[RFC 10/18] guest memory protection: Add guest memory protection interface

[David Gibson <david@gibson.dropbear.id.au>]

Several architectures have mechanisms which are designed to protect guest
memory from interference or eavesdropping by a compromised hypervisor.  AMD
SEV does this with in-chip memory encryption and Intel has a similar
mechanism.  POWER's Protected Execution Framework (PEF) accomplishes a
similar goal using an ultravisor and new memory protection features,
instead of encryption.

This introduces a new GuestMemoryProtection QOM interface which we'll use
to (partially) unify handling of these various mechanisms.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
---
 backends/Makefile.objs                 |  2 ++
 backends/guest-memory-protection.c     | 29 +++++++++++++++++++++
 include/exec/guest-memory-protection.h | 36 ++++++++++++++++++++++++++
 3 files changed, 67 insertions(+)
 create mode 100644 backends/guest-memory-protection.c
 create mode 100644 include/exec/guest-memory-protection.h

diff --git a/backends/Makefile.objs b/backends/Makefile.objs
index 28a847cd57..e4fb4f5280 100644
--- a/backends/Makefile.objs
+++ b/backends/Makefile.objs
@@ -21,3 +21,5 @@ common-obj-$(CONFIG_LINUX) += hostmem-memfd.o
 common-obj-$(CONFIG_GIO) += dbus-vmstate.o
 dbus-vmstate.o-cflags = $(GIO_CFLAGS)
 dbus-vmstate.o-libs = $(GIO_LIBS)
+
+common-obj-y += guest-memory-protection.o
diff --git a/backends/guest-memory-protection.c b/backends/guest-memory-protection.c
new file mode 100644
index 0000000000..7e538214f7
--- /dev/null
+++ b/backends/guest-memory-protection.c
@@ -0,0 +1,29 @@
+#/*
+ * QEMU Guest Memory Protection interface
+ *
+ * Copyright: David Gibson, Red Hat Inc. 2020
+ *
+ * Authors:
+ *  David Gibson <david@gibson.dropbear.id.au>
+ *
+ * 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 "exec/guest-memory-protection.h"
+
+static const TypeInfo guest_memory_protection_info = {
+    .name = TYPE_GUEST_MEMORY_PROTECTION,
+    .parent = TYPE_INTERFACE,
+    .class_size = sizeof(GuestMemoryProtectionClass),
+};
+
+static void guest_memory_protection_register_types(void)
+{
+    type_register_static(&guest_memory_protection_info);
+}
+
+type_init(guest_memory_protection_register_types)
diff --git a/include/exec/guest-memory-protection.h b/include/exec/guest-memory-protection.h
new file mode 100644
index 0000000000..38e9b01667
--- /dev/null
+++ b/include/exec/guest-memory-protection.h
@@ -0,0 +1,36 @@
+#/*
+ * QEMU Guest Memory Protection interface
+ *
+ * Copyright: David Gibson, Red Hat Inc. 2020
+ *
+ * Authors:
+ *  David Gibson <david@gibson.dropbear.id.au>
+ *
+ * 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 QEMU_GUEST_MEMORY_PROTECTION_H
+#define QEMU_GUEST_MEMORY_PROTECTION_H
+
+#include "qom/object.h"
+
+typedef struct GuestMemoryProtection GuestMemoryProtection;
+
+#define TYPE_GUEST_MEMORY_PROTECTION "guest-memory-protection"
+#define GUEST_MEMORY_PROTECTION(obj)                                    \
+    INTERFACE_CHECK(GuestMemoryProtection, (obj),                       \
+                    TYPE_GUEST_MEMORY_PROTECTION)
+#define GUEST_MEMORY_PROTECTION_CLASS(klass)                            \
+    OBJECT_CLASS_CHECK(GuestMemoryProtectionClass, (klass),             \
+                       TYPE_GUEST_MEMORY_PROTECTION)
+#define GUEST_MEMORY_PROTECTION_GET_CLASS(obj)                          \
+    OBJECT_GET_CLASS(GuestMemoryProtectionClass, (obj),                 \
+                     TYPE_GUEST_MEMORY_PROTECTION)
+
+typedef struct GuestMemoryProtectionClass {
+    InterfaceClass parent;
+} GuestMemoryProtectionClass;
+
+#endif /* QEMU_GUEST_MEMORY_PROTECTION_H */
+
-- 
2.26.2