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The nointxmask and disable_idle_d3 module parameters remain writable, but vfio-pci now latches their values into each device at init. Once a device is registered, changing the module parameter only affects future devices, leaving no direct way to confirm the effective policy for an existing device. Add a pci debugfs directory under the VFIO device debugfs root and report the per-device nointxmask and disable_idle_d3 values. These are read-only debugfs views and use the same Y/N bool output convention as the module parameters. Read-only vfio-pci parameters, such as disable_vga, are not exposed here because they cannot drift from the latched device value, therefore the existing module parameter exposure via sysfs is sufficient. Note that while only vfio-pci currently provides these options, the implementation is in vfio-pci-core and therefore properly reflects the device policy in the core, regardless of driver. Assisted-by: OpenAI Codex:gpt-5 Cc: Guixin Liu <kanie@linux.alibaba.com> Signed-off-by: Alex Williamson <alex.williamson@nvidia.com> Reviewed-by: Kevin Tian <kevin.tian@intel.com> Link: https://lore.kernel.org/r/20260615191241.688297-7-alex.williamson@nvidia.com Signed-off-by: Alex Williamson <alex@shazbot.org>
58 lines
2.2 KiB
Plaintext
58 lines
2.2 KiB
Plaintext
What: /sys/kernel/debug/vfio
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Date: December 2023
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KernelVersion: 6.8
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Contact: Longfang Liu <liulongfang@huawei.com>
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Description: This debugfs file directory is used for debugging
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of vfio devices, it's a common directory for all vfio devices.
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Vfio core will create a device subdirectory under this
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directory.
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What: /sys/kernel/debug/vfio/<device>/migration
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Date: December 2023
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KernelVersion: 6.8
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Contact: Longfang Liu <liulongfang@huawei.com>
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Description: This debugfs file directory is used for debugging
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of vfio devices that support live migration.
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The debugfs of each vfio device that supports live migration
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could be created under this directory.
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What: /sys/kernel/debug/vfio/<device>/migration/state
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Date: December 2023
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KernelVersion: 6.8
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Contact: Longfang Liu <liulongfang@huawei.com>
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Description: Read the live migration status of the vfio device.
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The contents of the state file reflects the migration state
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relative to those defined in the vfio_device_mig_state enum
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What: /sys/kernel/debug/vfio/<device>/migration/features
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Date: Oct 2025
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KernelVersion: 6.18
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Contact: Cédric Le Goater <clg@redhat.com>
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Description: Read the migration features of the vfio device.
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What: /sys/kernel/debug/vfio/<device>/pci
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Date: June 2026
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KernelVersion: 7.2
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Contact: Alex Williamson <alex.williamson@nvidia.com>
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Description: This debugfs file directory is used for debugging
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VFIO PCI devices.
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What: /sys/kernel/debug/vfio/<device>/pci/nointxmask
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Date: June 2026
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KernelVersion: 7.2
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Contact: Alex Williamson <alex.williamson@nvidia.com>
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Description: Read the nointxmask policy latched for this device. This
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policy governs whether the device may use PCI 2.3 style
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INTx masking when supported, reporting a value of "N", or
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requires APIC level INTx masking, reporting a value of "Y".
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What: /sys/kernel/debug/vfio/<device>/pci/disable_idle_d3
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Date: June 2026
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KernelVersion: 7.2
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Contact: Alex Williamson <alex.williamson@nvidia.com>
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Description: Read the disable_idle_d3 policy latched for this device. This
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policy governs whether the device PM runtime usage count is
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kept elevated while the device is bound to the driver and
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unused, reporting a value of "Y", or decremented to allow the
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device to enter a low power state, reporting a value of "N".
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