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Is > xen_released_pages expected to be non-zero for a domU? Oh, yes. In fact I think the patch here is wrong for PV dom0, as it shouldn't subtract xen_released_pages from xen_start_info->nr_pages. I will need to send v2. > IIRC, for a domU, xl writes the xenstore nodes as the ~build time memory > value, which doesn't include video ram. Later QEMU populates the videoram, > which increases current reservation. Then the two values don't match when > the domU initializes the balloon values. Yeah, the modifications done to the physmap by QEMU skew the target, so what's in xenstore doesn't match what `XENMEM_current_reservation` returns. However is very hard to fix this. We could attempt to make the toolstack write the xenstore node based on the return of XENMEM_current_reservation once QEMU has started. Sadly a domU would have no way to know whether the xenstore value accounts for the QEMU consumed memory or not. We would need to introduce a new target xenstore node, which is equally messy. Thanks for the testing. Roger.