From mboxrd@z Thu Jan 1 00:00:00 1970 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=-17.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, 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_SANE_1 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 3A35CC433DB for ; Wed, 3 Feb 2021 10:44:45 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D923A64F50 for ; Wed, 3 Feb 2021 10:44:44 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233865AbhBCKo2 (ORCPT ); Wed, 3 Feb 2021 05:44:28 -0500 Received: from us-smtp-delivery-124.mimecast.com ([216.205.24.124]:37257 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233671AbhBCKo0 (ORCPT ); Wed, 3 Feb 2021 05:44:26 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1612348979; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=oj/fRtwaugb2KEHyNX5mAT8ioDdcAkdWaaBzV6FQItM=; b=NFX0Kk6F5+dCvFBXznCzIxnNnFiXJdJuzy98XfDBt2SsgzAA6YgvGcoAjhtMK+mMMdzzPt aQxFujBGWzF1ASSGVSvFeKq43sQnyem3gvVSQJLnNa0e+31Y6m2GoqGzKF5BmheMe4s3Ur DrlnCUf4M+mozour0FsUHxF8uYHiPb4= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-507-l84PUT_BP26V9PpDkNfxBQ-1; Wed, 03 Feb 2021 05:42:57 -0500 X-MC-Unique: l84PUT_BP26V9PpDkNfxBQ-1 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.phx2.redhat.com [10.5.11.14]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 4EE8F192D786; Wed, 3 Feb 2021 10:42:55 +0000 (UTC) Received: from work-vm (ovpn-115-70.ams2.redhat.com [10.36.115.70]) by smtp.corp.redhat.com (Postfix) with ESMTPS id CC7E05D9E3; Wed, 3 Feb 2021 10:42:44 +0000 (UTC) Date: Wed, 3 Feb 2021 10:42:42 +0000 From: "Dr. David Alan Gilbert" To: David Gibson Cc: pair@us.ibm.com, qemu-devel@nongnu.org, brijesh.singh@amd.com, pasic@linux.ibm.com, 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, 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: Re: [PATCH v8 07/13] confidential guest support: Introduce cgs "ready" flag Message-ID: <20210203104242.GD2950@work-vm> References: <20210202041315.196530-1-david@gibson.dropbear.id.au> <20210202041315.196530-8-david@gibson.dropbear.id.au> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210202041315.196530-8-david@gibson.dropbear.id.au> User-Agent: Mutt/1.14.6 (2020-07-11) X-Scanned-By: MIMEDefang 2.79 on 10.5.11.14 Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org * David Gibson (david@gibson.dropbear.id.au) wrote: > 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 > --- > 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; > -- > 2.29.2 > -- Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK