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authorYi Liu <yi.l.liu@intel.com>2023-07-18 16:55:43 +0300
committerAlex Williamson <alex.williamson@redhat.com>2023-07-25 19:19:40 +0300
commit8b6f173a4ce47ef0606124710315560c64f2344e (patch)
tree56ab2b776667a44cb0a64e1d8d12474082f9528d /drivers/vfio/Kconfig
parent38c24544e10a541d92be9d4ec2dfc8a94f4d87ba (diff)
downloadlinux-8b6f173a4ce47ef0606124710315560c64f2344e.tar.xz
vfio: Add cdev for vfio_device
This adds cdev support for vfio_device. It allows the user to directly open a vfio device w/o using the legacy container/group interface, as a prerequisite for supporting new iommu features like nested translation and etc. The device fd opened in this manner doesn't have the capability to access the device as the fops open() doesn't open the device until the successful VFIO_DEVICE_BIND_IOMMUFD ioctl which will be added in a later patch. With this patch, devices registered to vfio core would have both the legacy group and the new device interfaces created. - group interface : /dev/vfio/$groupID - device interface: /dev/vfio/devices/vfioX - normal device ("X" is a unique number across vfio devices) For a given device, the user can identify the matching vfioX by searching the vfio-dev folder under the sysfs path of the device. Take PCI device (0000:6a:01.0) as an example, /sys/bus/pci/devices/0000\:6a\:01.0/vfio-dev/vfioX implies the matching vfioX under /dev/vfio/devices/, and vfio-dev/vfioX/dev contains the major:minor number of the matching /dev/vfio/devices/vfioX. The user can get device fd by opening the /dev/vfio/devices/vfioX. The vfio_device cdev logic in this patch: *) __vfio_register_dev() path ends up doing cdev_device_add() for each vfio_device if VFIO_DEVICE_CDEV configured. *) vfio_unregister_group_dev() path does cdev_device_del(); cdev interface does not support noiommu devices, so VFIO only creates the legacy group interface for the physical devices that do not have IOMMU. noiommu users should use the legacy group interface. Reviewed-by: Kevin Tian <kevin.tian@intel.com> Reviewed-by: Jason Gunthorpe <jgg@nvidia.com> Tested-by: Terrence Xu <terrence.xu@intel.com> Tested-by: Nicolin Chen <nicolinc@nvidia.com> Tested-by: Matthew Rosato <mjrosato@linux.ibm.com> Tested-by: Yanting Jiang <yanting.jiang@intel.com> Tested-by: Shameer Kolothum <shameerali.kolothum.thodi@huawei.com> Tested-by: Zhenzhong Duan <zhenzhong.duan@intel.com> Signed-off-by: Yi Liu <yi.l.liu@intel.com> Link: https://lore.kernel.org/r/20230718135551.6592-19-yi.l.liu@intel.com Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
Diffstat (limited to 'drivers/vfio/Kconfig')
-rw-r--r--drivers/vfio/Kconfig12
1 files changed, 12 insertions, 0 deletions
diff --git a/drivers/vfio/Kconfig b/drivers/vfio/Kconfig
index aba36f5be4ec..26f18d92eb97 100644
--- a/drivers/vfio/Kconfig
+++ b/drivers/vfio/Kconfig
@@ -12,6 +12,18 @@ menuconfig VFIO
If you don't know what to do here, say N.
if VFIO
+config VFIO_DEVICE_CDEV
+ bool "Support for the VFIO cdev /dev/vfio/devices/vfioX"
+ depends on IOMMUFD && !SPAPR_TCE_IOMMU
+ help
+ The VFIO device cdev is another way for userspace to get device
+ access. Userspace gets device fd by opening device cdev under
+ /dev/vfio/devices/vfioX, and then bind the device fd with an iommufd
+ to set up secure DMA context for device access. This interface does
+ not support noiommu.
+
+ If you don't know what to do here, say N.
+
config VFIO_CONTAINER
bool "Support for the VFIO container /dev/vfio/vfio"
select VFIO_IOMMU_TYPE1 if MMU && (X86 || S390 || ARM || ARM64)