When using GCC on x86-64 to compile an usdt prog with -O1 or higher
optimization, the compiler will generate SIB addressing mode for global
array and PC-relative addressing mode for global variable,
e.g. "1@-96(%rbp,%rax,8)" and "-1@4+t1(%rip)".
The current USDT implementation in libbpf cannot parse these two formats,
causing `bpf_program__attach_usdt()` to fail with -ENOENT
(unrecognized register).
This patch series adds support for SIB addressing mode in USDT probes.
The main changes include:
- add correct handling logic for SIB-addressed arguments in
`parse_usdt_arg`.
- add an usdt_o2 test case to cover SIB addressing mode.
Testing shows that the SIB probe correctly generates 8@(%rcx,%rax,8)
argument spec and passes all validation checks.
The modification history of this patch series:
Change since v1:
- refactor the code to make it more readable
- modify the commit message to explain why and how
Change since v2:
- fix the `scale` uninitialized error
Change since v3:
- force -O2 optimization for usdt.test.o to generate SIB addressing usdt
and pass all test cases.
Change since v4:
- split the patch into two parts, one for the fix and the other for the
test
Change since v5:
- Only enable optimization for x86 architecture to generate SIB addressing
usdt argument spec.
Change since v6:
- Add an usdt_o2 test case to cover SIB addressing mode.
- Reinstate the usdt.c test case.
Do we need to add support for PC-relative USDT argument spec handling in
libbpf? I have some interest in this question, but currently have no
ideas. Getting offsets based on symbols requires dependency on the symbol
table. However, once the binary file is stripped, the symtab will also be
removed, which will cause this approach to fail. Does anyone have any
thoughts on this?
Jiawei Zhao (2):
libbpf: fix USDT SIB argument handling causing unrecognized register
error
selftests/bpf: Force -O2 for USDT selftests to cover SIB handling
logic
tools/lib/bpf/usdt.bpf.h | 33 ++++++++-
tools/lib/bpf/usdt.c | 43 +++++++++--
tools/testing/selftests/bpf/Makefile | 8 +++
.../selftests/bpf/prog_tests/usdt_o2.c | 71 +++++++++++++++++++
.../selftests/bpf/progs/test_usdt_o2.c | 37 ++++++++++
5 files changed, 185 insertions(+), 7 deletions(-)
create mode 100644 tools/testing/selftests/bpf/prog_tests/usdt_o2.c
create mode 100644 tools/testing/selftests/bpf/progs/test_usdt_o2.c
--
2.43.0
When using GCC on x86-64 to compile an usdt prog with -O1 or higher
optimization, the compiler will generate SIB addressing mode for global
array and PC-relative addressing mode for global variable,
e.g. "1@-96(%rbp,%rax,8)" and "-1@4+t1(%rip)".
The current USDT implementation in libbpf cannot parse these two formats,
causing `bpf_program__attach_usdt()` to fail with -ENOENT
(unrecognized register).
This patch series adds support for SIB addressing mode in USDT probes.
The main changes include:
- add correct handling logic for SIB-addressed arguments in
`parse_usdt_arg`.
- add an usdt_o2 test case to cover SIB addressing mode.
Testing shows that the SIB probe correctly generates 8@(%rcx,%rax,8)
argument spec and passes all validation checks.
The modification history of this patch series:
Change since v1:
- refactor the code to make it more readable
- modify the commit message to explain why and how
Change since v2:
- fix the `scale` uninitialized error
Change since v3:
- force -O2 optimization for usdt.test.o to generate SIB addressing usdt
and pass all test cases.
Change since v4:
- split the patch into two parts, one for the fix and the other for the
test
Change since v5:
- Only enable optimization for x86 architecture to generate SIB addressing
usdt argument spec.
Change since v6:
- Add an usdt_o2 test case to cover SIB addressing mode.
- Reinstate the usdt.c test case.
Change since v7:
- Refactor modifications to __bpf_usdt_arg_spec to avoid increasing its size,
achieving better compatibility
- Fix some minor code style issues
- Refactor the usdt_o2 test case, removing semaphore and adding GCC attribute
to force -O2 optimization
Change since v8:
- Refactor the usdt_o2 test case, using assembly to force SIB addressing mode.
Change since v9:
- Only enable the usdt_o2 test case on x86_64 and i386 architectures since the
SIB addressing mode is only supported on x86_64 and i386.
Change since v10:
- Replace `__attribute__((optimize("O2")))` with `#pragma GCC optimize("O1")`
to fix the issue where the optimized compilation condition works improperly.
