From patchwork Tue Feb 2 04:13:14 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: David Gibson X-Patchwork-Id: 12060587 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 CBE2CC433DB for ; Tue, 2 Feb 2021 04:15:29 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A2CB264ED4 for ; Tue, 2 Feb 2021 04:15:29 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231452AbhBBEPZ (ORCPT ); Mon, 1 Feb 2021 23:15:25 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:36588 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231624AbhBBEOq (ORCPT ); Mon, 1 Feb 2021 23:14:46 -0500 Received: from ozlabs.org (ozlabs.org [IPv6:2401:3900:2:1::2]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 097EDC0613ED for ; Mon, 1 Feb 2021 20:14:06 -0800 (PST) Received: by ozlabs.org (Postfix, from userid 1007) id 4DVBJ042nvz9tlG; Tue, 2 Feb 2021 15:13:20 +1100 (AEDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=gibson.dropbear.id.au; s=201602; t=1612239200; bh=kIonU8SS9uqw0f6IgA4IJrI2gSOoAYwIy/ciHXZai4o=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=o/wUqoA4yNdX1eHOsJ/9p/nVHiCS5VE1aqXkXDnrCqnQ/v9q014bmFf/703OQhfbv +EU/D2AM5SeuKf2ZEz9a3T9ZSk5wmbjZZwT8fXXbPvAdtoo3pvR/WVtHlzbMM/mNUr ZUkVIFy+EExV/McXFTxdfFGyXfdmKcP30Cd79/W8= From: David Gibson To: dgilbert@redhat.com, pair@us.ibm.com, qemu-devel@nongnu.org, brijesh.singh@amd.com, pasic@linux.ibm.com Cc: pragyansri.pathi@intel.com, Greg Kurz , richard.henderson@linaro.org, berrange@redhat.com, David Hildenbrand , mdroth@linux.vnet.ibm.com, kvm@vger.kernel.org, Marcel Apfelbaum , pbonzini@redhat.com, mtosatti@redhat.com, borntraeger@de.ibm.com, Cornelia Huck , qemu-ppc@nongnu.org, David Gibson , qemu-s390x@nongnu.org, thuth@redhat.com, mst@redhat.com, frankja@linux.ibm.com, jun.nakajima@intel.com, andi.kleen@intel.com, Eduardo Habkost Subject: [PATCH v8 12/13] confidential guest support: Alter virtio default properties for protected guests Date: Tue, 2 Feb 2021 15:13:14 +1100 Message-Id: <20210202041315.196530-13-david@gibson.dropbear.id.au> X-Mailer: git-send-email 2.29.2 In-Reply-To: <20210202041315.196530-1-david@gibson.dropbear.id.au> References: <20210202041315.196530-1-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 94194ab82d..497949899b 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);