This patch set belongs to a list of series that add SVM support in VT-d.
Here we focus on introducing a common PCI-level API for ATS and PRI to be
used by virtual devices.
The API introduced in this series is mainly based on the PCIe Gen 5 spec.
What is ATS?
''''''''''''
ATS (Address Translation Service) is a PCIe-level protocol that
enables PCIe devices to query an IOMMU for virtual to physical
address translations in a specific address space (such as a userspace
process address space). When a device receives translation responses
from an IOMMU, it may decide to store them in an internal cache,
often known as "ATC" (Address Translation Cache) or "Device IOTLB".
To keep page tables and caches consistent, the IOMMU is allowed to
send asynchronous invalidation requests to its client devices.
What is PRI?
''''''''''''
PRI (Page Request Interface) is a PCIe-level protocol that
enables PCIe devices to request page fault resolutions to
the kernel through an IOMMU. PRI combined with ATS are the
2 cornerstones of a technology called SVM (Shared Virtual
Memory) or SVA (Shared Virtual Addressing) which allows
PCIe devices to read to and write from the memory of
userspace applications without requiring page pinning.
Here is a link to our GitHub repository that contains:
- Qemu with all the patches for SVM in VT-d
- ATS
- PRI
- Device IOTLB invalidations
- Requests with already pre-translated addresses
- A demo device
- A simple driver for the demo device
- A userspace program (for testing and demonstration purposes)
https://github.com/BullSequana/Qemu-in-guest-SVM-demo
Clement Mathieu--Drif (11):
pcie: Add helper to declare PASID capability for a pcie device
pcie: Helper functions to check if PASID is enabled
pcie: Helper function to check if ATS is enabled
pcie: Add a helper to declare the PRI capability for a pcie device
pcie: Helper functions to check to check if PRI is enabled
pci: Cache the bus mastering status in the device
pci: Add an API to get IOMMU's min page size and virtual address width
memory: Store user data pointer in the IOMMU notifiers
pci: Add a pci-level initialization function for IOMMU notifiers
pci: Add a pci-level API for ATS
pci: Add a PCI-level API for PRI
hw/pci/pci.c | 204 +++++++++++++++++++++--
hw/pci/pcie.c | 78 +++++++++
include/hw/pci/pci.h | 315 ++++++++++++++++++++++++++++++++++++
include/hw/pci/pci_device.h | 1 +
include/hw/pci/pcie.h | 13 +-
include/hw/pci/pcie_regs.h | 8 +
include/system/memory.h | 1 +
7 files changed, 609 insertions(+), 11 deletions(-)
--
2.49.0
