March 2024 - Linux-kselftest-mirror

[PATCH v6 0/5] KVM: arm64: Support for 2023 dpISA extensions

by Mark Brown

This series implements support for the 2023 dpISA extensions in KVM guests, it was previously posted as part of a series with the host support but that has now been merged so only the KVM portions remain. Most of these extensions add only new instructions so the guest support consists of adding the relevant ID registers, masking out other features like the 2023 MTE extensions. FEAT_FPMR introduces a new system register FPMR to the floating point state which we enable guest access to and context switch when the ID registers indicate that it is supported. Currently we implement visibility for FPMR with a fpmr_visibility() function as for other system registers, I will separately look into adding support for specifying this in the struct sys_reg_desc. Signed-off-by: Mark Brown <broonie(a)kernel.org> --- Changes in v6: - Rebase onto v6.9-rc1. - The host portions of the series were merged so only the KVM guest support remains. - Link to v5: https://lore.kernel.org/r/20240306-arm64-2023-dpisa-v5-0-c568edc8ed7f@kerne… Changes in v5: - Rebase onto v6.8-rc3. - Use u64 rather than unsigned long for storing FPMR. - Temporarily drop KVM guest support due to issues with KVM being a moving target. - Link to v4: https://lore.kernel.org/r/20240122-arm64-2023-dpisa-v4-0-776e094861df@kerne… Changes in v4: - Rebase onto v6.8-rc1. - Move KVM support to the end of the series. - Link to v3: https://lore.kernel.org/r/20231205-arm64-2023-dpisa-v3-0-dbcbcd867a7f@kerne… Changes in v3: - Rebase onto v6.7-rc3. - Hook up traps for FPMR in emulate-nested.c. - Link to v2: https://lore.kernel.org/r/20231114-arm64-2023-dpisa-v2-0-47251894f6a8@kerne… Changes in v2: - Rebase onto v6.7-rc1. - Link to v1: https://lore.kernel.org/r/20231026-arm64-2023-dpisa-v1-0-8470dd989bb2@kerne… --- Mark Brown (5): KVM: arm64: Share all userspace hardened thread data with the hypervisor KVM: arm64: Add newly allocated ID registers to register descriptions KVM: arm64: Support FEAT_FPMR for guests KVM: arm64: selftests: Document feature registers added in 2023 extensions KVM: arm64: selftests: Teach get-reg-list about FPMR arch/arm64/include/asm/kvm_host.h | 6 ++++-- arch/arm64/include/asm/processor.h | 2 +- arch/arm64/kvm/emulate-nested.c | 9 ++++++++ arch/arm64/kvm/fpsimd.c | 15 +++++++------- arch/arm64/kvm/hyp/include/hyp/switch.h | 9 ++++++-- arch/arm64/kvm/hyp/nvhe/hyp-main.c | 4 ++-- arch/arm64/kvm/sys_regs.c | 24 +++++++++++++++++++--- tools/testing/selftests/kvm/aarch64/get-reg-list.c | 11 ++++++++-- 8 files changed, 60 insertions(+), 20 deletions(-) --- base-commit: 4cece764965020c22cff7665b18a012006359095 change-id: 20231003-arm64-2023-dpisa-2f3d25746474 Best regards, -- Mark Brown <broonie(a)kernel.org>

4 weeks

2
15
0 0

[PATCH v4 0/7] Extend HID-BPF kfuncs (was: allow HID-BPF to do device IOs)

