From 343b7258687ecfbb363bfda8833a7cf641aac524 Mon Sep 17 00:00:00 2001 From: Max Gurtovoy Date: Thu, 26 Aug 2021 13:39:08 +0300 Subject: PCI: Add 'override_only' field to struct pci_device_id Add 'override_only' field to struct pci_device_id to be used as part of pci_match_device(). When set, a driver only matches the entry when dev->driver_override is set to that driver. In addition, add a helper macro named 'PCI_DEVICE_DRIVER_OVERRIDE' to enable setting some data on it. Next patch from this series will use the above functionality. Signed-off-by: Max Gurtovoy Signed-off-by: Jason Gunthorpe Acked-by: Bjorn Helgaas Signed-off-by: Yishai Hadas Link: https://lore.kernel.org/r/20210826103912.128972-10-yishaih@nvidia.com Signed-off-by: Alex Williamson --- include/linux/pci.h | 15 +++++++++++++++ 1 file changed, 15 insertions(+) (limited to 'include/linux/pci.h') diff --git a/include/linux/pci.h b/include/linux/pci.h index 540b377ca8f6..0506b1a8c921 100644 --- a/include/linux/pci.h +++ b/include/linux/pci.h @@ -901,6 +901,21 @@ struct pci_driver { .vendor = (vend), .device = (dev), \ .subvendor = PCI_ANY_ID, .subdevice = PCI_ANY_ID +/** + * PCI_DEVICE_DRIVER_OVERRIDE - macro used to describe a PCI device with + * override_only flags. + * @vend: the 16 bit PCI Vendor ID + * @dev: the 16 bit PCI Device ID + * @driver_override: the 32 bit PCI Device override_only + * + * This macro is used to create a struct pci_device_id that matches only a + * driver_override device. The subvendor and subdevice fields will be set to + * PCI_ANY_ID. + */ +#define PCI_DEVICE_DRIVER_OVERRIDE(vend, dev, driver_override) \ + .vendor = (vend), .device = (dev), .subvendor = PCI_ANY_ID, \ + .subdevice = PCI_ANY_ID, .override_only = (driver_override) + /** * PCI_DEVICE_SUB - macro used to describe a specific PCI device with subsystem * @vend: the 16 bit PCI Vendor ID -- cgit v1.2.3 From cc6711b0bf36de068b10490198d05ac168377989 Mon Sep 17 00:00:00 2001 From: Max Gurtovoy Date: Thu, 26 Aug 2021 13:39:09 +0300 Subject: PCI / VFIO: Add 'override_only' support for VFIO PCI sub system 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 Signed-off-by: Jason Gunthorpe Acked-by: Bjorn Helgaas # for pci.h Signed-off-by: Yishai Hadas Link: https://lore.kernel.org/r/20210826103912.128972-11-yishaih@nvidia.com Signed-off-by: Alex Williamson --- include/linux/pci.h | 14 ++++++++++++++ 1 file changed, 14 insertions(+) (limited to 'include/linux/pci.h') diff --git a/include/linux/pci.h b/include/linux/pci.h index 0506b1a8c921..527a1dfd1d06 100644 --- a/include/linux/pci.h +++ b/include/linux/pci.h @@ -916,6 +916,20 @@ struct pci_driver { .vendor = (vend), .device = (dev), .subvendor = PCI_ANY_ID, \ .subdevice = PCI_ANY_ID, .override_only = (driver_override) +/** + * PCI_DRIVER_OVERRIDE_DEVICE_VFIO - macro used to describe a VFIO + * "driver_override" PCI device. + * @vend: the 16 bit PCI Vendor ID + * @dev: the 16 bit PCI Device ID + * + * This macro is used to create a struct pci_device_id that matches a + * specific device. The subvendor and subdevice fields will be set to + * PCI_ANY_ID and the driver_override will be set to + * PCI_ID_F_VFIO_DRIVER_OVERRIDE. + */ +#define PCI_DRIVER_OVERRIDE_DEVICE_VFIO(vend, dev) \ + PCI_DEVICE_DRIVER_OVERRIDE(vend, dev, PCI_ID_F_VFIO_DRIVER_OVERRIDE) + /** * PCI_DEVICE_SUB - macro used to describe a specific PCI device with subsystem * @vend: the 16 bit PCI Vendor ID -- cgit v1.2.3