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arch_xen_unpopulated_init() gives up immediately on a domain that is using ACPI, so xen_alloc_unpopulated_pages() has no address space to hand out and falls back to ballooning the domain's own memory out instead. On arm64 that fallback grows the balloon through memory hotplug, and add_memory_resource() picks a range from iomem_resource with nothing to say whether it is safe to map. When it is not, arch_add_memory() walks into BUG_ON(!pgattr_change_is_safe(...)) in alloc_init_cont_pte(), and creating a guest takes dom0 down with it. The regions are not actually missing. Xen publishes them in the hypervisor node of the device tree it hands over whichever way the machine is described, and dt_scan_depth1_nodes() has already read that node during early boot -- it is how the tree was judged empty enough to use ACPI in the first place. What is missing is a reader: the tree is never unflattened when ACPI is in use, so of_find_compatible_node() below has nothing to walk. Read them from the flat tree in that case. The device tree path is unchanged. Signed-off-by: Alex Zenla <alex@edera.dev>
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arch_xen_unpopulated_init() gives up immediately on a domain that is using ACPI, so xen_alloc_unpopulated_pages() has no address space to hand out and falls back to ballooning the domain's own memory out instead. On arm64 that fallback grows the balloon through memory hotplug, and add_memory_resource() picks a range from iomem_resource with nothing to say whether it is safe to map. When it is not, arch_add_memory() walks into
in alloc_init_cont_pte(), and creating a guest takes dom0 down with it.
The regions are not actually missing. Xen publishes them in the hypervisor node of the device tree it hands over whichever way the machine is described, and dt_scan_depth1_nodes() has already read that node during early boot -- it is how the tree was judged empty enough to use ACPI in the first place. What is missing is a reader: the tree is never unflattened when ACPI is in use, so of_find_compatible_node() below has nothing to walk.
Read them from the flat tree in that case. The device tree path is unchanged.