+
+ for (; len > 0; len -= used_len) {
+ block = qemu_ram_block_from_host(addr, false, &offset);
+ if (unlikely(!block)) {
+ return;
We should never reach here, should we? Assuming the callers of this
function should always pass in a correct host address. If we are very
sure that the host addr should be valid, could we just assert?
Probably not the case, because of the corner case that the memory would be
hot unplugged after the free page is reported to QEMU.
Question: Do we allow to do hot plug/unplug for memory during
migration?
I think so. From the code, I don't find where it forbids memory hotplug
during migration.
I don't play with that much; do we need to do "device_add" after all?
(qemu) object_add
memory-backend-file,id=mem1,size=1G,mem-path=/mnt/hugepages-1GB
(qemu) device_add pc-dimm,id=dimm1,memdev=mem1
If so, we may not allow that since in qdev_device_add() we don't allow
that:
if (!migration_is_idle()) {
error_setg(errp, "device_add not allowed while migrating");
return NULL;
}