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[PATCH v3 1/6] kunit: move KUNIT_TABLE out of INIT_DATA

by Rae Moar

Alter the linker section of KUNIT_TABLE to move it out of INIT_DATA and into DATA_DATA. Data for KUnit tests does not need to be in the init section. In order to run tests again after boot the KUnit data cannot be labeled as init data as the kernel could write over it. Add a KUNIT_INIT_TABLE in the next patch for KUnit tests that test init data/functions. Signed-off-by: Rae Moar <rmoar(a)google.com> --- include/asm-generic/vmlinux.lds.h | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/include/asm-generic/vmlinux.lds.h b/include/asm-generic/vmlinux.lds.h index bae0fe4d499b..1107905d37fc 100644 --- a/include/asm-generic/vmlinux.lds.h +++ b/include/asm-generic/vmlinux.lds.h @@ -370,7 +370,8 @@ BRANCH_PROFILE() \ TRACE_PRINTKS() \ BPF_RAW_TP() \ - TRACEPOINT_STR() + TRACEPOINT_STR() \ + KUNIT_TABLE() /* * Data section helpers @@ -699,8 +700,7 @@ THERMAL_TABLE(governor) \ EARLYCON_TABLE() \ LSM_TABLE() \ - EARLY_LSM_TABLE() \ - KUNIT_TABLE() + EARLY_LSM_TABLE() #define INIT_TEXT \ *(.init.text .init.text.*) \ base-commit: b85ea95d086471afb4ad062012a4d73cd328fa86 -- 2.43.0.rc2.451.g8631bc7472-goog

1 year, 10 months

2
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[PATCH] kselftest/arm64: Log SVCR when the SME tests barf

by Mark Brown

On failure we log the actual and expected value of the register we detect a mismatch in. For SME one obvious potential source of corruption would be if we had corrupted SVCR since changes in streaming mode will reset the register values, log the value to aid in understanding issues. Signed-off-by: Mark Brown <broonie(a)kernel.org> --- tools/testing/selftests/arm64/fp/sve-test.S | 10 ++++++++++ tools/testing/selftests/arm64/fp/za-test.S | 6 ++++++ tools/testing/selftests/arm64/fp/zt-test.S | 5 +++++ 3 files changed, 21 insertions(+) diff --git a/tools/testing/selftests/arm64/fp/sve-test.S b/tools/testing/selftests/arm64/fp/sve-test.S index 547d077e3517..fff60e2a25ad 100644 --- a/tools/testing/selftests/arm64/fp/sve-test.S +++ b/tools/testing/selftests/arm64/fp/sve-test.S @@ -515,6 +515,10 @@ function barf mov x11, x1 // actual data mov x12, x2 // data size +#ifdef SSVE + mrs x13, S3_3_C4_C2_2 +#endif + puts "Mismatch: PID=" mov x0, x20 bl putdec @@ -534,6 +538,12 @@ function barf bl dumphex puts "]\n" +#ifdef SSVE + puts "\tSVCR: " + mov x0, x13 + bl putdecn +#endif + mov x8, #__NR_getpid svc #0 // fpsimd.c acitivty log dump hack diff --git a/tools/testing/selftests/arm64/fp/za-test.S b/tools/testing/selftests/arm64/fp/za-test.S index 9dcd70911397..095b45531640 100644 --- a/tools/testing/selftests/arm64/fp/za-test.S +++ b/tools/testing/selftests/arm64/fp/za-test.S @@ -333,6 +333,9 @@ function barf // mov w8, #__NR_exit // svc #0 // end hack + + mrs x13, S3_3_C4_C2_2 + smstop mov x10, x0 // expected data mov x11, x1 // actual data @@ -356,6 +359,9 @@ function barf mov x1, x12 bl dumphex puts "]\n" + puts "\tSVCR: " + mov x0, x13 + bl putdecn mov x8, #__NR_getpid svc #0 diff --git a/tools/testing/selftests/arm64/fp/zt-test.S b/tools/testing/selftests/arm64/fp/zt-test.S index d63286397638..b5c81e81a379 100644 --- a/tools/testing/selftests/arm64/fp/zt-test.S +++ b/tools/testing/selftests/arm64/fp/zt-test.S @@ -267,6 +267,8 @@ function barf // mov w8, #__NR_exit // svc #0 // end hack + + mrs x13, S3_3_C4_C2_2 smstop mov x10, x0 // expected data mov x11, x1 // actual data @@ -287,6 +289,9 @@ function barf mov x1, x12 bl dumphex puts "]\n" + puts "\tSVCR: " + mov x0, x13 + bl putdecn mov x8, #__NR_getpid svc #0 --- base-commit: 2cc14f52aeb78ce3f29677c2de1f06c0e91471ab change-id: 20231204-arm64-kselftest-log-svcr-372a210520ae Best regards, -- Mark Brown <broonie(a)kernel.org>

