Interrupts - 4.0 English

QDMA Subsystem for PCI Express Product Guide (PG302)

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4.0 English

The QDMA Subsystem for PCIe supports up to 2K total MSI-X vectors. A single MSI-X vector can be used to support multiple queues. Each function can support up to 8 vectors (8 *256 function = 2K vectors). When SR-IOV functions are not enabled, each PF function can support up to 32 vectors. Contact Xilinx Support if more than 8 vectors are needed for each function.

The QDMA supports Interrupt Aggregation. Each vector has an associated Interrupt Aggregation Ring. The QID and status of queues requiring service are written into the Interrupt Aggregation Ring. When a PCIe® MSI-X interrupt is received by the Host, the software reads the Interrupt Aggregation Ring to determine which queue needs service. Mapping of queues to vectors is programmable vector number provided in the queue context. It supports MSI-X interrupt modes for SR-IOV and non-SR-IOV.