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| author | Leon Romanovsky <leonro@nvidia.com> | 2021-04-04 10:22:18 +0300 |
|---|---|---|
| committer | Leon Romanovsky <leonro@nvidia.com> | 2021-04-04 10:26:30 +0300 |
| commit | c3d5c2d96d69f2578d6fbf66e39cc2cf840d9812 (patch) | |
| tree | 04d5f784853bafe12c034f35a9a013431a746217 /drivers/pci/pci.h | |
| parent | 26bf30902c10473ba38f220d3401a61c56d8db3b (diff) | |
| download | linux-c3d5c2d96d69f2578d6fbf66e39cc2cf840d9812.tar.xz | |
PCI/IOV: Add sysfs MSI-X vector assignment interface
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 assign
them to VFs before the VFs are passed through to a VM.
If the PF driver implements the ->sriov_get_vf_total_msix() callback,
"sriov_vf_total_msix" contains the total number of MSI-X vectors available
for distribution among VFs.
If no driver is bound to the VF, writing "N" to "sriov_vf_msix_count" uses
the PF driver ->sriov_set_msix_vec_count() callback to assign "N" MSI-X
vectors to the VF. When a VF driver subsequently reads the MSI-X Message
Control register, it will see the new Table Size "N".
Link: https://lore.kernel.org/linux-pci/20210314124256.70253-2-leon@kernel.org
Acked-by: Bjorn Helgaas <bhelgaas@google.com>
Signed-off-by: Leon Romanovsky <leonro@nvidia.com>
Diffstat (limited to 'drivers/pci/pci.h')
| -rw-r--r-- | drivers/pci/pci.h | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h index ef7c4661314f..afb87b917f07 100644 --- a/drivers/pci/pci.h +++ b/drivers/pci/pci.h @@ -501,7 +501,8 @@ void pci_iov_update_resource(struct pci_dev *dev, int resno); resource_size_t pci_sriov_resource_alignment(struct pci_dev *dev, int resno); void pci_restore_iov_state(struct pci_dev *dev); int pci_iov_bus_range(struct pci_bus *bus); -extern const struct attribute_group sriov_dev_attr_group; +extern const struct attribute_group sriov_pf_dev_attr_group; +extern const struct attribute_group sriov_vf_dev_attr_group; #else static inline int pci_iov_init(struct pci_dev *dev) { |