[Qemu-devel] [PATCH v2 02/13] kvm: introduce high-level API to support encrypted page migration

["Singh, Brijesh" <brijesh.singh@amd.com>]

When memory encryption is enabled in VM, the guest pages will be
encrypted with the guest-specific key, to protect the confidentiality
of data in transit. To support the live migration we need to use
platform specific hooks to access the guest memory.

The kvm_memcrypt_save_outgoing_page() can be used by the sender to write
the encrypted pages and metadata associated with it on the socket.

The kvm_memcrypt_load_incoming_page() can be used by receiver to read the
incoming encrypted pages from the socket and load into the guest memory.

Signed-off-by: Brijesh Singh <<brijesh.singh@amd.com>>
---
 accel/kvm/kvm-all.c    | 27 +++++++++++++++++++++++++++
 accel/kvm/sev-stub.c   | 11 +++++++++++
 accel/stubs/kvm-stub.c | 12 ++++++++++++
 include/sysemu/kvm.h   | 12 ++++++++++++
 include/sysemu/sev.h   |  3 +++
 5 files changed, 65 insertions(+)

diff --git a/accel/kvm/kvm-all.c b/accel/kvm/kvm-all.c
index 3d86ae5052..162a2d5085 100644
--- a/accel/kvm/kvm-all.c
+++ b/accel/kvm/kvm-all.c
@@ -110,6 +110,10 @@ struct KVMState
     /* memory encryption */
     void *memcrypt_handle;
     int (*memcrypt_encrypt_data)(void *handle, uint8_t *ptr, uint64_t len);
+    int (*memcrypt_save_outgoing_page)(void *ehandle, QEMUFile *f,
+            uint8_t *ptr, uint32_t sz, uint64_t *bytes_sent);
+    int (*memcrypt_load_incoming_page)(void *ehandle, QEMUFile *f,
+            uint8_t *ptr);
 };
 
 KVMState *kvm_state;
@@ -165,6 +169,29 @@ int kvm_memcrypt_encrypt_data(uint8_t *ptr, uint64_t len)
     return 1;
 }
 
+int kvm_memcrypt_save_outgoing_page(QEMUFile *f, uint8_t *ptr,
+                                    uint32_t size, uint64_t *bytes_sent)
+{
+    if (kvm_state->memcrypt_handle &&
+        kvm_state->memcrypt_save_outgoing_page) {
+        return kvm_state->memcrypt_save_outgoing_page(kvm_state->memcrypt_handle,
+                    f, ptr, size, bytes_sent);
+    }
+
+    return 1;
+}
+
+int kvm_memcrypt_load_incoming_page(QEMUFile *f, uint8_t *ptr)
+{
+    if (kvm_state->memcrypt_handle &&
+        kvm_state->memcrypt_load_incoming_page) {
+        return kvm_state->memcrypt_load_incoming_page(kvm_state->memcrypt_handle,
+                    f, ptr);
+    }
+
+    return 1;
+}
+
 static KVMSlot *kvm_get_free_slot(KVMMemoryListener *kml)
 {
     KVMState *s = kvm_state;
diff --git a/accel/kvm/sev-stub.c b/accel/kvm/sev-stub.c
index 4f97452585..c12a8e005e 100644
--- a/accel/kvm/sev-stub.c
+++ b/accel/kvm/sev-stub.c
@@ -24,3 +24,14 @@ void *sev_guest_init(const char *id)
 {
     return NULL;
 }
+
+int sev_save_outgoing_page(void *handle, QEMUFile *f, uint8_t *ptr,
+                           uint32_t size, uint64_t *bytes_sent)
+{
+    return 1;
+}
+
+int sev_load_incoming_page(void *handle, QEMUFile *f, uint8_t *ptr)
+{
+    return 1;
+}
diff --git a/accel/stubs/kvm-stub.c b/accel/stubs/kvm-stub.c
index 6feb66ed80..e14b879531 100644
--- a/accel/stubs/kvm-stub.c
+++ b/accel/stubs/kvm-stub.c
@@ -114,6 +114,18 @@ int kvm_memcrypt_encrypt_data(uint8_t *ptr, uint64_t len)
   return 1;
 }
 
+int kvm_memcrypt_save_outgoing_page(QEMUFile *f, uint8_t *ptr,
+                                    uint32_t size, uint64_t *bytes_sent)
+{
+    return 1;
+}
+
+int kvm_memcrypt_load_incoming_page(QEMUFile *f, uint8_t *ptr)
+{
+    return 1;
+}
+
+
 #ifndef CONFIG_USER_ONLY
 int kvm_irqchip_add_msi_route(KVMState *s, int vector, PCIDevice *dev)
 {
diff --git a/include/sysemu/kvm.h b/include/sysemu/kvm.h
index acd90aebb6..bb6bcc143c 100644
--- a/include/sysemu/kvm.h
+++ b/include/sysemu/kvm.h
@@ -247,6 +247,18 @@ bool kvm_memcrypt_enabled(void);
  */
 int kvm_memcrypt_encrypt_data(uint8_t *ptr, uint64_t len);
 
+/**
+ * kvm_memcrypt_save_outgoing_buffer - encrypt the outgoing buffer
+ * and write to the wire.
+ */
+int kvm_memcrypt_save_outgoing_page(QEMUFile *f, uint8_t *ptr, uint32_t size,
+                                    uint64_t *bytes_sent);
+
+/**
+ * kvm_memcrypt_load_incoming_buffer - read the encrypt incoming buffer and copy
+ * the buffer into the guest memory space.
+ */
+int kvm_memcrypt_load_incoming_page(QEMUFile *f, uint8_t *ptr);
 
 #ifdef NEED_CPU_H
 #include "cpu.h"
diff --git a/include/sysemu/sev.h b/include/sysemu/sev.h
index 98c1ec8d38..752a71b1c0 100644
--- a/include/sysemu/sev.h
+++ b/include/sysemu/sev.h
@@ -18,4 +18,7 @@
 
 void *sev_guest_init(const char *id);
 int sev_encrypt_data(void *handle, uint8_t *ptr, uint64_t len);
+int sev_save_outgoing_page(void *handle, QEMUFile *f, uint8_t *ptr,
+                           uint32_t size, uint64_t *bytes_sent);
+int sev_load_incoming_page(void *handle, QEMUFile *f, uint8_t *ptr);
 #endif
-- 
2.17.1