GCC gets a bit confused and reports:
In function '_test_cmd_get_hw_info',
inlined from 'iommufd_ioas_get_hw_info' at iommufd.c:779:3,
inlined from 'wrapper_iommufd_ioas_get_hw_info' at iommufd.c:752:1:
>> iommufd_utils.h:804:37: warning: array subscript 'struct iommu_test_hw_info[0]' is partly outside array bounds of 'struct iommu_test_hw_info_buffer_smaller[1]' [-Warray-bounds=]
804 | assert(!info->flags);
| ~~~~^~~~~~~
iommufd.c: In function 'wrapper_iommufd_ioas_get_hw_info':
iommufd.c:761:11: note: object 'buffer_smaller' of size 4
761 | } buffer_smaller;
| ^~~~~~~~~~~~~~
While it is true that "struct iommu_test_hw_info[0]" is partly out of
bounds of the input pointer, it is not true that info->flags is out of
bounds. Unclear why it warns on this.
Reuse an existing properly sized stack buffer and pass a truncated length
instead to test the same thing.
Fixes: af4fde93c3 ("iommufd/selftest: Add coverage for IOMMU_GET_HW_INFO ioctl")
Link: https://patch.msgid.link/r/0-v1-63a2cffb09da+4486-iommufd_gcc_bounds_jgg@nvidia.com
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Reviewed-by: Nicolin Chen <nicolinc@nvidia.com>
Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202512032344.kaAcKFIM-lkp@intel.com/
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Pull non-MM updates from Andrew Morton:
- "panic: sys_info: Refactor and fix a potential issue" (Andy Shevchenko)
fixes a build issue and does some cleanup in ib/sys_info.c
- "Implement mul_u64_u64_div_u64_roundup()" (David Laight)
enhances the 64-bit math code on behalf of a PWM driver and beefs up
the test module for these library functions
- "scripts/gdb/symbols: make BPF debug info available to GDB" (Ilya Leoshkevich)
makes BPF symbol names, sizes, and line numbers available to the GDB
debugger
- "Enable hung_task and lockup cases to dump system info on demand" (Feng Tang)
adds a sysctl which can be used to cause additional info dumping when
the hung-task and lockup detectors fire
- "lib/base64: add generic encoder/decoder, migrate users" (Kuan-Wei Chiu)
adds a general base64 encoder/decoder to lib/ and migrates several
users away from their private implementations
- "rbree: inline rb_first() and rb_last()" (Eric Dumazet)
makes TCP a little faster
- "liveupdate: Rework KHO for in-kernel users" (Pasha Tatashin)
reworks the KEXEC Handover interfaces in preparation for Live Update
Orchestrator (LUO), and possibly for other future clients
- "kho: simplify state machine and enable dynamic updates" (Pasha Tatashin)
increases the flexibility of KEXEC Handover. Also preparation for LUO
- "Live Update Orchestrator" (Pasha Tatashin)
is a major new feature targeted at cloud environments. Quoting the
cover letter:
This series introduces the Live Update Orchestrator, a kernel
subsystem designed to facilitate live kernel updates using a
kexec-based reboot. This capability is critical for cloud
environments, allowing hypervisors to be updated with minimal
downtime for running virtual machines. LUO achieves this by
preserving the state of selected resources, such as memory,
devices and their dependencies, across the kernel transition.
As a key feature, this series includes support for preserving
memfd file descriptors, which allows critical in-memory data, such
as guest RAM or any other large memory region, to be maintained in
RAM across the kexec reboot.
Mike Rappaport merits a mention here, for his extensive review and
testing work.
