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Leon Romanovsky authored
A typical cloud provider SR-IOV use case is to create many VFs for use by guest VMs. The VFs may not be assigned to a VM until a customer requests a VM of a certain size, e.g., number of CPUs. A VF may need MSI-X vectors proportional to the number of CPUs in the VM, but there is no standard way to change the number of MSI-X vectors supported by a VF. Some Mellanox ConnectX devices support dynamic assignment of MSI-X vectors to SR-IOV VFs. This can be done by the PF driver after VFs are enabled, and it can be done without affecting VFs that are already in use. The hardware supports a limited pool of MSI-X vectors that can be assigned to the PF or to individual VFs. This is device-specific behavior that requires support in the PF driver. Add a read-only "sriov_vf_total_msix" sysfs file for the PF and a writable "sriov_vf_msix_count" file for each VF. Management software may use these to learn how many MSI-X vectors are available and to dynamically assi...
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