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=-5.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,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 49437C48BE3 for ; Thu, 20 Jun 2019 13:21:31 +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 2366B206E0 for ; Thu, 20 Jun 2019 13:21:30 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 2366B206E0 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]:47696 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.86_2) (envelope-from ) id 1hdx0M-0004qn-1q for qemu-devel@archiver.kernel.org; Thu, 20 Jun 2019 09:21:30 -0400 Received: from eggs.gnu.org ([209.51.188.92]:51218) by lists.gnu.org with esmtp (Exim 4.86_2) (envelope-from ) id 1hdwxB-0002uC-LA for qemu-devel@nongnu.org; Thu, 20 Jun 2019 09:18:15 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1hdwuq-0004oZ-Uw for qemu-devel@nongnu.org; Thu, 20 Jun 2019 09:15:50 -0400 Received: from mx1.redhat.com ([209.132.183.28]:53750) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1hdwgI-0007or-QD for qemu-devel@nongnu.org; Thu, 20 Jun 2019 09:00:46 -0400 Received: from smtp.corp.redhat.com (int-mx08.intmail.prod.int.phx2.redhat.com [10.5.11.23]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id D66D43001D50; Thu, 20 Jun 2019 13:00:13 +0000 (UTC) Received: from xz-x1 (ovpn-12-68.pek2.redhat.com [10.72.12.68]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 0B92519C4F; Thu, 20 Jun 2019 13:00:00 +0000 (UTC) Date: Thu, 20 Jun 2019 20:59:55 +0800 From: Peter Xu To: Paolo Bonzini Message-ID: <20190620125955.GB9657@xz-x1> References: <1560934185-14152-1-git-send-email-yan.y.zhao@intel.com> <39c4c32b-e34a-8d8f-abbc-ab346ec5bed7@redhat.com> <20190620040230.GB9073@xz-x1> <6829b139-3eab-449e-04d6-07f1e381316d@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <6829b139-3eab-449e-04d6-07f1e381316d@redhat.com> User-Agent: Mutt/1.11.4 (2019-03-13) X-Scanned-By: MIMEDefang 2.84 on 10.5.11.23 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.42]); Thu, 20 Jun 2019 13:00:13 +0000 (UTC) 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] memory: do not do out of bound notification 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: Auger Eric , Yan Zhao , qemu-devel@nongnu.org Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On Thu, Jun 20, 2019 at 10:35:29AM +0200, Paolo Bonzini wrote: > On 20/06/19 06:02, Peter Xu wrote: > > Seems workable, to be explicit - we can even cut it into chunks with > > different size to be efficient. > > Yes, this is not hard (completely untested): > > diff --git a/hw/i386/intel_iommu.c b/hw/i386/intel_iommu.c > index 44b1231157..541538bc6c 100644 > --- a/hw/i386/intel_iommu.c > +++ b/hw/i386/intel_iommu.c > @@ -3388,39 +3388,34 @@ static void vtd_address_space_unmap(VTDAddressSpace *as, IOMMUNotifier *n) > } > > assert(start <= end); > - size = end - start; > + while (end > start) { > + size = end - start; > + /* Only keep the lowest bit of either size or start. */ > + size = MIN(size & -size, start & -start); I feel like this can be problematic. I'm imaging: start=0x1000_0000, size=0x1000_1000 This will get size=0x1000 but actually we can do size=0x1000_0000 as the first. > + /* Should not happen, but limit to address width too just in case */ > + size = MIN(size, 1ULL << s->aw_bits); > > - 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; > - } > + assert((start & (size - 1)) == 0); > > - 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; > + entry.target_as = &address_space_memory; > + entry.iova = start; > + /* This field is meaningless for unmap */ > + entry.translated_addr = 0; > + entry.perm = IOMMU_NONE; > + entry.addr_mask = size - 1; (some of the fields can be moved out of loop because they are constants) > > - trace_vtd_as_unmap_whole(pci_bus_num(as->bus), > - VTD_PCI_SLOT(as->devfn), > - VTD_PCI_FUNC(as->devfn), > - entry.iova, size); > + trace_vtd_as_unmap_whole(pci_bus_num(as->bus), > + VTD_PCI_SLOT(as->devfn), > + VTD_PCI_FUNC(as->devfn), > + entry.iova, size); Can move this out because this is a trace only so we don't have restriction on mask? > > - map.iova = entry.iova; > - map.size = entry.addr_mask; > - iova_tree_remove(as->iova_tree, &map); > + map.iova = entry.iova; > + map.size = entry.addr_mask; > + iova_tree_remove(as->iova_tree, &map); Same here? > > - memory_region_notify_one(n, &entry); > + memory_region_notify_one(n, &entry); > + start += size; > + } > } > > static void vtd_address_space_unmap_all(IntelIOMMUState *s) > > > Yan, > > if something like this works for you, let me know and I will submit it > as a proper patch. > > Paolo Since during review I'm thinking how to generate a correct sequence of these masks... here's my try below with above issues fixed... :) I've tried compile but not tested. Yan can test it, or I can do it too tomorrow after I find some machines. Thanks, ------------------------------------------------------------ diff --git a/hw/i386/intel_iommu.c b/hw/i386/intel_iommu.c index 44b1231157..cfbd225f0a 100644 --- a/hw/i386/intel_iommu.c +++ b/hw/i386/intel_iommu.c @@ -3363,11 +3363,32 @@ 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 +3409,28 @@ static void vtd_address_space_unmap(VTDAddressSpace *as, IOMMUNotifier *n) } assert(start <= end); - size = end - start; - - 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; - } - + size = remain = end - start; entry.target_as = &address_space_memory; - /* Adjust iova for the size */ - entry.iova = n->start & ~(size - 1); + entry.perm = IOMMU_NONE; /* This field is meaningless for unmap */ entry.translated_addr = 0; - entry.perm = IOMMU_NONE; - entry.addr_mask = size - 1; + + while (remain) { + uint64_t mask = vtd_get_next_mask(start, remain, s->aw_bits); + + entry.iova = start; + entry.addr_mask = mask - 1; + memory_region_notify_one(n, &entry); + } 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) ------------------------------------------------------------ Regards, -- Peter Xu