From patchwork Wed Jan 13 23:58:11 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: David Gibson X-Patchwork-Id: 12018191 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=-18.8 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,USER_AGENT_GIT autolearn=unavailable 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 C661EC4332D for ; Thu, 14 Jan 2021 01:53:46 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 984FF2074A for ; Thu, 14 Jan 2021 01:53:46 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728136AbhANBxU (ORCPT ); Wed, 13 Jan 2021 20:53:20 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:47524 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729704AbhANABN (ORCPT ); Wed, 13 Jan 2021 19:01:13 -0500 Received: from ozlabs.org (ozlabs.org [IPv6:2401:3900:2:1::2]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 74516C0617B9 for ; Wed, 13 Jan 2021 15:58:28 -0800 (PST) Received: by ozlabs.org (Postfix, from userid 1007) id 4DGPXR55cYz9sjD; Thu, 14 Jan 2021 10:58:15 +1100 (AEDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=gibson.dropbear.id.au; s=201602; t=1610582295; bh=Vj1RSGtq3tXPDmBRhrrfnvI3/OQqRk1glYDp8Wuofx4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=EMcifB8rGQ7bJ4C/bNq90cgIoKZ4gnlKZL7TKYI7fAWaQ17H9yHCBVqnnWlprnO2d 6q4Dnm7Is7OKZRL0lWjza6ZGKJbWnwJ5v0rxsQCU3T4U1QjX/MbUnCJSmllDyKwxp0 XJpp9zIfXm0eMZmBrSu8zjHCPwk6BEtyvZyHntdw= From: David Gibson To: brijesh.singh@amd.com, pair@us.ibm.com, dgilbert@redhat.com, pasic@linux.ibm.com, qemu-devel@nongnu.org Cc: cohuck@redhat.com, Richard Henderson , Marcelo Tosatti , David Hildenbrand , borntraeger@de.ibm.com, Marcel Apfelbaum , Paolo Bonzini , mst@redhat.com, jun.nakajima@intel.com, thuth@redhat.com, pragyansri.pathi@intel.com, kvm@vger.kernel.org, Eduardo Habkost , qemu-s390x@nongnu.org, qemu-ppc@nongnu.org, frankja@linux.ibm.com, Greg Kurz , mdroth@linux.vnet.ibm.com, David Gibson , berrange@redhat.com, andi.kleen@intel.com Subject: [PATCH v7 13/13] s390: Recognize confidential-guest-support option Date: Thu, 14 Jan 2021 10:58:11 +1100 Message-Id: <20210113235811.1909610-14-david@gibson.dropbear.id.au> X-Mailer: git-send-email 2.29.2 In-Reply-To: <20210113235811.1909610-1-david@gibson.dropbear.id.au> References: <20210113235811.1909610-1-david@gibson.dropbear.id.au> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org At least some s390 cpu models support "Protected Virtualization" (PV), a mechanism to protect guests from eavesdropping by a compromised hypervisor. This is similar in function to other mechanisms like AMD's SEV and POWER's PEF, which are controlled by the "confidential-guest-support" machine option. s390 is a slightly special case, because we already supported PV, simply by using a CPU model with the required feature (S390_FEAT_UNPACK). To integrate this with the option used by other platforms, we implement the following compromise: - When the confidential-guest-support option is set, s390 will recognize it, verify that the CPU can support PV (failing if not) and set virtio default options necessary for encrypted or protected guests, as on other platforms. i.e. if confidential-guest-support is set, we will either create a guest capable of entering PV mode, or fail outright. - If confidential-guest-support is not set, guests might still be able to enter PV mode, if the CPU has the right model. This may be a little surprising, but shouldn't actually be harmful. To start a guest supporting Protected Virtualization using the new option use the command line arguments: -object s390-pv-guest,id=pv0 -machine confidential-guest-support=pv0 Signed-off-by: David Gibson --- docs/confidential-guest-support.txt | 3 ++ docs/system/s390x/protvirt.rst | 19 ++++++--- hw/s390x/pv.c | 62 +++++++++++++++++++++++++++++ include/hw/s390x/pv.h | 1 + target/s390x/kvm.c | 3 ++ 5 files changed, 82 insertions(+), 6 deletions(-) diff --git a/docs/confidential-guest-support.txt b/docs/confidential-guest-support.txt index f0801814ff..50b976a082 100644 --- a/docs/confidential-guest-support.txt +++ b/docs/confidential-guest-support.txt @@ -43,4 +43,7 @@ AMD Secure Encrypted Virtualization (SEV) POWER Protected Execution Facility (PEF) docs/papr-pef.txt +s390x Protected Virtualization (PV) + docs/system/s390x/protvirt.rst + Other mechanisms may be supported in future. diff --git a/docs/system/s390x/protvirt.rst b/docs/system/s390x/protvirt.rst index 712974ad87..0f481043d9 100644 --- a/docs/system/s390x/protvirt.rst +++ b/docs/system/s390x/protvirt.rst @@ -22,15 +22,22 @@ If those requirements are met, the capability `KVM_CAP_S390_PROTECTED` will indicate that KVM can support PVMs on that LPAR. -QEMU Settings -------------- +Running a Protected Virtual Machine +----------------------------------- -To indicate to the VM that it can transition into protected mode, the +To run a PVM you will need to select a CPU model which includes the `Unpack facility` (stfle bit 161 represented by the feature -`unpack`/`S390_FEAT_UNPACK`) needs to be part of the cpu model of -the VM. +`unpack`/`S390_FEAT_UNPACK`), and add these options to the command line:: + + -object s390-pv-guest,id=pv0 \ + -machine confidential-guest-support=pv0 + +Adding these options will: + +* Ensure the `unpack` facility is available +* Enable the IOMMU by default for all I/O devices +* Initialize the PV mechanism -All I/O devices need to use the IOMMU. Passthrough (vfio) devices are currently not supported. Host huge page backings are not supported. However guests can use huge diff --git a/hw/s390x/pv.c b/hw/s390x/pv.c index ab3a2482aa..319d74dfcf 100644 --- a/hw/s390x/pv.c +++ b/hw/s390x/pv.c @@ -14,8 +14,11 @@ #include #include "cpu.h" +#include "qapi/error.h" #include "qemu/error-report.h" #include "sysemu/kvm.h" +#include "qom/object_interfaces.h" +#include "exec/confidential-guest-support.h" #include "hw/s390x/ipl.h" #include "hw/s390x/pv.h" @@ -111,3 +114,62 @@ void s390_pv_inject_reset_error(CPUState *cs) /* Report that we are unable to enter protected mode */ env->regs[r1 + 1] = DIAG_308_RC_INVAL_FOR_PV; } + +#define TYPE_S390_PV_GUEST "s390-pv-guest" +OBJECT_DECLARE_SIMPLE_TYPE(S390PVGuest, S390_PV_GUEST) + +/** + * S390PVGuest: + * + * The S390PVGuest object is basically a dummy used to tell the + * confidential guest support system to use s390's PV mechanism. + * + * # $QEMU \ + * -object s390-pv-guest,id=pv0 \ + * -machine ...,confidential-guest-support=pv0 + */ +struct S390PVGuest { + ConfidentialGuestSupport parent_obj; +}; + +typedef struct S390PVGuestClass S390PVGuestClass; + +struct S390PVGuestClass { + ConfidentialGuestSupportClass parent_class; +}; + +int s390_pv_init(ConfidentialGuestSupport *cgs, Error **errp) +{ + if (!object_dynamic_cast(OBJECT(cgs), TYPE_S390_PV_GUEST)) { + return 0; + } + + if (!s390_has_feat(S390_FEAT_UNPACK)) { + error_setg(errp, + "CPU model does not support Protected Virtualization"); + return -1; + } + + cgs->ready = true; + + return 0; +} + +OBJECT_DEFINE_TYPE_WITH_INTERFACES(S390PVGuest, + s390_pv_guest, + S390_PV_GUEST, + CONFIDENTIAL_GUEST_SUPPORT, + { TYPE_USER_CREATABLE }, + { NULL }) + +static void s390_pv_guest_class_init(ObjectClass *oc, void *data) +{ +} + +static void s390_pv_guest_init(Object *obj) +{ +} + +static void s390_pv_guest_finalize(Object *obj) +{ +} diff --git a/include/hw/s390x/pv.h b/include/hw/s390x/pv.h index aee758bc2d..9bbf66f356 100644 --- a/include/hw/s390x/pv.h +++ b/include/hw/s390x/pv.h @@ -43,6 +43,7 @@ void s390_pv_prep_reset(void); int s390_pv_verify(void); void s390_pv_unshare(void); void s390_pv_inject_reset_error(CPUState *cs); +int s390_pv_init(ConfidentialGuestSupport *cgs, Error **errp); #else /* CONFIG_KVM */ static inline bool s390_is_pv(void) { return false; } static inline int s390_pv_vm_enable(void) { return 0; } diff --git a/target/s390x/kvm.c b/target/s390x/kvm.c index b8385e6b95..d2435664dc 100644 --- a/target/s390x/kvm.c +++ b/target/s390x/kvm.c @@ -387,6 +387,9 @@ int kvm_arch_init(MachineState *ms, KVMState *s) } kvm_set_max_memslot_size(KVM_SLOT_MAX_BYTES); + + s390_pv_init(ms->cgs, &error_fatal); + return 0; }