1 year, 10 months

2
1
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[PATCH] kselftest/arm64: Improve output for skipped TPIDR2 ABI test

by Mark Brown

When TPIDR2 is not supported the tpidr2 ABI test prints the same message for each skipped test: ok 1 skipped, TPIDR2 not supported which isn't ideal for test automation software since it tracks kselftest results based on the string used to describe the test. This is also not standard KTAP output, the expected format is: ok 1 # SKIP default_value Updated the program to generate this, using the same set of test names that we would run if the test actually executed. Signed-off-by: Mark Brown <broonie(a)kernel.org> --- tools/testing/selftests/arm64/abi/tpidr2.c | 18 +++++++++++------- 1 file changed, 11 insertions(+), 7 deletions(-) diff --git a/tools/testing/selftests/arm64/abi/tpidr2.c b/tools/testing/selftests/arm64/abi/tpidr2.c index 351a098b503a..02ee3a91b780 100644 --- a/tools/testing/selftests/arm64/abi/tpidr2.c +++ b/tools/testing/selftests/arm64/abi/tpidr2.c @@ -254,6 +254,12 @@ static int write_clone_read(void) putnum(++tests_run); \ putstr(" " #name "\n"); +#define skip_test(name) \ + tests_skipped++; \ + putstr("ok "); \ + putnum(++tests_run); \ + putstr(" # SKIP " #name "\n"); + int main(int argc, char **argv) { int ret, i; @@ -283,13 +289,11 @@ int main(int argc, char **argv) } else { putstr("# SME support not present\n"); - for (i = 0; i < EXPECTED_TESTS; i++) { - putstr("ok "); - putnum(i); - putstr(" skipped, TPIDR2 not supported\n"); - } - - tests_skipped += EXPECTED_TESTS; + skip_test(default_value); + skip_test(write_read); + skip_test(write_sleep_read); + skip_test(write_fork_read); + skip_test(write_clone_read); } print_summary(); --- base-commit: 98b1cc82c4affc16f5598d4fa14b1858671b2263 change-id: 20231124-kselftest-arm64-tpidr2-skip-43764f4ff4f4 Best regards, -- Mark Brown <broonie(a)kernel.org>

1 year, 10 months

2
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[RFC PATCH v2 0/7] tun: Introduce virtio-net hashing feature

by Akihiko Odaki

virtio-net have two usage of hashes: one is RSS and another is hash reporting. Conventionally the hash calculation was done by the VMM. However, computing the hash after the queue was chosen defeats the purpose of RSS. Another approach is to use eBPF steering program. This approach has another downside: it cannot report the calculated hash due to the restrictive nature of eBPF. Extend the steering program feature by introducing a dedicated program type: BPF_PROG_TYPE_VNET_HASH. This program type is capable to report the hash value and the queue to use at the same time. This is a rewrite of a RFC patch series submitted by Yuri Benditovich that incorporates feedbacks for the series and V1 of this series: https://lore.kernel.org/lkml/20210112194143.1494-1-yuri.benditovich@daynix.… QEMU patched to use this new feature is available at: https://github.com/daynix/qemu/tree/akihikodaki/bpf The QEMU patches will soon be submitted to the upstream as RFC too. V1 -> V2: Changed to introduce a new BPF program type. Akihiko Odaki (7): bpf: Introduce BPF_PROG_TYPE_VNET_HASH bpf: Add vnet_hash members to __sk_buff skbuff: Introduce SKB_EXT_TUN_VNET_HASH virtio_net: Add virtio_net_hdr_v1_hash_from_skb() tun: Support BPF_PROG_TYPE_VNET_HASH selftests/bpf: Test BPF_PROG_TYPE_VNET_HASH vhost_net: Support VIRTIO_NET_F_HASH_REPORT Documentation/bpf/bpf_prog_run.rst | 1 + Documentation/bpf/libbpf/program_types.rst | 2 + drivers/net/tun.c | 158 +++++-- drivers/vhost/net.c | 16 +- include/linux/bpf_types.h | 2 + include/linux/filter.h | 7 + include/linux/skbuff.h | 10 + include/linux/virtio_net.h | 22 + include/uapi/linux/bpf.h | 5 + kernel/bpf/verifier.c | 6 + net/core/filter.c | 86 +++- net/core/skbuff.c | 3 + tools/include/uapi/linux/bpf.h | 5 + tools/lib/bpf/libbpf.c | 2 + tools/testing/selftests/bpf/config | 1 + tools/testing/selftests/bpf/config.aarch64 | 1 - .../selftests/bpf/prog_tests/vnet_hash.c | 385 ++++++++++++++++++ tools/testing/selftests/bpf/progs/vnet_hash.c | 16 + 18 files changed, 681 insertions(+), 47 deletions(-) create mode 100644 tools/testing/selftests/bpf/prog_tests/vnet_hash.c create mode 100644 tools/testing/selftests/bpf/progs/vnet_hash.c -- 2.42.0

