Nested translation is a hardware feature that is supported by many modern
IOMMU hardwares. It has two stages (stage-1, stage-2) address translation
to get access to the physical address. stage-1 translation table is owned
by userspace (e.g. by a guest OS), while stage-2 is owned by kernel. Changes
to stage-1 translation table should be followed by an IOTLB invalidation.
Take Intel VT-d as an example, the stage-1 translation table is I/O page
table. As the below diagram shows, guest I/O page table pointer in GPA
(guest physical address) is passed to host and be used to perform the stage-1
address translation. Along with it, modifications to present mappings in the
guest I/O page table should be followed with an IOTLB invalidation.
.-------------. .---------------------------.
| vIOMMU | | Guest I/O page table |
| | '---------------------------'
.----------------/
| PASID Entry |--- PASID cache flush --+
'-------------' |
| | V
| | I/O page table pointer in GPA
'-------------'
Guest
------| Shadow |---------------------------|--------
v v v
Host
.-------------. .------------------------.
| pIOMMU | | FS for GIOVA->GPA |
| | '------------------------'
.----------------/ |
| PASID Entry | V (Nested xlate)
'----------------\.----------------------------------.
| | | SS for GPA->HPA, unmanaged domain|
| | '----------------------------------'
'-------------'
Where:
- FS = First stage page tables
- SS = Second stage page tables
<Intel VT-d Nested translation>
In IOMMUFD, all the translation tables are tracked by hw_pagetable (hwpt)
and each has an iommu_domain allocated from iommu driver. So in this series
hw_pagetable and iommu_domain means the same thing if no special note.
IOMMUFD has already supported allocating hw_pagetable that is linked with
an IOAS. However, nesting requires IOMMUFD to allow allocating hw_pagetable
with driver specific parameters and interface to sync stage-1 IOTLB as user
owns the stage-1 translation table.
This series is based on the iommu hw info reporting series [1]. It first
extends domain_alloc_user to allocate domains with user data and adds new
op for invalidate stage-1 IOTLB for user-managed domains, then extends the
IOMMUFD internal infrastructure to accept user_data and parent hwpt, relay
the user_data/parent to iommu core to allocate user-managed iommu_domain.
After it, extends the ioctl IOMMU_HWPT_ALLOC to accept user data and stage-2
hwpt ID. Along with it, ioctl IOMMU_HWPT_INVALIDATE is added to invalidate
stage-1 IOTLB. This is needed for user-managed hwpts. Selftest is added as
well to cover the new ioctls.
Complete code can be found in [2], QEMU could can be found in [3].
At last, this is a team work together with Nicolin Chen, Lu Baolu. Thanks
them for the help. ^_^. Look forward to your feedbacks.
[1] https://lore.kernel.org/linux-iommu/20230818101033.4100-1-yi.l.liu@xxxxxxxxx/#r - merged
[2] https://github.com/yiliu1765/iommufd/tree/iommufd_nesting
[3] https://github.com/yiliu1765/qemu/tree/zhenzhong/wip/iommufd_nesting_rfcv1
Change log:
v4:
- Separate HWPT alloc/destroy/abort functions between user-managed HWPTs
and kernel-managed HWPTs
- Rework invalidate uAPI to be a multi-request array-based design
- Add a struct iommu_user_data_array and a helper for driver to sanitize
and copy the entry data from user space invalidation array
- Add a patch fixing TEST_LENGTH() in selftest program
- Drop IOMMU_RESV_IOVA_RANGES patches
- Update kdoc and inline comments
- Drop the code to add IOMMU_RESV_SW_MSI to kernel-managed HWPT in nested translation,
this does not change the rule that resv regions should only be added to the
kernel-managed HWPT. The IOMMU_RESV_SW_MSI stuff will be added in later series
as it is needed only by SMMU so far.
v3: https://lore.kernel.org/linux-iommu/20230724110406.107212-1-yi.l.liu@xxxxxxxxx/
- Add new uAPI things in alphabetical order
- Pass in "enum iommu_hwpt_type hwpt_type" to op->domain_alloc_user for
sanity, replacing the previous op->domain_alloc_user_data_len solution
- Return ERR_PTR from domain_alloc_user instead of NULL
- Only add IOMMU_RESV_SW_MSI to kernel-managed HWPT in nested translation (Kevin)
- Add IOMMU_RESV_IOVA_RANGES to report resv iova ranges to userspace hence
userspace is able to exclude the ranges in the stage-1 HWPT (e.g. guest I/O
page table). (Kevin)
- Add selftest coverage for the new IOMMU_RESV_IOVA_RANGES ioctl
- Minor changes per Kevin's inputs
v2: https://lore.kernel.org/linux-iommu/20230511143844.22693-1-yi.l.liu@xxxxxxxxx/
- Add union iommu_domain_user_data to include all user data structures to avoid
passing void * in kernel APIs.
- Add iommu op to return user data length for user domain allocation
- Rename struct iommu_hwpt_alloc::data_type to be hwpt_type
- Store the invalidation data length in iommu_domain_ops::cache_invalidate_user_data_len
- Convert cache_invalidate_user op to be int instead of void
- Remove @data_type in struct iommu_hwpt_invalidate
- Remove out_hwpt_type_bitmap in struct iommu_hw_info hence drop patch 08 of v1
v1: https://lore.kernel.org/linux-iommu/20230309080910.607396-1-yi.l.liu@xxxxxxxxx/
Thanks,
Yi Liu
Lu Baolu (1):
iommu: Add nested domain support
Nicolin Chen (12):
iommufd: Unite all kernel-managed members into a struct
iommufd: Separate kernel-managed HWPT alloc/destroy/abort functions
iommufd: Add shared alloc_fn function pointer and mutex pointer
iommufd: Add user-managed hw_pagetable support
iommufd: Always setup MSI and anforce cc on kernel-managed domains
iommufd/device: Add helpers to enforce/remove device reserved regions
iommufd/selftest: Rework TEST_LENGTH to test min_size explicitly
iommufd/selftest: Add nested domain allocation for mock domain
iommufd/selftest: Add coverage for IOMMU_HWPT_ALLOC with nested HWPTs
iommufd/selftest: Add mock_domain_cache_invalidate_user support
iommufd/selftest: Add IOMMU_TEST_OP_MD_CHECK_IOTLB test op
iommufd/selftest: Add coverage for IOMMU_HWPT_INVALIDATE ioctl
Yi Liu (4):
iommu: Add hwpt_type with user_data for domain_alloc_user op
iommufd: Pass in hwpt_type/user_data to iommufd_hw_pagetable_alloc()
iommufd: Support IOMMU_HWPT_ALLOC allocation with user data
iommufd: Add IOMMU_HWPT_INVALIDATE
drivers/iommu/intel/iommu.c | 5 +-
drivers/iommu/iommufd/device.c | 51 +++-
drivers/iommu/iommufd/hw_pagetable.c | 257 ++++++++++++++++--
drivers/iommu/iommufd/iommufd_private.h | 59 +++-
drivers/iommu/iommufd/iommufd_test.h | 40 +++
drivers/iommu/iommufd/main.c | 3 +
drivers/iommu/iommufd/selftest.c | 184 ++++++++++++-
include/linux/iommu.h | 110 +++++++-
include/uapi/linux/iommufd.h | 60 +++-
tools/testing/selftests/iommu/iommufd.c | 209 +++++++++++++-
.../selftests/iommu/iommufd_fail_nth.c | 3 +-
tools/testing/selftests/iommu/iommufd_utils.h | 91 ++++++-
12 files changed, 998 insertions(+), 74 deletions(-)
--
2.34.1