by Benjamin Tissoires

New version of the sleepable bpf_timer code, without BPF changes, as they can now go through the HID tree independantly: https://lore.kernel.org/all/20240315-hid-bpf-sleepable-v4-0-5658f2540564@ke… For reference, the use cases I have in mind: --- Basically, I need to be able to defer a HID-BPF program for the following reasons (from the aforementioned patch): 1. defer an event: Sometimes we receive an out of proximity event, but the device can not be trusted enough, and we need to ensure that we won't receive another one in the following n milliseconds. So we need to wait those n milliseconds, and eventually re-inject that event in the stack. 2. inject new events in reaction to one given event: We might want to transform one given event into several. This is the case for macro keys where a single key press is supposed to send a sequence of key presses. But this could also be used to patch a faulty behavior, if a device forgets to send a release event. 3. communicate with the device in reaction to one event: We might want to communicate back to the device after a given event. For example a device might send us an event saying that it came back from sleeping state and needs to be re-initialized. Currently we can achieve that by keeping a userspace program around, raise a bpf event, and let that userspace program inject the events and commands. However, we are just keeping that program alive as a daemon for just scheduling commands. There is no logic in it, so it doesn't really justify an actual userspace wakeup. So a kernel workqueue seems simpler to handle. bpf_timers are currently running in a soft IRQ context, this patch series implements a sleppable context for them. Cheers, Benjamin To: Jiri Kosina <jikos(a)kernel.org> To: Benjamin Tissoires <benjamin.tissoires(a)redhat.com> To: Jonathan Corbet <corbet(a)lwn.net> To: Shuah Khan <shuah(a)kernel.org> Cc: Benjamin Tissoires <bentiss(a)kernel.org> Cc: <linux-input(a)vger.kernel.org> Cc: <linux-kernel(a)vger.kernel.org> Cc: <bpf(a)vger.kernel.org> Cc: <linux-doc(a)vger.kernel.org> Cc: <linux-kselftest(a)vger.kernel.org> --- Changes in v4: - dropped the BPF changes, they can go independently in bpf-core - dropped the HID-BPF integration tests with the sleppable timers, I'll re-add them once both series (this and sleepable timers) are merged - Link to v3: https://lore.kernel.org/r/20240221-hid-bpf-sleepable-v3-0-1fb378ca6301@kern… Changes in v3: - fixed the crash from v2 - changed the API to have only BPF_F_TIMER_SLEEPABLE for bpf_timer_start() - split the new kfuncs/verifier patch into several sub-patches, for easier reviews - Link to v2: https://lore.kernel.org/r/20240214-hid-bpf-sleepable-v2-0-5756b054724d@kern… Changes in v2: - make use of bpf_timer (and dropped the custom HID handling) - implemented bpf_timer_set_sleepable_cb as a kfunc - still not implemented global subprogs - no sleepable bpf_timer selftests yet - Link to v1: https://lore.kernel.org/r/20240209-hid-bpf-sleepable-v1-0-4cc895b5adbd@kern… --- Benjamin Tissoires (7): HID: bpf/dispatch: regroup kfuncs definitions HID: bpf: export hid_hw_output_report as a BPF kfunc selftests/hid: add KASAN to the VM tests selftests/hid: Add test for hid_bpf_hw_output_report HID: bpf: allow to inject HID event from BPF selftests/hid: add tests for hid_bpf_input_report HID: bpf: allow to use bpf_timer_set_sleepable_cb() in tracing callbacks. Documentation/hid/hid-bpf.rst | 2 +- drivers/hid/bpf/hid_bpf_dispatch.c | 226 ++++++++++++++------- drivers/hid/hid-core.c | 2 + include/linux/hid_bpf.h | 3 + tools/testing/selftests/hid/config.common | 1 + tools/testing/selftests/hid/hid_bpf.c | 112 +++++++++- tools/testing/selftests/hid/progs/hid.c | 46 +++++ .../testing/selftests/hid/progs/hid_bpf_helpers.h | 6 + 8 files changed, 324 insertions(+), 74 deletions(-) --- base-commit: 3e78a6c0d3e02e4cf881dc84c5127e9990f939d6 change-id: 20240314-b4-hid-bpf-new-funcs-ecf05d0ef870 Best regards, -- Benjamin Tissoires <bentiss(a)kernel.org>

