PCI: Add pci_irq_type() to query the allocated interrupt typegrafted

Add a helper that returns PCI_IRQ_MSIX, PCI_IRQ_MSI, or PCI_IRQ_INTX
based on the interrupt type the PCI core selected after
pci_alloc_irq_vectors().

Several drivers already open-code this check against pdev->msix_enabled
and pdev->msi_enabled, or even open code this helper [1].

A common helper avoids the duplication and keeps drivers from accessing
the bitfield directly (see also [2]).

Acked-by: Bjorn Helgaas <bhelgaas@google.com>
Tested-by: John Hubbard <jhubbard@nvidia.com>
Link: https://elixir.bootlin.com/linux/v7.1/source/drivers/net/ethernet/aquantia/atlantic/aq_pci_func.c#L196 [1]
Inspired-by: John Hubbard <jhubbard@nvidia.com>
Link: https://lore.kernel.org/all/DKKG2QM3YJYB.Z2H2B2UXJ75N@kernel.org/ [2]
Reviewed-by: Gary Guo <gary@garyguo.net>
Link: https://patch.msgid.link/20260813165234.620555-5-dakr@kernel.org
[ Add missing pci_irq_type() stub for CONFIG_PCI=n. ]
Signed-off-by: Danilo Krummrich <dakr@kernel.org>

1 files changed, 57 insertions, 0 deletions

diff --git a/Documentation/ABI/testing/debugfs-vfio b/Documentation/ABI/testing/debugfs-vfio
new file mode 100644
index 000000000..ed2f29c3a
--- /dev/null
+++ b/Documentation/ABI/testing/debugfs-vfio
@@ -0,0 +1,57 @@
+What:		/sys/kernel/debug/vfio
+Date:		December 2023
+KernelVersion:	6.8
+Contact:	Longfang Liu <liulongfang@huawei.com>
+Description:	This debugfs file directory is used for debugging
+		of vfio devices, it's a common directory for all vfio devices.
+		Vfio core will create a device subdirectory under this
+		directory.
+
+What:		/sys/kernel/debug/vfio/<device>/migration
+Date:		December 2023
+KernelVersion:	6.8
+Contact:	Longfang Liu <liulongfang@huawei.com>
+Description:	This debugfs file directory is used for debugging
+		of vfio devices that support live migration.
+		The debugfs of each vfio device that supports live migration
+		could be created under this directory.
+
+What:		/sys/kernel/debug/vfio/<device>/migration/state
+Date:		December 2023
+KernelVersion:	6.8
+Contact:	Longfang Liu <liulongfang@huawei.com>
+Description:	Read the live migration status of the vfio device.
+		The contents of the state file reflects the migration state
+		relative to those defined in the vfio_device_mig_state enum
+
+What:		/sys/kernel/debug/vfio/<device>/migration/features
+Date:		Oct 2025
+KernelVersion:	6.18
+Contact:	Cédric Le Goater <clg@redhat.com>
+Description:	Read the migration features of the vfio device.
+
+What:		/sys/kernel/debug/vfio/<device>/pci
+Date:		June 2026
+KernelVersion:	7.2
+Contact:	Alex Williamson <alex.williamson@nvidia.com>
+Description:	This debugfs file directory is used for debugging
+		VFIO PCI devices.
+
+What:		/sys/kernel/debug/vfio/<device>/pci/nointxmask
+Date:		June 2026
+KernelVersion:	7.2
+Contact:	Alex Williamson <alex.williamson@nvidia.com>
+Description:	Read the nointxmask policy latched for this device.  This
+		policy governs whether the device may use PCI 2.3 style
+		INTx masking when supported, reporting a value of "N", or
+		requires APIC level INTx masking, reporting a value of "Y".
+
+What:		/sys/kernel/debug/vfio/<device>/pci/disable_idle_d3
+Date:		June 2026
+KernelVersion:	7.2
+Contact:	Alex Williamson <alex.williamson@nvidia.com>
+Description:	Read the disable_idle_d3 policy latched for this device.  This
+		policy governs whether the device PM runtime usage count is
+		kept elevated while the device is bound to the driver and
+		unused, reporting a value of "Y", or decremented to allow the
+		device to enter a low power state, reporting a value of "N".