1 year, 10 months

5
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[PATCH] kselftests: add per_test_log support

by Hangbin Liu

By default, all the test output will be printed to stdout or output.log if -s supplied. The kselftest/runner.sh also supports per test log if the variable per_test_logging is set. So add new option -p to set this veriable. Note the -p option is conflict with -s option. Signed-off-by: Hangbin Liu <liuhangbin(a)gmail.com> --- tools/testing/selftests/run_kselftest.sh | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/tools/testing/selftests/run_kselftest.sh b/tools/testing/selftests/run_kselftest.sh index 92743980e553..965220a314ce 100755 --- a/tools/testing/selftests/run_kselftest.sh +++ b/tools/testing/selftests/run_kselftest.sh @@ -20,7 +20,8 @@ usage() { cat <<EOF Usage: $0 [OPTIONS] - -s | --summary Print summary with detailed log in output.log + -s | --summary Print summary with detailed log in output.log (conflict with -p) + -p | --per_test_log Print test log in /tmp with each test name (conflict with -s) -t | --test COLLECTION:TEST Run TEST from COLLECTION -c | --collection COLLECTION Run all tests from COLLECTION -l | --list List the available collection:test entries @@ -41,6 +42,9 @@ while true; do logfile="$BASE_DIR"/output.log cat /dev/null > $logfile shift ;; + -p | --per_test_log) + per_test_logging=1 + shift ;; -t | --test) TESTS="$TESTS $2" shift 2 ;; -- 2.41.0

1 year, 10 months

1
2
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[PATCH v3 00/11] A minor flurry of selftest/mm fixes

by John Hubbard

Hi, Changes since v2 [1]: * Added a new patch (sent separately earlier) at the end, to error out if "make headers" has not yet been run. * Reworked and simplified the uffd movement patch. Now it only moves some uffd*() routines, not all, and doesn't have to touch the Makefile at all. This lighter touch also allowed me to drop the "move psize(), pshift() into vm_utils.c" entirely. I expect Peter Xu will be a little happier with this new approach. * Fixed the commit description for the MADV_COLLAPSE patch. * Added more Reviewed-by tags from David Hildenbrand and Peter Xu. [1] https://lore.kernel.org/all/20230603021558.95299-1-jhubbard@nvidia.com/ John Hubbard (11): selftests/mm: fix uffd-stress unused function warning selftests/mm: fix unused variable warnings in hugetlb-madvise.c, migration.c selftests/mm: fix "warning: expression which evaluates to zero..." in mlock2-tests.c selftests/mm: fix invocation of tests that are run via shell scripts selftests/mm: .gitignore: add mkdirty, va_high_addr_switch selftests/mm: fix two -Wformat-security warnings in uffd builds selftests/mm: fix a "possibly uninitialized" warning in pkey-x86.h selftests/mm: fix build failures due to missing MADV_COLLAPSE selftests/mm: move certain uffd*() routines from vm_util.c to uffd-common.c Documentation: kselftest: "make headers" is a prerequisite selftests: error out if kernel header files are not yet built Documentation/dev-tools/kselftest.rst | 1 + tools/testing/selftests/lib.mk | 36 +++++++++++- tools/testing/selftests/mm/.gitignore | 2 + tools/testing/selftests/mm/cow.c | 7 --- tools/testing/selftests/mm/hugetlb-madvise.c | 8 ++- tools/testing/selftests/mm/khugepaged.c | 10 ---- tools/testing/selftests/mm/migration.c | 5 +- tools/testing/selftests/mm/mlock2-tests.c | 1 - tools/testing/selftests/mm/pkey-x86.h | 2 +- tools/testing/selftests/mm/run_vmtests.sh | 6 +- tools/testing/selftests/mm/uffd-common.c | 59 ++++++++++++++++++++ tools/testing/selftests/mm/uffd-common.h | 5 ++ tools/testing/selftests/mm/uffd-stress.c | 10 ---- tools/testing/selftests/mm/uffd-unit-tests.c | 16 ++---- tools/testing/selftests/mm/vm_util.c | 59 -------------------- tools/testing/selftests/mm/vm_util.h | 14 +++-- 16 files changed, 130 insertions(+), 111 deletions(-) base-commit: f8dba31b0a826e691949cd4fdfa5c30defaac8c5 -- 2.40.1

