1 files changed, 137 insertions, 0 deletions

diff --git a/migration/savevm.c b/migration/savevm.c
index b3868f7fb5..013098581f 100644
--- a/migration/savevm.c
+++ b/migration/savevm.c
@@ -57,6 +57,7 @@
 #include "sysemu/replay.h"
 #include "qjson.h"
 #include "migration/colo.h"
+#include "qemu/bitmap.h"
 #include "net/announce.h"
 
 const unsigned int postcopy_ram_discard_version = 0;
@@ -249,6 +250,8 @@ typedef struct SaveState {
     uint32_t len;
     const char *name;
     uint32_t target_page_bits;
+    uint32_t caps_count;
+    MigrationCapability *capabilities;
 } SaveState;
 
 static SaveState savevm_state = {
@@ -256,15 +259,51 @@ static SaveState savevm_state = {
     .global_section_id = 0,
 };
 
+static bool should_validate_capability(int capability)
+{
+    assert(capability >= 0 && capability < MIGRATION_CAPABILITY__MAX);
+    /* Validate only new capabilities to keep compatibility. */
+    switch (capability) {
+    case MIGRATION_CAPABILITY_X_IGNORE_SHARED:
+        return true;
+    default:
+        return false;
+    }
+}
+
+static uint32_t get_validatable_capabilities_count(void)
+{
+    MigrationState *s = migrate_get_current();
+    uint32_t result = 0;
+    int i;
+    for (i = 0; i < MIGRATION_CAPABILITY__MAX; i++) {
+        if (should_validate_capability(i) && s->enabled_capabilities[i]) {
+            result++;
+        }
+    }
+    return result;
+}
+
 static int configuration_pre_save(void *opaque)
 {
     SaveState *state = opaque;
     const char *current_name = MACHINE_GET_CLASS(current_machine)->name;
+    MigrationState *s = migrate_get_current();
+    int i, j;
 
     state->len = strlen(current_name);
     state->name = current_name;
     state->target_page_bits = qemu_target_page_bits();
 
+    state->caps_count = get_validatable_capabilities_count();
+    state->capabilities = g_renew(MigrationCapability, state->capabilities,
+                                  state->caps_count);
+    for (i = j = 0; i < MIGRATION_CAPABILITY__MAX; i++) {
+        if (should_validate_capability(i) && s->enabled_capabilities[i]) {
+            state->capabilities[j++] = i;
+        }
+    }
+
     return 0;
 }
 
@@ -280,6 +319,40 @@ static int configuration_pre_load(void *opaque)
     return 0;
 }
 
+static bool configuration_validate_capabilities(SaveState *state)
+{
+    bool ret = true;
+    MigrationState *s = migrate_get_current();
+    unsigned long *source_caps_bm;
+    int i;
+
+    source_caps_bm = bitmap_new(MIGRATION_CAPABILITY__MAX);
+    for (i = 0; i < state->caps_count; i++) {
+        MigrationCapability capability = state->capabilities[i];
+        set_bit(capability, source_caps_bm);
+    }
+
+    for (i = 0; i < MIGRATION_CAPABILITY__MAX; i++) {
+        bool source_state, target_state;
+        if (!should_validate_capability(i)) {
+            continue;
+        }
+        source_state = test_bit(i, source_caps_bm);
+        target_state = s->enabled_capabilities[i];
+        if (source_state != target_state) {
+            error_report("Capability %s is %s, but received capability is %s",
+                         MigrationCapability_str(i),
+                         target_state ? "on" : "off",
+                         source_state ? "on" : "off");
+            ret = false;
+            /* Don't break here to report all failed capabilities */
+        }
+    }
+
+    g_free(source_caps_bm);
+    return ret;
+}
+
 static int configuration_post_load(void *opaque, int version_id)
 {
     SaveState *state = opaque;
@@ -297,9 +370,53 @@ static int configuration_post_load(void *opaque, int version_id)
         return -EINVAL;
     }
 
+    if (!configuration_validate_capabilities(state)) {
+        return -EINVAL;
+    }
+
     return 0;
 }
 
+static int get_capability(QEMUFile *f, void *pv, size_t size,
+                          const VMStateField *field)
+{
+    MigrationCapability *capability = pv;
+    char capability_str[UINT8_MAX + 1];
+    uint8_t len;
+    int i;
+
+    len = qemu_get_byte(f);
+    qemu_get_buffer(f, (uint8_t *)capability_str, len);
+    capability_str[len] = '\0';
+    for (i = 0; i < MIGRATION_CAPABILITY__MAX; i++) {
+        if (!strcmp(MigrationCapability_str(i), capability_str)) {
+            *capability = i;
+            return 0;
+        }
+    }
+    error_report("Received unknown capability %s", capability_str);
+    return -EINVAL;
+}
+
+static int put_capability(QEMUFile *f, void *pv, size_t size,
+                          const VMStateField *field, QJSON *vmdesc)
+{
+    MigrationCapability *capability = pv;
+    const char *capability_str = MigrationCapability_str(*capability);
+    size_t len = strlen(capability_str);
+    assert(len <= UINT8_MAX);
+
+    qemu_put_byte(f, len);
+    qemu_put_buffer(f, (uint8_t *)capability_str, len);
+    return 0;
+}
+
+static const VMStateInfo vmstate_info_capability = {
+    .name = "capability",
+    .get  = get_capability,
+    .put  = put_capability,
+};
+
 /* The target-page-bits subsection is present only if the
  * target page size is not the same as the default (ie the
  * minimum page size for a variable-page-size guest CPU).
@@ -324,6 +441,25 @@ static const VMStateDescription vmstate_target_page_bits = {
     }
 };
 
+static bool vmstate_capabilites_needed(void *opaque)
+{
+    return get_validatable_capabilities_count() > 0;
+}
+
+static const VMStateDescription vmstate_capabilites = {
+    .name = "configuration/capabilities",
+    .version_id = 1,
+    .minimum_version_id = 1,
+    .needed = vmstate_capabilites_needed,
+    .fields = (VMStateField[]) {
+        VMSTATE_UINT32_V(caps_count, SaveState, 1),
+        VMSTATE_VARRAY_UINT32_ALLOC(capabilities, SaveState, caps_count, 1,
+                                    vmstate_info_capability,
+                                    MigrationCapability),
+        VMSTATE_END_OF_LIST()
+    }
+};
+
 static const VMStateDescription vmstate_configuration = {
     .name = "configuration",
     .version_id = 1,
@@ -337,6 +473,7 @@ static const VMStateDescription vmstate_configuration = {
     },
     .subsections = (const VMStateDescription*[]) {
         &vmstate_target_page_bits,
+        &vmstate_capabilites,
         NULL
     }
 };