From patchwork Mon Feb 8 06:05:37 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: David Gibson X-Patchwork-Id: 12073999 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=-18.8 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 68C84C433E0 for ; Mon, 8 Feb 2021 06:07:25 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 37BF564E27 for ; Mon, 8 Feb 2021 06:07:25 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229756AbhBHGHV (ORCPT ); Mon, 8 Feb 2021 01:07:21 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:47592 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229745AbhBHGHN (ORCPT ); Mon, 8 Feb 2021 01:07:13 -0500 Received: from ozlabs.org (ozlabs.org [IPv6:2401:3900:2:1::2]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 2EC99C06178B for ; Sun, 7 Feb 2021 22:05:56 -0800 (PST) Received: by ozlabs.org (Postfix, from userid 1007) id 4DYwVt2mp3z9sWQ; Mon, 8 Feb 2021 17:05:42 +1100 (AEDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=gibson.dropbear.id.au; s=201602; t=1612764342; bh=rGrCUIDaja9zftftkqQIdjL/kYsYIfZR7xVO077v4wc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=AnWxRqvviaZUD7kIPhNWbtRxAjt3/WWEuf/bycf9gmjR+im/2Q/fmjha6oBz3eFKH jXrnF5HF1pYPnGWacmtFIbn5ZPDs3q+4injHA5V96M6yTeuAg/eDjinTf/43lJ/0RA txThkvKcyUNZjKOkpMptkHlBVCO8QMaGNEiBfiys= From: David Gibson To: pasic@linux.ibm.com, dgilbert@redhat.com, pair@us.ibm.com, qemu-devel@nongnu.org, brijesh.singh@amd.com Cc: ehabkost@redhat.com, mtosatti@redhat.com, mst@redhat.com, jun.nakajima@intel.com, kvm@vger.kernel.org, Richard Henderson , qemu-s390x@nongnu.org, Marcel Apfelbaum , pbonzini@redhat.com, frankja@linux.ibm.com, andi.kleen@intel.com, cohuck@redhat.com, Thomas Huth , borntraeger@de.ibm.com, mdroth@linux.vnet.ibm.com, David Gibson , =?utf-8?q?Daniel_P=2E_Berrang=C3=A9?= , qemu-ppc@nongnu.org, David Hildenbrand , Greg Kurz , pragyansri.pathi@intel.com Subject: [PULL v9 12/13] confidential guest support: Alter virtio default properties for protected guests Date: Mon, 8 Feb 2021 17:05:37 +1100 Message-Id: <20210208060538.39276-13-david@gibson.dropbear.id.au> X-Mailer: git-send-email 2.29.2 In-Reply-To: <20210208060538.39276-1-david@gibson.dropbear.id.au> References: <20210208060538.39276-1-david@gibson.dropbear.id.au> MIME-Version: 1.0 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 confidential guest 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 Reviewed-by: Cornelia Huck Reviewed-by: Greg Kurz --- hw/core/machine.c | 13 +++++++++++++ 1 file changed, 13 insertions(+) diff --git a/hw/core/machine.c b/hw/core/machine.c index f45a795478..970046f438 100644 --- a/hw/core/machine.c +++ b/hw/core/machine.c @@ -33,6 +33,8 @@ #include "migration/global_state.h" #include "migration/vmstate.h" #include "exec/confidential-guest-support.h" +#include "hw/virtio/virtio.h" +#include "hw/virtio/virtio-pci.h" GlobalProperty hw_compat_5_2[] = {}; const size_t hw_compat_5_2_len = G_N_ELEMENTS(hw_compat_5_2); @@ -1196,6 +1198,17 @@ 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);