[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: RMRRs and Phantom Functions
On 27.04.2022 12:05, Andrew Cooper wrote: > On 27/04/2022 07:59, Jan Beulich wrote: >> On 26.04.2022 19:51, Andrew Cooper wrote: >>> Hello, >>> >>> Edvin has found a machine with some very weird properties. It is an HP >>> ProLiant BL460c Gen8 with: >>> >>> \-[0000:00]-+-00.0 Intel Corporation Xeon E5/Core i7 DMI2 >>> +-01.0-[11]-- >>> +-01.1-[02]-- >>> +-02.0-[04]--+-00.0 Emulex Corporation OneConnect 10Gb NIC >>> (be3) >>> | +-00.1 Emulex Corporation OneConnect 10Gb NIC >>> (be3) >>> | +-00.2 Emulex Corporation OneConnect 10Gb >>> iSCSI Initiator (be3) >>> | \-00.3 Emulex Corporation OneConnect 10Gb >>> iSCSI Initiator (be3) >>> >>> yet all 4 other functions on the device periodically hit IOMMU faults >>> (~once every 5 mins, so definitely stats). >>> >>> (XEN) [VT-D]DMAR:[DMA Write] Request device [0000:04:00.4] fault addr >>> bdf80000 >>> (XEN) [VT-D]DMAR:[DMA Write] Request device [0000:04:00.5] fault addr >>> bdf80000 >>> (XEN) [VT-D]DMAR:[DMA Write] Request device [0000:04:00.6] fault addr >>> bdf80000 >>> (XEN) [VT-D]DMAR:[DMA Write] Request device [0000:04:00.7] fault addr >>> bdf80000 >>> >>> There are several RMRRs covering the these devices, with: >>> >>> (XEN) [VT-D]found ACPI_DMAR_RMRR: >>> (XEN) [VT-D] endpoint: 0000:03:00.0 >>> (XEN) [VT-D] endpoint: 0000:01:00.0 >>> (XEN) [VT-D] endpoint: 0000:01:00.2 >>> (XEN) [VT-D] endpoint: 0000:04:00.0 >>> (XEN) [VT-D] endpoint: 0000:04:00.1 >>> (XEN) [VT-D] endpoint: 0000:04:00.2 >>> (XEN) [VT-D] endpoint: 0000:04:00.3 >>> (XEN) [VT-D]dmar.c:608: RMRR region: base_addr bdf8f000 end_addr bdf92fff >>> >>> being the one relevant to these faults. I've not manually decoded the >>> DMAR table because device paths are horrible to follow but there are at >>> least the correct number of endpoints. The functions all have SR-IOV >>> (disabled) and ARI (enabled). None have any Phantom functions described. >>> >>> Specifying pci-phantom=04:00,1 does appear to work around the faults, >>> but it's not right, because functions 1 thru 3 aren't actually phantom. >> Indeed, and I think you really mean "pci-phantom=04:00,4". > > As a quick tangent, the cmdline docs for pci-phantom= are in desperate > need of an example and a description of how stride works. I've got some > ideas and notes jotted down. > > Do we really mean ,4 here? What happens for function 1? With stride 4 function 1's single phantom function is function 5. With stride 1, as you had it before, functions 1...7 would all be considered phantom functions of function 0. Jan
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