linux/drivers/pci
Leon Romanovsky c3d5c2d96d 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>
2021-04-04 10:26:30 +03:00
..
controller pci-v5.12-changes 2021-02-25 09:56:08 -08:00
endpoint PCI: endpoint: Add EP function driver to provide NTB functionality 2021-02-23 14:12:28 -06:00
hotplug PCI: acpiphp: Remove unused acpiphp_callback typedef 2021-02-18 17:32:37 -06:00
pcie pci-v5.12-changes 2021-02-25 09:56:08 -08:00
switch PCI: switchtec: Add missing __iomem tag to fix sparse warnings 2020-07-31 11:23:45 -05:00
access.c Merge branch 'pci/misc' 2020-08-05 18:24:16 -05:00
ats.c Merge branch 'pci/doc' 2020-08-05 18:24:22 -05:00
bus.c PCI: Add device even if driver attach failed 2020-07-07 17:33:41 -05:00
ecam.c PCI: Unify ECAM constants in native PCI Express drivers 2020-12-10 14:55:49 -06:00
host-bridge.c
iov.c PCI/IOV: Add sysfs MSI-X vector assignment interface 2021-04-04 10:26:30 +03:00
irq.c PCI: Remove unused pci_lost_interrupt() 2020-07-29 14:25:18 -05:00
Kconfig pci-v5.10-changes 2020-10-22 12:41:00 -07:00
Makefile PCI: Apply CONFIG_PCI_DEBUG to entire drivers/pci hierarchy 2021-02-09 15:10:20 -06:00
mmap.c
msi.c PCI/MSI: Set device flag indicating only 32-bit MSI support 2020-12-04 12:17:04 -06:00
of.c PCI: of: Warn if non-prefetchable memory aperture size is > 32-bit 2020-11-18 16:16:38 +00:00
p2pdma.c RDMA 5.11 pull request 2020-12-16 13:42:26 -08:00
pci-acpi.c pci-v5.11-changes 2020-12-15 16:49:59 -08:00
pci-bridge-emul.c PCI: pci-bridge-emul: Fix array overruns, improve safety 2021-02-17 17:25:31 -06:00
pci-bridge-emul.h PCI: pci-bridge-emul: Fix big-endian support 2019-10-17 12:42:48 +01:00
pci-driver.c Merge branch 'pci/misc' 2020-12-15 15:11:08 -06:00
pci-label.c PCI: Replace http:// links with https:// 2020-06-30 13:05:09 -05:00
pci-mid.c PCI: intel-mid: Convert to new X86 CPU match macros 2020-03-24 21:35:06 +01:00
pci-pf-stub.c PCI/IOV: Simplify pci-pf-stub with module_pci_driver() 2020-09-17 12:40:20 -05:00
pci-stub.c
pci-sysfs.c PCI/IOV: Add sysfs MSI-X vector assignment interface 2021-04-04 10:26:30 +03:00
pci.c pci-v5.12-changes 2021-02-25 09:56:08 -08:00
pci.h PCI/IOV: Add sysfs MSI-X vector assignment interface 2021-04-04 10:26:30 +03:00
probe.c Merge branch 'pci/msi' 2020-12-15 15:11:08 -06:00
proc.c PCI: Revoke mappings like devmem 2021-02-11 15:59:19 +01:00
quirks.c Merge branch 'remotes/lorenzo/pci/dwc' 2020-12-15 15:11:11 -06:00
remove.c PCI: Fix pci_host_bridge struct device release/free handling 2020-05-14 16:36:35 -05:00
rom.c PCI: Use ioremap(), not phys_to_virt() for platform ROM 2020-03-30 09:52:23 -05:00
search.c PCI: Remove WARN_ON(in_interrupt()) 2021-02-10 16:46:29 -06:00
setup-bus.c treewide: Use fallthrough pseudo-keyword 2020-08-23 17:36:59 -05:00
setup-irq.c
setup-res.c PCI: Decline to resize resources if boot config must be preserved 2021-01-12 16:39:52 -06:00
slot.c Merge branch 'pci/misc' 2020-12-15 15:11:08 -06:00
syscall.c PCI: Align checking of syscall user config accessors 2021-01-27 10:41:59 -06:00
vc.c PCI: Fix kerneldoc warnings 2020-08-05 18:23:14 -05:00
vpd.c PCI/VPD: Prevent VPD access for Amazon's Annapurna Labs Root Port 2019-09-16 14:10:09 +01:00
xen-pcifront.c dma-mapping: split <linux/dma-mapping.h> 2020-10-06 07:07:03 +02:00