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 CA3C1C43613 for ; Thu, 20 Jun 2019 13:36:03 +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 A2AE12064A for ; Thu, 20 Jun 2019 13:36:02 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org A2AE12064A 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]:47812 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.86_2) (envelope-from ) id 1hdxEQ-0008Pj-2X for qemu-devel@archiver.kernel.org; Thu, 20 Jun 2019 09:36:02 -0400 Received: from eggs.gnu.org ([209.51.188.92]:51285) by lists.gnu.org with esmtp (Exim 4.86_2) (envelope-from ) id 1hdwxe-0002ux-AD for qemu-devel@nongnu.org; Thu, 20 Jun 2019 09:18:44 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1hdwkR-0000gG-P7 for qemu-devel@nongnu.org; Thu, 20 Jun 2019 09:06:55 -0400 Received: from mx1.redhat.com ([209.132.183.28]:38096) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1hdwkR-0000ff-Fy for qemu-devel@nongnu.org; Thu, 20 Jun 2019 09:05:03 -0400 Received: from smtp.corp.redhat.com (int-mx07.intmail.prod.int.phx2.redhat.com [10.5.11.22]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id D4EFC30BDE4B; Thu, 20 Jun 2019 13:04:55 +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 2EB041001DD1; Thu, 20 Jun 2019 13:04:47 +0000 (UTC) Date: Thu, 20 Jun 2019 21:04:43 +0800 From: Peter Xu To: Paolo Bonzini Message-ID: <20190620130443.GC9657@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> <20190620125955.GB9657@xz-x1> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20190620125955.GB9657@xz-x1> User-Agent: Mutt/1.11.4 (2019-03-13) X-Scanned-By: MIMEDefang 2.84 on 10.5.11.22 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.40]); Thu, 20 Jun 2019 13:05:01 +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 08:59:55PM +0800, Peter Xu wrote: > 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); Sorry, I at least missed these lines: start += mask; remain -= mask; > + } > > 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 Regards, -- Peter Xu