- "kexec: reorganize kexec and kdump sysfs" (Sourabh Jain)
moves the kexec and kdump sysfs entries from /sys/kernel/ to
/sys/kernel/kexec/ and adds back-compatibility symlinks which can
hopefully be removed one day
- "kho: fixes for vmalloc restoration" (Mike Rapoport)
fixes a BUG which was being hit during KHO restoration of vmalloc()
regions
* tag 'mm-nonmm-stable-2025-12-06-11-14' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (139 commits)
calibrate: update header inclusion
Reinstate "resource: avoid unnecessary lookups in find_next_iomem_res()"
vmcoreinfo: track and log recoverable hardware errors
kho: fix restoring of contiguous ranges of order-0 pages
kho: kho_restore_vmalloc: fix initialization of pages array
MAINTAINERS: TPM DEVICE DRIVER: update the W-tag
init: replace simple_strtoul with kstrtoul to improve lpj_setup
KHO: fix boot failure due to kmemleak access to non-PRESENT pages
Documentation/ABI: new kexec and kdump sysfs interface
Documentation/ABI: mark old kexec sysfs deprecated
kexec: move sysfs entries to /sys/kernel/kexec
test_kho: always print restore status
kho: free chunks using free_page() instead of kfree()
selftests/liveupdate: add kexec test for multiple and empty sessions
selftests/liveupdate: add simple kexec-based selftest for LUO
selftests/liveupdate: add userspace API selftests
docs: add documentation for memfd preservation via LUO
mm: memfd_luo: allow preserving memfd
liveupdate: luo_file: add private argument to store runtime state
mm: shmem: export some functions to internal.h
...
Pull iommufd updates from Jason Gunthorpe:
"This is a pretty consequential cycle for iommufd, though this pull is
not too big. It is based on a shared branch with VFIO that introduces
VFIO_DEVICE_FEATURE_DMA_BUF a DMABUF exporter for VFIO device's MMIO
PCI BARs. This was a large multiple series journey over the last year
and a half.
Based on that work IOMMUFD gains support for VFIO DMABUF's in its
existing IOMMU_IOAS_MAP_FILE, which closes the last major gap to
support PCI peer to peer transfers within VMs.
In Joerg's iommu tree we have the "generic page table" work which aims
to consolidate all the duplicated page table code in every iommu
driver into a single algorithm. This will be used by iommufd to
implement unique page table operations to start adding new features
and improve performance.
In here:
- Expand IOMMU_IOAS_MAP_FILE to accept a DMABUF exported from VFIO.
This is the first step to broader DMABUF support in iommufd, right
now it only works with VFIO. This closes the last functional gap
with classic VFIO type 1 to safely support PCI peer to peer DMA by
mapping the VFIO device's MMIO into the IOMMU.
- Relax SMMUv3 restrictions on nesting domains to better support
qemu's sequence to have an identity mapping before the vSID is
established"
* tag 'for-linus-iommufd' of git://git.kernel.org/pub/scm/linux/kernel/git/jgg/iommufd:
iommu/arm-smmu-v3-iommufd: Allow attaching nested domain for GBPA cases
iommufd/selftest: Add some tests for the dmabuf flow
iommufd: Accept a DMABUF through IOMMU_IOAS_MAP_FILE
iommufd: Have iopt_map_file_pages convert the fd to a file
iommufd: Have pfn_reader process DMABUF iopt_pages
iommufd: Allow MMIO pages in a batch
iommufd: Allow a DMABUF to be revoked
iommufd: Do not map/unmap revoked DMABUFs
iommufd: Add DMABUF to iopt_pages
vfio/pci: Add vfio_pci_dma_buf_iommufd_map()
Jason Gunthorpe says:
====================
This series is the start of adding full DMABUF support to
iommufd. Currently it is limited to only work with VFIO's DMABUF exporter.
It sits on top of Leon's series to add a DMABUF exporter to VFIO:
https://lore.kernel.org/all/20251120-dmabuf-vfio-v9-0-d7f71607f371@nvidia.com/
The existing IOMMU_IOAS_MAP_FILE is enhanced to detect DMABUF fd's, but
otherwise works the same as it does today for a memfd. The user can select
a slice of the FD to map into the ioas and if the underliyng alignment
requirements are met it will be placed in the iommu_domain.
