[PATCH v2 18/19] virtio-mem: Migration sanity checks

David Hildenbrand
2020-05-20T12:33:28Z

We want to make sure that certain properties don't change during
migration, especially to catch user errors in a nice way. Let's migrate
a temporary structure and validate that the properties didn't change.

Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: "Dr. David Alan Gilbert" <dgilbert@redhat.com>
Signed-off-by: David Hildenbrand <david@redhat.com>
---
hw/virtio/virtio-mem.c | 69 ++++++++++++++++++++++++++++++++++++++++++
1 file changed, 69 insertions(+)

diff --git a/hw/virtio/virtio-mem.c b/hw/virtio/virtio-mem.c
index 11c500960c..d863f336e8 100644
--- a/hw/virtio/virtio-mem.c
+++ b/hw/virtio/virtio-mem.c
@@ -511,12 +511,81 @@ static int virtio_mem_post_load(void *opaque, int version_id)
return virtio_mem_restore_unplugged(VIRTIO_MEM(opaque));
}

+typedef struct VirtIOMEMMigSanityChecks {
+ VirtIOMEM *parent;
+ uint64_t addr;
+ uint64_t region_size;
+ uint32_t block_size;
+ uint32_t node;
+} VirtIOMEMMigSanityChecks;
+
+static int virtio_mem_mig_sanity_checks_pre_save(void *opaque)
+{
+ VirtIOMEMMigSanityChecks *tmp = opaque;
+ VirtIOMEM *vmem = tmp->parent;
+
+ tmp->addr = vmem->addr;
+ tmp->region_size = memory_region_size(&vmem->memdev->mr);
+ tmp->block_size = vmem->block_size;
+ tmp->node = vmem->node;
+ return 0;
+}
+
+static int virtio_mem_mig_sanity_checks_post_load(void *opaque, int version_id)
+{
+ VirtIOMEMMigSanityChecks *tmp = opaque;
+ VirtIOMEM *vmem = tmp->parent;
+ const uint64_t new_region_size = memory_region_size(&vmem->memdev->mr);
+
+ if (tmp->addr != vmem->addr) {
+ error_report("Property '%s' changed from 0x%" PRIx64 " to 0x%" PRIx64,
+ VIRTIO_MEM_ADDR_PROP, tmp->addr, vmem->addr);
+ return -EINVAL;
+ }
+ /*
+ * Note: Preparation for resizeable memory regions. The maximum size
+ * of the memory region must not change during migration.
+ */
+ if (tmp->region_size != new_region_size) {
+ error_report("region size changed from 0x%" PRIx64 " to 0x%" PRIx64,
+ tmp->region_size, new_region_size);
+ return -EINVAL;
+ }
+ if (tmp->block_size != vmem->block_size) {
+ error_report("Property '%s' changed from %0x" PRIx32 " to %0x" PRIx32,
+ VIRTIO_MEM_BLOCK_SIZE_PROP, tmp->block_size,
+ vmem->block_size);
+ return -EINVAL;
+ }
+ if (tmp->node != vmem->node) {
+ error_report("Property '%s' changed from %" PRIu32 " to %" PRIu32,
+ VIRTIO_MEM_NODE_PROP, tmp->node, vmem->node);
+ return -EINVAL;
+ }
+ return 0;
+}
+
+static const VMStateDescription vmstate_virtio_mem_sanity_checks = {
+ .name = "virtio-mem-device/sanity-checks",
+ .pre_save = virtio_mem_mig_sanity_checks_pre_save,
+ .post_load = virtio_mem_mig_sanity_checks_post_load,
+ .fields = (VMStateField[]) {
+ VMSTATE_UINT64(addr, VirtIOMEMMigSanityChecks),
+ VMSTATE_UINT64(region_size, VirtIOMEMMigSanityChecks),
+ VMSTATE_UINT32(block_size, VirtIOMEMMigSanityChecks),
+ VMSTATE_UINT32(node, VirtIOMEMMigSanityChecks),
+ VMSTATE_END_OF_LIST(),
+ },
+};
+
static const VMStateDescription vmstate_virtio_mem_device = {
.name = "virtio-mem-device",
.minimum_version_id = 1,
.version_id = 1,
.post_load = virtio_mem_post_load,
.fields = (VMStateField[]) {
+ VMSTATE_WITH_TMP(VirtIOMEM, VirtIOMEMMigSanityChecks,
+ vmstate_virtio_mem_sanity_checks),
VMSTATE_UINT64(usable_region_size, VirtIOMEM),
VMSTATE_UINT64(size, VirtIOMEM),
VMSTATE_UINT64(requested_size, VirtIOMEM),
--
2.25.4