Max Gurtovoy 1958a6bbec PCI / VFIO: Add 'override_only' support for VFIO PCI sub system ... commit cc6711b0bf upstream. Expose an 'override_only' helper macro (i.e. PCI_DRIVER_OVERRIDE_DEVICE_VFIO) for VFIO PCI sub system and add the required code to prefix its matching entries with "vfio_" in modules.alias file. It allows VFIO device drivers to include match entries in the modules.alias file produced by kbuild that are not used for normal driver autoprobing and module autoloading. Drivers using these match entries can be connected to the PCI device manually, by userspace, using the existing driver_override sysfs. For example the resulting modules.alias may have: alias pci:v000015B3d00001021sv*sd*bc*sc*i* mlx5_core alias vfio_pci:v000015B3d00001021sv*sd*bc*sc*i* mlx5_vfio_pci alias vfio_pci:v*d*sv*sd*bc*sc*i* vfio_pci In this example mlx5_core and mlx5_vfio_pci match to the same PCI device. The kernel will autoload and autobind to mlx5_core but the kernel and udev mechanisms will ignore mlx5_vfio_pci. When userspace wants to change a device to the VFIO subsystem it can implement a generic algorithm: 1) Identify the sysfs path to the device: /sys/devices/pci0000:00/0000:00:01.0/0000:01:00.0 2) Get the modalias string from the kernel: $ cat /sys/bus/pci/devices/0000:01:00.0/modalias pci:v000015B3d00001021sv000015B3sd00000001bc02sc00i00 3) Prefix it with vfio_: vfio_pci:v000015B3d00001021sv000015B3sd00000001bc02sc00i00 4) Search modules.alias for the above string and select the entry that has the fewest *'s: alias vfio_pci:v000015B3d00001021sv*sd*bc*sc*i* mlx5_vfio_pci 5) modprobe the matched module name: $ modprobe mlx5_vfio_pci 6) cat the matched module name to driver_override: echo mlx5_vfio_pci > /sys/bus/pci/devices/0000:01:00.0/driver_override 7) unbind device from original module echo 0000:01:00.0 > /sys/bus/pci/devices/0000:01:00.0/driver/unbind 8) probe PCI drivers (or explicitly bind to mlx5_vfio_pci) echo 0000:01:00.0 > /sys/bus/pci/drivers_probe The algorithm is independent of bus type. In future the other buses with VFIO device drivers, like platform and ACPI, can use this algorithm as well. This patch is the infrastructure to provide the information in the modules.alias to userspace. Convert the only VFIO pci_driver which results in one new line in the modules.alias: alias vfio_pci:v*d*sv*sd*bc*sc*i* vfio_pci Later series introduce additional HW specific VFIO PCI drivers, such as mlx5_vfio_pci. Signed-off-by: Max Gurtovoy <mgurtovoy@nvidia.com> Signed-off-by: Jason Gunthorpe <jgg@nvidia.com> Acked-by: Bjorn Helgaas <bhelgaas@google.com> # for pci.h Signed-off-by: Yishai Hadas <yishaih@nvidia.com> Link: https://lore.kernel.org/r/20210826103912.128972-11-yishaih@nvidia.com Signed-off-by: Alex Williamson <alex.williamson@redhat.com> Signed-off-by: Chen Zhuo <sagazchen@tencent.com> Signed-off-by: Xinghui Li <korantli@tencent.com>		2024-06-11 21:15:47 +08:00
..
.gitignore	kbuild: trivial - remove trailing empty lines	2014-06-10 00:04:06 +02:00
Makefile	kbuild: move modpost out of 'scripts' target	2018-12-01 23:09:34 +09:00
devicetable-offsets.c	PCI / VFIO: Add 'override_only' support for VFIO PCI sub system	2024-06-11 21:15:47 +08:00
empty.c	Linux-2.6.12-rc2	2005-04-16 15:20:36 -07:00
file2alias.c	PCI / VFIO: Add 'override_only' support for VFIO PCI sub system	2024-06-11 21:15:47 +08:00
mk_elfconfig.c	License cleanup: add SPDX GPL-2.0 license identifier to files with no license	2017-11-02 11:10:55 +01:00
modpost.c	ock: sync codes to ock 5.4.119-20.0009.21	2024-06-11 20:27:38 +08:00
modpost.h	symbol namespaces: revert to previous __ksymtab name scheme	2019-10-18 15:32:52 +02:00
sumversion.c	kbuild: remove the first line of *.mod files	2019-07-18 02:19:31 +09:00