Though limited, it is enough to allow a VMM like QEMU to connect MMIO BAR
memory from VFIO to an iommu_domain controlled by iommufd. This is used
for PCI Peer to Peer support in VMs, and is the last feature that the VFIO
type 1 container has that iommufd couldn't do.
The VFIO type1 version extracts raw PFNs from VMAs, which has no lifetime
control and is a use-after-free security problem.
Instead iommufd relies on revokable DMABUFs. Whenever VFIO thinks there
should be no access to the MMIO it can shoot down the mapping in iommufd
which will unmap it from the iommu_domain. There is no automatic remap,
this is a safety protocol so the kernel doesn't get stuck. Userspace is
expected to know it is doing something that will revoke the dmabuf and
map/unmap it around the activity. Eg when QEMU goes to issue FLR it should
do the map/unmap to iommufd.
Since DMABUF is missing some key general features for this use case it
relies on a "private interconnect" between VFIO and iommufd via the
vfio_pci_dma_buf_iommufd_map() call.
The call confirms the DMABUF has revoke semantics and delivers a phys_addr
for the memory suitable for use with iommu_map().
Medium term there is a desire to expand the supported DMABUFs to include
GPU drivers to support DPDK/SPDK type use cases so future series will work
to add a general concept of revoke and a general negotiation of
interconnect to remove vfio_pci_dma_buf_iommufd_map().
I also plan another series to modify iommufd's vfio_compat to
transparently pull a dmabuf out of a VFIO VMA to emulate more of the uAPI
of type1.
The latest series for interconnect negotation to exchange a phys_addr is:
https://lore.kernel.org/r/20251027044712.1676175-1-vivek.kasireddy@intel.com
And the discussion for design of revoke is here:
https://lore.kernel.org/dri-devel/20250114173103.GE5556@nvidia.com/
====================
Based on a shared branch with vfio.
* iommufd_dmabuf:
iommufd/selftest: Add some tests for the dmabuf flow
iommufd: Accept a DMABUF through IOMMU_IOAS_MAP_FILE
iommufd: Have iopt_map_file_pages convert the fd to a file
iommufd: Have pfn_reader process DMABUF iopt_pages
iommufd: Allow MMIO pages in a batch
iommufd: Allow a DMABUF to be revoked
iommufd: Do not map/unmap revoked DMABUFs
iommufd: Add DMABUF to iopt_pages
vfio/pci: Add vfio_pci_dma_buf_iommufd_map()
vfio/nvgrace: Support get_dmabuf_phys
vfio/pci: Add dma-buf export support for MMIO regions
vfio/pci: Enable peer-to-peer DMA transactions by default
vfio/pci: Share the core device pointer while invoking feature functions
vfio: Export vfio device get and put registration helpers
dma-buf: provide phys_vec to scatter-gather mapping routine
PCI/P2PDMA: Document DMABUF model
PCI/P2PDMA: Provide an access to pci_p2pdma_map_type() function
PCI/P2PDMA: Refactor to separate core P2P functionality from memory allocation
PCI/P2PDMA: Simplify bus address mapping API
PCI/P2PDMA: Separate the mmap() support from the core logic
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
The iommufd self test uses an xarray to store the pfns and their orders to
emulate a page table. Make it act more like a real iommu driver by
replacing the xarray with an iommupt based page table. The new AMDv1 mock
format behaves similarly to the xarray.
Add set_dirty() as a iommu_pt operation to allow the test suite to
simulate HW dirty.
Userspace can select between several formats including the normal AMDv1
format and a special MOCK_IOMMUPT_HUGE variation for testing huge page
dirty tracking. To make the dirty tracking test work the page table must
only store exactly 2M huge pages otherwise the logic the test uses
fails. They cannot be broken up or combined.
Aside from aligning the selftest with a real page table implementation,
this helps test the iommupt code itself.
