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https://github.com/AuxXxilium/linux_dsm_epyc7002.git
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ATU (Address Translation Unit) is a new IOMMU in SPARC supported with Hypervisor IOMMU v2 APIs. Current SPARC IOMMU supports only 32bit address ranges and one TSB per PCIe root complex that has a 2GB per root complex DVMA space limit. The limit has become a scalability bottleneck nowadays that a typical 10G/40G NIC can consume 300MB-500MB DVMA space per instance. When DVMA resource is exhausted, devices will not be usable since the driver can't allocate DVMA. ATU removes bottleneck by allowing guest os to create IOTSB of size 32G (or more) with 64bit address ranges available in ATU HW. 32G is more than enough DVMA space to be shared by all PCIe devices under root complex contrast to 2G space provided by legacy IOMMU. ATU allows PCIe devices to use 64bit DMA addressing. Devices which choose to use 32bit DMA mask will continue to work with the existing legacy IOMMU. Signed-off-by: Tushar Dave <tushar.n.dave@oracle.com> Reviewed-by: chris hyser <chris.hyser@oracle.com> Acked-by: Sowmini Varadhan <sowmini.varadhan@oracle.com> Signed-off-by: David S. Miller <davem@davemloft.net> |
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| net | ||
| oprofile | ||
| power | ||
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