linux/Documentation
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
..
ABI PCI/IOV: Add sysfs MSI-X vector assignment interface 2021-04-04 10:26:30 +03:00
accounting Documentation: Replace lkml.org links with lore 2021-01-11 12:47:38 -07:00
admin-guide More new code for 5.12: 2021-02-28 11:45:25 -08:00
arm Documentation: ARM: fix reference to DT format documentation 2021-01-28 15:37:43 -07:00
arm64
block block/bfq: update comments and default value in docs for fifo_expire 2021-03-02 11:25:38 -07:00
bpf bpf, docs: Update build procedure for manually compiling LLVM and Clang 2021-01-23 00:09:03 +01:00
cdrom
core-api Merge branch 'akpm' (patches from Andrew) 2021-02-24 16:20:38 -08:00
cpu-freq
crypto
dev-tools kasan: clarify that only first bug is reported in HW_TAGS 2021-02-26 09:41:03 -08:00
devicetree Devicetree fixes for v5.12-rc: 2021-03-05 12:12:28 -08:00
doc-guide docs: Document cross-referencing using relative path 2021-02-04 16:24:12 -07:00
driver-api Char/Misc driver patches for 5.12-rc1 2021-02-24 10:25:37 -08:00
fault-injection
fb
features Documentation: features: refresh feature list 2021-02-25 11:25:57 -07:00
filesystems Merge branch 'work.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2021-02-27 08:07:12 -08:00
firmware_class
firmware-guide Merge branch 'acpi-messages' 2021-02-15 17:04:53 +01:00
fpga fpga: dfl-pci: rectify ReST formatting 2021-01-14 18:05:52 +01:00
gpu It has been a relatively quiet cycle in docsland. 2021-02-22 10:57:46 -08:00
hid
hwmon hwmon: add Texas Instruments TPS23861 driver 2021-02-12 07:02:55 -08:00
i2c i2c: testunit: add support for block process calls 2021-02-12 11:11:04 +01:00
ia64
ide
iio docs: iio: Correct a typo 2021-01-21 14:06:00 -07:00
infiniband
input Documentation: input: define ABS_PRESSURE/ABS_MT_PRESSURE resolution as grams 2021-01-28 16:43:04 -07:00
isdn
kbuild Kbuild updates for v5.12 2021-02-25 10:17:31 -08:00
kernel-hacking docs: kernel-hacking: be more civil 2021-02-11 10:00:40 -07:00
leds
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livepatch Documentation: livepatch: document reliable stacktrace 2021-01-26 11:50:00 +01:00
locking
m68k
maintainer
mhi
mips
misc-devices
netlabel
networking Staging/IIO driver patches for 5.12-rc1 2021-02-20 21:36:51 -08:00
nios2
nvdimm
openrisc
parisc
PCI Documentation: PCI: Add PCI endpoint NTB function user guide 2021-02-23 14:15:45 -06:00
pcmcia
power It has been a relatively quiet cycle in docsland. 2021-02-22 10:57:46 -08:00
powerpc docs: powerpc: Fix tables in syscall64-abi.rst 2021-02-25 13:04:24 -07:00
process A handful of late-arriving documentation fixes, nothing all that notable. 2021-02-26 14:21:18 -08:00
RCU It has been a relatively quiet cycle in docsland. 2021-02-22 10:57:46 -08:00
riscv
s390
scheduler It has been a relatively quiet cycle in docsland. 2021-02-22 10:57:46 -08:00
scsi SCSI misc on 20210219 2021-02-22 10:24:58 -08:00
security Keyrings miscellany 2021-02-23 16:09:23 -08:00
sh
sound ALSA: jack: implement software jack injection via debugfs 2021-02-02 10:37:07 +01:00
sparc
sphinx docs: Enable usage of relative paths to docs on automarkup 2021-02-04 16:23:43 -07:00
sphinx-static
spi
staging
target
timers Documentation: Replace lkml.org links with lore 2021-01-11 12:47:38 -07:00
trace Char/Misc driver patches for 5.12-rc1 2021-02-24 10:25:37 -08:00
translations A handful of late-arriving documentation fixes, nothing all that notable. 2021-02-26 14:21:18 -08:00
usb usb: raw-gadget: update documentation and Kconfig 2021-01-26 18:38:45 +01:00
userspace-api Char/Misc driver patches for 5.12-rc1 2021-02-24 10:25:37 -08:00
virt * Doc fixes 2021-03-04 11:26:17 -08:00
vm mm/debug_vm_pgtable/basic: add validation for dirtiness after write protect 2021-02-24 13:38:27 -08:00
w1
watchdog
x86 Documentation/x86/boot.rst: Correct the example of SETUP_INDIRECT 2021-01-28 15:25:31 -07:00
xtensa
.gitignore
asm-annotations.rst x86/entry: Emit a symbol for register restoring thunk 2021-01-14 17:18:25 +01:00
atomic_bitops.txt
atomic_t.txt
Changes
CodingStyle
conf.py Fix unaesthetic indentation 2021-02-22 14:35:04 -07:00
COPYING-logo
docutils.conf
dontdiff
index.rst docs: Include ext4 documentation via filesystems/ 2021-01-11 13:01:51 -07:00
Kconfig
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Makefile kbuild: remove PYTHON variable 2021-02-01 10:37:19 +09:00
memory-barriers.txt
SubmittingPatches
watch_queue.rst