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Reviewed-by: Samiullah Khawaja <skhawaja@google.com>
Tested-by: Alejandro Jimenez <alejandro.j.jimenez@oracle.com>
Tested-by: Pasha Tatashin <pasha.tatashin@soleen.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
Fix to avoid the usage of the `res` variable uninitialized in the
following macro expansions.
It solves the following warning:
In function ‘iommufd_viommu_vdevice_alloc’,
inlined from ‘wrapper_iommufd_viommu_vdevice_alloc’ at iommufd.c:2889:1:
../kselftest_harness.h:760:12: warning: ‘ret’ may be used uninitialized [-Wmaybe-uninitialized]
760 | if (!(__exp _t __seen)) { \
| ^
../kselftest_harness.h:513:9: note: in expansion of macro ‘__EXPECT’
513 | __EXPECT(expected, #expected, seen, #seen, ==, 1)
| ^~~~~~~~
iommufd_utils.h:1057:9: note: in expansion of macro ‘ASSERT_EQ’
1057 | ASSERT_EQ(0, _test_cmd_trigger_vevents(self->fd, dev_id, nvevents))
| ^~~~~~~~~
iommufd.c:2924:17: note: in expansion of macro ‘test_cmd_trigger_vevents’
2924 | test_cmd_trigger_vevents(dev_id, 3);
| ^~~~~~~~~~~~~~~~~~~~~~~~
The issue can be reproduced, building the tests, with the command: make -C
tools/testing/selftests TARGETS=iommu
Link: https://patch.msgid.link/r/20250924171629.50266-1-alessandro.zanni87@gmail.com
Fixes: 97717a1f28 ("iommufd/selftest: Add IOMMU_VEVENTQ_ALLOC test coverage")
Signed-off-by: Alessandro Zanni <alessandro.zanni87@gmail.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Pull iommufd updates from Jason Gunthorpe:
"This broadly brings the assigned HW command queue support to iommufd.
This feature is used to improve SVA performance in VMs by avoiding
paravirtualization traps during SVA invalidations.
Along the way I think some of the core logic is in a much better state
to support future driver backed features.
Summary:
- IOMMU HW now has features to directly assign HW command queues to a
guest VM. In this mode the command queue operates on a limited set
of invalidation commands that are suitable for improving guest
invalidation performance and easy for the HW to virtualize.
This brings the generic infrastructure to allow IOMMU drivers to
expose such command queues through the iommufd uAPI, mmap the
doorbell pages, and get the guest physical range for the command
queue ring itself.
- An implementation for the NVIDIA SMMUv3 extension "cmdqv" is built
on the new iommufd command queue features. It works with the
existing SMMU driver support for cmdqv in guest VMs.
- Many precursor cleanups and improvements to support the above
cleanly, changes to the general ioctl and object helpers, driver
support for VDEVICE, and mmap pgoff cookie infrastructure.
- Sequence VDEVICE destruction to always happen before VFIO device
destruction. When using the above type features, and also in future
confidential compute, the internal virtual device representation
becomes linked to HW or CC TSM configuration and objects. If a VFIO
device is removed from iommufd those HW objects should also be
cleaned up to prevent a sort of UAF. This became important now that
we have HW backing the VDEVICE.
- Fix one syzkaller found error related to math overflows during iova
allocation"
* tag 'for-linus-iommufd' of git://git.kernel.org/pub/scm/linux/kernel/git/jgg/iommufd: (57 commits)
iommu/arm-smmu-v3: Replace vsmmu_size/type with get_viommu_size
iommu/arm-smmu-v3: Do not bother impl_ops if IOMMU_VIOMMU_TYPE_ARM_SMMUV3
iommufd: Rename some shortterm-related identifiers
iommufd/selftest: Add coverage for vdevice tombstone
iommufd/selftest: Explicitly skip tests for inapplicable variant
iommufd/vdevice: Remove struct device reference from struct vdevice
iommufd: Destroy vdevice on idevice destroy
iommufd: Add a pre_destroy() op for objects
iommufd: Add iommufd_object_tombstone_user() helper
iommufd/viommu: Roll back to use iommufd_object_alloc() for vdevice
iommufd/selftest: Test reserved regions near ULONG_MAX
iommufd: Prevent ALIGN() overflow
iommu/tegra241-cmdqv: import IOMMUFD module namespace
iommufd: Do not allow _iommufd_object_alloc_ucmd if abort op is set
iommu/tegra241-cmdqv: Add IOMMU_VEVENTQ_TYPE_TEGRA241_CMDQV support
iommu/tegra241-cmdqv: Add user-space use support
iommu/tegra241-cmdqv: Do not statically map LVCMDQs
iommu/tegra241-cmdqv: Simplify deinit flow in tegra241_cmdqv_remove_vintf()
iommu/tegra241-cmdqv: Use request_threaded_irq
iommu/arm-smmu-v3-iommufd: Add hw_info to impl_ops
...