- Renamed test case usdt_o2 and relevant files name to usdt_o1 in that O1
level optimization is enough to generate SIB addressing usdt argument spec.
Change since v11:
- Replace `STAP_PROBE1` with `STAP_PROBE_ASM`
- Use bit fields instead of bit shifting operations
- Merge the usdt_o1 test case into the usdt test case
Jiawei Zhao (2):
libbpf: fix USDT SIB argument handling causing unrecognized register
error
selftests/bpf: Enrich subtest_basic_usdt case in selftests to cover
SIB handling logic
tools/lib/bpf/usdt.bpf.h | 47 ++++++++++++++-
tools/lib/bpf/usdt.c | 58 +++++++++++++++++--
tools/testing/selftests/bpf/prog_tests/usdt.c | 44 +++++++++++++-
tools/testing/selftests/bpf/progs/test_usdt.c | 30 ++++++++++
4 files changed, 170 insertions(+), 9 deletions(-)
--
2.43.0
Recently, I reviewed a patch on the mm/kselftest mailing list about a
test which had obvious type mismatch fix in it. It was strange why that
wasn't caught during development and when patch was accepted. This led
me to discover that those extra compiler options to catch these warnings
aren't being used. When I added them, I found tens of warnings in just
mm suite.
In this series, I'm adding these flags and fixing those warnings. In the
last try several months ago [1], I'd patches for individual tests. I've
made patches better by grouping the same type of fixes together. Hence
there is no changelog for individual patches.
The changes have been build tested on x86_64, arm64, powerpc64 and partially
on riscv64. The test run with and without this series has been done on
x86_64.
---
Changes since v1:
- Drop test harness patch which isn't needed anymore
- Revamp how patches are written per same kind of failure
Muhammad Usama Anjum (8):
selftests/mm: Add -Wunreachable-code and fix warnings
selftests/mm: protection_keys: Fix dead code
selftests: kselftest.h: Add __unused macro
selftests/mm: Add -Wunused family of flags
selftests/mm: Remove unused parameters
selftests/mm: Mark unused arguments with __unused
selftests/mm: Mark unused arguments with __unused
selftests/mm: Fix unused parameter warnings for different
architectures
tools/testing/selftests/kselftest.h | 4 ++
tools/testing/selftests/mm/Makefile | 3 +-
tools/testing/selftests/mm/compaction_test.c | 2 +-
tools/testing/selftests/mm/cow.c | 22 +++++------
tools/testing/selftests/mm/droppable.c | 2 +-
tools/testing/selftests/mm/gup_longterm.c | 2 +-
tools/testing/selftests/mm/hmm-tests.c | 5 +--
tools/testing/selftests/mm/hugepage-vmemmap.c | 2 +-
tools/testing/selftests/mm/hugetlb-madvise.c | 2 +-
.../selftests/mm/hugetlb-soft-offline.c | 2 +-
.../selftests/mm/hugetlb_fault_after_madv.c | 4 +-
.../selftests/mm/hugetlb_madv_vs_map.c | 6 +--
tools/testing/selftests/mm/ksm_tests.c | 17 ++++-----
tools/testing/selftests/mm/madv_populate.c | 2 +-
tools/testing/selftests/mm/map_populate.c | 2 +-
tools/testing/selftests/mm/memfd_secret.c | 6 +--
.../testing/selftests/mm/mlock-random-test.c | 2 +-
tools/testing/selftests/mm/mlock2-tests.c | 2 +-
tools/testing/selftests/mm/mseal_test.c | 8 +++-
tools/testing/selftests/mm/on-fault-limit.c | 2 +-
tools/testing/selftests/mm/pfnmap.c | 2 +-
tools/testing/selftests/mm/pkey-arm64.h | 5 ++-
tools/testing/selftests/mm/pkey-powerpc.h | 2 +-
tools/testing/selftests/mm/pkey-x86.h | 3 +-
.../selftests/mm/pkey_sighandler_tests.c | 35 ++++++++++++-----
tools/testing/selftests/mm/protection_keys.c | 22 +++++------
tools/testing/selftests/mm/soft-dirty.c | 6 +--
.../selftests/mm/split_huge_page_test.c | 8 ++--
tools/testing/selftests/mm/uffd-common.c | 15 ++++----
tools/testing/selftests/mm/uffd-common.h | 2 +-
tools/testing/selftests/mm/uffd-stress.c | 2 +-
tools/testing/selftests/mm/uffd-unit-tests.c | 38 +++++++++----------
tools/testing/selftests/mm/uffd-wp-mremap.c | 2 +-
.../selftests/mm/virtual_address_range.c | 2 +-
34 files changed, 130 insertions(+), 111 deletions(-)
--
2.39.5
This series introduces VFIO selftests, located in
tools/testing/selftests/vfio/.
