From: David Gibson <david@gibson.dropbear.id.au> To: pasic@linux.ibm.com, dgilbert@redhat.com, pair@us.ibm.com, qemu-devel@nongnu.org, brijesh.singh@amd.com Cc: ehabkost@redhat.com, mtosatti@redhat.com, mst@redhat.com, jun.nakajima@intel.com, kvm@vger.kernel.org, "Richard Henderson" <richard.henderson@linaro.org>, qemu-s390x@nongnu.org, "Marcel Apfelbaum" <marcel.apfelbaum@gmail.com>, pbonzini@redhat.com, frankja@linux.ibm.com, andi.kleen@intel.com, cohuck@redhat.com, "Thomas Huth" <thuth@redhat.com>, borntraeger@de.ibm.com, mdroth@linux.vnet.ibm.com, "David Gibson" <david@gibson.dropbear.id.au>, "Daniel P. Berrangé" <berrange@redhat.com>, qemu-ppc@nongnu.org, "David Hildenbrand" <david@redhat.com>, "Greg Kurz" <groug@kaod.org>, pragyansri.pathi@intel.com Subject: [PULL v9 07/13] confidential guest support: Introduce cgs "ready" flag Date: Mon, 8 Feb 2021 17:05:32 +1100 [thread overview] Message-ID: <20210208060538.39276-8-david@gibson.dropbear.id.au> (raw) In-Reply-To: <20210208060538.39276-1-david@gibson.dropbear.id.au> 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> Reviewed-by: Greg Kurz <groug@kaod.org> --- 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..ba2dd4b5df 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 feasible 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 0d934844ff..9eb9dab1fc 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" @@ -2498,6 +2499,8 @@ 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(); @@ -2517,6 +2520,13 @@ 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
WARNING: multiple messages have this Message-ID (diff)
From: David Gibson <david@gibson.dropbear.id.au> To: pasic@linux.ibm.com, dgilbert@redhat.com, pair@us.ibm.com, qemu-devel@nongnu.org, brijesh.singh@amd.com Cc: "Thomas Huth" <thuth@redhat.com>, cohuck@redhat.com, "Daniel P. Berrangé" <berrange@redhat.com>, ehabkost@redhat.com, kvm@vger.kernel.org, mst@redhat.com, mtosatti@redhat.com, "Richard Henderson" <richard.henderson@linaro.org>, mdroth@linux.vnet.ibm.com, borntraeger@de.ibm.com, qemu-s390x@nongnu.org, "Greg Kurz" <groug@kaod.org>, qemu-ppc@nongnu.org, pragyansri.pathi@intel.com, jun.nakajima@intel.com, andi.kleen@intel.com, pbonzini@redhat.com, "David Hildenbrand" <david@redhat.com>, "David Gibson" <david@gibson.dropbear.id.au>, frankja@linux.ibm.com Subject: [PULL v9 07/13] confidential guest support: Introduce cgs "ready" flag Date: Mon, 8 Feb 2021 17:05:32 +1100 [thread overview] Message-ID: <20210208060538.39276-8-david@gibson.dropbear.id.au> (raw) In-Reply-To: <20210208060538.39276-1-david@gibson.dropbear.id.au> 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> Reviewed-by: Greg Kurz <groug@kaod.org> --- 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..ba2dd4b5df 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 feasible 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 0d934844ff..9eb9dab1fc 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" @@ -2498,6 +2499,8 @@ 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(); @@ -2517,6 +2520,13 @@ 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
next prev parent reply other threads:[~2021-02-08 6:06 UTC|newest] Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top 2021-02-08 6:05 [PULL v9 00/13] Cgs patches David Gibson 2021-02-08 6:05 ` David Gibson 2021-02-08 6:05 ` [PULL v9 01/13] qom: Allow optional sugar props David Gibson 2021-02-08 6:05 ` David Gibson 2021-02-08 6:05 ` [PULL v9 02/13] confidential guest support: Introduce new confidential guest support class David Gibson 2021-02-08 6:05 ` David Gibson 2021-02-08 6:05 ` [PULL v9 03/13] sev: Remove false abstraction of flash encryption David Gibson 2021-02-08 6:05 ` David Gibson 2021-02-08 6:05 ` [PULL v9 04/13] confidential guest support: Move side effect out of machine_set_memory_encryption() David Gibson 2021-02-08 6:05 ` David Gibson 2021-02-08 6:05 ` [PULL v9 05/13] confidential guest support: Rework the "memory-encryption" property David Gibson 2021-02-08 6:05 ` David Gibson 2021-02-08 6:05 ` [PULL v9 06/13] sev: Add Error ** to sev_kvm_init() David Gibson 2021-02-08 6:05 ` David Gibson 2021-02-08 6:05 ` David Gibson [this message] 2021-02-08 6:05 ` [PULL v9 07/13] confidential guest support: Introduce cgs "ready" flag David Gibson 2021-02-08 6:05 ` [PULL v9 08/13] confidential guest support: Move SEV initialization into arch specific code David Gibson 2021-02-08 6:05 ` David Gibson 2021-02-08 6:05 ` [PULL v9 09/13] confidential guest support: Update documentation David Gibson 2021-02-08 6:05 ` David Gibson 2021-02-08 6:05 ` [PULL v9 10/13] spapr: Add PEF based confidential guest support David Gibson 2021-02-08 6:05 ` David Gibson 2021-02-08 6:05 ` [PULL v9 11/13] spapr: PEF: prevent migration David Gibson 2021-02-08 6:05 ` David Gibson 2021-02-08 6:05 ` [PULL v9 12/13] confidential guest support: Alter virtio default properties for protected guests David Gibson 2021-02-08 6:05 ` David Gibson 2021-02-08 6:05 ` [PULL v9 13/13] s390: Recognize confidential-guest-support option David Gibson 2021-02-08 6:05 ` David Gibson 2021-02-08 13:00 ` [PULL v9 00/13] Cgs patches Peter Maydell 2021-02-08 13:00 ` Peter Maydell 2021-05-17 10:58 ` Philippe Mathieu-Daudé 2021-05-17 10:58 ` Philippe Mathieu-Daudé 2021-02-08 6:07 David Gibson 2021-02-08 6:07 ` [PULL v9 07/13] confidential guest support: Introduce cgs "ready" flag David Gibson 2021-02-08 6:07 ` David Gibson
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