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Message-ID: <YFW8yPWT8yyXzy6c@unreal>
Date: Sat, 20 Mar 2021 11:13:44 +0200
From: Leon Romanovsky <leon@...nel.org>
To: Bjorn Helgaas <bhelgaas@...gle.com>,
Saeed Mahameed <saeedm@...dia.com>
Cc: Jason Gunthorpe <jgg@...dia.com>,
Alexander Duyck <alexander.duyck@...il.com>,
Jakub Kicinski <kuba@...nel.org>, linux-pci@...r.kernel.org,
linux-rdma@...r.kernel.org, netdev@...r.kernel.org,
Don Dutile <ddutile@...hat.com>,
Alex Williamson <alex.williamson@...hat.com>,
"David S . Miller" <davem@...emloft.net>,
Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Subject: Re: [PATCH mlx5-next v8 0/4] Dynamically assign MSI-X vectors count
Gentle reminder
Thanks
On Sun, Mar 14, 2021 at 02:42:52PM +0200, Leon Romanovsky wrote:
> ---------------------------------------------------------------------------------
> Changelog
> v8:
> * Added "physical/virtual function" words near PF and VF acronyms.
> v7: https://lore.kernel.org/linux-pci/20210301075524.441609-1-leon@kernel.org
> * Rebase on top v5.12-rc1
> * More english fixes
> * Returned to static sysfs creation model as was implemented in v0/v1.
> v6: https://lore.kernel.org/linux-pci/20210209133445.700225-1-leon@kernel.org
> * Patch 1:
> * English fixes
> * Moved pci_vf_set_msix_vec_count() from msi.c to iov.c
> * Embedded pci_vf_set_msix_vec_count() into sriov_vf_msix_count_store
> * Deleted sriov_vf_msix_count_show
> * Deleted vfs_overlay folder
> * Renamed functions *_vfs_overlay_* to be *_vf_overlay_*
> * Deleted is_supported and attribute_group because it confused people more than
> it gave advantage.
> * Changed vf_total_msix to be callback
> * Patch 3:
> * Fixed english as suggested by Bjorn
> * Added more explanations to the commit message
> * Patch 4:
> * Protected enable/disable with capability check
> v5: https://lore.kernel.org/linux-pci/20210126085730.1165673-1-leon@kernel.org
> * Patch 1:
> * Added forgotten "inline" keyword when declaring empty functions.
> v4: https://lore.kernel.org/linux-pci/20210124131119.558563-1-leon@kernel.org
> * Used sysfs_emit() instead of sprintf() in new sysfs entries.
> * Changed EXPORT_SYMBOL to be EXPORT_SYMBOL_GPL for pci_iov_virtfn_devfn().
> * Rewrote sysfs registration code to be driven by PF that wants to enable VF
> overlay instead of creating to all SR-IOV devices.
> * Grouped all such functionality under new "vfs_overlay" folder.
> * Combined two PCI patches into one.
> v3: https://lore.kernel.org/linux-pci/20210117081548.1278992-1-leon@kernel.org
> * Renamed pci_set_msix_vec_count to be pci_vf_set_msix_vec_count.
> * Added VF msix_cap check to hide sysfs entry if device doesn't support msix.
> * Changed "-" to be ":" in the mlx5 patch to silence CI warnings about missing
> kdoc description.
> * Split differently error print in mlx5 driver to avoid checkpatch warning.
> v2: https://lore.kernel.org/linux-pci/20210114103140.866141-1-leon@kernel.org
> * Patch 1:
> * Renamed vf_msix_vec sysfs knob to be sriov_vf_msix_count
> * Added PF and VF device locks during set MSI-X call to protect from parallel
> driver bind/unbind operations.
> * Removed extra checks when reading sriov_vf_msix, because users will
> be able to distinguish between supported/not supported by looking on
> sriov_vf_total_msix count.
> * Changed all occurrences of "numb" to be "count"
> * Changed returned error from EOPNOTSUPP to be EBUSY if user tries to set
> MSI-X count after driver already bound to the VF.
> * Added extra comment in pci_set_msix_vec_count() to emphasize that driver
> should not be bound.
> * Patch 2:
> * Changed vf_total_msix from int to be u32 and updated function signatures
> accordingly.
> * Improved patch title
> v1: https://lore.kernel.org/linux-pci/20210110150727.1965295-1-leon@kernel.org
> * 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@kernel.org
>
> --------------------------------------------------------------------
> 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@...ver ~]# 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/sriov_vf_msix_count
>
> After this series:
> [root@...ver ~]# 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 (4):
> PCI: Add a sysfs file to change the MSI-X table size of SR-IOV VFs
> net/mlx5: Add dynamic MSI-X capabilities bits
> net/mlx5: Dynamically assign MSI-X vectors count
> net/mlx5: Implement sriov_get_vf_total_msix/count() callbacks
>
> Documentation/ABI/testing/sysfs-bus-pci | 29 +++++
> .../net/ethernet/mellanox/mlx5/core/main.c | 6 ++
> .../ethernet/mellanox/mlx5/core/mlx5_core.h | 12 +++
> .../net/ethernet/mellanox/mlx5/core/pci_irq.c | 73 +++++++++++++
> .../net/ethernet/mellanox/mlx5/core/sriov.c | 48 ++++++++-
> drivers/pci/iov.c | 102 ++++++++++++++++--
> drivers/pci/pci-sysfs.c | 3 +-
> drivers/pci/pci.h | 3 +-
> include/linux/mlx5/mlx5_ifc.h | 11 +-
> include/linux/pci.h | 8 ++
> 10 files changed, 284 insertions(+), 11 deletions(-)
>
> --
> 2.30.2
>
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