Commit 869c788909 ("selftests: harness: Stop using setjmp()/longjmp()")
changed the harness structure. For some unknown reason, two build warnings
occur to the iommufd selftest:
iommufd.c: In function ‘wrapper_iommufd_mock_domain_all_aligns’:
iommufd.c:1807:17: warning: ‘mfd’ may be used uninitialized in this function
1807 | close(mfd);
| ^~~~~~~~~~
iommufd.c:1767:13: note: ‘mfd’ was declared here
1767 | int mfd;
| ^~~
iommufd.c: In function ‘wrapper_iommufd_mock_domain_all_aligns_copy’:
iommufd.c:1870:17: warning: ‘mfd’ may be used uninitialized in this function
1870 | close(mfd);
| ^~~~~~~~~~
iommufd.c:1819:13: note: ‘mfd’ was declared here
1819 | int mfd;
| ^~~
All the mfd have been used in the variant->file path only, so it's likely
a false alarm.
FWIW, the commit mentioned above does not cause this, yet it might affect
gcc in a certain way that resulted in the warnings. It is also found that
ading a dummy setjmp (which doesn't make sense) could mute the warnings:
https://lore.kernel.org/all/aEi8DV+ReF3v3Rlf@nvidia.com/
The job of this selftest is to catch kernel bug, while such warnings will
unlikely disrupt its role. Mute the warning by force initializing the mfd
and add an ASSERT_GT().
Link: https://patch.msgid.link/r/6951d85d5cd34cbf22abab7714542654e63ecc44.1750787928.git.nicolinc@nvidia.com
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Signed-off-by: Nicolin Chen <nicolinc@nvidia.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
The hugepage test cases of iommufd_dirty_tracking have the 64MB and 128MB
coverages. Both of them are smaller than the default hugepage size 512MB,
when CONFIG_PAGE_SIZE_64KB=y. However, these test cases have a variant of
using huge pages, which would mmap(MAP_HUGETLB) using these smaller sizes
than the system hugepag size. This results in the kernel aligning up the
smaller size to 512MB. If a memory was located between the upper 64/128MB
size boundary and the hugepage 512MB boundary, it would get wiped out:
https://lore.kernel.org/all/aEoUhPYIAizTLADq@nvidia.com/
Given that this aligning up behavior is well documented, we have no choice
but to allocate a hugepage aligned size to avoid this unintended wipe out.
Instead of relying on the kernel's internal force alignment, pass the same
size to posix_memalign() and map().
Also, fix the FIXTURE_TEARDOWN() misusing munmap() to free the memory from
posix_memalign(), as munmap() doesn't destroy the allocator meta data. So,
call free() instead.
Fixes: a9af47e382 ("iommufd/selftest: Test IOMMU_HWPT_GET_DIRTY_BITMAP")
Link: https://patch.msgid.link/r/1ea8609ae6d523fdd4d8efb179ddee79c8582cb6.1750787928.git.nicolinc@nvidia.com
Cc: stable@vger.kernel.org
Suggested-by: Jason Gunthorpe <jgg@nvidia.com>
Signed-off-by: Nicolin Chen <nicolinc@nvidia.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
