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[RFC v2 17/18] spapr: Added PEF based guest memory protection
From: |
David Gibson |
Subject: |
[RFC v2 17/18] spapr: Added PEF based guest memory protection |
Date: |
Thu, 21 May 2020 13:43:03 +1000 |
Some upcoming POWER machines have a system called PEF (Protected
Execution Framework) 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 havint 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 guest-memory-protection machine
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, so we can't know if the guest actually is secure until
well after machine creation time.
Signed-off-by: David Gibson <address@hidden>
---
target/ppc/Makefile.objs | 2 +-
target/ppc/pef.c | 81 ++++++++++++++++++++++++++++++++++++++++
2 files changed, 82 insertions(+), 1 deletion(-)
create mode 100644 target/ppc/pef.c
diff --git a/target/ppc/Makefile.objs b/target/ppc/Makefile.objs
index e8fa18ce13..ac93b9700e 100644
--- a/target/ppc/Makefile.objs
+++ b/target/ppc/Makefile.objs
@@ -6,7 +6,7 @@ obj-y += machine.o mmu_helper.o mmu-hash32.o monitor.o
arch_dump.o
obj-$(TARGET_PPC64) += mmu-hash64.o mmu-book3s-v3.o compat.o
obj-$(TARGET_PPC64) += mmu-radix64.o
endif
-obj-$(CONFIG_KVM) += kvm.o
+obj-$(CONFIG_KVM) += kvm.o pef.o
obj-$(call lnot,$(CONFIG_KVM)) += kvm-stub.o
obj-y += dfp_helper.o
obj-y += excp_helper.o
diff --git a/target/ppc/pef.c b/target/ppc/pef.c
new file mode 100644
index 0000000000..823daf3e9c
--- /dev/null
+++ b/target/ppc/pef.c
@@ -0,0 +1,81 @@
+/*
+ * PEF (Protected Execution Framework) 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"
+
+#define TYPE_PEF_GUEST "pef-guest"
+#define PEF_GUEST(obj) \
+ OBJECT_CHECK(PefGuestState, (obj), TYPE_SEV_GUEST)
+
+typedef struct PefGuestState PefGuestState;
+
+/**
+ * PefGuestState:
+ *
+ * The PefGuestState object is used for creating and managing a PEF
+ * guest.
+ *
+ * # $QEMU \
+ * -object pef-guest,id=pef0 \
+ * -machine ...,guest-memory-protection=pef0
+ */
+struct PefGuestState {
+ Object parent_obj;
+};
+
+static Error *pef_mig_blocker;
+
+static int pef_kvm_init(GuestMemoryProtection *gmpo, Error **errp)
+{
+ PefGuestState *pef = PEF_GUEST(gmpo);
+
+ 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;
+}
+
+static void pef_guest_class_init(ObjectClass *oc, void *data)
+{
+ GuestMemoryProtectionClass *gmpc = GUEST_MEMORY_PROTECTION_CLASS(oc);
+
+ gmpc->kvm_init = pef_kvm_init;
+}
+
+static const TypeInfo pef_guest_info = {
+ .parent = TYPE_OBJECT,
+ .name = TYPE_PEF_GUEST,
+ .instance_size = sizeof(PefGuestState),
+ .class_init = pef_guest_class_init,
+ .interfaces = (InterfaceInfo[]) {
+ { TYPE_GUEST_MEMORY_PROTECTION },
+ { TYPE_USER_CREATABLE },
+ { }
+ }
+};
+
+static void
+pef_register_types(void)
+{
+ type_register_static(&pef_guest_info);
+}
+
+type_init(pef_register_types);
--
2.26.2
- [RFC v2 09/18] target/i386: sev: Unify SEVState and SevGuestState, (continued)
- [RFC v2 09/18] target/i386: sev: Unify SEVState and SevGuestState, David Gibson, 2020/05/20
- [RFC v2 05/18] target/i386: sev: Partial cleanup to sev_state global, David Gibson, 2020/05/20
- [RFC v2 11/18] guest memory protection: Handle memory encrption via interface, David Gibson, 2020/05/20
- [RFC v2 06/18] target/i386: sev: Remove redundant cbitpos and reduced_phys_bits fields, David Gibson, 2020/05/20
- [RFC v2 13/18] guest memory protection: Move side effect out of machine_set_memory_encryption(), David Gibson, 2020/05/20
- [RFC v2 15/18] guest memory protection: Decouple kvm_memcrypt_*() helpers from KVM, David Gibson, 2020/05/20
- [RFC v2 18/18] guest memory protection: Alter virtio default properties for protected guests, David Gibson, 2020/05/20
- [RFC v2 17/18] spapr: Added PEF based guest memory protection,
David Gibson <=
- [RFC v2 10/18] guest memory protection: Add guest memory protection interface, David Gibson, 2020/05/20
- [RFC v2 12/18] guest memory protection: Perform KVM init via interface, David Gibson, 2020/05/20
- [RFC v2 16/18] guest memory protection: Add Error ** to GuestMemoryProtection::kvm_init, David Gibson, 2020/05/20
- [RFC v2 14/18] guest memory protection: Rework the "memory-encryption" property, David Gibson, 2020/05/20
- Re: [RFC v2 00/18] Refactor configuration of guest memory protection, Sean Christopherson, 2020/05/29