4 weeks

3
11
0 0

[PATCH v2] selftests: sud_test: return correct emulated syscall value on RISC-V

by Clément Léger

Currently, the sud_test expects the emulated syscall to return the emulated syscall number. This assumption only works on architectures were the syscall calling convention use the same register for syscall number/syscall return value. This is not the case for RISC-V and thus the return value must be also emulated using the provided ucontext. Signed-off-by: Clément Léger <cleger(a)rivosinc.com> Reviewed-by: Palmer Dabbelt <palmer(a)rivosinc.com> Acked-by: Palmer Dabbelt <palmer(a)rivosinc.com> --- Changes in V2: - Changes comment to be more explicit - Use A7 syscall arg rather than hardcoding MAGIC_SYSCALL_1 --- .../selftests/syscall_user_dispatch/sud_test.c | 14 ++++++++++++++ 1 file changed, 14 insertions(+) diff --git a/tools/testing/selftests/syscall_user_dispatch/sud_test.c b/tools/testing/selftests/syscall_user_dispatch/sud_test.c index b5d592d4099e..d975a6767329 100644 --- a/tools/testing/selftests/syscall_user_dispatch/sud_test.c +++ b/tools/testing/selftests/syscall_user_dispatch/sud_test.c @@ -158,6 +158,20 @@ static void handle_sigsys(int sig, siginfo_t *info, void *ucontext) /* In preparation for sigreturn. */ SYSCALL_DISPATCH_OFF(glob_sel); + + /* + * The tests for argument handling assume that `syscall(x) == x`. This + * is a NOP on x86 because the syscall number is passed in %rax, which + * happens to also be the function ABI return register. Other + * architectures may need to swizzle the arguments around. + */ +#if defined(__riscv) +/* REG_A7 is not defined in libc headers */ +# define REG_A7 (REG_A0 + 7) + + ((ucontext_t *)ucontext)->uc_mcontext.__gregs[REG_A0] = + ((ucontext_t *)ucontext)->uc_mcontext.__gregs[REG_A7]; +#endif } TEST(dispatch_and_return) -- 2.43.0

