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Thu, 14 Jan 2021 11:39:12 +0100 Authentication-Results: garm.ovh; auth=pass (GARM-101G0043d001bfc-f5a1-40ed-b22b-90615f5c680f, 0A7C53367AF3A9CD096E542ECC3C8B2C2D100868) smtp.auth=groug@kaod.org X-OVh-ClientIp: 82.253.208.248 Date: Thu, 14 Jan 2021 11:39:11 +0100 From: Greg Kurz To: David Gibson Subject: Re: [PATCH v7 10/13] spapr: Add PEF based confidential guest support Message-ID: <20210114113911.374d954a@bahia.lan> In-Reply-To: <20210113235811.1909610-11-david@gibson.dropbear.id.au> References: <20210113235811.1909610-1-david@gibson.dropbear.id.au> <20210113235811.1909610-11-david@gibson.dropbear.id.au> X-Mailer: Claws Mail 3.17.8 (GTK+ 2.24.32; x86_64-redhat-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit X-Originating-IP: [37.59.142.101] X-ClientProxiedBy: DAG6EX1.mxp5.local (172.16.2.51) To DAG8EX1.mxp5.local (172.16.2.71) X-Ovh-Tracer-GUID: ffc809bc-175b-485a-8432-ed601f67249e X-Ovh-Tracer-Id: 2256584891148638620 X-VR-SPAMSTATE: OK X-VR-SPAMSCORE: -100 X-VR-SPAMCAUSE: gggruggvucftvghtrhhoucdtuddrgedukedrtdehgdduiecutefuodetggdotefrodftvfcurfhrohhfihhlvgemucfqggfjpdevjffgvefmvefgnecuuegrihhlohhuthemucehtddtnecusecvtfgvtghiphhivghnthhsucdlqddutddtmdenucfjughrpeffhffvuffkjghfofggtgfgihesthejredtredtvdenucfhrhhomhepifhrvghgucfmuhhriicuoehgrhhouhhgsehkrghougdrohhrgheqnecuggftrfgrthhtvghrnhepfedutdeijeejveehkeeileetgfelteekteehtedtieefffevhffflefftdefleejnecukfhppedtrddtrddtrddtpdefjedrheelrddugedvrddutddunecuvehluhhsthgvrhfuihiivgeptdenucfrrghrrghmpehmohguvgepshhmthhpqdhouhhtpdhhvghlohepmhigphhlrghnhedrmhgrihhlrdhovhhhrdhnvghtpdhinhgvtheptddrtddrtddrtddpmhgrihhlfhhrohhmpehgrhhouhhgsehkrghougdrohhrghdprhgtphhtthhopegrnhguihdrkhhlvggvnhesihhnthgvlhdrtghomh Received-SPF: pass client-ip=178.32.121.110; envelope-from=groug@kaod.org; helo=1.mo51.mail-out.ovh.net X-Spam_score_int: -18 X-Spam_score: -1.9 X-Spam_bar: - X-Spam_report: (-1.9 / 5.0 requ) BAYES_00=-1.9, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H2=-0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=unavailable 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, cohuck@redhat.com, brijesh.singh@amd.com, kvm@vger.kernel.org, David Hildenbrand , qemu-devel@nongnu.org, frankja@linux.ibm.com, pragyansri.pathi@intel.com, mst@redhat.com, pasic@linux.ibm.com, borntraeger@de.ibm.com, andi.kleen@intel.com, thuth@redhat.com, Eduardo Habkost , Richard Henderson , dgilbert@redhat.com, qemu-s390x@nongnu.org, jun.nakajima@intel.com, berrange@redhat.com, Marcelo Tosatti , qemu-ppc@nongnu.org, Paolo Bonzini Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On Thu, 14 Jan 2021 10:58:08 +1100 David Gibson wrote: > Some upcoming POWER machines have a system called PEF (Protected > Execution Facility) which uses a small ultravisor to allow guests to > run in a way that they can't be eavesdropped by the hypervisor. The > effect is roughly similar to AMD SEV, although the mechanisms are > quite different. > > Most of the work of this is done between the guest, KVM and the > ultravisor, with little need for involvement by qemu. However qemu > does need to tell KVM to allow secure VMs. > > Because the availability of secure mode is