From patchwork Thu May 21 03:43:04 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: David Gibson X-Patchwork-Id: 282217 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=-9.6 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH, MAILING_LIST_MULTI, SIGNED_OFF_BY, SPF_HELO_NONE, SPF_PASS, URIBL_BLOCKED, USER_AGENT_GIT autolearn=unavailable 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 776EFC433DF for ; Thu, 21 May 2020 03:57:19 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 4672720671 for ; Thu, 21 May 2020 03:57:19 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=gibson.dropbear.id.au header.i=@gibson.dropbear.id.au header.b="hKD3NL+M" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 4672720671 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=gibson.dropbear.id.au Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:42964 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1jbcKc-0002SV-G6 for qemu-devel@archiver.kernel.org; Wed, 20 May 2020 23:57:18 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:53344) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1jbc7N-0003Ie-LX; Wed, 20 May 2020 23:43:37 -0400 Received: from bilbo.ozlabs.org ([203.11.71.1]:47881 helo=ozlabs.org) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1jbc7M-0003YU-8c; Wed, 20 May 2020 23:43:37 -0400 Received: by ozlabs.org (Postfix, from userid 1007) id 49SFnt6QqDz9sVG; Thu, 21 May 2020 13:43:14 +1000 (AEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=gibson.dropbear.id.au; s=201602; t=1590032594; bh=FeXJqAbqicMbULwoyafKv73wne8M05KzRx96/hIBYS8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=hKD3NL+MimoyWtFhDKs3K9p+VZwC6KMyzmpIeq1qoV1LFv5JdiDY1wejmyv0RUKjk ONF9bpuW5w2G8jCr8Hb7sCO79YxbenlKa4w6Cfmz8+F2wEdgzdDCl7Dh1Ft2cdt6z9 mNxWLF8UT0kuEbn9hhCJ+pZsYJMSpsqAJM855Xjs= From: David Gibson To: qemu-devel@nongnu.org, brijesh.singh@amd.com, frankja@linux.ibm.com, dgilbert@redhat.com, pair@us.ibm.com Subject: [RFC v2 18/18] guest memory protection: Alter virtio default properties for protected guests Date: Thu, 21 May 2020 13:43:04 +1000 Message-Id: <20200521034304.340040-19-david@gibson.dropbear.id.au> X-Mailer: git-send-email 2.26.2 In-Reply-To: <20200521034304.340040-1-david@gibson.dropbear.id.au> References: <20200521034304.340040-1-david@gibson.dropbear.id.au> MIME-Version: 1.0 Received-SPF: pass client-ip=203.11.71.1; envelope-from=dgibson@ozlabs.org; helo=ozlabs.org X-detected-operating-system: by eggs.gnu.org: First seen = 2020/05/20 23:43:13 X-ACL-Warn: Detected OS = Linux 2.2.x-3.x [generic] 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=0.249, SPF_HELO_PASS=-0.001, SPF_PASS=-0.001, URIBL_BLOCKED=0.001 autolearn=_AUTOLEARN 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: Eduardo Habkost , kvm@vger.kernel.org, "Michael S. Tsirkin" , cohuck@redhat.com, mdroth@linux.vnet.ibm.com, qemu-ppc@nongnu.org, Paolo Bonzini , Richard Henderson , David Gibson Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" 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 guest memory protection 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 --- hw/core/machine.c | 11 +++++++++++ 1 file changed, 11 insertions(+) diff --git a/hw/core/machine.c b/hw/core/machine.c index 88d699bceb..cb6580954e 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/guest-memory-protection.h" +#include "hw/virtio/virtio.h" +#include "hw/virtio/virtio-pci.h" GlobalProperty hw_compat_5_0[] = {}; const size_t hw_compat_5_0_len = G_N_ELEMENTS(hw_compat_5_0); @@ -1159,6 +1161,15 @@ 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);