[PATCH v12 12/13] virtio-iommu: Support migration

[Eric Auger <eric.auger@redhat.com>]

Add Migration support. We rely on recently added gtree and qlist
migration. We only migrate the domain gtree. The endpoint gtree
is re-constructed in a post-load operation.

Signed-off-by: Eric Auger <eric.auger@redhat.com>

---

v11 -> v12:
- do not migrate the endpoint gtree but reconstruct it from the
  domain gtree (Peter's suggestion)
- add MIG_PRI_IOMMU
---
 hw/virtio/virtio-iommu.c | 109 +++++++++++++++++++++++++++++++++++----
 1 file changed, 99 insertions(+), 10 deletions(-)

diff --git a/hw/virtio/virtio-iommu.c b/hw/virtio/virtio-iommu.c
index 09193970ee..b0fde3af6f 100644
--- a/hw/virtio/virtio-iommu.c
+++ b/hw/virtio/virtio-iommu.c
@@ -655,16 +655,6 @@ static uint64_t virtio_iommu_get_features(VirtIODevice *vdev, uint64_t f,
     return f;
 }
 
-/*
- * Migration is not yet supported: most of the state consists
- * of balanced binary trees which are not yet ready for getting
- * migrated
- */
-static const VMStateDescription vmstate_virtio_iommu_device = {
-    .name = "virtio-iommu-device",
-    .unmigratable = 1,
-};
-
 static gint int_cmp(gconstpointer a, gconstpointer b, gpointer user_data)
 {
     guint ua = GPOINTER_TO_UINT(a);
@@ -748,9 +738,108 @@ static void virtio_iommu_instance_init(Object *obj)
 {
 }
 
+#define VMSTATE_INTERVAL                               \
+{                                                      \
+    .name = "interval",                                \
+    .version_id = 1,                                   \
+    .minimum_version_id = 1,                           \
+    .fields = (VMStateField[]) {                       \
+        VMSTATE_UINT64(low, VirtIOIOMMUInterval),      \
+        VMSTATE_UINT64(high, VirtIOIOMMUInterval),     \
+        VMSTATE_END_OF_LIST()                          \
+    }                                                  \
+}
+
+#define VMSTATE_MAPPING                               \
+{                                                     \
+    .name = "mapping",                                \
+    .version_id = 1,                                  \
+    .minimum_version_id = 1,                          \
+    .fields = (VMStateField[]) {                      \
+        VMSTATE_UINT64(phys_addr, VirtIOIOMMUMapping),\
+        VMSTATE_UINT32(flags, VirtIOIOMMUMapping),    \
+        VMSTATE_END_OF_LIST()                         \
+    },                                                \
+}
+
+static const VMStateDescription vmstate_interval_mapping[2] = {
+    VMSTATE_MAPPING,   /* value */
+    VMSTATE_INTERVAL   /* key   */
+};
+
+static int domain_preload(void *opaque)
+{
+    VirtIOIOMMUDomain *domain = opaque;
+
+    domain->mappings = g_tree_new_full((GCompareDataFunc)interval_cmp,
+                                       NULL, g_free, g_free);
+    return 0;
+}
+
+static const VMStateDescription vmstate_endpoint = {
+    .name = "endpoint",
+    .version_id = 1,
+    .minimum_version_id = 1,
+    .fields = (VMStateField[]) {
+        VMSTATE_UINT32(id, VirtIOIOMMUEndpoint),
+        VMSTATE_END_OF_LIST()
+    }
+};
+
+static const VMStateDescription vmstate_domain = {
+    .name = "domain",
+    .version_id = 1,
+    .minimum_version_id = 1,
+    .pre_load = domain_preload,
+    .fields = (VMStateField[]) {
+        VMSTATE_UINT32(id, VirtIOIOMMUDomain),
+        VMSTATE_GTREE_V(mappings, VirtIOIOMMUDomain, 1,
+                        vmstate_interval_mapping,
+                        VirtIOIOMMUInterval, VirtIOIOMMUMapping),
+        VMSTATE_QLIST_V(endpoint_list, VirtIOIOMMUDomain, 1,
+                        vmstate_endpoint, VirtIOIOMMUEndpoint, next),
+        VMSTATE_END_OF_LIST()
+    }
+};
+
+static gboolean reconstruct_endpoints(gpointer key, gpointer value,
+                                      gpointer data)
+{
+    VirtIOIOMMU *s = (VirtIOIOMMU *)data;
+    VirtIOIOMMUDomain *d = (VirtIOIOMMUDomain *)value;
+    VirtIOIOMMUEndpoint *iter;
+
+    QLIST_FOREACH(iter, &d->endpoint_list, next) {
+        iter->domain = d;
+        g_tree_insert(s->endpoints, GUINT_TO_POINTER(iter->id), iter);
+    }
+    return false; /* continue the domain traversal */
+}
+
+static int iommu_post_load(void *opaque, int version_id)
+{
+    VirtIOIOMMU *s = opaque;
+
+    g_tree_foreach(s->domains, reconstruct_endpoints, s);
+    return 0;
+}
+
+static const VMStateDescription vmstate_virtio_iommu_device = {
+    .name = "virtio-iommu-device",
+    .minimum_version_id = 1,
+    .version_id = 1,
+    .post_load = iommu_post_load,
+    .fields = (VMStateField[]) {
+        VMSTATE_GTREE_DIRECT_KEY_V(domains, VirtIOIOMMU, 1,
+                                   &vmstate_domain, VirtIOIOMMUDomain),
+        VMSTATE_END_OF_LIST()
+    },
+};
+
 static const VMStateDescription vmstate_virtio_iommu = {
     .name = "virtio-iommu",
     .minimum_version_id = 1,
+    .priority = MIG_PRI_IOMMU,
     .version_id = 1,
     .fields = (VMStateField[]) {
         VMSTATE_VIRTIO_DEVICE,
-- 
2.20.1