[RFC PATCH 17/26] migration: Stop VM after loading confidential RAM

[Dov Murik <dovmurik@linux.vnet.ibm.com>]

Register a dummy device state (EndOfConfidentialRAMState) with high
priority so it is the first device which is loaded in the target.  The
post_load handler of this device stops the VM, which makes things easier
when loading devices' states which expect the VM not to be running at
the same time.

Signed-off-by: Dov Murik <dovmurik@linux.vnet.ibm.com>
---
 migration/confidential-ram.h |  2 ++
 migration/confidential-ram.c | 31 +++++++++++++++++++++++++++++++
 softmmu/runstate.c           |  1 +
 target/i386/sev.c            |  2 ++
 4 files changed, 36 insertions(+)

diff --git a/migration/confidential-ram.h b/migration/confidential-ram.h
index 9a1027bdaf..2822c5ee3d 100644
--- a/migration/confidential-ram.h
+++ b/migration/confidential-ram.h
@@ -18,4 +18,6 @@ int cgs_mh_save_encrypted_page(QEMUFile *f, ram_addr_t src_gpa, uint32_t size,
 
 int cgs_mh_load_encrypted_page(QEMUFile *f, ram_addr_t dest_gpa);
 
+void register_end_of_confidential_ram(void);
+
 #endif
diff --git a/migration/confidential-ram.c b/migration/confidential-ram.c
index 0b821af774..982cf9b874 100644
--- a/migration/confidential-ram.c
+++ b/migration/confidential-ram.c
@@ -8,6 +8,8 @@
 #include "io/channel.h"
 #include "qapi/error.h"
 #include "exec/memory.h"
+#include "migration/vmstate.h"
+#include "sysemu/runstate.h"
 #include "trace.h"
 #include "confidential-ram.h"
 
@@ -225,3 +227,32 @@ int cgs_mh_load_encrypted_page(QEMUFile *f, ram_addr_t dest_gpa)
     }
     return ret;
 }
+
+typedef struct {
+    bool dummy;
+} EndOfConfidentialRAMState;
+
+static EndOfConfidentialRAMState end_of_confidential_ram_state = { .dummy = false };
+
+static int end_of_confidential_ram_post_load(void *opaque, int version_id)
+{
+    vm_stop(RUN_STATE_INMIGRATE);
+    return 0;
+}
+
+static const VMStateDescription vmstate_end_of_confidential_ram = {
+    .name = "end-of-confidential-ram",
+    .priority = MIG_PRI_GICV3, /* TODO define new (higher) priority level */
+    .version_id = 1,
+    .post_load = end_of_confidential_ram_post_load,
+    .fields = (VMStateField[]) {
+        VMSTATE_BOOL(dummy, EndOfConfidentialRAMState),
+        VMSTATE_END_OF_LIST()
+    },
+};
+
+void register_end_of_confidential_ram(void)
+{
+    vmstate_register(NULL, 0, &vmstate_end_of_confidential_ram,
+                     &end_of_confidential_ram_state);
+}
diff --git a/softmmu/runstate.c b/softmmu/runstate.c
index 2874417b61..193413246d 100644
--- a/softmmu/runstate.c
+++ b/softmmu/runstate.c
@@ -131,6 +131,7 @@ static const RunStateTransition runstate_transitions_def[] = {
     { RUN_STATE_RUNNING, RUN_STATE_INTERNAL_ERROR },
     { RUN_STATE_RUNNING, RUN_STATE_IO_ERROR },
     { RUN_STATE_RUNNING, RUN_STATE_PAUSED },
+    { RUN_STATE_RUNNING, RUN_STATE_INMIGRATE },
     { RUN_STATE_RUNNING, RUN_STATE_FINISH_MIGRATE },
     { RUN_STATE_RUNNING, RUN_STATE_RESTORE_VM },
     { RUN_STATE_RUNNING, RUN_STATE_SAVE_VM },
diff --git a/target/i386/sev.c b/target/i386/sev.c
index 0f414df02f..da2d0cc699 100644
--- a/target/i386/sev.c
+++ b/target/i386/sev.c
@@ -33,6 +33,7 @@
 #include "exec/address-spaces.h"
 #include "monitor/monitor.h"
 #include "exec/confidential-guest-support.h"
+#include "migration/confidential-ram.h"
 #include "hw/i386/pc.h"
 
 #define TYPE_SEV_GUEST "sev-guest"
@@ -1011,6 +1012,7 @@ static void
 sev_register_types(void)
 {
     type_register_static(&sev_guest_info);
+    register_end_of_confidential_ram();
 }
 
 type_init(sev_register_types);
-- 
2.20.1