VFIO selftests aim to enable kernel developers to write and run tests
that take the form of userspace programs that interact with VFIO and
IOMMUFD uAPIs. VFIO selftests can be used to write functional tests for
new features, regression tests for bugs, and performance tests for
optimizations.
These tests are designed to interact with real PCI devices, i.e. they do
not rely on mocking out or faking any behavior in the kernel. This
allows the tests to exercise not only VFIO but also IOMMUFD, the IOMMU
driver, interrupt remapping, IRQ handling, etc.
For more background on the motivation and design of this series, please
see the RFC:
https://lore.kernel.org/kvm/20250523233018.1702151-1-dmatlack@google.com/
This series can also be found on GitHub:
https://github.com/dmatlack/linux/tree/vfio/selftests/v1
Changelog
-----------------------------------------------------------------------
RFC: https://lore.kernel.org/kvm/20250523233018.1702151-1-dmatlack@google.com/
- Add symlink to linux/pci_ids.h instead of copying (Jason)
- Add symlinks to drivers/dma/*/*.h instead of copying (Jason)
- Automatically replicate vfio_dma_mapping_test across backing
sources using fixture variants (Jason)
- Automatically replicate vfio_dma_mapping_test and
vfio_pci_driver_test across all iommu_modes using fixture
variants (Jason)
- Invert access() check in vfio_dma_mapping_test (me)
- Use driver_override instead of add/remove_id (Alex)
- Allow tests to get BDF from env var (Alex)
- Use KSFT_FAIL instead of 1 to exit with failure (Alex)
- Unconditionally create $(LIBVFIO_O_DIRS) to avoid target
conflict with ../cgroup/lib/libcgroup.mk when building
KVM selftests (me)
- Allow VFIO selftests to run automatically by switching from
TEST_GEN_PROGS_EXTENDED to TEST_GEN_PROGS. Automatically run
selftests will use $VFIO_SELFTESTS_BDF environment variable
to know which device to use (Alex)
- Replace hardcoded SZ_4K with getpagesize() in vfio_dma_mapping_test
to support platforms with other page sizes (me)
- Make all global variables static where possible (me)
- Pass argc and argv to test_harness_main() so that users can
pass flags to the kselftest harness (me)
Instructions
-----------------------------------------------------------------------
Running VFIO selftests requires at a PCI device bound to vfio-pci for
the tests to use. The address of this device is passed to the test as
a segment:bus:device.function string, which must match the path to
the device in /sys/bus/pci/devices/ (e.g. 0000:00:04.0).
Once you have chosen a device, there is a helper script provided to
unbind the device from its current driver, bind it to vfio-pci, export
the environment variable $VFIO_SELFTESTS_BDF, and launch a shell:
$ tools/testing/selftests/vfio/run.sh -d 0000:00:04.0 -s
The -d option tells the script which device to use and the -s option
tells the script to launch a shell.
Additionally, the VFIO selftest vfio_dma_mapping_test has test cases
that rely on HugeTLB pages being available, otherwise they are skipped.
To enable those tests make sure at least 1 2MB and 1 1GB HugeTLB pages
are available.
$ echo 1 > /sys/kernel/mm/hugepages/hugepages-2048kB/nr_hugepages
$ echo 1 > /sys/kernel/mm/hugepages/hugepages-1048576kB/nr_hugepages
To run all VFIO selftests using make:
$ make -C tools/testing/selftests/vfio run_tests
To run individual tests:
$ tools/testing/selftests/vfio/vfio_dma_mapping_test
$ tools/testing/selftests/vfio/vfio_dma_mapping_test -v iommufd_anonymous_hugetlb_2mb
$ tools/testing/selftests/vfio/vfio_dma_mapping_test -r vfio_dma_mapping_test.iommufd_anonymous_hugetlb_2mb.dma_map_unmap
The environment variable $VFIO_SELFTESTS_BDF can be overridden for a
specific test by passing in the BDF on the command line as the last
positional argument.
$ tools/testing/selftests/vfio/vfio_dma_mapping_test 0000:00:04.0
$ tools/testing/selftests/vfio/vfio_dma_mapping_test -v iommufd_anonymous_hugetlb_2mb 0000:00:04.0
$ tools/testing/selftests/vfio/vfio_dma_mapping_test -r vfio_dma_mapping_test.iommufd_anonymous_hugetlb_2mb.dma_map_unmap 0000:00:04.0
When you are done, free the HugeTLB pages and exit the shell started by
run.sh. Exiting the shell will cause the device to be unbound from
vfio-pci and bound back to its original driver.
