From patchwork Mon Feb 8 06:07:34 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: David Gibson X-Patchwork-Id: 12074023 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 AF368C433E0 for ; Mon, 8 Feb 2021 06:09:53 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 7F21264E27 for ; Mon, 8 Feb 2021 06:09:53 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229861AbhBHGJt (ORCPT ); Mon, 8 Feb 2021 01:09:49 -0500 Received: from bilbo.ozlabs.org ([203.11.71.1]:39937 "EHLO ozlabs.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229839AbhBHGI3 (ORCPT ); Mon, 8 Feb 2021 01:08:29 -0500 Received: by ozlabs.org (Postfix, from userid 1007) id 4DYwY70l51z9sWS; Mon, 8 Feb 2021 17:07:38 +1100 (AEDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=gibson.dropbear.id.au; s=201602; t=1612764459; bh=rGrCUIDaja9zftftkqQIdjL/kYsYIfZR7xVO077v4wc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=X+YCwuKHWMxwRxztHXyBCr4NQiDkTf/1oCN41IZ9QT4RGKGQ9hZYy3Ft75ySt3/fZ gzaLBvRsoZEfkfgmhVBVEFYNz8F+hoi0SNwzFC85HwCIS4NXh8EWJSWFyXu6MEcsR6 2KkGDTeVOGM1AumR1L5qWgMSJC6f9Lz01Eu3tS0A= From: David Gibson To: pair@us.ibm.com, qemu-devel@nongnu.org, peter.maydell@linaro.org, dgilbert@redhat.com, brijesh.singh@amd.com, pasic@linux.ibm.com Cc: richard.henderson@linaro.org, ehabkost@redhat.com, cohuck@redhat.com, david@redhat.com, berrange@redhat.com, mtosatti@redhat.com, Marcel Apfelbaum , mst@redhat.com, borntraeger@de.ibm.com, mdroth@linux.vnet.ibm.com, Paolo Bonzini , David Gibson , jun.nakajima@intel.com, frankja@linux.ibm.com, pragyansri.pathi@intel.com, kvm@vger.kernel.org, qemu-ppc@nongnu.org, Thomas Huth , andi.kleen@intel.com, Greg Kurz , qemu-s390x@nongnu.org Subject: [PULL v9 12/13] confidential guest support: Alter virtio default properties for protected guests Date: Mon, 8 Feb 2021 17:07:34 +1100 Message-Id: <20210208060735.39838-13-david@gibson.dropbear.id.au> X-Mailer: git-send-email 2.29.2 In-Reply-To: <20210208060735.39838-1-david@gibson.dropbear.id.au> References: <20210208060735.39838-1-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);