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=-17.2 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED 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 EAAD8C4361A for ; Fri, 4 Dec 2020 08:18:51 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 8CD84224F4 for ; Fri, 4 Dec 2020 08:18:51 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728096AbgLDISu (ORCPT ); Fri, 4 Dec 2020 03:18:50 -0500 Received: from us-smtp-delivery-124.mimecast.com ([216.205.24.124]:23412 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725866AbgLDISu (ORCPT ); Fri, 4 Dec 2020 03:18:50 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1607069843; 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: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=OMu6Ts4aXegHwTfI5K4+wIFUI7ZOjwyzufO+hy2X5v0=; b=htnOy2Y24XjqrC7RQU8BoFsfYIvzB32OXMiASal+Xx6aS7I9BR3o0y7adUWYs2I0I7n1Pv m1H5dkttGWaSv1T28YKFm0KPyvr70a1bbReh4J5RRQS5IAmWlLFsKXvOp28c7mGiTo93e+ vtbrnsn8w4rEfb0013c2zC1cY90ynnQ= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-507-PkCGHXBdOoW3IS7HMSFR1g-1; Fri, 04 Dec 2020 03:17:21 -0500 X-MC-Unique: PkCGHXBdOoW3IS7HMSFR1g-1 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.phx2.redhat.com [10.5.11.16]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id A3581800D53; Fri, 4 Dec 2020 08:17:19 +0000 (UTC) Received: from gondolin (ovpn-113-97.ams2.redhat.com [10.36.113.97]) by smtp.corp.redhat.com (Postfix) with ESMTP id 700395C1CF; Fri, 4 Dec 2020 08:17:09 +0000 (UTC) Date: Fri, 4 Dec 2020 09:17:06 +0100 From: Cornelia Huck To: Christian Borntraeger Cc: David Gibson , pair@us.ibm.com, pbonzini@redhat.com, frankja@linux.ibm.com, brijesh.singh@amd.com, dgilbert@redhat.com, qemu-devel@nongnu.org, Eduardo Habkost , qemu-ppc@nongnu.org, rth@twiddle.net, thuth@redhat.com, berrange@redhat.com, mdroth@linux.vnet.ibm.com, Marcelo Tosatti , "Michael S. Tsirkin" , Marcel Apfelbaum , david@redhat.com, Richard Henderson , kvm@vger.kernel.org, qemu-s390x@nongnu.org, pasic@linux.ibm.com Subject: Re: [for-6.0 v5 12/13] securable guest memory: Alter virtio default properties for protected guests Message-ID: <20201204091706.4432dc1e.cohuck@redhat.com> In-Reply-To: References: <20201204054415.579042-1-david@gibson.dropbear.id.au> <20201204054415.579042-13-david@gibson.dropbear.id.au> Organization: Red Hat GmbH MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-Scanned-By: MIMEDefang 2.79 on 10.5.11.16 Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org On Fri, 4 Dec 2020 09:10:36 +0100 Christian Borntraeger wrote: > On 04.12.20 06:44, David Gibson wrote: > > The default behaviour for virtio devices is not to use the platforms normal > > DMA paths, but instead to use the fact that it's running in a hypervisor > > to directly access guest memory. That doesn't work if the guest's memory > > is protected from hypervisor access, such as with AMD's SEV or POWER's PEF. > > > > So, if a securable guest memory mechanism is enabled, then apply the > > iommu_platform=on option so it will go through normal DMA mechanisms. > > Those will presumably have some way of marking memory as shared with > > the hypervisor or hardware so that DMA will work. > > > > Signed-off-by: David Gibson > > Reviewed-by: Dr. David Alan Gilbert > > --- > > hw/core/machine.c | 13 +++++++++++++ > > 1 file changed, 13 insertions(+) > > > > diff --git a/hw/core/machine.c b/hw/core/machine.c > > index a67a27d03c..d16273d75d 100644 > > --- a/hw/core/machine.c > > +++ b/hw/core/machine.c > > @@ -28,6 +28,8 @@ > > #include "hw/mem/nvdimm.h" > > #include "migration/vmstate.h" > > #include "exec/securable-guest-memory.h" > > +#include "hw/virtio/virtio.h" > > +#include "hw/virtio/virtio-pci.h" > > > > GlobalProperty hw_compat_5_1[] = { > > { "vhost-scsi", "num_queues", "1"}, > > @@ -1169,6 +1171,17 @@ void machine_run_board_init(MachineState *machine) > > * areas. > > */ > > machine_set_mem_merge(OBJECT(machine), false, &error_abort); > > + > > + /* > > + * Virtio devices can't count on directly accessing guest > > + * memory, so they need iommu_platform=on to use normal DMA > > + * mechanisms. That requires also disabling legacy virtio > > + * support for those virtio pci devices which allow it. > > + */ > > + object_register_sugar_prop(TYPE_VIRTIO_PCI, "disable-legacy", > > + "on", true); > > + object_register_sugar_prop(TYPE_VIRTIO_DEVICE, "iommu_platform", > > + "on", false); > > I have not followed all the history (sorry). Should we also set iommu_platform > for virtio-ccw? Halil? > That line should add iommu_platform for all virtio devices, shouldn't it?