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Design for Mediated Device Driver:
Main purpose of this driver is to provide a common interface for mediated
device management that can be used by different drivers of different
devices.
This module provides a generic interface to create the device, add it to
mediated bus, add device to IOMMU group and then add it to vfio group.
Below is the high Level block diagram, with Nvidia, Intel and IBM devices
as example, since these are the devices which are going to actively use
this module as of now.
+---------------+
| |
| +-----------+ | mdev_register_driver() +--------------+
| | | +<------------------------+ __init() |
| | mdev | | | |
| | bus | +------------------------>+ |<-> VFIO user
| | driver | | probe()/remove() | vfio_mdev.ko | APIs
| | | | | |
| +-----------+ | +--------------+
| |
| MDEV CORE |
| MODULE |
| mdev.ko |
| +-----------+ | mdev_register_device() +--------------+
| | | +<------------------------+ |
| | | | | nvidia.ko |<-> physical
| | | +------------------------>+ | device
| | | | callback +--------------+
| | Physical | |
| | device | | mdev_register_device() +--------------+
| | interface | |<------------------------+ |
| | | | | i915.ko |<-> physical
| | | +------------------------>+ | device
| | | | callback +--------------+
| | | |
| | | | mdev_register_device() +--------------+
| | | +<------------------------+ |
| | | | | ccw_device.ko|<-> physical
| | | +------------------------>+ | device
| | | | callback +--------------+
| +-----------+ |
+---------------+
Core driver provides two types of registration interfaces:
1. Registration interface for mediated bus driver:
/**
* struct mdev_driver - Mediated device's driver
* @name: driver name
* @probe: called when new device created
* @remove:called when device removed
* @driver:device driver structure
*
**/
struct mdev_driver {
const char *name;
int (*probe) (struct device *dev);
void (*remove) (struct device *dev);
struct device_driver driver;
};
Mediated bus driver for mdev device should use this interface to register
and unregister with core driver respectively:
int mdev_register_driver(struct mdev_driver *drv, struct module *owner);
void mdev_unregister_driver(struct mdev_driver *drv);
Mediated bus driver is responsible to add/delete mediated devices to/from
VFIO group when devices are bound and unbound to the driver.
2. Physical device driver interface
This interface provides vendor driver the set APIs to manage physical
device related work in its driver. APIs are :
* dev_attr_groups: attributes of the parent device.
* mdev_attr_groups: attributes of the mediated device.
* supported_type_groups: attributes to define supported type. This is
mandatory field.
* create: to allocate basic resources in vendor driver for a mediated
device. This is mandatory to be provided by vendor driver.
* remove: to free resources in vendor driver when mediated device is
destroyed. This is mandatory to be provided by vendor driver.
* open: open callback of mediated device
* release: release callback of mediated device
* read : read emulation callback.
* write: write emulation callback.
* ioctl: ioctl callback.
* mmap: mmap emulation callback.
Drivers should use these interfaces to register and unregister device to
mdev core driver respectively:
extern int mdev_register_device(struct device *dev,
const struct parent_ops *ops);
extern void mdev_unregister_device(struct device *dev);
There are no locks to serialize above callbacks in mdev driver and
vfio_mdev driver. If required, vendor driver can have locks to serialize
above APIs in their driver.
Signed-off-by: Kirti Wankhede <kwankhede@nvidia.com>
Signed-off-by: Neo Jia <cjia@nvidia.com>
Reviewed-by: Jike Song <jike.song@intel.com>
Reviewed-by: Dong Jia Shi <bjsdjshi@linux.vnet.ibm.com>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
53 lines
1.5 KiB
Plaintext
53 lines
1.5 KiB
Plaintext
config VFIO_IOMMU_TYPE1
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tristate
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depends on VFIO
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default n
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config VFIO_IOMMU_SPAPR_TCE
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tristate
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depends on VFIO && SPAPR_TCE_IOMMU
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default n
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config VFIO_SPAPR_EEH
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tristate
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depends on EEH && VFIO_IOMMU_SPAPR_TCE
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default n
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config VFIO_VIRQFD
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tristate
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depends on VFIO && EVENTFD
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default n
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menuconfig VFIO
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tristate "VFIO Non-Privileged userspace driver framework"
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depends on IOMMU_API
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select VFIO_IOMMU_TYPE1 if (X86 || S390 || ARM_SMMU || ARM_SMMU_V3)
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select VFIO_IOMMU_SPAPR_TCE if (PPC_POWERNV || PPC_PSERIES)
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select VFIO_SPAPR_EEH if (PPC_POWERNV || PPC_PSERIES)
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select ANON_INODES
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help
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VFIO provides a framework for secure userspace device drivers.
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See Documentation/vfio.txt for more details.
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If you don't know what to do here, say N.
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menuconfig VFIO_NOIOMMU
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bool "VFIO No-IOMMU support"
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depends on VFIO
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help
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VFIO is built on the ability to isolate devices using the IOMMU.
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Only with an IOMMU can userspace access to DMA capable devices be
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considered secure. VFIO No-IOMMU mode enables IOMMU groups for
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devices without IOMMU backing for the purpose of re-using the VFIO
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infrastructure in a non-secure mode. Use of this mode will result
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in an unsupportable kernel and will therefore taint the kernel.
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Device assignment to virtual machines is also not possible with
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this mode since there is no IOMMU to provide DMA translation.
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If you don't know what to do here, say N.
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source "drivers/vfio/pci/Kconfig"
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source "drivers/vfio/platform/Kconfig"
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source "drivers/vfio/mdev/Kconfig"
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source "virt/lib/Kconfig"
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