On 06/10/2014 06:55 AM, Eric Blake wrote: > On 06/10/2014 03:29 AM, Peter Lieven wrote: >> if a saved vm has unknown flags in the memory data qemu >> currently simply ignores this flag and continues which >> yields in an unpredictable result. >> >> This patch catches all unknown flags and aborts the >> loading of the vm. Additionally error reports are thrown >> if the migration aborts abnormally. >>
>> } else if (flags & RAM_SAVE_FLAG_HOOK) {
>> ram_control_load_hook(f, flags);
>> + } else if (flags & RAM_SAVE_FLAG_EOS) {
>
> Umm, is the migration format specifically documented as having at most
> one flag per operation, or is it valid to send two flags at once? That
> is, can I send RAM_SAVE_FLAG_XBZRLE | RAM_SAVE_FLAG_HOOK on a single
> packet? Should we be flagging streams that send unexpected flag
> combinations as invalid, even when each flag is in isolation okay,
> rather than the current behavior of silently prioritizing one flag and
> ignoring the other?
For that matter, would it be better to change the if-tree into a switch,
so that the default case catches unsupported combinations?
switch (flags) {
...
case RAM_SAVE_FLAG_HOOK: ...
case RAM_SAVE_FLAG_EOS: ...
default: report unsupported flags value
}
--
Eric Blake eblake redhat com +1-919-301-3266
Libvirt virtualization library http://libvirt.org
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