From b0104664c69c54ba58cec25a5a74541bfe283e9f Mon Sep 17 00:00:00 2001
From: Peter Krempa <pkrempa@redhat.com>
Date: Mon, 8 Feb 2021 10:42:28 +0100
Subject: [PATCH] qemu: migration_params: Add infrastructure for
 'dirty-bitmaps' migration feature

Add the migration capability flag and the propagation of the
corresponding mapping configuration. The mapping will be produced from
the bitmaps on disk depending on both sides of the migration and the
necessity to perform merges.

Signed-off-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Jiri Denemark <jdenemar@redhat.com>
---
 src/qemu/qemu_migration_params.c | 29 +++++++++++++++++++++++++++++
 src/qemu/qemu_migration_params.h |  5 +++++
 2 files changed, 34 insertions(+)

diff --git a/src/qemu/qemu_migration_params.c b/src/qemu/qemu_migration_params.c
index 510dad783a..e9b4601510 100644
--- a/src/qemu/qemu_migration_params.c
+++ b/src/qemu/qemu_migration_params.c
@@ -63,6 +63,7 @@ struct _qemuMigrationParams {
     unsigned long long compMethods; /* bit-wise OR of qemuMigrationCompressMethod */
     virBitmapPtr caps;
     qemuMigrationParamValue params[QEMU_MIGRATION_PARAM_LAST];
+    virJSONValuePtr blockDirtyBitmapMapping;
 };
 
 typedef enum {
@@ -89,6 +90,7 @@ VIR_ENUM_IMPL(qemuMigrationCapability,
               "pause-before-switchover",
               "late-block-activate",
               "multifd",
+              "dirty-bitmaps",
 );
 
 
@@ -265,6 +267,7 @@ qemuMigrationParamsFree(qemuMigrationParamsPtr migParams)
     }
 
     virBitmapFree(migParams->caps);
+    virJSONValueFree(migParams->blockDirtyBitmapMapping);
     g_free(migParams);
 }
 
@@ -524,6 +527,20 @@ qemuMigrationParamsSetCompression(virTypedParameterPtr params,
 }
 
 
+void
+qemuMigrationParamsSetBlockDirtyBitmapMapping(qemuMigrationParamsPtr migParams,
+                                              virJSONValuePtr *params)
+{
+    virJSONValueFree(migParams->blockDirtyBitmapMapping);
+    migParams->blockDirtyBitmapMapping = g_steal_pointer(params);
+
+    if (migParams->blockDirtyBitmapMapping)
+        ignore_value(virBitmapSetBit(migParams->caps, QEMU_MIGRATION_CAP_BLOCK_DIRTY_BITMAPS));
+    else
+        ignore_value(virBitmapClearBit(migParams->caps, QEMU_MIGRATION_CAP_BLOCK_DIRTY_BITMAPS));
+}
+
+
 qemuMigrationParamsPtr
 qemuMigrationParamsFromFlags(virTypedParameterPtr params,
                              int nparams,
@@ -747,6 +764,17 @@ qemuMigrationParamsToJSON(qemuMigrationParamsPtr migParams)
             return NULL;
     }
 
+    if (migParams->blockDirtyBitmapMapping) {
+        g_autoptr(virJSONValue) mapping = virJSONValueCopy(migParams->blockDirtyBitmapMapping);
+
+        if (!mapping)
+            return NULL;
+
+        if (virJSONValueObjectAppend(params, "block-bitmap-mapping", mapping) < 0)
+            return NULL;
+        mapping = NULL;
+    }
+
     return g_steal_pointer(&params);
 }
 
@@ -1202,6 +1230,7 @@ qemuMigrationParamsReset(virQEMUDriverPtr driver,
         goto cleanup;
 
     qemuMigrationParamsResetTLS(driver, vm, asyncJob, origParams, apiFlags);
+    /* We don't reset 'block-bitmap-mapping' as it can't be unset */
 
  cleanup:
     virErrorRestore(&err);
diff --git a/src/qemu/qemu_migration_params.h b/src/qemu/qemu_migration_params.h
index 9876101bfc..f1db42ce94 100644
--- a/src/qemu/qemu_migration_params.h
+++ b/src/qemu/qemu_migration_params.h
@@ -39,6 +39,7 @@ typedef enum {
     QEMU_MIGRATION_CAP_PAUSE_BEFORE_SWITCHOVER,
     QEMU_MIGRATION_CAP_LATE_BLOCK_ACTIVATE,
     QEMU_MIGRATION_CAP_MULTIFD,
+    QEMU_MIGRATION_CAP_BLOCK_DIRTY_BITMAPS,
 
     QEMU_MIGRATION_CAP_LAST
 } qemuMigrationCapability;
@@ -132,6 +133,10 @@ qemuMigrationParamsGetULL(qemuMigrationParamsPtr migParams,
                           qemuMigrationParam param,
                           unsigned long long *value);
 
+void
+qemuMigrationParamsSetBlockDirtyBitmapMapping(qemuMigrationParamsPtr migParams,
+                                              virJSONValuePtr *params);
+
 int
 qemuMigrationParamsCheck(virQEMUDriverPtr driver,
                          virDomainObjPtr vm,
-- 
2.39.5