From patchwork Fri Jul 24 02:57:43 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: David Gibson X-Patchwork-Id: 11681915 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id E8EF613B4 for ; Fri, 24 Jul 2020 02:57:53 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id C6EAC207FC for ; Fri, 24 Jul 2020 02:57:53 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=gibson.dropbear.id.au header.i=@gibson.dropbear.id.au header.b="Fsw/pl4E" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726863AbgGXC5x (ORCPT ); Thu, 23 Jul 2020 22:57:53 -0400 Received: from ozlabs.org ([203.11.71.1]:37083 "EHLO ozlabs.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726807AbgGXC5w (ORCPT ); Thu, 23 Jul 2020 22:57:52 -0400 Received: by ozlabs.org (Postfix, from userid 1007) id 4BCYlw2CWGz9sTR; Fri, 24 Jul 2020 12:57:48 +1000 (AEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=gibson.dropbear.id.au; s=201602; t=1595559468; bh=S0SoxbGMoHrm4nxccN2FECIGesfK+qvLP0XWEh7c1/Y=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Fsw/pl4ETCgZRnUMnWoMvWLxPNqj0W0aX0j5oGnZxcSxibV0Nu6T7QHmXii5ZyiXd gwcHi8Gw1/rAeCHONaMwMfFat3Kj/nmQxVEVXbnIC3hWgbdO8VZRrKsxwbkkzFOO7K fD6aaWybXL1omHTDqn5vbbG9IPhzpY7SOwrln0IM= From: David Gibson To: dgilbert@redhat.com, frankja@linux.ibm.com, pair@us.ibm.com, qemu-devel@nongnu.org, pbonzini@redhat.com, brijesh.singh@amd.com Cc: ehabkost@redhat.com, marcel.apfelbaum@gmail.com, "Michael S. Tsirkin" , qemu-ppc@nongnu.org, kvm@vger.kernel.org, pasic@linux.ibm.com, qemu-s390x@nongnu.org, David Gibson , David Hildenbrand , Christian Borntraeger , Richard Henderson , =?utf-8?q?Daniel_P=2E_Berrang=C3=A9?= , mdroth@linux.vnet.ibm.com, Thomas Huth , Cornelia Huck Subject: [for-5.2 v4 09/10] host trust limitation: Alter virtio default properties for protected guests Date: Fri, 24 Jul 2020 12:57:43 +1000 Message-Id: <20200724025744.69644-10-david@gibson.dropbear.id.au> X-Mailer: git-send-email 2.26.2 In-Reply-To: <20200724025744.69644-1-david@gibson.dropbear.id.au> References: <20200724025744.69644-1-david@gibson.dropbear.id.au> MIME-Version: 1.0 Sender: kvm-owner@vger.kernel.org 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 host trust limitation 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: Halil Pasic --- hw/core/machine.c | 11 +++++++++++ 1 file changed, 11 insertions(+) diff --git a/hw/core/machine.c b/hw/core/machine.c index b599b0ba65..2a723bf07b 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/host-trust-limitation.h" +#include "hw/virtio/virtio.h" +#include "hw/virtio/virtio-pci.h" GlobalProperty hw_compat_5_0[] = { { "virtio-balloon-device", "page-poison", "false" }, @@ -1161,6 +1163,15 @@ 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 disabling legacy virtio support + * for virtio pci devices + */ + object_register_sugar_prop(TYPE_VIRTIO_PCI, "disable-legacy", "on"); + object_register_sugar_prop(TYPE_VIRTIO_DEVICE, "iommu_platform", "on"); } machine_class->init(machine);