From: Leon Romanovsky <leonro@xxxxxxxxxx> Changelog v1: * Improved wording and commit messages of first PCI patch * Added extra PCI patch to provide total number of MSI-X vectors * Prohibited read of vf_msix_vec sysfs file if driver doesn't support write * Removed extra function definition in pci.h v0: https://lore.kernel.org/linux-pci/20210103082440.34994-1-leon@xxxxxxxxxx -------------------------------------------------------------------- Hi, The number of MSI-X vectors is PCI property visible through lspci, that field is read-only and configured by the device. The static assignment of an amount of MSI-X vectors doesn't allow utilize the newly created VF because it is not known to the device the future load and configuration where that VF will be used. The VFs are created on the hypervisor and forwarded to the VMs that have different properties (for example number of CPUs). To overcome the inefficiency in the spread of such MSI-X vectors, we allow the kernel to instruct the device with the needed number of such vectors, before VF is initialized and bounded to the driver. Before this series: [root@server ~]# lspci -vs 0000:08:00.2 08:00.2 Ethernet controller: Mellanox Technologies MT27800 Family [ConnectX-5 Virtual Function] .... Capabilities: [9c] MSI-X: Enable- Count=12 Masked- Configuration script: 1. Start fresh echo 0 > /sys/bus/pci/devices/0000\:08\:00.0/sriov_numvfs modprobe -q -r mlx5_ib mlx5_core 2. Ensure that driver doesn't run and it is safe to change MSI-X echo 0 > /sys/bus/pci/devices/0000\:08\:00.0/sriov_drivers_autoprobe 3. Load driver for the PF modprobe mlx5_core 4. Configure one of the VFs with new number echo 2 > /sys/bus/pci/devices/0000\:08\:00.0/sriov_numvfs echo 21 > /sys/bus/pci/devices/0000\:08\:00.2/vf_msix_vec After this series: [root@server ~]# lspci -vs 0000:08:00.2 08:00.2 Ethernet controller: Mellanox Technologies MT27800 Family [ConnectX-5 Virtual Function] .... Capabilities: [9c] MSI-X: Enable- Count=21 Masked- Thanks Leon Romanovsky (5): PCI: Add sysfs callback to allow MSI-X table size change of SR-IOV VFs PCI: Add SR-IOV sysfs entry to read number of MSI-X vectors net/mlx5: Add dynamic MSI-X capabilities bits net/mlx5: Dynamically assign MSI-X vectors count net/mlx5: Allow to the users to configure number of MSI-X vectors Documentation/ABI/testing/sysfs-bus-pci | 34 +++++++ .../net/ethernet/mellanox/mlx5/core/main.c | 5 + .../ethernet/mellanox/mlx5/core/mlx5_core.h | 6 ++ .../net/ethernet/mellanox/mlx5/core/pci_irq.c | 62 +++++++++++++ .../net/ethernet/mellanox/mlx5/core/sriov.c | 52 ++++++++++- drivers/pci/iov.c | 93 +++++++++++++++++++ drivers/pci/msi.c | 29 ++++++ drivers/pci/pci-sysfs.c | 1 + drivers/pci/pci.h | 5 + include/linux/mlx5/mlx5_ifc.h | 11 ++- include/linux/pci.h | 10 +- 11 files changed, 304 insertions(+), 4 deletions(-) -- 2.29.2