4 weeks

3
2
0 0

[RFC PATCH v3 0/8] mm: workingset reporting

by Yuanchu Xie

This patch series provides workingset reporting of user pages in lruvecs, of which coldness can be tracked by accessed bits and fd references. However, the concept of workingset applies generically to all types of memory, which could be kernel slab caches, discardable userspace caches (databases), or CXL.mem. Therefore, data sources might come from slab shrinkers, device drivers, or the userspace. IMO, the kernel should provide a set of workingset interfaces that should be generic enough to accommodate the various use cases, and be extensible to potential future use cases. The current proposed interfaces are not sufficient in that regard, but I would like to start somewhere, solicit feedback, and iterate. Use cases ========== Job scheduling For data center machines, workingset information allows the job scheduler to right-size each job and land more jobs on the same host or NUMA node, and in the case of a job with increasing workingset, policy decisions can be made to migrate other jobs off the host/NUMA node, or oom-kill the misbehaving job. If the job shape is very different from the machine shape, knowing the workingset per-node can also help inform page allocation policies. Proactive reclaim Workingset information allows the a container manager to proactively reclaim memory while not impacting a job's performance. While PSI may provide a reactive measure of when a proactive reclaim has reclaimed too much, workingset reporting enables the policy to be more accurate and flexible. Ballooning (similar to proactive reclaim) While this patch series does not extend the virtio-balloon device, balloon policies benefit from workingset to more precisely determine the size of the memory balloon. On desktops/laptops/mobile devices where memory is scarce and overcommitted, the balloon sizing in multiple VMs running on the same device can be orchestrated with workingset reports from each one. Promotion/Demotion Similar to proactive reclaim, a workingset report enables demotion to a slower tier of memory. For promotion, the workingset report interfaces need to be extended to report hotness and gather hotness information from the devices[1]. [1] https://www.opencompute.org/documents/ocp-cms-hotness-tracking-requirements… Sysfs and Cgroup Interfaces ========== The interfaces are detailed in the patches that introduce them. The main idea here is we break down the workingset per-node per-memcg into time intervals (ms), e.g. 1000 anon=137368 file=24530 20000 anon=34342 file=0 30000 anon=353232 file=333608 40000 anon=407198 file=206052 9223372036854775807 anon=4925624 file=892892 I realize this does not generalize well to hotness information, but I lack the intuition for an abstraction that presents hotness in a useful way. Based on a recent proposal for move_phys_pages[2], it seems like userspace tiering software would like to move specific physical pages, instead of informing the kernel "move x number of hot pages to y device". Please advise. [2] https://lore.kernel.org/lkml/20240319172609.332900-1-gregory.price@memverge… Implementation ========== Currently, the reporting of user pages is based off of MGLRU, and therefore requires CONFIG_LRU_GEN=y. We would benefit from more MGLRU generations for a more fine-grained workingset report. I will make the generation count configurable in the next version. The workingset reporting mechanism is gated behind CONFIG_WORKINGSET_REPORT, and the aging thread is behind CONFIG_WORKINGSET_REPORT_AGING. -- Changes from RFC v2 -> RFC v3: - Update to v6.8 - Added an aging kernel thread (gated behind config) - Added basic selftests for sysfs interface files - Track swapped out pages for reaccesses - Refactoring and cleanup - Dropped the virtio-balloon extension to make things manageable Changes from RFC v1 -> RFC v2: - Refactored the patchs into smaller pieces - Renamed interfaces and functions from wss to wsr (Working Set Reporting) - Fixed build errors when CONFIG_WSR is not set - Changed working_set_num_bins to u8 for virtio-balloon - Added support for per-NUMA node reporting for virtio-balloon [rfc v1] https://lore.kernel.org/linux-mm/20230509185419.1088297-1-yuanchu@google.co… [rfc v2] https://lore.kernel.org/linux-mm/20230621180454.973862-1-yuanchu@google.com/ Yuanchu Xie (8): mm: multi-gen LRU: ignore non-leaf pmd_young for force_scan=true mm: aggregate working set information into histograms mm: use refresh interval to rate-limit workingset report aggregation mm: report workingset during memory pressure driven scanning mm: extend working set reporting to memcgs mm: add per-memcg reaccess histogram mm: add kernel aging thread for workingset reporting mm: test system-wide workingset reporting drivers/base/node.c | 3 + include/linux/memcontrol.h | 5 + include/linux/mmzone.h | 4 + include/linux/workingset_report.h | 107 +++ mm/Kconfig | 15 + mm/Makefile | 2 + mm/internal.h | 45 ++ mm/memcontrol.c | 386 ++++++++- mm/mmzone.c | 2 + mm/vmscan.c | 95 ++- mm/workingset.c | 9 +- mm/workingset_report.c | 757 ++++++++++++++++++ mm/workingset_report_aging.c | 127 +++ tools/testing/selftests/mm/.gitignore | 1 + tools/testing/selftests/mm/Makefile | 3 + .../testing/selftests/mm/workingset_report.c | 315 ++++++++ .../testing/selftests/mm/workingset_report.h | 37 + .../selftests/mm/workingset_report_test.c | 328 ++++++++ 18 files changed, 2231 insertions(+), 10 deletions(-) create mode 100644 include/linux/workingset_report.h create mode 100644 mm/workingset_report.c create mode 100644 mm/workingset_report_aging.c create mode 100644 tools/testing/selftests/mm/workingset_report.c create mode 100644 tools/testing/selftests/mm/workingset_report.h create mode 100644 tools/testing/selftests/mm/workingset_report_test.c -- 2.44.0.396.g6e790dbe36-goog