a guest visible difference > which depends on having the right hardware and firmware, we don't > enable this by default. In order to run a secure guest you need to > create a "pef-guest" object and set the confidential-guest-support > property to point to it. > > Note that this just *allows* secure guests, the architecture of PEF is > such that the guest still needs to talk to the ultravisor to enter > secure mode. Qemu has no directl way of knowing if the guest is in typo "directl" missed in V6... sorry. > secure mode, and certainly can't know until well after machine > creation time. > > To start a PEF-capable guest, use the command line options: > -object pef-guest,id=pef0 -machine confidential-guest-support=pef0 > > Signed-off-by: David Gibson > --- > docs/confidential-guest-support.txt | 3 + > docs/papr-pef.txt | 30 +++++++ > hw/ppc/meson.build | 1 + > hw/ppc/pef.c | 119 ++++++++++++++++++++++++++++ > hw/ppc/spapr.c | 6 ++ > include/hw/ppc/pef.h | 25 ++++++ > target/ppc/kvm.c | 18 ----- > target/ppc/kvm_ppc.h | 6 -- > 8 files changed, 184 insertions(+), 24 deletions(-) > create mode 100644 docs/papr-pef.txt > create mode 100644 hw/ppc/pef.c > create mode 100644 include/hw/ppc/pef.h > > diff --git a/docs/confidential-guest-support.txt b/docs/confidential-guest-support.txt > index 2790425b38..f0801814ff 100644 > --- a/docs/confidential-guest-support.txt > +++ b/docs/confidential-guest-support.txt > @@ -40,4 +40,7 @@ Currently supported confidential guest mechanisms are: > AMD Secure Encrypted Virtualization (SEV) > docs/amd-memory-encryption.txt > > +POWER Protected Execution Facility (PEF) > + docs/papr-pef.txt > + > Other mechanisms may be supported in future. > diff --git a/docs/papr-pef.txt b/docs/papr-pef.txt > new file mode 100644 > index 0000000000..6419e995cf > --- /dev/null > +++ b/docs/papr-pef.txt > @@ -0,0 +1,30 @@ > +POWER (PAPR) Protected Execution Facility (PEF) > +=============================================== > + > +Protected Execution Facility (PEF), also known as Secure Guest support > +is a feature found on IBM POWER9 and POWER10 processors. > + > +If a suitable firmware including an Ultravisor is installed, it adds > +an extra memory protection mode to the CPU. The ultravisor manages a > +pool of secure memory which cannot be accessed by the hypervisor. > + > +When this feature is enabled in qemu, a guest can use ultracalls to > +enter "secure mode". This transfers most of its memory to secure > +memory, where it cannot be eavesdropped by a compromised hypervisor. > + > +Launching > +--------- > + > +To launch a guest which will be permitted to enter PEF secure mode: > + > +# ${QEMU} \ > + -object pef-guest,id=pef0 \ > + -machine confidential-guest-support=pef0 \ > + ... > + > +Live Migration > +---------------- > + > +Live migration is not yet implemented for PEF guests. For > +consistency, we currently prevent migration if the PEF feature is > +enabled, whether or not the guest has actually entered secure mode. > diff --git a/hw/ppc/meson.build b/hw/ppc/meson.build > index ffa2ec37fa..218631c883 100644 > --- a/hw/ppc/meson.build > +++ b/hw/ppc/meson.build > @@ -27,6 +27,7 @@ ppc_ss.add(when: 'CONFIG_PSERIES', if_true: files( > 'spapr_nvdimm.c', > 'spapr_rtas_ddw.c', > 'spapr_numa.c', > + 'pef.c', > )) > ppc_ss.add(when: 'CONFIG_SPAPR_RNG', if_true: files('spapr_rng.c')) > ppc_ss.add(when: ['CONFIG_PSERIES', 'CONFIG_LINUX'], if_true: files( > diff --git a/hw/ppc/pef.c b/hw/ppc/pef.c > new file mode 100644 > index 0000000000..02b9b3b460 > --- /dev/null > +++ b/hw/ppc/pef.c > @@ -0,0 +1,119 @@ > +/* > + * PEF (Protected Execution Facility) for POWER support > + * > + * Copyright David Gibson, Redhat Inc. 2020 > + * > + * This work is licensed under the terms of the GNU GPL, version 2 or later. > + * See the COPYING file in the top-level directory. > + * > + */ > + > +#include "qemu/osdep.h" > + > +#include "qapi/error.h" > +#include "qom/object_interfaces.h" > +#include "sysemu/kvm.h" > +#include "migration/blocker.h" > +#include "exec/confidential-guest-support.h" > +#include "hw/ppc/pef.h" > + > +#define TYPE_PEF_GUEST "pef-guest" > +OBJECT_DECLARE_SIMPLE_TYPE(PefGuest, PEF_GUEST) > + > +typedef struct PefGuest PefGuest; > +typedef struct PefGuestClass PefGuestClass; > + > +struct PefGuestClass { > + ConfidentialGuestSupportClass parent_class; > +}; > + > +/** > + * PefGuest: > + * > + * The PefGuest object is used for creating and managing a PEF > + * guest. > + * > + * # $QEMU \ > + * -object pef-guest,id=pef0 \ > + * -machine ...,confidential-guest-support=pef0 > + */ > +struct PefGuest { > + ConfidentialGuestSupport parent_obj; > +}; > + > +#ifdef CONFIG_KVM > +static int kvmppc_svm_init(Error **errp) > +{ > + if (!kvm_check_extension(kvm_state, KVM_CAP_PPC_SECURE_GUEST)) { > + error_setg(errp, > + "KVM implementation does not support Secure VMs (is an ultravisor running?)"); > + return -1; > + } else { > + int ret = kvm_vm_enable_cap(kvm_state, KVM_CAP_PPC_SECURE_GUEST, 0, 1); > + > + if (ret < 0) { > + error_setg(errp, > + "Error enabling PEF with KVM"); > + return -1; > + } > + } > + > + return 0; > +} > + > +/* > + * Don't set error if KVM_PPC_SVM_OFF ioctl is invoked on kernels > + * that don't support this ioctl. > + */ > +void kvmppc_svm_off(Error **errp) > +{ > + int rc; > + > + if (!kvm_enabled()) { > + return; > + } > + > + rc = kvm_vm_ioctl(KVM_STATE(current_accel()), KVM_PPC_SVM_OFF); > + if (rc && rc != -ENOTTY) { > + error_setg_errno(errp, -rc, "KVM_PPC_SVM_OFF ioctl failed"); > + } > +} > +#else > +static int kvmppc_svm_init(Error **errp) > +{ > + g_assert_not_reached(); > +} > +#endif > + > +int pef_kvm_init(ConfidentialGuestSupport *cgs, Error **errp) > +{ > + if (!object_dynamic_cast(OBJECT(cgs), TYPE_PEF_GUEST)) { > + return 0; > + } > + > + if (!kvm_enabled()) { > + error_setg(errp, "PEF requires KVM"); > + return -1; > + } > + > + return kvmppc_svm_init(errp); > +} > + > +OBJECT_DEFINE_TYPE_WITH_INTERFACES(PefGuest, > + pef_guest, > + PEF_GUEST, > + CONFIDENTIAL_GUEST_SUPPORT, > + { TYPE_USER_CREATABLE }, > + { NULL }) > + > +static void pef_guest_class_init(ObjectClass *oc, void *data) > +{ > +} > + > +static void pef_guest_init(Object *obj) > +{ > +} > + > +static void pef_guest_finalize(Object *obj) > +{ > +} > diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c > index 2c403b574e..accf7a834b 100644 > --- a/hw/ppc/spapr.c > +++ b/hw/ppc/spapr.c > @@ -83,6 +83,7 @@ > #include "hw/ppc/spapr_tpm_proxy.h" > #include "hw/ppc/spapr_nvdimm.h" > #include "hw/ppc/spapr_numa.h" > +#include "hw/ppc/pef.h" > > #include "monitor/monitor.h" > > @@ -2658,6 +2659,11 @@ static void spapr_machine_init(MachineState *machine) > char *filename; > Error *resize_hpt_err = NULL; > > + /* > + * if Secure VM (PEF) support is configured, then initialize it > + */ > + pef_kvm_init(machine->cgs, &error_fatal); > + > msi_nonbroken = true; > > QLIST_INIT(&spapr->phbs); > diff --git a/include/hw/ppc/pef.h b/include/hw/ppc/pef.h > new file mode 100644 > index 0000000000..57d4ec9fe6 > --- /dev/null > +++ b/include/hw/ppc/pef.h > @@ -0,0 +1,25 @@ > +/* > + * PEF (Protected Execution Facility) for POWER support > + * > + * Copyright David Gibson, Redhat Inc. 2020 > + * > + * This work is licensed under the terms of the GNU GPL, version 2 or later. > + * See the COPYING file in the top-level directory. > + * > + */ > + > +#ifndef HW_PPC_PEF_H > +#define HW_PPC_PEF_H > + > +int pef_kvm_init(ConfidentialGuestSupport *cgs, Error **errp); > + > +#ifdef CONFIG_KVM > +void kvmppc_svm_off(Error **errp); > +#else > +static inline void kvmppc_svm_off(Error **errp) > +{ > +} > +#endif The API seems a bit inconsistent. On one side, we have pef_kvm_init() which hides all the implementation details (including KVM stubs) in the C file. And on the other side, we expose kvmppc_svm_off() to the machine code... Especially, I was expecting to see a g_assert_not_reached() in the kvmppc_svm_off() stub, just like kvmppc_svm_init(). Maybe introduce an intermediate pef_kvm_off() API, that matches what pef_kvm_init() does with kvmppc_svm_init() ? > + > + > +#endif /* HW_PPC_PEF_H */ > diff --git a/target/ppc/kvm.c b/target/ppc/kvm.c > index daf690a678..0c5056dd5b 100644 > --- a/target/ppc/kvm.c > +++ b/target/ppc/kvm.c > @@ -2929,21 +2929,3 @@ void kvmppc_set_reg_tb_offset(PowerPCCPU *cpu, int64_t tb_offset) > kvm_set_one_reg(cs, KVM_REG_PPC_TB_OFFSET, &tb_offset); > } > } > - > -/* > - * Don't set error if KVM_PPC_SVM_OFF ioctl is invoked on kernels > - * that don't support this ioctl. > - */ > -void kvmppc_svm_off(Error **errp) > -{ > - int rc; > - > - if (!kvm_enabled()) { > - return; > - } > - > - rc = kvm_vm_ioctl(KVM_STATE(current_accel()), KVM_PPC_SVM_OFF); > - if (rc && rc != -ENOTTY) { > - error_setg_errno(errp, -rc, "KVM_PPC_SVM_OFF ioctl failed"); > - } > -} > diff --git a/target/ppc/kvm_ppc.h b/target/ppc/kvm_ppc.h > index 73ce2bc951..989f61ace0 100644 > --- a/target/ppc/kvm_ppc.h > +++ b/target/ppc/kvm_ppc.h > @@ -39,7 +39,6 @@ int kvmppc_booke_watchdog_enable(PowerPCCPU *cpu); > target_ulong kvmppc_configure_v3_mmu(PowerPCCPU *cpu, > bool radix, bool gtse, > uint64_t proc_tbl); > -void kvmppc_svm_off(Error **errp); > #ifndef CONFIG_USER_ONLY > bool kvmppc_spapr_use_multitce(void); > int kvmppc_spapr_enable_inkernel_multitce(void); > @@ -216,11 +215,6 @@ static inline target_ulong kvmppc_configure_v3_mmu(PowerPCCPU *cpu, > return 0; > } > > -static inline void kvmppc_svm_off(Error **errp) > -{ > - return; > -} > - > static inline void kvmppc_set_reg_ppc_online(PowerPCCPU *cpu, > unsigned int online) > {