$ echo 0 > /sys/kernel/mm/hugepages/hugepages-2048kB/nr_hugepages
$ echo 0 > /sys/kernel/mm/hugepages/hugepages-1048576kB/nr_hugepages
$ exit
It's also possible to use run.sh to run just a single test hermetically,
rather than dropping into a shell:
$ tools/testing/selftests/vfio/run.sh -d 0000:00:04.0 -- tools/testing/selftests/vfio/vfio_dma_mapping_test -v iommufd_anonymous
Tests
-----------------------------------------------------------------------
There are 5 tests in this series, mostly to demonstrate as a
proof-of-concept:
- tools/testing/selftests/vfio/vfio_pci_device_test.c
- tools/testing/selftests/vfio/vfio_pci_driver_test.c
- tools/testing/selftests/vfio/vfio_iommufd_setup_test.c
- tools/testing/selftests/vfio/vfio_dma_mapping_test.c
- tools/testing/selftests/kvm/vfio_pci_device_irq_test.c
Future Areas of Development
-----------------------------------------------------------------------
Library:
- Driver support for devices that can be used on AMD, ARM, and other
platforms (e.g. mlx5).
- Driver support for a device available in QEMU VMs (e.g.
pcie-ats-testdev [1])
- Support for tests that use multiple devices.
- Support for IOMMU groups with multiple devices.
- Support for multiple devices sharing the same container/iommufd.
- Sharing TEST_ASSERT() macros and other common code between KVM
and VFIO selftests.
Tests:
- DMA mapping performance tests for BARs/HugeTLB/etc.
- Porting tests from
https://github.com/awilliam/tests/commits/for-clg/ to selftests.
- Live Update selftests.
- Porting Sean's KVM selftest for posted interrupts to use the VFIO
selftests library [2]
Cc: Alex Williamson <alex.williamson(a)redhat.com>
Cc: Jason Gunthorpe <jgg(a)nvidia.com>
Cc: Kevin Tian <kevin.tian(a)intel.com>
Cc: Paolo Bonzini <pbonzini(a)redhat.com>
Cc: Sean Christopherson <seanjc(a)google.com>
Cc: Vipin Sharma <vipinsh(a)google.com>
Cc: Josh Hilke <jrhilke(a)google.com>
Cc: Aaron Lewis <aaronlewis(a)google.com>
Cc: Pasha Tatashin <pasha.tatashin(a)soleen.com>
Cc: Saeed Mahameed <saeedm(a)nvidia.com>
Cc: Adithya Jayachandran <ajayachandra(a)nvidia.com>
Cc: Joel Granados <joel.granados(a)kernel.org>
[1] https://github.com/Joelgranados/qemu/blob/pcie-testdev/hw/misc/pcie-ats-tes…
[2] https://lore.kernel.org/kvm/20250404193923.1413163-68-seanjc@google.com/
David Matlack (28):
selftests: Create tools/testing/selftests/vfio
vfio: selftests: Add a helper library for VFIO selftests
vfio: selftests: Introduce vfio_pci_device_test
tools headers: Add stub definition for __iomem
tools headers: Import asm-generic MMIO helpers
tools headers: Import x86 MMIO helper overrides
tools headers: Import iosubmit_cmds512()
tools headers: Add symlink to linux/pci_ids.h
vfio: selftests: Keep track of DMA regions mapped into the device
vfio: selftests: Enable asserting MSI eventfds not firing
vfio: selftests: Add a helper for matching vendor+device IDs
vfio: selftests: Add driver framework
vfio: sefltests: Add vfio_pci_driver_test
dmaengine: ioat: Move system_has_dca_enabled() to dma.h
vfio: selftests: Add driver for Intel CBDMA
dmaengine: idxd: Allow registers.h to be included from tools/
vfio: selftests: Add driver for Intel DSA
vfio: selftests: Move helper to get cdev path to libvfio
vfio: selftests: Encapsulate IOMMU mode
vfio: selftests: Replicate tests across all iommu_modes
vfio: selftests: Add vfio_type1v2_mode
vfio: selftests: Add iommufd_compat_type1{,v2} modes
vfio: selftests: Add iommufd mode
vfio: selftests: Make iommufd the default iommu_mode
vfio: selftests: Add a script to help with running VFIO selftests
KVM: selftests: Build and link sefltests/vfio/lib into KVM selftests
KVM: selftests: Test sending a vfio-pci device IRQ to a VM
KVM: selftests: Add -d option to vfio_pci_device_irq_test for
device-sent MSIs
Josh Hilke (5):
vfio: selftests: Test basic VFIO and IOMMUFD integration
vfio: selftests: Move vfio dma mapping test to their own file
vfio: selftests: Add test to reset vfio device.
vfio: selftests: Add DMA mapping tests for 2M and 1G HugeTLB
vfio: selftests: Validate 2M/1G HugeTLB are mapped as 2M/1G in IOMMU
MAINTAINERS | 7 +
drivers/dma/idxd/registers.h | 4 +
drivers/dma/ioat/dma.h | 2 +
drivers/dma/ioat/hw.h | 3 -
tools/arch/x86/include/asm/io.h | 101 +++
tools/arch/x86/include/asm/special_insns.h | 27 +
tools/include/asm-generic/io.h | 482 ++++++++++++++
tools/include/asm/io.h | 11 +
tools/include/linux/compiler.h | 4 +
tools/include/linux/io.h | 4 +-
tools/include/linux/pci_ids.h | 1 +
tools/testing/selftests/Makefile | 1 +
tools/testing/selftests/kvm/Makefile.kvm | 4 +
.../testing/selftests/kvm/include/kvm_util.h | 4 +
tools/testing/selftests/kvm/lib/kvm_util.c | 21 +
.../selftests/kvm/vfio_pci_device_irq_test.c | 172 +++++
tools/testing/selftests/vfio/.gitignore | 7 +
tools/testing/selftests/vfio/Makefile | 21 +
.../selftests/vfio/lib/drivers/dsa/dsa.c | 416 ++++++++++++
.../vfio/lib/drivers/dsa/registers.h | 1 +
.../selftests/vfio/lib/drivers/ioat/hw.h | 1 +
.../selftests/vfio/lib/drivers/ioat/ioat.c | 235 +++++++
.../vfio/lib/drivers/ioat/registers.h | 1 +
.../selftests/vfio/lib/include/vfio_util.h | 295 +++++++++
tools/testing/selftests/vfio/lib/libvfio.mk | 24 +
.../selftests/vfio/lib/vfio_pci_device.c | 594 ++++++++++++++++++
.../selftests/vfio/lib/vfio_pci_driver.c | 126 ++++
tools/testing/selftests/vfio/run.sh | 109 ++++
.../selftests/vfio/vfio_dma_mapping_test.c | 199 ++++++
.../selftests/vfio/vfio_iommufd_setup_test.c | 127 ++++
.../selftests/vfio/vfio_pci_device_test.c | 176 ++++++
.../selftests/vfio/vfio_pci_driver_test.c | 247 ++++++++
32 files changed, 3423 insertions(+), 4 deletions(-)
create mode 100644 tools/arch/x86/include/asm/io.h
create mode 100644 tools/arch/x86/include/asm/special_insns.h
create mode 100644 tools/include/asm-generic/io.h
create mode 100644 tools/include/asm/io.h
create mode 120000 tools/include/linux/pci_ids.h
create mode 100644 tools/testing/selftests/kvm/vfio_pci_device_irq_test.c
create mode 100644 tools/testing/selftests/vfio/.gitignore
create mode 100644 tools/testing/selftests/vfio/Makefile
create mode 100644 tools/testing/selftests/vfio/lib/drivers/dsa/dsa.c
create mode 120000 tools/testing/selftests/vfio/lib/drivers/dsa/registers.h
create mode 120000 tools/testing/selftests/vfio/lib/drivers/ioat/hw.h
create mode 100644 tools/testing/selftests/vfio/lib/drivers/ioat/ioat.c
create mode 120000 tools/testing/selftests/vfio/lib/drivers/ioat/registers.h
create mode 100644 tools/testing/selftests/vfio/lib/include/vfio_util.h
create mode 100644 tools/testing/selftests/vfio/lib/libvfio.mk
create mode 100644 tools/testing/selftests/vfio/lib/vfio_pci_device.c
create mode 100644 tools/testing/selftests/vfio/lib/vfio_pci_driver.c
create mode 100755 tools/testing/selftests/vfio/run.sh
create mode 100644 tools/testing/selftests/vfio/vfio_dma_mapping_test.c
create mode 100644 tools/testing/selftests/vfio/vfio_iommufd_setup_test.c
create mode 100644 tools/testing/selftests/vfio/vfio_pci_device_test.c
create mode 100644 tools/testing/selftests/vfio/vfio_pci_driver_test.c
base-commit: e271ed52b344ac02d4581286961d0c40acc54c03
prerequisite-patch-id: c1decca4653262d3d2451e6fd4422ebff9c0b589
--
2.50.0.rc2.701.gf1e915cc24-goog