This RFC's intention is to show what an interface to access device properties for the VFIO platform driver can look like. These properties can be from the device tree node describing the device, or ACPI properties in the future. If a device property corresponding to a platform device bound by VFIO PLATFORM or VFIO AMBA is available, this patch series will allow the user to query for this information. This can be useful for userspace drivers to automatically query parameters related to the device. Specifically for QEMU, reading the "compatible" property of the device tree node could be of use to find out what device is being assigned to the guest and handle appropriately a wider range of devices in the future, and to generate an appropriate device tree for the guest. Older versions of this series where specifically targeted at device tree properties. This version has been reworked on top of Rafael J. Wysocki's uniform device properties API for device tree and ACPI devices. This will allow us to use the API in the future with devices described via ACPI. This also means a kernel including the uniform device properties API is needed to apply these patches, in additon to the VFIO patches, e.g. branch pm+acpi-3.19-rc1 from https://git.kernel.org/cgit/linux/kernel/git/rafael/linux-pm.git/ The API to get the list of available properties and the device tree full_name have been removed. These probably don't serve an useful purpose, as the user of this API need to know anyway what properties are specific to the device he wants to access with VFIO. If we decide to reintroduce the list of properties in the future, the generic device properties API in the kernel will have to be extended accordingly. A kernel with this series and all the dependencies applied can be pulled from branch vfio-device-properties-v3 from the repository: https://github.com/virtualopensystems/linux-kvm-arm.git Changes since v2: - Reworked on top of Rafael J. Wysocki's uniform device properties API for device tree and ACPI - Support for u64 array properties - Removed API to get list of available properties and device tree full_name Changes since v1: - Updated for VFIO platform patch series v8: VFIO AMBA devices now supported in addition to VFIO PLATFORM devices - Refactored and cleaned up the code Antonios Motakis (3): vfio: platform: add device properties skeleton and user API vfio: platform: access device property as a list of strings vfio: platform: return device properties as arrays of unsigned integers drivers/vfio/platform/Makefile | 3 +- drivers/vfio/platform/properties.c | 162 ++++++++++++++++++++++++++ drivers/vfio/platform/vfio_platform_common.c | 35 ++++++ drivers/vfio/platform/vfio_platform_private.h | 7 ++ include/uapi/linux/vfio.h | 26 +++++ 5 files changed, 232 insertions(+), 1 deletion(-) create mode 100644 drivers/vfio/platform/properties.c -- 2.1.3 _______________________________________________ kvmarm mailing list kvmarm@xxxxxxxxxxxxxxxxxxxxx https://lists.cs.columbia.edu/mailman/listinfo/kvmarm