1 year, 10 months

6
38
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[PATCH RFT v4 0/5] fork: Support shadow stacks in clone3()

by Mark Brown

The kernel has recently added support for shadow stacks, currently x86 only using their CET feature but both arm64 and RISC-V have equivalent features (GCS and Zicfiss respectively), I am actively working on GCS[1]. With shadow stacks the hardware maintains an additional stack containing only the return addresses for branch instructions which is not generally writeable by userspace and ensures that any returns are to the recorded addresses. This provides some protection against ROP attacks and making it easier to collect call stacks. These shadow stacks are allocated in the address space of the userspace process. Our API for shadow stacks does not currently offer userspace any flexiblity for managing the allocation of shadow stacks for newly created threads, instead the kernel allocates a new shadow stack with the same size as the normal stack whenever a thread is created with the feature enabled. The stacks allocated in this way are freed by the kernel when the thread exits or shadow stacks are disabled for the thread. This lack of flexibility and control isn't ideal, in the vast majority of cases the shadow stack will be over allocated and the implicit allocation and deallocation is not consistent with other interfaces. As far as I can tell the interface is done in this manner mainly because the shadow stack patches were in development since before clone3() was implemented. Since clone3() is readily extensible let's add support for specifying a shadow stack when creating a new thread or process in a similar manner to how the normal stack is specified, keeping the current implicit allocation behaviour if one is not specified either with clone3() or through the use of clone(). Unlike normal stacks only the shadow stack size is specified, similar issues to those that lead to the creation of map_shadow_stack() apply. Please note that the x86 portions of this code are build tested only, I don't appear to have a system that can run CET avaible to me, I have done testing with an integration into my pending work for GCS. There is some possibility that the arm64 implementation may require the use of clone3() and explicit userspace allocation of shadow stacks, this is still under discussion. A new architecture feature Kconfig option for shadow stacks is added as here, this was suggested as part of the review comments for the arm64 GCS series and since we need to detect if shadow stacks are supported it seemed sensible to roll it in here. [1] https://lore.kernel.org/r/20231009-arm64-gcs-v6-0-78e55deaa4dd@kernel.org/ Signed-off-by: Mark Brown <broonie(a)kernel.org> --- Changes in v4: - Formatting changes. - Use a define for minimum shadow stack size and move some basic validation to fork.c. - Link to v3: https://lore.kernel.org/r/20231120-clone3-shadow-stack-v3-0-a7b8ed3e2acc@ke… Changes in v3: - Rebase onto v6.7-rc2. - Remove stale shadow_stack in internal kargs. - If a shadow stack is specified unconditionally use it regardless of CLONE_ parameters. - Force enable shadow stacks in the selftest. - Update changelogs for RISC-V feature rename. - Link to v2: https://lore.kernel.org/r/20231114-clone3-shadow-stack-v2-0-b613f8681155@ke… Changes in v2: - Rebase onto v6.7-rc1. - Remove ability to provide preallocated shadow stack, just specify the desired size. - Link to v1: https://lore.kernel.org/r/20231023-clone3-shadow-stack-v1-0-d867d0b5d4d0@ke… --- Mark Brown (5): mm: Introduce ARCH_HAS_USER_SHADOW_STACK fork: Add shadow stack support to clone3() selftests/clone3: Factor more of main loop into test_clone3() selftests/clone3: Allow tests to flag if -E2BIG is a valid error code kselftest/clone3: Test shadow stack support arch/x86/Kconfig | 1 + arch/x86/include/asm/shstk.h | 11 +- arch/x86/kernel/process.c | 2 +- arch/x86/kernel/shstk.c | 56 ++++-- fs/proc/task_mmu.c | 2 +- include/linux/mm.h | 2 +- include/linux/sched/task.h | 1 + include/uapi/linux/sched.h | 4 + kernel/fork.c | 53 ++++-- mm/Kconfig | 6 + tools/testing/selftests/clone3/clone3.c | 200 +++++++++++++++++----- tools/testing/selftests/clone3/clone3_selftests.h | 7 + 12 files changed, 268 insertions(+), 77 deletions(-) --- base-commit: 98b1cc82c4affc16f5598d4fa14b1858671b2263 change-id: 20231019-clone3-shadow-stack-15d40d2bf536 Best regards, -- Mark Brown <broonie(a)kernel.org>

