For things like hot-plugging of new QPI/UPI segments (e.g. populating a new CPU socket ) or of new DIMMs an attention button is used to invoke the SMM handler and reconfigure the SAD and the TAD in each node.
But if the OS remaps a PCI device (e.g. changing the value of one of its BARs) attached to a socket's local PCIe link, it can potentially use an address not routed to that socket by the current SAD configuration.
How is this case handled? How is the physical address space mapped between sockets (particularly, the part not backed by the RAM)?
