From patchwork Tue Jan 12 04:45:07 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: David Gibson X-Patchwork-Id: 12012381 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 CED9CC433DB for ; Tue, 12 Jan 2021 04:46:35 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 8A63F221FE for ; Tue, 12 Jan 2021 04:46:35 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732292AbhALEqe (ORCPT ); Mon, 11 Jan 2021 23:46:34 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:52634 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730151AbhALEqd (ORCPT ); Mon, 11 Jan 2021 23:46:33 -0500 Received: from ozlabs.org (ozlabs.org [IPv6:2401:3900:2:1::2]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 63260C0617A3 for ; Mon, 11 Jan 2021 20:45:21 -0800 (PST) Received: by ozlabs.org (Postfix, from userid 1007) id 4DFJ0S4ppQz9t19; Tue, 12 Jan 2021 15:45:12 +1100 (AEDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=gibson.dropbear.id.au; s=201602; t=1610426712; bh=jDlQh4dkOChKe9I+7t8fXV6AkND1gF3W8x1pj2YrgnI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=BSc8LaAZyfK2Z+AIy8zflV4xZJRJrMFMR4Bq9ofE49vUji5vlDitGnheQQEgayLX6 DuRmQvHUllwj1EJWlC07dQv8la3vRAZtXqUkXqRvqR6iDEQkMYFMcJlL3wpy7HDYYc Y4Mb1XnI2L2i0U/Gp/OLROhzadu3oyaX59o5YUVA= From: David Gibson To: pasic@linux.ibm.com, brijesh.singh@amd.com, pair@us.ibm.com, dgilbert@redhat.com, qemu-devel@nongnu.org Cc: andi.kleen@intel.com, qemu-ppc@nongnu.org, Paolo Bonzini , Marcelo Tosatti , David Gibson , Greg Kurz , frankja@linux.ibm.com, thuth@redhat.com, Christian Borntraeger , mdroth@linux.vnet.ibm.com, richard.henderson@linaro.org, kvm@vger.kernel.org, =?utf-8?q?Daniel_P=2E_Be?= =?utf-8?q?rrang=C3=A9?= , Marcel Apfelbaum , Eduardo Habkost , david@redhat.com, Cornelia Huck , mst@redhat.com, qemu-s390x@nongnu.org, pragyansri.pathi@intel.com, jun.nakajima@intel.com Subject: [PATCH v6 12/13] confidential guest support: Alter virtio default properties for protected guests Date: Tue, 12 Jan 2021 15:45:07 +1100 Message-Id: <20210112044508.427338-13-david@gibson.dropbear.id.au> X-Mailer: git-send-email 2.29.2 In-Reply-To: <20210112044508.427338-1-david@gibson.dropbear.id.au> References: <20210112044508.427338-1-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 --- hw/core/machine.c | 13 +++++++++++++ 1 file changed, 13 insertions(+) diff --git a/hw/core/machine.c b/hw/core/machine.c index 5a7433332b..61ae363559 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); @@ -1204,6 +1206,17 @@ 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);