1 year, 10 months

6
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[PATCH v1 00/23] Enable FRED with KVM VMX

by Xin Li

This patch set enables the Intel flexible return and event delivery (FRED) architecture with KVM VMX to allow guests to utilize FRED. The FRED architecture defines simple new transitions that change privilege level (ring transitions). The FRED architecture was designed with the following goals: 1) Improve overall performance and response time by replacing event delivery through the interrupt descriptor table (IDT event delivery) and event return by the IRET instruction with lower latency transitions. 2) Improve software robustness by ensuring that event delivery establishes the full supervisor context and that event return establishes the full user context. The new transitions defined by the FRED architecture are FRED event delivery and, for returning from events, two FRED return instructions. FRED event delivery can effect a transition from ring 3 to ring 0, but it is used also to deliver events incident to ring 0. One FRED instruction (ERETU) effects a return from ring 0 to ring 3, while the other (ERETS) returns while remaining in ring 0. Collectively, FRED event delivery and the FRED return instructions are FRED transitions. Intel VMX architecture is extended to run FRED guests, and the changes are majorly: 1) New VMCS fields for FRED context management, which includes two new event data VMCS fields, eight new guest FRED context VMCS fields and eight new host FRED context VMCS fields. 2) VMX nested-Exception support for proper virtualization of stack levels introduced with FRED architecture. Search for the latest FRED spec in most search engines with this search pattern: site:intel.com FRED (flexible return and event delivery) specification We want to send out the FRED VMX patch set for review while the FRED native patch set v12 is being reviewed @ https://lkml.kernel.org/kvm/20231003062458.23552-1-xin3.li@intel.com/. For easier review, I have set up a base tree with the latest FRED native patch set on top of tip tree in the 'fred_v12' branch of repo https://github.com/xinli-intel/linux-fred-public.git. Patch 1-2 are cleanups to VMX basic and misc MSRs, which were sent out earlier as a preparation for FRED changes: https://lore.kernel.org/kvm/20231030233940.438233-1-xin@zytor.com/. Patch 3-14 add FRED support to VMX. Patch 15-18 add FRED support to nested VMX. Patch 19 exposes FRED to KVM guests to complete the enabling. Patch 20-23 adds FRED selftests. Shan Kang (1): KVM: selftests: Add fred exception tests Xin Li (22): KVM: VMX: Cleanup VMX basic information defines and usages KVM: VMX: Cleanup VMX misc information defines and usages KVM: VMX: Add support for the secondary VM exit controls KVM: x86: Mark CR4.FRED as not reserved KVM: VMX: Initialize FRED VM entry/exit controls in vmcs_config KVM: VMX: Defer enabling FRED MSRs save/load until after set CPUID KVM: VMX: Disable intercepting FRED MSRs KVM: VMX: Initialize VMCS FRED fields KVM: VMX: Switch FRED RSP0 between host and guest KVM: VMX: Add support for FRED context save/restore KVM: x86: Add kvm_is_fred_enabled() KVM: VMX: Handle FRED event data KVM: VMX: Handle VMX nested exception for FRED KVM: VMX: Dump FRED context in dump_vmcs() KVM: nVMX: Add support for the secondary VM exit controls KVM: nVMX: Add FRED VMCS fields KVM: nVMX: Add support for VMX FRED controls KVM: nVMX: Add VMCS FRED states checking KVM: x86: Allow FRED/LKGS/WRMSRNS to be exposed to guests KVM: selftests: Add FRED VMCS fields to evmcs KVM: selftests: Run debug_regs test with FRED enabled KVM: selftests: Add a new VM guest mode to run user level code Documentation/virt/kvm/x86/nested-vmx.rst | 19 + arch/x86/include/asm/hyperv-tlfs.h | 19 + arch/x86/include/asm/kvm_host.h | 9 +- arch/x86/include/asm/msr-index.h | 15 +- arch/x86/include/asm/vmx.h | 57 ++- arch/x86/kvm/cpuid.c | 4 +- arch/x86/kvm/kvm_cache_regs.h | 10 + arch/x86/kvm/svm/svm.c | 4 +- arch/x86/kvm/vmx/capabilities.h | 20 +- arch/x86/kvm/vmx/hyperv.c | 61 ++- arch/x86/kvm/vmx/nested.c | 315 ++++++++++++-- arch/x86/kvm/vmx/nested.h | 2 +- arch/x86/kvm/vmx/vmcs.h | 1 + arch/x86/kvm/vmx/vmcs12.c | 19 + arch/x86/kvm/vmx/vmcs12.h | 38 ++ arch/x86/kvm/vmx/vmcs_shadow_fields.h | 6 +- arch/x86/kvm/vmx/vmx.c | 404 ++++++++++++++++-- arch/x86/kvm/vmx/vmx.h | 14 +- arch/x86/kvm/x86.c | 55 ++- arch/x86/kvm/x86.h | 5 +- tools/testing/selftests/kvm/Makefile | 1 + .../selftests/kvm/include/kvm_util_base.h | 1 + .../selftests/kvm/include/x86_64/evmcs.h | 146 +++++++ .../selftests/kvm/include/x86_64/processor.h | 33 ++ .../selftests/kvm/include/x86_64/vmx.h | 20 + tools/testing/selftests/kvm/lib/kvm_util.c | 5 +- .../selftests/kvm/lib/x86_64/processor.c | 15 +- tools/testing/selftests/kvm/lib/x86_64/vmx.c | 4 +- .../testing/selftests/kvm/x86_64/debug_regs.c | 50 ++- .../testing/selftests/kvm/x86_64/fred_test.c | 262 ++++++++++++ 30 files changed, 1464 insertions(+), 150 deletions(-) create mode 100644 tools/testing/selftests/kvm/x86_64/fred_test.c base-commit: d49b86c24e836941c85c4906e9519fca9426a6e0 -- 2.42.0

