vfio/pci: Cleanup Kconfig

It should be possible to select vfio-pci variant drivers without building
vfio-pci itself, which implies each variant driver should select
vfio-pci-core.

Fix the top level vfio Makefile to traverse pci based on vfio-pci-core
rather than vfio-pci.

Mark MMAP and INTX options depending on vfio-pci-core to cleanup resulting
config if core is not enabled.

Push all PCI related vfio options to a sub-menu and make descriptions
consistent.
Reviewed-by: Cédric Le Goater <clg@redhat.com>
Reviewed-by: Eric Auger <eric.auger@redhat.com>
Reviewed-by: Shameer Kolothum <shameerali.kolothum.thodi@huawei.com>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Link: https://lore.kernel.org/r/20230614193948.477036-2-alex.williamson@redhat.comSigned-off-by: Alex Williamson <alex.williamson@redhat.com>

drivers/vfio/Makefile

@@ -10,7 +10,7 @@ vfio-$(CONFIG_VFIO_VIRQFD) += virqfd.o
 
 obj-$(CONFIG_VFIO_IOMMU_TYPE1) += vfio_iommu_type1.o
 obj-$(CONFIG_VFIO_IOMMU_SPAPR_TCE) += vfio_iommu_spapr_tce.o
-obj-$(CONFIG_VFIO_PCI) += pci/
+obj-$(CONFIG_VFIO_PCI_CORE) += pci/
 obj-$(CONFIG_VFIO_PLATFORM) += platform/
 obj-$(CONFIG_VFIO_MDEV) += mdev/
 obj-$(CONFIG_VFIO_FSL_MC) += fsl-mc/

drivers/vfio/pci/Kconfig

 # SPDX-License-Identifier: GPL-2.0-only
-if PCI && MMU
+menu "VFIO support for PCI devices"
+	depends on PCI && MMU
+
 config VFIO_PCI_CORE
 	tristate
 	select VFIO_VIRQFD
@@ -7,9 +9,11 @@ config VFIO_PCI_CORE
 
 config VFIO_PCI_MMAP
 	def_bool y if !S390
+	depends on VFIO_PCI_CORE
 
 config VFIO_PCI_INTX
 	def_bool y if !S390
+	depends on VFIO_PCI_CORE
 
 config VFIO_PCI
 	tristate "Generic VFIO support for any PCI device"
@@ -59,4 +63,4 @@ source "drivers/vfio/pci/mlx5/Kconfig"
 
 source "drivers/vfio/pci/hisilicon/Kconfig"
 
-endif
+endmenu

drivers/vfio/pci/hisilicon/Kconfig

 # SPDX-License-Identifier: GPL-2.0-only
 config HISI_ACC_VFIO_PCI
-	tristate "VFIO PCI support for HiSilicon ACC devices"
+	tristate "VFIO support for HiSilicon ACC PCI devices"
 	depends on ARM64 || (COMPILE_TEST && 64BIT)
-	depends on VFIO_PCI_CORE
 	depends on PCI_MSI
 	depends on CRYPTO_DEV_HISI_QM
 	depends on CRYPTO_DEV_HISI_HPRE
 	depends on CRYPTO_DEV_HISI_SEC2
 	depends on CRYPTO_DEV_HISI_ZIP
+	select VFIO_PCI_CORE
 	help
 	  This provides generic PCI support for HiSilicon ACC devices
 	  using the VFIO framework.

drivers/vfio/pci/mlx5/Kconfig

@@ -2,7 +2,7 @@
 config MLX5_VFIO_PCI
 	tristate "VFIO support for MLX5 PCI devices"
 	depends on MLX5_CORE
-	depends on VFIO_PCI_CORE
+	select VFIO_PCI_CORE
 	help
 	  This provides migration support for MLX5 devices using the VFIO
 	  framework.