From patchwork Tue Feb 2 04:13:09 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: David Gibson X-Patchwork-Id: 12060575 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=-18.7 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 7F7CEC433E0 for ; Tue, 2 Feb 2021 04:14:58 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 4B15764DE1 for ; Tue, 2 Feb 2021 04:14:58 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231628AbhBBEO4 (ORCPT ); Mon, 1 Feb 2021 23:14:56 -0500 Received: from ozlabs.org ([203.11.71.1]:33985 "EHLO ozlabs.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231608AbhBBEOp (ORCPT ); Mon, 1 Feb 2021 23:14:45 -0500 Received: by ozlabs.org (Postfix, from userid 1007) id 4DVBHz1qqjz9tkv; Tue, 2 Feb 2021 15:13:19 +1100 (AEDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=gibson.dropbear.id.au; s=201602; t=1612239199; bh=sgqCxTU3ldDr2MDL7pZNPx7v/t7kq8/KrSPm5nvDlJE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=X4L0x6hTVEYQusVRvDY1CcV4UGEiEcPCuk9+WDLdo9sE7z5an7PriJbbRMDxD/Bkr mu4pFJJ7QQ9Tpbb346NHIz09+JQosqqaiyEtjhXMHVOU2UwYAEGLZ2cb7wuOlKW/rr ezh64AAFsarEEY9WswP2jPNrEJqReUUYpHXfoUg8= From: David Gibson To: dgilbert@redhat.com, pair@us.ibm.com, qemu-devel@nongnu.org, brijesh.singh@amd.com, pasic@linux.ibm.com Cc: pragyansri.pathi@intel.com, Greg Kurz , richard.henderson@linaro.org, berrange@redhat.com, David Hildenbrand , mdroth@linux.vnet.ibm.com, kvm@vger.kernel.org, Marcel Apfelbaum , pbonzini@redhat.com, mtosatti@redhat.com, borntraeger@de.ibm.com, Cornelia Huck , qemu-ppc@nongnu.org, David Gibson , qemu-s390x@nongnu.org, thuth@redhat.com, mst@redhat.com, frankja@linux.ibm.com, jun.nakajima@intel.com, andi.kleen@intel.com, Eduardo Habkost Subject: [PATCH v8 07/13] confidential guest support: Introduce cgs "ready" flag Date: Tue, 2 Feb 2021 15:13:09 +1100 Message-Id: <20210202041315.196530-8-david@gibson.dropbear.id.au> X-Mailer: git-send-email 2.29.2 In-Reply-To: <20210202041315.196530-1-david@gibson.dropbear.id.au> References: <20210202041315.196530-1-david@gibson.dropbear.id.au> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org The platform specific details of mechanisms for implementing confidential guest support may require setup at various points during initialization. Thus, it's not really feasible to have a single cgs initialization hook, but instead each mechanism needs its own initialization calls in arch or machine specific code. However, to make it harder to have a bug where a mechanism isn't properly initialized under some circumstances, we want to have a common place, late in boot, where we verify that cgs has been initialized if it was requested. This patch introduces a ready flag to the ConfidentialGuestSupport base type to accomplish this, which we verify in qemu_machine_creation_done(). Signed-off-by: David Gibson Reviewed-by: Dr. David Alan Gilbert Reviewed-by: Greg Kurz --- include/exec/confidential-guest-support.h | 24 +++++++++++++++++++++++ softmmu/vl.c | 10 ++++++++++ target/i386/sev.c | 2 ++ 3 files changed, 36 insertions(+) diff --git a/include/exec/confidential-guest-support.h b/include/exec/confidential-guest-support.h index 3db6380e63..5dcf602047 100644 --- a/include/exec/confidential-guest-support.h +++ b/include/exec/confidential-guest-support.h @@ -27,6 +27,30 @@ OBJECT_DECLARE_SIMPLE_TYPE(ConfidentialGuestSupport, CONFIDENTIAL_GUEST_SUPPORT) struct ConfidentialGuestSupport { Object parent; + + /* + * ready: flag set by CGS initialization code once it's ready to + * start executing instructions in a potentially-secure + * guest + * + * The definition here is a bit fuzzy, because this is essentially + * part of a self-sanity-check, rather than a strict mechanism. + * + * It's not fasible to have a single point in the common machine + * init path to configure confidential guest support, because + * different mechanisms have different interdependencies requiring + * initialization in different places, often in arch or machine + * type specific code. It's also usually not possible to check + * for invalid configurations until that initialization code. + * That means it would be very easy to have a bug allowing CGS + * init to be bypassed entirely in certain configurations. + * + * Silently ignoring a requested security feature would be bad, so + * to avoid that we check late in init that this 'ready' flag is + * set if CGS was requested. If the CGS init hasn't happened, and + * so 'ready' is not set, we'll abort. + */ + bool ready; }; typedef struct ConfidentialGuestSupportClass { diff --git a/softmmu/vl.c b/softmmu/vl.c index 1b464e3474..1869ed54a9 100644 --- a/softmmu/vl.c +++ b/softmmu/vl.c @@ -101,6 +101,7 @@ #include "qemu/plugin.h" #include "qemu/queue.h" #include "sysemu/arch_init.h" +#include "exec/confidential-guest-support.h" #include "ui/qemu-spice.h" #include "qapi/string-input-visitor.h" @@ -2497,6 +2498,8 @@ static void qemu_create_cli_devices(void) static void qemu_machine_creation_done(void) { + MachineState *machine = MACHINE(qdev_get_machine()); + /* Did we create any drives that we failed to create a device for? */ drive_check_orphaned(); @@ -2516,6 +2519,13 @@ static void qemu_machine_creation_done(void) qdev_machine_creation_done(); + if (machine->cgs) { + /* + * Verify that Confidential Guest Support has actually been initialized + */ + assert(machine->cgs->ready); + } + if (foreach_device_config(DEV_GDB, gdbserver_start) < 0) { exit(1); } diff --git a/target/i386/sev.c b/target/i386/sev.c index 590cb31fa8..f9e9b5d8ae 100644 --- a/target/i386/sev.c +++ b/target/i386/sev.c @@ -737,6 +737,8 @@ int sev_kvm_init(ConfidentialGuestSupport *cgs, Error **errp) qemu_add_machine_init_done_notifier(&sev_machine_done_notify); qemu_add_vm_change_state_handler(sev_vm_state_change, sev); + cgs->ready = true; + return 0; err: sev_guest = NULL;