cdx: Create symbol namespaces for cdx subsystem

Create CDX_BUS and CDX_BUS_CONTROLLER symbol namespace for cdx bus
subsystem. CDX controller modules are required to import symbols from
CDX_BUS_CONTROLLER namespace and other than controller modules to
import from CDX_BUS namespace.

Signed-off-by: Abhijit Gangurde <abhijit.gangurde@amd.com>
Link: https://lore.kernel.org/r/20231017160505.10640-4-abhijit.gangurde@amd.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

vfio/cdx: Add parentheses between bitwise AND expression and logical NOT

When building with clang, there is a warning (or error with
CONFIG_WERROR=y) due to a bitwise AND and logical NOT in
vfio_cdx_bm_ctrl():

drivers/vfio/cdx/main.c:77:6: error: logical not is only applied to the left hand side of this bitwise operator [-Werror,-Wlogical-not-parentheses]
77 | if (!vdev->flags & BME_SUPPORT)
| ^ ~
drivers/vfio/cdx/main.c:77:6: note: add parentheses after the '!' to evaluate the bitwise operator first
77 | if (!vdev->flags & BME_SUPPORT)
| ^
| ( )
drivers/vfio/cdx/main.c:77:6: note: add parentheses around left hand side expression to silence this warning
77 | if (!vdev->flags & BME_SUPPORT)
| ^
| ( )
1 error generated.

Add the parentheses as suggested in the first note, which is clearly
what was intended here.

Closes: https://github.com/ClangBuiltLinux/linux/issues/1939
Fixes: 8a97ab9b8b31 ("vfio-cdx: add bus mastering device feature support")
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Acked-by: Nikhil Agarwal <nikhil.agarwal@amd.com>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Link: https://lore.kernel.org/r/20231002-vfio-cdx-logical-not-parentheses-v1-1-a8846c7adfb6@kernel.org
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>

vfio-cdx: add bus mastering device feature support

Support Bus master enable and disable on VFIO-CDX devices using
VFIO_DEVICE_FEATURE_BUS_MASTER flag over VFIO_DEVICE_FEATURE IOCTL.

Co-developed-by: Shubham Rohila <shubham.rohila@amd.com>
Signed-off-by: Shubham Rohila <shubham.rohila@amd.com>
Signed-off-by: Nipun Gupta <nipun.gupta@amd.com>
Link: https://lore.kernel.org/r/20230915045423.31630-3-nipun.gupta@amd.com
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>

vfio/cdx: Remove redundant initialization owner in vfio_cdx_driver

The cdx_driver_register() will set "THIS_MODULE" to driver.owner when
register a cdx_driver driver, so it is redundant initialization to set
driver.owner in the statement. Remove it for clean code.

Signed-off-by: Li Zetao <lizetao1@huawei.com>
Acked-by: Nikhil Agarwal <nikhil.agarwal@amd.com>
Link: https://lore.kernel.org/r/20230808020937.2975196-1-lizetao1@huawei.com
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>

vfio/cdx: add support for CDX bus

vfio-cdx driver enables IOCTLs for user space to query
MMIO regions for CDX devices and mmap them. This change
also adds support for reset of CDX devices. With VFIO
enabled on CDX devices, user-space applications can also
exercise DMA securely via IOMMU on these devices.

This change adds the VFIO CDX driver and enables the following
ioctls for CDX devices:
- VFIO_DEVICE_GET_INFO:
- VFIO_DEVICE_GET_REGION_INFO
- VFIO_DEVICE_RESET

Signed-off-by: Nipun Gupta <nipun.gupta@amd.com>
Reviewed-by: Pieter Jansen van Vuuren <pieter.jansen-van-vuuren@amd.com>
Tested-by: Nikhil Agarwal <nikhil.agarwal@amd.com>
Link: https://lore.kernel.org/r/20230531124557.11009-1-nipun.gupta@amd.com
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>