4 weeks, 1 day

4
16
0 0

[PATCH] KVM: selftests: Use TAP in the steal_time test

by Thomas Huth

For easier use of the tests in automation and for having some status information for the user while the test is running, let's provide some TAP output in this test. Signed-off-by: Thomas Huth <thuth(a)redhat.com> --- NB: This patch does not use the interface from kselftest_harness.h since it is not very suitable for the for-loop in this patch. tools/testing/selftests/kvm/steal_time.c | 46 ++++++++++++------------ 1 file changed, 23 insertions(+), 23 deletions(-) diff --git a/tools/testing/selftests/kvm/steal_time.c b/tools/testing/selftests/kvm/steal_time.c index 171adfb2a6cb..aa6149eb9ea1 100644 --- a/tools/testing/selftests/kvm/steal_time.c +++ b/tools/testing/selftests/kvm/steal_time.c @@ -81,20 +81,18 @@ static void steal_time_init(struct kvm_vcpu *vcpu, uint32_t i) static void steal_time_dump(struct kvm_vm *vm, uint32_t vcpu_idx) { struct kvm_steal_time *st = addr_gva2hva(vm, (ulong)st_gva[vcpu_idx]); - int i; - pr_info("VCPU%d:\n", vcpu_idx); - pr_info(" steal: %lld\n", st->steal); - pr_info(" version: %d\n", st->version); - pr_info(" flags: %d\n", st->flags); - pr_info(" preempted: %d\n", st->preempted); - pr_info(" u8_pad: "); - for (i = 0; i < 3; ++i) - pr_info("%d", st->u8_pad[i]); - pr_info("\n pad: "); - for (i = 0; i < 11; ++i) - pr_info("%d", st->pad[i]); - pr_info("\n"); + ksft_print_msg("VCPU%d:\n", vcpu_idx); + ksft_print_msg(" steal: %lld\n", st->steal); + ksft_print_msg(" version: %d\n", st->version); + ksft_print_msg(" flags: %d\n", st->flags); + ksft_print_msg(" preempted: %d\n", st->preempted); + ksft_print_msg(" u8_pad: %d %d %d\n", + st->u8_pad[0], st->u8_pad[1], st->u8_pad[2]); + ksft_print_msg(" pad: %d %d %d %d %d %d %d %d %d %d %d\n", + st->pad[0], st->pad[1], st->pad[2], st->pad[3], + st->pad[4], st->pad[5], st->pad[6], st->pad[7], + st->pad[8], st->pad[9], st->pad[10]); } #elif defined(__aarch64__) @@ -197,10 +195,10 @@ static void steal_time_dump(struct kvm_vm *vm, uint32_t vcpu_idx) { struct st_time *st = addr_gva2hva(vm, (ulong)st_gva[vcpu_idx]); - pr_info("VCPU%d:\n", vcpu_idx); - pr_info(" rev: %d\n", st->rev); - pr_info(" attr: %d\n", st->attr); - pr_info(" st_time: %ld\n", st->st_time); + ksft_print_msg("VCPU%d:\n", vcpu_idx); + ksft_print_msg(" rev: %d\n", st->rev); + ksft_print_msg(" attr: %d\n", st->attr); + ksft_print_msg(" st_time: %ld\n", st->st_time); } #endif @@ -267,7 +265,9 @@ int main(int ac, char **av) vm_userspace_mem_region_add(vm, VM_MEM_SRC_ANONYMOUS, ST_GPA_BASE, 1, gpages, 0); virt_map(vm, ST_GPA_BASE, ST_GPA_BASE, gpages); + ksft_print_header(); TEST_REQUIRE(is_steal_time_supported(vcpus[0])); + ksft_set_plan(NR_VCPUS); /* Run test on each VCPU */ for (i = 0; i < NR_VCPUS; ++i) { @@ -308,14 +308,14 @@ int main(int ac, char **av) run_delay, stolen_time); if (verbose) { - pr_info("VCPU%d: total-stolen-time=%ld test-stolen-time=%ld", i, - guest_stolen_time[i], stolen_time); - if (stolen_time == run_delay) - pr_info(" (BONUS: guest test-stolen-time even exactly matches test-run_delay)"); - pr_info("\n"); + ksft_print_msg("VCPU%d: total-stolen-time=%ld test-stolen-time=%ld%s\n", + i, guest_stolen_time[i], stolen_time, + stolen_time == run_delay ? + " (BONUS: guest test-stolen-time even exactly matches test-run_delay)" : ""); steal_time_dump(vm, i); } + ksft_test_result_pass("vcpu%d\n", i); } - return 0; + ksft_finished(); /* Print results and exit() accordingly */ } -- 2.41.0

