FILE UNKNOWN X-Amp-File-Uploaded: False Received: from fmsmga008.fm.intel.com ([10.253.24.58]) by orsmga106.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 24 Jun 2019 01:28:16 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.63,411,1557212400"; d="scan'208";a="161558728" Received: from joy-optiplex-7040.sh.intel.com (HELO joy-OptiPlex-7040) ([10.239.13.9]) by fmsmga008.fm.intel.com with ESMTP; 24 Jun 2019 01:28:14 -0700 Date: Mon, 24 Jun 2019 04:22:21 -0400 From: Yan Zhao To: Peter Xu Message-ID: <20190624082221.GE27894@joy-OptiPlex-7040> References: <20190624063733.22079-1-peterx@redhat.com> <20190624063733.22079-3-peterx@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190624063733.22079-3-peterx@redhat.com> User-Agent: Mutt/1.9.4 (2018-02-28) X-detected-operating-system: by eggs.gnu.org: Genre and OS details not recognized. X-Received-From: 134.134.136.126 Subject: Re: [Qemu-devel] [PATCH 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: , Reply-To: Yan Zhao Cc: Paolo Bonzini , Jason Wang , "Michael S . Tsirkin" , "qemu-devel@nongnu.org" , Auger Eric Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" Tested-by: Yan Zhao On Mon, Jun 24, 2019 at 02:37:33PM +0800, Peter Xu wrote: > From: Paolo Bonzini > > 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. 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: Paolo Bonzini > [peterx: fixup mask generation algos and other touchups, introduce > vtd_get_next_mask(), write commit message] > Signed-off-by: Peter Xu > --- > hw/i386/intel_iommu.c | 70 +++++++++++++++++++++++++++---------------- > 1 file changed, 44 insertions(+), 26 deletions(-) > > diff --git a/hw/i386/intel_iommu.c b/hw/i386/intel_iommu.c > index 719ce19ab3..39cedf73b8 100644 > --- a/hw/i386/intel_iommu.c > +++ b/hw/i386/intel_iommu.c > @@ -3363,11 +3363,31 @@ VTDAddressSpace *vtd_find_add_as(IntelIOMMUState *s, PCIBus *bus, int devfn) > return vtd_dev_as; > } > > +static uint64_t vtd_get_next_mask(uint64_t start, uint64_t size, int gaw) > +{ > + /* Tries to find smallest mask from start first */ > + uint64_t rmask = start & -start, max_mask = 1ULL << gaw; > + > + assert(size && gaw > 0 && gaw < 64); > + > + /* Zero start, or too big */ > + if (!rmask || rmask > max_mask) { > + rmask = max_mask; > + } > + > + /* If the start mask worked, then use it */ > + if (rmask <= size) { > + return rmask; > + } > + > + /* 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, IOMMUNotifier *n) > { > - IOMMUTLBEntry entry; > - hwaddr size; > + hwaddr size, remain; > hwaddr start = n->start; > hwaddr end = n->end; > IntelIOMMUState *s = as->iommu_state; > @@ -3388,39 +3408,37 @@ static void vtd_address_space_unmap(VTDAddressSpace *as, IOMMUNotifier *n) > } > > assert(start <= end); > - size = end - start; > + size = remain = end - start + 1; > > - if (ctpop64(size) != 1) { > - /* > - * This size cannot format a correct mask. Let's enlarge it to > - * suite the minimum available mask. > - */ > - int n = 64 - clz64(size); > - if (n > s->aw_bits) { > - /* should not happen, but in case it happens, limit it */ > - n = s->aw_bits; > - } > - size = 1ULL << n; > + while (remain > 0) { > + IOMMUTLBEntry entry; > + uint64_t mask = vtd_get_next_mask(start, remain, s->aw_bits); > + > + assert(mask); > + > + entry.iova = start; > + entry.addr_mask = mask - 1; > + entry.target_as = &address_space_memory; > + entry.perm = IOMMU_NONE; > + /* This field is meaningless for unmap */ > + entry.translated_addr = 0; > + > + memory_region_notify_one(n, &entry); > + > + start += mask; > + remain -= mask; > } > > - entry.target_as = &address_space_memory; > - /* Adjust iova for the size */ > - entry.iova = n->start & ~(size - 1); > - /* This field is meaningless for unmap */ > - entry.translated_addr = 0; > - entry.perm = IOMMU_NONE; > - entry.addr_mask = size - 1; > + assert(!remain); > > 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); > > - map.iova = entry.iova; > - map.size = entry.addr_mask; > + map.iova = n->start; > + map.size = size; > iova_tree_remove(as->iova_tree, &map); > - > - memory_region_notify_one(n, &entry); > } > > static void vtd_address_space_unmap_all(IntelIOMMUState *s) > -- > 2.21.0 >