From: "Dr. David Alan Gilbert" <dgilbert@redhat.com> To: David Gibson <david@gibson.dropbear.id.au> Cc: pair@us.ibm.com, qemu-devel@nongnu.org, brijesh.singh@amd.com, pasic@linux.ibm.com, pragyansri.pathi@intel.com, Greg Kurz <groug@kaod.org>, richard.henderson@linaro.org, berrange@redhat.com, David Hildenbrand <david@redhat.com>, mdroth@linux.vnet.ibm.com, kvm@vger.kernel.org, Marcel Apfelbaum <marcel.apfelbaum@gmail.com>, pbonzini@redhat.com, mtosatti@redhat.com, borntraeger@de.ibm.com, Cornelia Huck <cohuck@redhat.com>, 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 <ehabkost@redhat.com> Subject: Re: [PATCH v8 07/13] confidential guest support: Introduce cgs "ready" flag Date: Wed, 3 Feb 2021 10:42:42 +0000 [thread overview] Message-ID: <20210203104242.GD2950@work-vm> (raw) In-Reply-To: <20210202041315.196530-8-david@gibson.dropbear.id.au> * 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 <david@gibson.dropbear.id.au> Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com> > --- > 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
WARNING: multiple messages have this Message-ID (diff)
From: "Dr. David Alan Gilbert" <dgilbert@redhat.com> To: David Gibson <david@gibson.dropbear.id.au> Cc: pair@us.ibm.com, mtosatti@redhat.com, brijesh.singh@amd.com, kvm@vger.kernel.org, David Hildenbrand <david@redhat.com>, 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 <ehabkost@redhat.com>, richard.henderson@linaro.org, Greg Kurz <groug@kaod.org>, qemu-s390x@nongnu.org, jun.nakajima@intel.com, berrange@redhat.com, Cornelia Huck <cohuck@redhat.com>, qemu-ppc@nongnu.org, pbonzini@redhat.com Subject: Re: [PATCH v8 07/13] confidential guest support: Introduce cgs "ready" flag Date: Wed, 3 Feb 2021 10:42:42 +0000 [thread overview] Message-ID: <20210203104242.GD2950@work-vm> (raw) In-Reply-To: <20210202041315.196530-8-david@gibson.dropbear.id.au> * 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 <david@gibson.dropbear.id.au> Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com> > --- > 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
next prev parent reply other threads:[~2021-02-03 10:44 UTC|newest] Thread overview: 50+ messages / expand[flat|nested] mbox.gz Atom feed top 2021-02-02 4:13 [PATCH v8 00/13] Generalize memory encryption models David Gibson 2021-02-02 4:13 ` David Gibson 2021-02-02 4:13 ` [PATCH v8 01/13] qom: Allow optional sugar props David Gibson 2021-02-02 4:13 ` David Gibson 2021-02-02 4:13 ` [PATCH v8 02/13] confidential guest support: Introduce new confidential guest support class David Gibson 2021-02-02 4:13 ` David Gibson 2021-02-02 4:13 ` [PATCH v8 03/13] sev: Remove false abstraction of flash encryption David Gibson 2021-02-02 4:13 ` David Gibson 2021-02-02 4:13 ` [PATCH v8 04/13] confidential guest support: Move side effect out of machine_set_memory_encryption() David Gibson 2021-02-02 4:13 ` David Gibson 2021-02-02 4:13 ` [PATCH v8 05/13] confidential guest support: Rework the "memory-encryption" property David Gibson 2021-02-02 4:13 ` David Gibson 2021-02-02 4:13 ` [PATCH v8 06/13] sev: Add Error ** to sev_kvm_init() David Gibson 2021-02-02 4:13 ` David Gibson 2021-02-02 4:13 ` [PATCH v8 07/13] confidential guest support: Introduce cgs "ready" flag David Gibson 2021-02-02 4:13 ` David Gibson 2021-02-03 10:42 ` Dr. David Alan Gilbert [this message] 2021-02-03 10:42 ` Dr. David Alan Gilbert 2021-02-03 16:15 ` Greg Kurz 2021-02-03 16:15 ` Greg Kurz 2021-02-04 2:45 ` David Gibson 2021-02-04 2:45 ` David Gibson 2021-02-10 16:25 ` Venu Busireddy 2021-02-10 16:25 ` Venu Busireddy 2021-02-11 23:48 ` David Gibson 2021-02-11 23:48 ` David Gibson 2021-02-02 4:13 ` [PATCH v8 08/13] confidential guest support: Move SEV initialization into arch specific code David Gibson 2021-02-02 4:13 ` David Gibson 2021-02-03 16:19 ` Greg Kurz 2021-02-03 16:19 ` Greg Kurz 2021-02-02 4:13 ` [PATCH v8 09/13] confidential guest support: Update documentation David Gibson 2021-02-02 4:13 ` David Gibson 2021-02-02 4:13 ` [PATCH v8 10/13] spapr: Add PEF based confidential guest support David Gibson 2021-02-02 4:13 ` David Gibson 2021-02-03 17:50 ` Greg Kurz 2021-02-03 17:50 ` Greg Kurz 2021-02-04 2:47 ` David Gibson 2021-02-04 2:47 ` David Gibson 2021-02-02 4:13 ` [PATCH v8 11/13] spapr: PEF: prevent migration David Gibson 2021-02-02 4:13 ` David Gibson 2021-02-02 4:13 ` [PATCH v8 12/13] confidential guest support: Alter virtio default properties for protected guests David Gibson 2021-02-02 4:13 ` David Gibson 2021-02-02 23:06 ` Michael S. Tsirkin 2021-02-02 23:06 ` Michael S. Tsirkin 2021-02-03 4:53 ` David Gibson 2021-02-03 4:53 ` David Gibson 2021-02-02 4:13 ` [PATCH v8 13/13] s390: Recognize confidential-guest-support option David Gibson 2021-02-02 4:13 ` David Gibson 2021-02-03 9:05 ` Christian Borntraeger 2021-02-03 9:05 ` Christian Borntraeger
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