From nobody Wed Nov 5 18:32:10 2025 Delivered-To: importer@patchew.org Received-SPF: pass (zoho.com: domain of gnu.org designates 208.118.235.17 as permitted sender) client-ip=208.118.235.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Authentication-Results: mx.zohomail.com; spf=pass (zoho.com: domain of gnu.org designates 208.118.235.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org; dmarc=fail(p=none dis=none) header.from=redhat.com Return-Path: Received: from lists.gnu.org (208.118.235.17 [208.118.235.17]) by mx.zohomail.com with SMTPS id 1536825410838633.648529610658; Thu, 13 Sep 2018 00:56:50 -0700 (PDT) Received: from localhost ([::1]:40985 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1g0MUT-0007Io-1H for importer@patchew.org; Thu, 13 Sep 2018 03:56:41 -0400 Received: from eggs.gnu.org ([2001:4830:134:3::10]:60401) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1g0MTT-0006uU-Ib for qemu-devel@nongnu.org; Thu, 13 Sep 2018 03:55:40 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1g0MTQ-0003ot-CD for qemu-devel@nongnu.org; Thu, 13 Sep 2018 03:55:39 -0400 Received: from mx1.redhat.com ([209.132.183.28]:33534) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1g0MTQ-0003nu-36; Thu, 13 Sep 2018 03:55:36 -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 7EE5330832C8; Thu, 13 Sep 2018 07:55:34 +0000 (UTC) Received: from xz-x1.redhat.com (ovpn-12-49.pek2.redhat.com [10.72.12.49]) by smtp.corp.redhat.com (Postfix) with ESMTP id BC5F45D6AA; Thu, 13 Sep 2018 07:55:18 +0000 (UTC) From: Peter Xu To: qemu-devel@nongnu.org Date: Thu, 13 Sep 2018 15:55:17 +0800 Message-Id: <20180913075517.11140-1-peterx@redhat.com> 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 [10.5.110.44]); Thu, 13 Sep 2018 07:55:34 +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: [Qemu-devel] [PATCH] intel_iommu: handle invalid ce for shadow sync X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: "Michael S . Tsirkin" , Jason Wang , Alex Williamson , peterx@redhat.com, QEMU Stable , Maxime Coquelin , Pei Zhang Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: "Qemu-devel" X-ZohoMail: RDMRC_1 RSF_0 Z_629925259 SPT_0 Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" There are two callers for vtd_sync_shadow_page_table_range(), one provided a valid context entry and one not. Move that fetching operation into the caller vtd_sync_shadow_page_table() where we need to fetch the context entry. Meanwhile, we should handle VTD_FR_CONTEXT_ENTRY_P properly when synchronizing shadow page tables. Having invalid context entry there is perfectly valid when we move a device out of an existing domain. When that happens, instead of posting an error we invalidate the whole region. Without this patch, QEMU will crash if we do these steps: (1) start QEMU with VT-d IOMMU and two 10G NICs (ixgbe) (2) bind the NICs with vfio-pci in the guest (3) start testpmd with the NICs applied (4) stop testpmd (5) rebind the NIC back to ixgbe kernel driver The patch should fix it. Reported-by: Pei Zhang Tested-by: Pei Zhang CC: Pei Zhang CC: Alex Williamson CC: Jason Wang CC: Maxime Coquelin CC: Michael S. Tsirkin CC: QEMU Stable Fixes: https://bugzilla.redhat.com/show_bug.cgi?id=3D1627272 Signed-off-by: Peter Xu Acked-by: Maxime Coquelin Reviewed-by: Jason Wang --- hw/i386/intel_iommu.c | 54 ++++++++++++++++++++++++++----------------- 1 file changed, 33 insertions(+), 21 deletions(-) diff --git a/hw/i386/intel_iommu.c b/hw/i386/intel_iommu.c index 3dfada19a6..2509520d6f 100644 --- a/hw/i386/intel_iommu.c +++ b/hw/i386/intel_iommu.c @@ -37,6 +37,8 @@ #include "kvm_i386.h" #include "trace.h" =20 +static void vtd_address_space_unmap(VTDAddressSpace *as, IOMMUNotifier *n); + static void vtd_define_quad(IntelIOMMUState *s, hwaddr addr, uint64_t val, uint64_t wmask, uint64_t w1cmask) { @@ -1047,39 +1049,49 @@ static int vtd_sync_shadow_page_table_range(VTDAddr= essSpace *vtd_as, .notify_unmap =3D true, .aw =3D s->aw_bits, .as =3D vtd_as, + .domain_id =3D VTD_CONTEXT_ENTRY_DID(ce->hi), }; - VTDContextEntry ce_cache; + + return vtd_page_walk(ce, addr, addr + size, &info); +} + +static int vtd_sync_shadow_page_table(VTDAddressSpace *vtd_as) +{ int ret; + VTDContextEntry ce; + IOMMUNotifier *n; =20 - if (ce) { - /* If the caller provided context entry, use it */ - ce_cache =3D *ce; - } else { - /* If the caller didn't provide ce, try to fetch */ - ret =3D vtd_dev_to_context_entry(s, pci_bus_num(vtd_as->bus), - vtd_as->devfn, &ce_cache); - if (ret) { + ret =3D vtd_dev_to_context_entry(vtd_as->iommu_state, + pci_bus_num(vtd_as->bus), + vtd_as->devfn, &ce); + if (ret) { + if (ret =3D=3D -VTD_FR_CONTEXT_ENTRY_P) { + /* + * It's a valid scenario to have a context entry that is + * not present. For example, when a device is removed + * from an existing domain then the context entry will be + * zeroed by the guest before it was put into another + * domain. When this happens, instead of synchronizing + * the shadow pages we should invalidate all existing + * mappings and notify the backends. + */ + IOMMU_NOTIFIER_FOREACH(n, &vtd_as->iommu) { + vtd_address_space_unmap(vtd_as, n); + } + } else { /* * This should not really happen, but in case it happens, * we just skip the sync for this time. After all we even * don't have the root table pointer! */ error_report_once("%s: invalid context entry for bus 0x%x" - " devfn 0x%x", - __func__, pci_bus_num(vtd_as->bus), - vtd_as->devfn); - return 0; + " devfn 0x%x", __func__, + pci_bus_num(vtd_as->bus), vtd_as->devfn); } + return 0; } =20 - info.domain_id =3D VTD_CONTEXT_ENTRY_DID(ce_cache.hi); - - return vtd_page_walk(&ce_cache, addr, addr + size, &info); -} - -static int vtd_sync_shadow_page_table(VTDAddressSpace *vtd_as) -{ - return vtd_sync_shadow_page_table_range(vtd_as, NULL, 0, UINT64_MAX); + return vtd_sync_shadow_page_table_range(vtd_as, &ce, 0, UINT64_MAX); } =20 /* --=20 2.17.1