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=-6.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS 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 6FC69C3A59F for ; Thu, 29 Aug 2019 18:18:46 +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 451A72173E for ; Thu, 29 Aug 2019 18:18:46 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 451A72173E 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]:53218 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1i3P0N-0006an-Lf for qemu-devel@archiver.kernel.org; Thu, 29 Aug 2019 14:18:44 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:42826) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1i3Owx-0004qb-W9 for qemu-devel@nongnu.org; Thu, 29 Aug 2019 14:15:12 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1i3Owv-0005Vz-Qf for qemu-devel@nongnu.org; Thu, 29 Aug 2019 14:15:11 -0400 Received: from mx1.redhat.com ([209.132.183.28]:58354) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1i3Owo-0005Qc-6h; Thu, 29 Aug 2019 14:15:03 -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 E1894807063; Thu, 29 Aug 2019 18:15:00 +0000 (UTC) Received: from x1.home (ovpn-118-102.phx2.redhat.com [10.3.118.102]) by smtp.corp.redhat.com (Postfix) with ESMTP id 04EE452C8; Thu, 29 Aug 2019 18:14:49 +0000 (UTC) Date: Thu, 29 Aug 2019 12:14:49 -0600 From: Alex Williamson To: Eric Auger Message-ID: <20190829121449.5c42073e@x1.home> In-Reply-To: <20190829090141.21821-3-eric.auger@redhat.com> References: <20190829090141.21821-1-eric.auger@redhat.com> <20190829090141.21821-3-eric.auger@redhat.com> Organization: Red Hat MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-Scanned-By: MIMEDefang 2.84 on 10.5.11.23 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.6.2 (mx1.redhat.com [10.5.110.67]); Thu, 29 Aug 2019 18:15:00 +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 v5 2/2] hw/vfio/common: Fail on VFIO/HW nested paging detection 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: peter.maydell@linaro.org, aik@ozlabs.ru, qemu-devel@nongnu.org, peterx@redhat.com, qemu-arm@nongnu.org, pbonzini@redhat.com, eric.auger.pro@gmail.com Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On Thu, 29 Aug 2019 11:01:41 +0200 Eric Auger wrote: > As of today, VFIO only works along with vIOMMU supporting > caching mode. The SMMUv3 does not support this mode and > requires HW nested paging to work properly with VFIO. > > So any attempt to run a VFIO device protected by such IOMMU > would prevent the assigned device from working and at the > moment the guest does not even boot as the default > memory_region_iommu_replay() implementation attempts to > translate the whole address space and completely stalls > the guest. Why doesn't this stall an x86 guest? I'm a bit confused about what this provides versus the flag_changed notifier looking for IOMMU_NOTIFIER_MAP, which AIUI is the common deficiency between VT-d w/o caching-mode and SMMUv3 w/o nested mode. The iommu notifier is registered prior to calling iommu_replay, so it seems we already have an opportunity to do something there. Help me understand why this is needed. Thanks, Alex > > So let's fail on that case. > > Signed-off-by: Eric Auger > > --- > > v3 -> v4: > - use IOMMU_ATTR_HW_NESTED_PAGING > - do not abort anymore but jump to fail > --- > hw/vfio/common.c | 10 ++++++++++ > 1 file changed, 10 insertions(+) > > diff --git a/hw/vfio/common.c b/hw/vfio/common.c > index 3e03c495d8..e8c009d019 100644 > --- a/hw/vfio/common.c > +++ b/hw/vfio/common.c > @@ -606,9 +606,19 @@ static void vfio_listener_region_add(MemoryListener *listener, > if (memory_region_is_iommu(section->mr)) { > VFIOGuestIOMMU *giommu; > IOMMUMemoryRegion *iommu_mr = IOMMU_MEMORY_REGION(section->mr); > + bool nested; > int iommu_idx; > > trace_vfio_listener_region_add_iommu(iova, end); > + > + if (!memory_region_iommu_get_attr(iommu_mr, > + IOMMU_ATTR_NEED_HW_NESTED_PAGING, > + (void *)&nested) && nested) { > + error_report("VFIO/vIOMMU integration based on HW nested paging " > + "is not yet supported"); > + ret = -EINVAL; > + goto fail; > + } > /* > * FIXME: For VFIO iommu types which have KVM acceleration to > * avoid bouncing all map/unmaps through qemu this way, this