Sharing message-signaled interrupts between peripheral component interconnect (PCI) I/O devices

摘要

A PCI function, such as a device driver, may request that additional MSI resources be allocated to an I/O device coupled to a PCI Host Bridge (PHB). However, there may not be any unallocated MSI resource remaining in the PHB. Instead, a hypervisor may request to borrow MSI resources assigned to other PCI functions in the system. For example, the PCI function requesting the additional MSI resources may ask for a certain number of MSI resources for a certain period of time—e.g., a lease. The hypervisor then determines which of the other PCI functions (referred to as a loaning PCI functions) are willing to lend or loan their MSI resources. Once the MSI resources available for lease are known, the hypervisor informs the requesting PCI function of these resources which, in turn, binds the additional MSI resources to the I/O device.

主权项

1. A computing system, comprising:
a first Peripheral Component Interconnect (PCI) enabled I/O device; a second PCI-enabled I/O device that is allocated Message Signaled Interrupt (MSI) resources; a PCI Host Bridge (PHB) coupled to the first and second I/O devices; and a hypervisor configured to:
upon receiving a first request to increase MSI resources allocated to the first I/O device, transmit a second request to a managing entity corresponding to the second I/O device, the second request indicating a desired number of MSI resources and a desired lease time;receive a confirmation from the managing entity, the confirmation indicating a number of MSI resources available for lease from the second I/O device and a negotiated lease time associated with each of the MSI resources available for lease, wherein at least one of the MSI resources available for lease is allocated to the first I/O device based on the negotiated lease time.