This patch series aims to implement VFIO support for platform devices that
reside behind an IOMMU. Examples of such devices are devices behind an ARM SMMU,
or behind a Samsung Exynos System MMU.
The API used is based on the existing VFIO API that is also used with PCI
devices. Only devices that include a basic set of IRQs and memory regions are
targeted; devices with complex relationships with other devices on a device tree
are not taken into account at this stage.
These patches apply on the latest version of Will Deacon's iommu/devel branch
for the ARM SMMU driver, with also Kim Phillips' patches to allow platform
drivers to bind to any device.
A copy with all the dependencies applied can be cloned from branch
vfio-platform-v3 at git@xxxxxxxxxx:virtualopensystems/linux-kvm-arm.git
The following IOCTLs have been found to be working on FastModels with an
ARM SMMU (MMU400). Testing was based on the ARM PL330 DMA Controller featured
on those models.
- VFIO_GET_API_VERSION
- VFIO_CHECK_EXTENSION
The TYPE1 fix proposed here enables the following IOCTLs:
- VFIO_GROUP_GET_STATUS
- VFIO_GROUP_SET_CONTAINER
- VFIO_SET_IOMMU
- VFIO_IOMMU_GET_INFO
- VFIO_IOMMU_MAP_DMA
For this ioctl specifically, a new flag has been added:
VFIO_DMA_MAP_FLAG_EXEC. This flag is taken into account on systems with an
ARM SMMU.
The VFIO platform driver proposed here implements the following:
- VFIO_GROUP_GET_DEVICE_FD
- VFIO_DEVICE_GET_INFO
- VFIO_DEVICE_GET_REGION_INFO
- VFIO_DEVICE_GET_IRQ_INFO
- VFIO_DEVICE_SET_IRQS
IRQs are implemented partially using this ioctl. Handling incoming
interrupts with an eventfd is supported, as is masking and unmasking.
Level sensitive interrupts are automasked. What is not implemented is
masking/unmasking via eventfd.
In addition, the VFIO platform driver implements the following through
the VFIO device file descriptor:
- MMAPing memory regions to the virtual address space of the VFIO user.
- Read / write of memory regions directly through the file descriptor.
What still needs to be done, includes:
- Eventfd for masking/unmasking
- Extend the driver and API for device tree metadata
- QEMU / KVM integration
- Device specific functionality (e.g. VFIO_DEVICE_RESET)
- Improve VFIO_IOMMU_TYPE1 driver to support multiple buses at the same time
- Bind to ARM AMBA devices
- IOMMUs with nested page tables (Stage 1 & 2 translation on ARM SMMUs)
Changes since v2:
- Fixed Read/Write and MMAP on device regions
- Removed dependency on Device Tree
- Interrupts support
- Interrupt masking/unmasking
- Automask level sensitive interrupts
- Introduced VFIO_DMA_MAP_FLAG_EXEC
- Code clean ups
Antonios Motakis (9):
VFIO_IOMMU_TYPE1: Introduce the VFIO_DMA_MAP_FLAG_EXEC flag
VFIO_IOMMU_TYPE1: workaround to build for platform devices
VFIO_PLATFORM: Initial skeleton of VFIO support for platform devices
VFIO_PLATFORM: Return info for device and its memory mapped IO regions
VFIO_PLATFORM: Read and write support for the device fd
VFIO_PLATFORM: Support MMAP of MMIO regions
VFIO_PLATFORM: Return IRQ info
VFIO_PLATFORM: Initial interrupts support
VFIO_PLATFORM: Support for maskable and automasked interrupts
drivers/vfio/Kconfig | 3 +-
drivers/vfio/Makefile | 1 +
drivers/vfio/platform/Kconfig | 9 +
drivers/vfio/platform/Makefile | 4 +
drivers/vfio/platform/vfio_platform.c | 448 ++++++++++++++++++++++++++
drivers/vfio/platform/vfio_platform_irq.c | 289 +++++++++++++++++
drivers/vfio/platform/vfio_platform_private.h | 50 +++
drivers/vfio/vfio_iommu_type1.c | 27 +-
include/uapi/linux/vfio.h | 2 +
9 files changed, 827 insertions(+), 6 deletions(-)
create mode 100644 drivers/vfio/platform/Kconfig
create mode 100644 drivers/vfio/platform/Makefile
create mode 100644 drivers/vfio/platform/vfio_platform.c
create mode 100644 drivers/vfio/platform/vfio_platform_irq.c
create mode 100644 drivers/vfio/platform/vfio_platform_private.h
--
1.8.3.2
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