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=-18.7 required=3.0 tests=BAYES_00,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, USER_AGENT_GIT 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 CB85BC4361B for ; Fri, 4 Dec 2020 05:46:11 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 98B81224BE for ; Fri, 4 Dec 2020 05:46:11 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728260AbgLDFpo (ORCPT ); Fri, 4 Dec 2020 00:45:44 -0500 Received: from ozlabs.org ([203.11.71.1]:38533 "EHLO ozlabs.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728191AbgLDFpn (ORCPT ); Fri, 4 Dec 2020 00:45:43 -0500 Received: by ozlabs.org (Postfix, from userid 1007) id 4CnM8j2ctRz9sWD; Fri, 4 Dec 2020 16:44:21 +1100 (AEDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=gibson.dropbear.id.au; s=201602; t=1607060661; bh=VJ+LxQJOkUVbhfEUmAX9VA/bXYtOMYSQX40lQmDmveM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=n/hPt3e/EfOiifh/tLDcORyx4cp37QBDhJC+dZIUX84hluIDTzl9WSZvn2hpjXPci iutHioNHKh8PvMKfetFpm85FIdF3HrtE9XlCKmt8JHPB0ePHauUOLRQyH6eq8Y1d0P K3T3aL3fPzr4KyCGKJ9rj8SPkzOU8TG8bRBuz+E0= From: David Gibson To: pair@us.ibm.com, pbonzini@redhat.com, frankja@linux.ibm.com, brijesh.singh@amd.com, dgilbert@redhat.com, qemu-devel@nongnu.org Cc: 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 , borntraeger@de.ibm.com, David Gibson , cohuck@redhat.com, kvm@vger.kernel.org, qemu-s390x@nongnu.org, pasic@linux.ibm.com Subject: [for-6.0 v5 12/13] securable guest memory: Alter virtio default properties for protected guests Date: Fri, 4 Dec 2020 16:44:14 +1100 Message-Id: <20201204054415.579042-13-david@gibson.dropbear.id.au> X-Mailer: git-send-email 2.28.0 In-Reply-To: <20201204054415.579042-1-david@gibson.dropbear.id.au> References: <20201204054415.579042-1-david@gibson.dropbear.id.au> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org 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); } machine_class->init(machine); -- 2.28.0