This branch has three new iommufd capabilities:
- Dirty tracking for DMA. AMD/ARM/Intel CPUs can now record if a DMA
writes to a page in the IOPTEs within the IO page table. This can be used
to generate a record of what memory is being dirtied by DMA activities
during a VM migration process. A VMM like qemu will combine the IOMMU
dirty bits with the CPU's dirty log to determine what memory to
transfer.
VFIO already has a DMA dirty tracking framework that requires PCI
devices to implement tracking HW internally. The iommufd version
provides an alternative that the VMM can select, if available. The two
are designed to have very similar APIs.
- Userspace controlled attributes for hardware page
tables (HWPT/iommu_domain). There are currently a few generic attributes
for HWPTs (support dirty tracking, and parent of a nest). This is an
entry point for the userspace iommu driver to control the HW in detail.
- Nested translation support for HWPTs. This is a 2D translation scheme
similar to the CPU where a DMA goes through a first stage to determine
an intermediate address which is then translated trough a second stage
to a physical address.
Like for CPU translation the first stage table would exist in VM
controlled memory and the second stage is in the kernel and matches the
VM's guest to physical map.
As every IOMMU has a unique set of parameter to describe the S1 IO page
table and its associated parameters the userspace IOMMU driver has to
marshal the information into the correct format.
This is 1/3 of the feature, it allows creating the nested translation
and binding it to VFIO devices, however the API to support IOTLB and
ATC invalidation of the stage 1 io page table, and forwarding of IO
faults are still in progress.
The series includes AMD and Intel support for dirty tracking. Intel
support for nested translation.
Along the way are a number of internal items:
- New iommu core items: ops->domain_alloc_user(), ops->set_dirty_tracking,
ops->read_and_clear_dirty(), IOMMU_DOMAIN_NESTED, and iommu_copy_struct_from_user
- UAF fix in iopt_area_split()
- Spelling fixes and some test suite improvement
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Merge tag 'for-linus-iommufd' of git://git.kernel.org/pub/scm/linux/kernel/git/jgg/iommufd
Pull iommufd updates from Jason Gunthorpe:
"This brings three new iommufd capabilities:
- Dirty tracking for DMA.
AMD/ARM/Intel CPUs can now record if a DMA writes to a page in the
IOPTEs within the IO page table. This can be used to generate a
record of what memory is being dirtied by DMA activities during a
VM migration process. A VMM like qemu will combine the IOMMU dirty
bits with the CPU's dirty log to determine what memory to transfer.
VFIO already has a DMA dirty tracking framework that requires PCI
devices to implement tracking HW internally. The iommufd version
provides an alternative that the VMM can select, if available. The
two are designed to have very similar APIs.
- Userspace controlled attributes for hardware page tables
(HWPT/iommu_domain). There are currently a few generic attributes
for HWPTs (support dirty tracking, and parent of a nest). This is
an entry point for the userspace iommu driver to control the HW in
detail.
- Nested translation support for HWPTs. This is a 2D translation
scheme similar to the CPU where a DMA goes through a first stage to
determine an intermediate address which is then translated trough a
second stage to a physical address.
Like for CPU translation the first stage table would exist in VM
controlled memory and the second stage is in the kernel and matches
the VM's guest to physical map.
As every IOMMU has a unique set of parameter to describe the S1 IO
page table and its associated parameters the userspace IOMMU driver
has to marshal the information into the correct format.
This is 1/3 of the feature, it allows creating the nested
translation and binding it to VFIO devices, however the API to
support IOTLB and ATC invalidation of the stage 1 io page table,
and forwarding of IO faults are still in progress.
The series includes AMD and Intel support for dirty tracking. Intel
support for nested translation.
Along the way are a number of internal items:
- New iommu core items: ops->domain_alloc_user(),
ops->set_dirty_tracking, ops->read_and_clear_dirty(),
IOMMU_DOMAIN_NESTED, and iommu_copy_struct_from_user
- UAF fix in iopt_area_split()
- Spelling fixes and some test suite improvement"
* tag 'for-linus-iommufd' of git://git.kernel.org/pub/scm/linux/kernel/git/jgg/iommufd: (52 commits)
iommufd: Organize the mock domain alloc functions closer to Joerg's tree
iommufd/selftest: Fix page-size check in iommufd_test_dirty()
iommufd: Add iopt_area_alloc()
iommufd: Fix missing update of domains_itree after splitting iopt_area
iommu/vt-d: Disallow read-only mappings to nest parent domain
iommu/vt-d: Add nested domain allocation
iommu/vt-d: Set the nested domain to a device
iommu/vt-d: Make domain attach helpers to be extern
iommu/vt-d: Add helper to setup pasid nested translation
iommu/vt-d: Add helper for nested domain allocation
iommu/vt-d: Extend dmar_domain to support nested domain
iommufd: Add data structure for Intel VT-d stage-1 domain allocation
iommu/vt-d: Enhance capability check for nested parent domain allocation
iommufd/selftest: Add coverage for IOMMU_HWPT_ALLOC with nested HWPTs
iommufd/selftest: Add nested domain allocation for mock domain
iommu: Add iommu_copy_struct_from_user helper
iommufd: Add a nested HW pagetable object
iommu: Pass in parent domain with user_data to domain_alloc_user op
iommufd: Share iommufd_hwpt_alloc with IOMMUFD_OBJ_HWPT_NESTED
iommufd: Derive iommufd_hwpt_paging from iommufd_hw_pagetable
...
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