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 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 smtp.lore.kernel.org (Postfix) with ESMTPS id 2C123C433FE for ; Wed, 30 Nov 2022 06:34:54 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1p0Gfc-0005LZ-UW; Wed, 30 Nov 2022 01:34:12 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1p0Gfb-0005LR-O8 for qemu-devel@nongnu.org; Wed, 30 Nov 2022 01:34:11 -0500 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1p0GfZ-00066v-ON for qemu-devel@nongnu.org; Wed, 30 Nov 2022 01:34:11 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1669790048; 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: in-reply-to:in-reply-to:references:references; bh=+Hw2IEQx9K/iF4Uz9AYZJVM7MO1s5cgLR2Vxhe2CclQ=; b=LV3Z72aWMotcQyWgQn/8S8/6fmJz+fsewUXy6R61XT5taY4DwvxBe82Va+QkZ0K09F5VGc AOX+kLlNuYdRN5rtXCkaeC16A2G+TIUcEWJe19UbMfLmFVQNTp2sQ8T/aohheYQtz2KPZO 5SrIvD7qwl2L3CZA4ipkRUayUHn9lqQ= Received: from mail-ot1-f69.google.com (mail-ot1-f69.google.com [209.85.210.69]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_128_GCM_SHA256) id us-mta-516-grcOnm9RP3-lvY1LePAEDg-1; Wed, 30 Nov 2022 01:34:03 -0500 X-MC-Unique: grcOnm9RP3-lvY1LePAEDg-1 Received: by mail-ot1-f69.google.com with SMTP id cp19-20020a056830661300b0066e6c22eb3cso96937otb.0 for ; Tue, 29 Nov 2022 22:34:03 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=cc:to:subject:message-id:date:from:in-reply-to:references :mime-version:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=+Hw2IEQx9K/iF4Uz9AYZJVM7MO1s5cgLR2Vxhe2CclQ=; b=aTI204CUCdWMf5vOBytLrZ25NPwaU9q1CvPAFeuxurZPi8z/kmZ9uu0Jw+gw/BZgBn s15N2amIUF9ScCiLo8PPWRnA0PXRcQcbQLSqsFUiMNd2VUs0ENvab0g+4zNWmOMUQ3uK uWjUnHr2ZMeryJmWjgp+wOKyjVEt6F1mhpc0qIhWZgq4vZD1fBjKv4rWu57YpRIDdZur hgqoXP01OBrCFVmN/grViTlozLkGlHzVEGFH37HXEWKxllUj2Jj6vaxcAe67il6ImfA7 II5Nn/KCz6IOyT2Nuu2tcOAaY/OJmU42F0XPfzOfWt2y+axU5oIb7d/9r2tdMzNdpj1b HkZA== X-Gm-Message-State: ANoB5pmkorXvS3FZVss13YHzxWOOLZ2raasAR9oiOKVW+SSZUFFNnC9U f+Prw/VmZMzwXuWKRA0MBvsrfSOcHXX3qhCAnihDDEXXkwKk6qSCmuXMiCDd99P5ZykeIxJhCz2 z+OyCvhYNnPnv+tTPfcXMYCPxwylp4gs= X-Received: by 2002:a05:6870:1e83:b0:132:7b3:29ac with SMTP id pb3-20020a0568701e8300b0013207b329acmr22903676oab.35.1669790042927; Tue, 29 Nov 2022 22:34:02 -0800 (PST) X-Google-Smtp-Source: AA0mqf7R/086HJx2QI2HyK0WSBSn0utIvZ5VK6ZMJICiPyUzFk2avDy/hcFGGqLXLYhV9FqMmuzdH3XD6j84irFbMTo= X-Received: by 2002:a05:6870:1e83:b0:132:7b3:29ac with SMTP id pb3-20020a0568701e8300b0013207b329acmr22903666oab.35.1669790042706; Tue, 29 Nov 2022 22:34:02 -0800 (PST) MIME-Version: 1.0 References: <20221129081037.12099-1-jasowang@redhat.com> <20221129081037.12099-4-jasowang@redhat.com> In-Reply-To: From: Jason Wang Date: Wed, 30 Nov 2022 14:33:51 +0800 Message-ID: Subject: Re: [PATCH 3/3] intel-iommu: build iova tree during IOMMU translation To: Peter Xu Cc: mst@redhat.com, qemu-devel@nongnu.org, eric.auger@redhat.com, viktor@daynix.com Content-Type: text/plain; charset="UTF-8" Received-SPF: pass client-ip=170.10.133.124; envelope-from=jasowang@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.001, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H2=-0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org On Tue, Nov 29, 2022 at 11:57 PM Peter Xu wrote: > > On Tue, Nov 29, 2022 at 04:10:37PM +0800, Jason Wang wrote: > > The IOVA tree is only built during page walk this breaks the device > > that tries to use UNMAP notifier only. One example is vhost-net, it > > tries to use UNMAP notifier when vIOMMU doesn't support DEVIOTLB_UNMAP > > notifier (e.g when dt mode is not enabled). The interesting part is > > that it doesn't use MAP since it can query the IOMMU translation by > > itself upon a IOTLB miss. > > > > This doesn't work since Qemu doesn't build IOVA tree in IOMMU > > translation which means the UNMAP notifier won't be triggered during > > the page walk since Qemu think it is never mapped. This could be > > noticed when vIOMMU is used with vhost_net but dt is disabled. > > > > Fixing this by build the iova tree during IOMMU translation, this > > makes sure the UNMAP notifier event could be identified during page > > walk. And we need to walk page table not only for UNMAP notifier but > > for MAP notifier during PSI. > > > > Signed-off-by: Jason Wang > > --- > > hw/i386/intel_iommu.c | 43 ++++++++++++++++++------------------------- > > 1 file changed, 18 insertions(+), 25 deletions(-) > > > > diff --git a/hw/i386/intel_iommu.c b/hw/i386/intel_iommu.c > > index d025ef2873..edeb62f4b2 100644 > > --- a/hw/i386/intel_iommu.c > > +++ b/hw/i386/intel_iommu.c > > @@ -1834,6 +1834,8 @@ static bool vtd_do_iommu_translate(VTDAddressSpace *vtd_as, PCIBus *bus, > > uint8_t access_flags; > > bool rid2pasid = (pasid == PCI_NO_PASID) && s->root_scalable; > > VTDIOTLBEntry *iotlb_entry; > > + const DMAMap *mapped; > > + DMAMap target; > > > > /* > > * We have standalone memory region for interrupt addresses, we > > @@ -1954,6 +1956,21 @@ out: > > entry->translated_addr = vtd_get_slpte_addr(slpte, s->aw_bits) & page_mask; > > entry->addr_mask = ~page_mask; > > entry->perm = access_flags; > > + > > + target.iova = entry->iova; > > + target.size = entry->addr_mask; > > + target.translated_addr = entry->translated_addr; > > + target.perm = entry->perm; > > + > > + mapped = iova_tree_find(vtd_as->iova_tree, &target); > > + if (!mapped) { > > + /* To make UNMAP notifier work, we need build iova tree here > > + * in order to have the UNMAP iommu notifier to be triggered > > + * during the page walk. > > + */ > > + iova_tree_insert(vtd_as->iova_tree, &target); > > + } > > + > > return true; > > > > error: > > @@ -2161,31 +2178,7 @@ static void vtd_iotlb_page_invalidate_notify(IntelIOMMUState *s, > > ret = vtd_dev_to_context_entry(s, pci_bus_num(vtd_as->bus), > > vtd_as->devfn, &ce); > > if (!ret && domain_id == vtd_get_domain_id(s, &ce, vtd_as->pasid)) { > > - if (vtd_as_has_map_notifier(vtd_as)) { > > - /* > > - * As long as we have MAP notifications registered in > > - * any of our IOMMU notifiers, we need to sync the > > - * shadow page table. > > - */ > > - vtd_sync_shadow_page_table_range(vtd_as, &ce, addr, size); > > - } else { > > - /* > > - * For UNMAP-only notifiers, we don't need to walk the > > - * page tables. We just deliver the PSI down to > > - * invalidate caches. > > - */ > > - IOMMUTLBEvent event = { > > - .type = IOMMU_NOTIFIER_UNMAP, > > - .entry = { > > - .target_as = &address_space_memory, > > - .iova = addr, > > - .translated_addr = 0, > > - .addr_mask = size - 1, > > - .perm = IOMMU_NONE, > > - }, > > - }; > > - memory_region_notify_iommu(&vtd_as->iommu, 0, event); > > Isn't this path the one that will be responsible for pass-through the UNMAP > events from guest to vhost when there's no MAP notifier requested? Yes, but it doesn't do the iova tree removing. More below. > > At least that's what I expected when introducing the iova tree, because for > unmap-only device hierachy I thought we didn't need the tree at all. Then the problem is the UNMAP notifier won't be trigger at all during DSI page walk in vtd_page_walk_one() because there's no DMAMap stored in the iova tree.: if (!mapped) { /* Skip since we didn't map this range at all */ trace_vtd_page_walk_one_skip_unmap(entry->iova, entry->addr_mask); return 0; } So I choose to build the iova tree in translate then we won't go within the above condition. Thanks > > Jason, do you know where I miss? > > Thanks, > > > - } > > + vtd_sync_shadow_page_table_range(vtd_as, &ce, addr, size); > > } > > } > > } > > -- > > 2.25.1 > > > > -- > Peter Xu >