1 year, 10 months

7
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[RFC PATCH v3 00/12] Device Memory TCP

by Mina Almasry

Changes in RFC v3: ------------------ 1. Pulled in the memory-provider dependency from Jakub's RFC[1] to make the series reviewable and mergable. 2. Implemented multi-rx-queue binding which was a todo in v2. 3. Fix to cmsg handling. The sticking point in RFC v2[2] was the device reset required to refill the device rx-queues after the dmabuf bind/unbind. The solution suggested as I understand is a subset of the per-queue management ops Jakub suggested or similar: https://lore.kernel.org/netdev/20230815171638.4c057dcd@kernel.org/ This is not addressed in this revision, because: 1. This point was discussed at netconf & netdev and there is openness to using the current approach of requiring a device reset. 2. Implementing individual queue resetting seems to be difficult for my test bed with GVE. My prototype to test this ran into issues with the rx-queues not coming back up properly if reset individually. At the moment I'm unsure if it's a mistake in the POC or a genuine issue in the virtualization stack behind GVE, which currently doesn't test individual rx-queue restart. 3. Our usecases are not bothered by requiring a device reset to refill the buffer queues, and we'd like to support NICs that run into this limitation with resetting individual queues. My thought is that drivers that have trouble with per-queue configs can use the support in this series, while drivers that support new netdev ops to reset individual queues can automatically reset the queue as part of the dma-buf bind/unbind. The same approach with device resets is presented again for consideration with other sticking points addressed. This proposal includes the rx devmem path only proposed for merge. For a snapshot of my entire tree which includes the GVE POC page pool support & device memory support: https://github.com/torvalds/linux/compare/master...mina:linux:tcpdevmem-v3 [1] https://lore.kernel.org/netdev/f8270765-a27b-6ccf-33ea-cda097168d79@redhat.… [2] https://lore.kernel.org/netdev/CAHS8izOVJGJH5WF68OsRWFKJid1_huzzUK+hpKbLcL4… Cc: Shakeel Butt <shakeelb(a)google.com> Cc: Jeroen de Borst <jeroendb(a)google.com> Cc: Praveen Kaligineedi <pkaligineedi(a)google.com> Changes in RFC v2: ------------------ The sticking point in RFC v1[1] was the dma-buf pages approach we used to deliver the device memory to the TCP stack. RFC v2 is a proof-of-concept that attempts to resolve this by implementing scatterlist support in the networking stack, such that we can import the dma-buf scatterlist directly. This is the approach proposed at a high level here[2]. Detailed changes: 1. Replaced dma-buf pages approach with importing scatterlist into the page pool. 2. Replace the dma-buf pages centric API with a netlink API. 3. Removed the TX path implementation - there is no issue with implementing the TX path with scatterlist approach, but leaving out the TX path makes it easier to review. 4. Functionality is tested with this proposal, but I have not conducted perf testing yet. I'm not sure there are regressions, but I removed perf claims from the cover letter until they can be re-confirmed. 5. Added Signed-off-by: contributors to the implementation. 6. Fixed some bugs with the RX path since RFC v1. Any feedback welcome, but specifically the biggest pending questions needing feedback IMO are: 1. Feedback on the scatterlist-based approach in general. 2. Netlink API (Patch 1 & 2). 