4 weeks, 1 day

5
6
0 0

[PATCH RFC 00/11] riscv: support Sdtrig extension hcontext/scontext CSRs

by Max Hsu

riscv-debug-spec [1] Chapter 5: Sdtrig extension introduces trigger CSRs which can cause a breakpoint exception, entry into Debug Mode, or a trace action without having to execute a special instruction. The focus in the following patches is on the two CSRs from the Sdtrig extension: hcontext and scontext. These two CSRs are optional according to the spec, apart from the Smstateen extension [2], which has bit 57 to control the accessbility of the hcontext/scontext CSRs. We also introduce dt-binding in the CPU DTS for the existence of the CSRs in situations where the Smstaten extension is not available. The hcontext/scontext CSRs can help to raise triggers with the textra32/textra64 CSRs set up correctly. (Chapter 5.7.17/ 5.7.18 [1]) Therefore, as part of Linux awareness debugging. We propose the scontext CSR be filled by the Linux PID, And the hcontext CSR be filled with a self-maintained Guest OS ID. The reason for using the self-maintained Guest OS ID instead of VMID is that VMID might change over time, and the user setting up the trigger might enter the previous value, invoking the wrong VM for debugging. The tests have been done on QEMU with Sdtrig CSRs (mcontext/hcontext/scontext implemented) [3] boot on virt machine and also run the Guest OS as virt machine with KVM enabled, the two hcontext/scontext CSRs can be written correctly. This patch series is based on v6.9-rc1. Link: https://github.com/riscv/riscv-debug-spec/releases/download/ar20231208/risc… [1] Link: https://github.com/riscvarchive/riscv-state-enable/releases/download/v1.0.0… [2] Link: https://github.com/sifive/qemu/tree/dev/maxh/sdtrig_ISA [3] Signed-off-by: Max Hsu <max.hsu(a)sifive.com> --- Max Hsu (7): dt-bindings: riscv: Add Sdtrig ISA extension dt-bindings: riscv: Add Sdtrig optional CSRs existence on DT riscv: Add ISA extension parsing for Sdtrig riscv: Add Sdtrig CSRs definition, Smstateen bit to access Sdtrig CSRs riscv: cpufeature: Add Sdtrig optional CSRs checks riscv: suspend: add Smstateen CSRs save/restore riscv: Add task switch support for scontext CSR Yong-Xuan Wang (4): riscv: KVM: Add Sdtrig Extension Support for Guest/VM riscv: KVM: Add scontext to ONE_REG riscv: KVM: Add hcontext support KVM: riscv: selftests: Add Sdtrig Extension to get-reg-list test Documentation/devicetree/bindings/riscv/cpus.yaml | 18 +++ .../devicetree/bindings/riscv/extensions.yaml | 7 + arch/riscv/include/asm/csr.h | 6 + arch/riscv/include/asm/hwcap.h | 1 + arch/riscv/include/asm/kvm_host.h | 14 ++ arch/riscv/include/asm/kvm_vcpu_debug.h | 24 +++ arch/riscv/include/asm/suspend.h | 7 + arch/riscv/include/asm/switch_to.h | 15 ++ arch/riscv/include/uapi/asm/kvm.h | 9 ++ arch/riscv/kernel/cpufeature.c | 162 +++++++++++++++++++++ arch/riscv/kernel/suspend.c | 25 ++++ arch/riscv/kvm/Makefile | 1 + arch/riscv/kvm/main.c | 4 + arch/riscv/kvm/vcpu.c | 8 + arch/riscv/kvm/vcpu_debug.c | 107 ++++++++++++++ arch/riscv/kvm/vcpu_onereg.c | 63 +++++++- arch/riscv/kvm/vm.c | 4 + tools/testing/selftests/kvm/riscv/get-reg-list.c | 27 ++++ 18 files changed, 500 insertions(+), 2 deletions(-) --- base-commit: 317c7bc0ef035d8ebfc3e55c5dde0566fd5fb171 change-id: 20240329-dev-maxh-lin-452-6-9-c6209e6db67f Best regards, -- Max Hsu <max.hsu(a)sifive.com>

