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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 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 Received-SPF: pass client-ip=216.205.24.124; envelope-from=dgilbert@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -31 X-Spam_score: -3.2 X-Spam_bar: --- X-Spam_report: (-3.2 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.386, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_LOW=-0.7, RCVD_IN_MSPIKE_H3=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham 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: pair@us.ibm.com, mtosatti@redhat.com, brijesh.singh@amd.com, kvm@vger.kernel.org, David Hildenbrand , qemu-devel@nongnu.org, frankja@linux.ibm.com, borntraeger@de.ibm.com, mst@redhat.com, mdroth@linux.vnet.ibm.com, pasic@linux.ibm.com, pragyansri.pathi@intel.com, andi.kleen@intel.com, thuth@redhat.com, Eduardo Habkost , richard.henderson@linaro.org, Greg Kurz , qemu-s390x@nongnu.org, jun.nakajima@intel.com, berrange@redhat.com, Cornelia Huck , qemu-ppc@nongnu.org, pbonzini@redhat.com Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" * 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