3. Approach to handle all the drivers that expect to receive pages from the page pool (Patch 6). [1] https://lore.kernel.org/netdev/dfe4bae7-13a0-3c5d-d671-f61b375cb0b4@gmail.c… [2] https://lore.kernel.org/netdev/CAHS8izPm6XRS54LdCDZVd0C75tA1zHSu6jLVO8nzTLX… ---------------------- * TL;DR: Device memory TCP (devmem TCP) is a proposal for transferring data to and/or from device memory efficiently, without bouncing the data to a host memory buffer. * Problem: A large amount of data transfers have device memory as the source and/or destination. Accelerators drastically increased the volume of such transfers. Some examples include: - ML accelerators transferring large amounts of training data from storage into GPU/TPU memory. In some cases ML training setup time can be as long as 50% of TPU compute time, improving data transfer throughput & efficiency can help improving GPU/TPU utilization. - Distributed training, where ML accelerators, such as GPUs on different hosts, exchange data among them. - Distributed raw block storage applications transfer large amounts of data with remote SSDs, much of this data does not require host processing. Today, the majority of the Device-to-Device data transfers the network are implemented as the following low level operations: Device-to-Host copy, Host-to-Host network transfer, and Host-to-Device copy. The implementation is suboptimal, especially for bulk data transfers, and can put significant strains on system resources, such as host memory bandwidth, PCIe bandwidth, etc. One important reason behind the current state is the kernel’s lack of semantics to express device to network transfers. * Proposal: In this patch series we attempt to optimize this use case by implementing socket APIs that enable the user to: 1. send device memory across the network directly, and 2. receive incoming network packets directly into device memory. Packet _payloads_ go directly from the NIC to device memory for receive and from device memory to NIC for transmit. Packet _headers_ go to/from host memory and are processed by the TCP/IP stack normally. The NIC _must_ support header split to achieve this. Advantages: - Alleviate host memory bandwidth pressure, compared to existing network-transfer + device-copy semantics. - Alleviate PCIe BW pressure, by limiting data transfer to the lowest level of the PCIe tree, compared to traditional path which sends data through the root complex. * Patch overview: ** Part 1: netlink API Gives user ability to bind dma-buf to an RX queue. ** Part 2: scatterlist support Currently the standard for device memory sharing is DMABUF, which doesn't generate struct pages. On the other hand, networking stack (skbs, drivers, and page pool) operate on pages. We have 2 options: 1. Generate struct pages for dmabuf device memory, or, 2. Modify the networking stack to process scatterlist. Approach #1 was attempted in RFC v1. RFC v2 implements approach #2. ** part 3: page pool support We piggy back on page pool memory providers proposal: https://github.com/kuba-moo/linux/tree/pp-providers It allows the page pool to define a memory provider that provides the page allocation and freeing. It helps abstract most of the device memory TCP changes from the driver. ** part 4: support for unreadable skb frags Page pool iovs are not accessible by the host; we implement changes throughput the networking stack to correctly handle skbs with unreadable frags. ** Part 5: recvmsg() APIs We define user APIs for the user to send and receive device memory. Not included with this RFC is the GVE devmem TCP support, just to simplify the review. Code available here if desired: https://github.com/mina/linux/tree/tcpdevmem This RFC is built on top of net-next with Jakub's pp-providers changes cherry-picked. * NIC dependencies: 1. (strict) Devmem TCP require the NIC to support header split, i.e. the capability to split incoming packets into a header + payload and to put each into a separate buffer. Devmem TCP works by using device memory for the packet payload, and host memory for the packet headers. 