4 weeks, 1 day

4
15
0 0

[PATCH] KVM: selftests: fix max_guest_memory_test with more that 256 vCPUs

by Maxim Levitsky

max_guest_memory_test uses ucalls to sync with the host, but it also resets the guest RIP back to its initial value in between tests stages. This makes the guest never reach the code which frees the ucall struct and since a fixed pool of 512 ucall structs is used, the test starts to fail when more that 256 vCPUs are used. Fix that by replacing the manual register reset with a loop in the guest code. Signed-off-by: Maxim Levitsky <mlevitsk(a)redhat.com> --- .../testing/selftests/kvm/max_guest_memory_test.c | 15 ++++++--------- 1 file changed, 6 insertions(+), 9 deletions(-) diff --git a/tools/testing/selftests/kvm/max_guest_memory_test.c b/tools/testing/selftests/kvm/max_guest_memory_test.c index 6628dc4dda89f3c..1a6da7389bf1f5b 100644 --- a/tools/testing/selftests/kvm/max_guest_memory_test.c +++ b/tools/testing/selftests/kvm/max_guest_memory_test.c @@ -22,10 +22,11 @@ static void guest_code(uint64_t start_gpa, uint64_t end_gpa, uint64_t stride) { uint64_t gpa; - for (gpa = start_gpa; gpa < end_gpa; gpa += stride) - *((volatile uint64_t *)gpa) = gpa; - - GUEST_DONE(); + for (;;) { + for (gpa = start_gpa; gpa < end_gpa; gpa += stride) + *((volatile uint64_t *)gpa) = gpa; + GUEST_SYNC(0); + } } struct vcpu_info { @@ -55,7 +56,7 @@ static void rendezvous_with_boss(void) static void run_vcpu(struct kvm_vcpu *vcpu) { vcpu_run(vcpu); - TEST_ASSERT_EQ(get_ucall(vcpu, NULL), UCALL_DONE); + TEST_ASSERT_EQ(get_ucall(vcpu, NULL), UCALL_SYNC); } static void *vcpu_worker(void *data) @@ -64,17 +65,13 @@ static void *vcpu_worker(void *data) struct kvm_vcpu *vcpu = info->vcpu; struct kvm_vm *vm = vcpu->vm; struct kvm_sregs sregs; - struct kvm_regs regs; vcpu_args_set(vcpu, 3, info->start_gpa, info->end_gpa, vm->page_size); - /* Snapshot regs before the first run. */ - vcpu_regs_get(vcpu, &regs); rendezvous_with_boss(); run_vcpu(vcpu); rendezvous_with_boss(); - vcpu_regs_set(vcpu, &regs); vcpu_sregs_get(vcpu, &sregs); #ifdef __x86_64__ /* Toggle CR0.WP to trigger a MMU context reset. */ -- 2.40.1

