Abstract:
A method and apparatus for reporting events into at least one event log are presented. An “access” event entry may be added to an event log stored in memory when a peripheral device accesses an address of a memory page described by a page table entry (PTE). A “dirty” event entry may be added to an event log stored in memory when a page writes to a memory page. The event log may reside in an input/output memory management unit (IOMMU) that includes a translation lookaside buffer (TLB). The IOMMU may report the event log entries to system memory. When there is no entry in the TLB and a direct memory access (DMA) read operation enters the IOMMU, a PTE may be loaded into the TLB after updating an access log to calculate an address. If the DMA operation is not a read operation, both dirty and access logs may be updated.
Abstract:
A system and method of managing requests from peripherals in a computer system are provided. In the system and method, an input/output memory management unit (IOMMU) receives a peripheral page request (PPR) from a peripheral. In response to a determination that a criterion regarding an available capacity of a PPR log is satisfied, a completion message is sent to the peripheral indicating that the PPR is complete and the PPR is discarded without queuing the PPR in the PPR log.
Abstract:
A data processing device is provided that employs multiple translation look-aside buffers (TLBs) associated with respective processors that are configured to store selected address translations of a page table of a memory shared by the processors. The processing device is configured such that when an address translation is requested by a processor and is not found in the TLB associated with that processor, another TLB is probed for the requested address translation. The probe across to the other TLB may occur in advance of a walk of the page table for the requested address or alternatively a walk can be initiated concurrently with the probe. Where the probe successfully finds the requested address translation, the page table walk can be avoided or discontinued.
Abstract:
A method of managing peripherals is performed in a device coupled to a processor in a computer system. For example, the method is performed in an input/output memory management unit (IOMMU) or a peripheral. The method includes recording information associated with I/O activity for one or more peripherals in a log that has a first base address. The method also includes, without pausing the I/O activity, specifying a second base address for the log and setting a head pointer and a tail pointer for the log to indicate that the log is empty. The second base address is distinct from the first base address.
Abstract:
A data processing device is provided that employs multiple translation look-aside buffers (TLBs) associated with respective processors that are configured to store selected address translations of a page table of a memory shared by the processors. The processing device is configured such that when an address translation is requested by a processor and is not found in the TLB associated with that processor, another TLB is probed for the requested address translation. The probe across to the other TLB may occur in advance of a walk of the page table for the requested address or alternatively a walk can be initiated concurrently with the probe. Where the probe successfully finds the requested address translation, the page table walk can be avoided or discontinued.
Abstract:
A method of managing peripherals is performed in a device coupled to a processor in a computer system. For example, the method is performed in an input/output memory management unit (IOMMU) or a peripheral. The method includes recording information associated with I/O activity for one or more peripherals in a log that has a first base address. The method also includes, without pausing the I/O activity, specifying a second base address for the log and setting a head pointer and a tail pointer for the log to indicate that the log is empty. The second base address is distinct from the first base address.
Abstract:
A system and method of managing requests from peripherals in a computer system are provided. In the system and method, an input/output memory management unit (IOMMU) receives a peripheral page request (PPR) from a peripheral. In response to a determination that a criterion regarding an available capacity of a PPR log is satisfied, a completion message is sent to the peripheral indicating that the PPR is complete and the PPR is discarded without queuing the PPR in the PPR log.