2. (optional) Devmem TCP works better with flow steering support & RSS support, i.e. the NIC's ability to steer flows into certain rx queues. This allows the sysadmin to enable devmem TCP on a subset of the rx queues, and steer devmem TCP traffic onto these queues and non devmem TCP elsewhere. The NIC I have access to with these properties is the GVE with DQO support running in Google Cloud, but any NIC that supports these features would suffice. I may be able to help reviewers bring up devmem TCP on their NICs. * Testing: The series includes a udmabuf kselftest that show a simple use case of devmem TCP and validates the entire data path end to end without a dependency on a specific dmabuf provider. ** Test Setup Kernel: net-next with this RFC and memory provider API cherry-picked locally. Hardware: Google Cloud A3 VMs. NIC: GVE with header split & RSS & flow steering support. Jakub Kicinski (2): net: page_pool: factor out releasing DMA from releasing the page net: page_pool: create hooks for custom page providers Mina Almasry (10): net: netdev netlink api to bind dma-buf to a net device netdev: support binding dma-buf to netdevice netdev: netdevice devmem allocator memory-provider: dmabuf devmem memory provider page-pool: device memory support net: support non paged skb frags net: add support for skbs with unreadable frags tcp: RX path for devmem TCP net: add SO_DEVMEM_DONTNEED setsockopt to release RX pages selftests: add ncdevmem, netcat for devmem TCP Documentation/netlink/specs/netdev.yaml | 28 ++ include/linux/netdevice.h | 93 ++++ include/linux/skbuff.h | 56 ++- include/linux/socket.h | 1 + include/net/netdev_rx_queue.h | 1 + include/net/page_pool/helpers.h | 151 ++++++- include/net/page_pool/types.h | 55 +++ include/net/sock.h | 2 + include/net/tcp.h | 5 +- include/uapi/asm-generic/socket.h | 6 + include/uapi/linux/netdev.h | 10 + include/uapi/linux/uio.h | 10 + net/core/datagram.c | 6 + net/core/dev.c | 240 +++++++++++ net/core/gro.c | 7 +- net/core/netdev-genl-gen.c | 14 + net/core/netdev-genl-gen.h | 1 + net/core/netdev-genl.c | 118 +++++ net/core/page_pool.c | 209 +++++++-- net/core/skbuff.c | 80 +++- net/core/sock.c | 36 ++ net/ipv4/tcp.c | 205 ++++++++- net/ipv4/tcp_input.c | 13 +- net/ipv4/tcp_ipv4.c | 7 + net/ipv4/tcp_output.c | 5 +- net/packet/af_packet.c | 4 +- tools/include/uapi/linux/netdev.h | 10 + tools/net/ynl/generated/netdev-user.c | 42 ++ tools/net/ynl/generated/netdev-user.h | 47 ++ tools/testing/selftests/net/.gitignore | 1 + tools/testing/selftests/net/Makefile | 5 + tools/testing/selftests/net/ncdevmem.c | 546 ++++++++++++++++++++++++ 32 files changed, 1950 insertions(+), 64 deletions(-) create mode 100644 tools/testing/selftests/net/ncdevmem.c -- 2.42.0.869.gea05f2083d-goog

1 year, 10 months

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[PATCH] kunit: test: Use an action wrapper instead of a cast

by David Gow

We missed one of the casts of kfree() to kunit_action_t in kunit-test, which was only enabled when debugfs was in use. This could potentially break CFI. Use the existing wrapper function instead. Signed-off-by: David Gow <davidgow(a)google.com> --- lib/kunit/kunit-test.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/lib/kunit/kunit-test.c b/lib/kunit/kunit-test.c index 3e9c5192d095..ee6927c60979 100644 --- a/lib/kunit/kunit-test.c +++ b/lib/kunit/kunit-test.c @@ -559,7 +559,7 @@ static void kunit_log_test(struct kunit *test) KUNIT_EXPECT_TRUE(test, test->log->append_newlines); full_log = string_stream_get_string(test->log); - kunit_add_action(test, (kunit_action_t *)kfree, full_log); + kunit_add_action(test, kfree_wrapper, full_log); KUNIT_EXPECT_NOT_ERR_OR_NULL(test, strstr(full_log, "put this in log.")); KUNIT_EXPECT_NOT_ERR_OR_NULL(test, -- 2.43.0.rc2.451.g8631bc7472-goog

1 year, 10 months

2
1
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