From nobody Tue Feb 10 06:58:02 2026 Delivered-To: importer@patchew.org Authentication-Results: mx.zohomail.com; dkim=fail; spf=pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org ARC-Seal: i=1; a=rsa-sha256; t=1610582866; cv=none; d=zohomail.com; s=zohoarc; b=G7wO11Rl8wOepkMDXBV6B4mgBma5cz9GY5w2zm5+kY5tetnkOhb2vywqpwh2yBtkbTLWnOoeMhDhz4SKsXE7erWZ1BTNZ3AdaMk3uq+UtEzmRNR8suh2LcsPHeby9iNBWW2PG9ORYeCVQ69sqtSeU8u8J6Xer/yuFJAVkvGeTlw= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=zohomail.com; s=zohoarc; t=1610582866; h=Content-Transfer-Encoding:Cc:Date:From:In-Reply-To:List-Subscribe:List-Post:List-Id:List-Archive:List-Help:List-Unsubscribe:MIME-Version:Message-ID:References:Sender:Subject:To; bh=NYbwxpJ4pyIbWAHg+3LV1OJkKdaYvyv5/nsP3grZh2U=; b=FCNbnvbaeWxjptrrbR0xRTXV66A/BMOXd92zzIzXSEetjtPu75H5g+kwLfwj34MTE8xwPqV+k5qI0irrhVpVcZVYLdNTrLIaKxaSNID73Le3x3KPsCA8oAdvAF31KUeH2xUisrxn8s+/3fE/5Uyb3cRuhQzRzPEtvNZtf9epFMo= ARC-Authentication-Results: i=1; mx.zohomail.com; dkim=fail; spf=pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org Return-Path: Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) by mx.zohomail.com with SMTPS id 1610582866045167.8194641333754; Wed, 13 Jan 2021 16:07:46 -0800 (PST) Received: from localhost ([::1]:49344 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1kzqAy-0008VE-Rg for importer@patchew.org; Wed, 13 Jan 2021 19:07:44 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]:36550) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1kzq2A-0007QE-JG; Wed, 13 Jan 2021 18:58:38 -0500 Received: from ozlabs.org ([2401:3900:2:1::2]:36387) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1kzq28-0006iO-Ou; Wed, 13 Jan 2021 18:58:38 -0500 Received: by ozlabs.org (Postfix, from userid 1007) id 4DGPXR4BBWz9sjB; Thu, 14 Jan 2021 10:58:15 +1100 (AEDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=gibson.dropbear.id.au; s=201602; t=1610582295; bh=cJPi6/8rIQ8cwCcDD17pu1Q0OOK2AVCJGI2N7uMc4L4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=js6IfPg2vCEVsr0cG7Nxp8qFRit3WOJkeDIsZ8aQeKhwDiqQPOb3AGyScr2AmcdAp KWqhmn1YJ74MYBKVi7g7d1CbNZE1gWPrhThn8PocuUl2refDqTV35XG5Rlhqzr6CWg FVRgbPz7EsmIRCa/VafgxuLxHw4yvB53y/TSD/dc= From: David Gibson To: brijesh.singh@amd.com, pair@us.ibm.com, dgilbert@redhat.com, pasic@linux.ibm.com, qemu-devel@nongnu.org Subject: [PATCH v7 12/13] confidential guest support: Alter virtio default properties for protected guests Date: Thu, 14 Jan 2021 10:58:10 +1100 Message-Id: <20210113235811.1909610-13-david@gibson.dropbear.id.au> X-Mailer: git-send-email 2.29.2 In-Reply-To: <20210113235811.1909610-1-david@gibson.dropbear.id.au> References: <20210113235811.1909610-1-david@gibson.dropbear.id.au> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Received-SPF: pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) client-ip=209.51.188.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Received-SPF: pass client-ip=2401:3900:2:1::2; envelope-from=dgibson@ozlabs.org; helo=ozlabs.org X-Spam_score_int: -17 X-Spam_score: -1.8 X-Spam_bar: - X-Spam_report: (-1.8 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, HEADER_FROM_DIFFERENT_DOMAINS=0.248, SPF_HELO_PASS=-0.001, SPF_PASS=-0.001 autolearn=no autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: qemu-ppc@nongnu.org, thuth@redhat.com, Marcelo Tosatti , berrange@redhat.com, jun.nakajima@intel.com, kvm@vger.kernel.org, David Hildenbrand , cohuck@redhat.com, Richard Henderson , Greg Kurz , mdroth@linux.vnet.ibm.com, borntraeger@de.ibm.com, qemu-s390x@nongnu.org, frankja@linux.ibm.com, mst@redhat.com, pragyansri.pathi@intel.com, andi.kleen@intel.com, Paolo Bonzini , David Gibson , Eduardo Habkost Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: "Qemu-devel" X-ZohoMail-DKIM: fail (Header signature does not verify) Content-Type: text/plain; charset="utf-8" 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=3Don 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 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" =20 GlobalProperty hw_compat_5_2[] =3D {}; const size_t hw_compat_5_2_len =3D 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=3Don 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); } =20 machine_class->init(machine); --=20 2.29.2