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linux/drivers/vfio/Kconfig
Longfang Liu 2202844e44 vfio/migration: Add debugfs to live migration driver
There are multiple devices, software and operational steps involved
in the process of live migration. An error occurred on any node may
cause the live migration operation to fail.
This complex process makes it very difficult to locate and analyze
the cause when the function fails.

In order to quickly locate the cause of the problem when the
live migration fails, I added a set of debugfs to the vfio
live migration driver.

    +-------------------------------------------+
    |                                           |
    |                                           |
    |                  QEMU                     |
    |                                           |
    |                                           |
    +---+----------------------------+----------+
        |      ^                     |      ^
        |      |                     |      |
        |      |                     |      |
        v      |                     v      |
     +---------+--+               +---------+--+
     |src vfio_dev|               |dst vfio_dev|
     +--+---------+               +--+---------+
        |      ^                     |      ^
        |      |                     |      |
        v      |                     |      |
   +-----------+----+           +-----------+----+
   |src dev debugfs |           |dst dev debugfs |
   +----------------+           +----------------+

The entire debugfs directory will be based on the definition of
the CONFIG_DEBUG_FS macro. If this macro is not enabled, the
interfaces in vfio.h will be empty definitions, and the creation
and initialization of the debugfs directory will not be executed.

   vfio
    |
    +---<dev_name1>
    |    +---migration
    |        +--state
    |
    +---<dev_name2>
         +---migration
             +--state

debugfs will create a public root directory "vfio" file.
then create a dev_name() file for each live migration device.
First, create a unified state acquisition file of "migration"
in this device directory.
Then, create a public live migration state lookup file "state".

Signed-off-by: Longfang Liu <liulongfang@huawei.com>
Reviewed-by: Cédric Le Goater <clg@redhat.com>
Link: https://lore.kernel.org/r/20231106072225.28577-2-liulongfang@huawei.com
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
2023-12-04 14:29:08 -07:00

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# SPDX-License-Identifier: GPL-2.0-only
menuconfig VFIO
tristate "VFIO Non-Privileged userspace driver framework"
select IOMMU_API
depends on IOMMUFD || !IOMMUFD
select INTERVAL_TREE
select VFIO_GROUP if SPAPR_TCE_IOMMU || IOMMUFD=n
select VFIO_DEVICE_CDEV if !VFIO_GROUP
select VFIO_CONTAINER if IOMMUFD=n
help
VFIO provides a framework for secure userspace device drivers.
See Documentation/driver-api/vfio.rst for more details.
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
default !VFIO_GROUP
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_GROUP
bool "Support for the VFIO group /dev/vfio/$group_id"
default y
help
VFIO group support provides the traditional model for accessing
devices through VFIO and is used by the majority of userspace
applications and drivers making use of VFIO.
If you don't know what to do here, say Y.
config VFIO_CONTAINER
bool "Support for the VFIO container /dev/vfio/vfio"
select VFIO_IOMMU_TYPE1 if MMU && (X86 || S390 || ARM || ARM64)
depends on VFIO_GROUP
default y
help
The VFIO container is the classic interface to VFIO for establishing
IOMMU mappings. If N is selected here then IOMMUFD must be used to
manage the mappings.
Unless testing IOMMUFD say Y here.
if VFIO_CONTAINER
config VFIO_IOMMU_TYPE1
tristate
default n
config VFIO_IOMMU_SPAPR_TCE
tristate
depends on SPAPR_TCE_IOMMU
default VFIO
endif
config VFIO_NOIOMMU
bool "VFIO No-IOMMU support"
depends on VFIO_GROUP
help
VFIO is built on the ability to isolate devices using the IOMMU.
Only with an IOMMU can userspace access to DMA capable devices be
considered secure. VFIO No-IOMMU mode enables IOMMU groups for
devices without IOMMU backing for the purpose of re-using the VFIO
infrastructure in a non-secure mode. Use of this mode will result
in an unsupportable kernel and will therefore taint the kernel.
Device assignment to virtual machines is also not possible with
this mode since there is no IOMMU to provide DMA translation.
If you don't know what to do here, say N.
config VFIO_VIRQFD
bool
select EVENTFD
default n
config VFIO_DEBUGFS
bool "Export VFIO internals in DebugFS"
depends on DEBUG_FS
help
Allows exposure of VFIO device internals. This option enables
the use of debugfs by VFIO drivers as required. The device can
cause the VFIO code create a top-level debug/vfio directory
during initialization, and then populate a subdirectory with
entries as required.
source "drivers/vfio/pci/Kconfig"
source "drivers/vfio/platform/Kconfig"
source "drivers/vfio/mdev/Kconfig"
source "drivers/vfio/fsl-mc/Kconfig"
source "drivers/vfio/cdx/Kconfig"
endif
source "virt/lib/Kconfig"