1 month

2
3
0 0

[RFC PATCH net-next v6 00/15] Device Memory TCP

by Mina Almasry

RFC v6: ======= Major Changes: -------------- This revision largely rebases on top of net-next and addresses the little feedback RFCv5 received. The series remains in RFC because the queue-API ndos defined in this series are not yet implemented. I have a GVE implementation I carry out of tree for my testing. A upstreamable GVE implementation is in the works. Aside from that, in my estimation all the patches are ready for review/merge. Please do take a look. As usual the full devmem TCP changes including the full GVE driver implementation is here: https://github.com/mina/linux/commits/tcpdevmem-v6/ This version also comes with some performance data recorded in the cover letter (see below changelog). Detailed changelog: - Rebased on top of the merged netmem_ref changes. - Converted skb->dmabuf to skb->readable (Pavel). Pavel's original suggestion was to remove the skb->dmabuf flag entirely, but when I looked into it closely, I found the issue that if we remove the flag we have to dereference the shinfo(skb) pointer to obtain the first frag to tell whether an skb is readable or not. This can cause a performance regression if it dirties the cache line when the shinfo(skb) was not really needed. Instead, I converted the skb->dmabuf flag into a generic skb->readable flag which can be re-used by io_uring 0-copy RX. - Squashed a few locking optimizations from Eric Dumazet in the RX path and the DEVMEM_DONTNEED setsockopt. - Expanded the tests a bit. Added validation for invalid scenarios and added some more coverage. Perf - page-pool benchmark: --------------------------- bench_page_pool_simple.ko tests with and without these changes: https://pastebin.com/raw/ncHDwAbn AFAIK the number that really matters in the perf tests is the 'tasklet_page_pool01_fast_path Per elem'. This one measures at about 8 cycles without the changes but there is some 1 cycle noise in some results. With the patches this regresses to 9 cycles with the changes but there is 1 cycle noise occasionally running this test repeatedly. Lastly I tried disable the static_branch_unlikely() in netmem_is_net_iov() check. To my surprise disabling the static_branch_unlikely() check reduces the fast path back to 8 cycles, but the 1 cycle noise remains. Perf - Devmem TCP benchmark: --------------------- 189/200gbps bi-directional throughput with RX devmem TCP and regular TCP TX i.e. ~95% line rate. Major changes in RFC v5: ======================== 1. Rebased on top of 'Abstract page from net stack' series and used the new netmem type to refer to LSB set pointers instead of re-using struct page. 2. Downgraded this series back to RFC and called it RFC v5. This is because this series is now dependent on 'Abstract page from net stack'[1] and the queue API. Both are removed from the series to reduce the patch # and those bits are fairly independent or pre-requisite work. 3. Reworked the page_pool devmem support to use netmem and for some more unified handling. 4. Reworked the reference counting of net_iov (renamed from page_pool_iov) to use pp_ref_count for refcounting. The full changes including the dependent series and GVE page pool support is here: https://github.com/mina/linux/commits/tcpdevmem-rfcv5/ [1] https://patchwork.kernel.org/project/netdevbpf/list/?series=810774 Major changes in v1: ==================== 1. Implemented MVP queue API ndos to remove the userspace-visible driver reset. 2. Fixed issues in the napi_pp_put_page() devmem frag unref path. 3. Removed RFC tag. Many smaller addressed comments across all the patches (patches have individual change log). Full tree including the rest of the GVE driver changes: https://github.com/mina/linux/commits/tcpdevmem-v1 Changes in RFC v3: ================== 1. Pulled in the memory-provider dependency from Jakub's RFC[1] to make the series reviewable and mergeable. 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… 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 series is the GVE devmem TCP support, just to simplify the review. Code available here if desired: https://github.com/mina/linux/tree/tcpdevmem This series 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 series and memory provider API cherry-picked locally. Hardware: Google Cloud A3 VMs. NIC: GVE with header split & RSS & flow steering support. Cc: Pavel Begunkov <asml.silence(a)gmail.com> Cc: David Wei <dw(a)davidwei.uk> Cc: Jason Gunthorpe <jgg(a)ziepe.ca> Cc: Yunsheng Lin <linyunsheng(a)huawei.com> Cc: Shailend Chand <shailend(a)google.com> Cc: Harshitha Ramamurthy <hramamurthy(a)google.com> Cc: Shakeel Butt <shakeelb(a)google.com> Cc: Jeroen de Borst <jeroendb(a)google.com> Cc: Praveen Kaligineedi <pkaligineedi(a)google.com> Jakub Kicinski (1): net: page_pool: create hooks for custom page providers Mina Almasry (14): queue_api: define queue api net: page_pool: factor out page_pool recycle check net: netdev netlink api to bind dma-buf to a net device netdev: support binding dma-buf to netdevice netdev: netdevice devmem allocator page_pool: convert to use netmem page_pool: devmem support memory-provider: dmabuf devmem memory provider 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 frags net: add devmem TCP documentation selftests: add ncdevmem, netcat for devmem TCP Documentation/netlink/specs/netdev.yaml | 52 +++ Documentation/networking/devmem.rst | 271 ++++++++++++ Documentation/networking/index.rst | 1 + arch/alpha/include/uapi/asm/socket.h | 6 + arch/mips/include/uapi/asm/socket.h | 6 + arch/parisc/include/uapi/asm/socket.h | 6 + arch/sparc/include/uapi/asm/socket.h | 6 + include/linux/netdevice.h | 24 ++ include/linux/skbuff.h | 67 ++- include/linux/socket.h | 1 + include/net/devmem.h | 127 ++++++ include/net/netdev_rx_queue.h | 1 + include/net/netmem.h | 234 +++++++++- include/net/page_pool/helpers.h | 154 +++++-- include/net/page_pool/types.h | 28 +- include/net/sock.h | 2 + include/net/tcp.h | 5 +- include/trace/events/page_pool.h | 29 +- include/uapi/asm-generic/socket.h | 6 + include/uapi/linux/netdev.h | 19 + include/uapi/linux/uio.h | 14 + net/bpf/test_run.c | 5 +- net/core/Makefile | 2 +- net/core/datagram.c | 6 + net/core/dev.c | 6 +- net/core/devmem.c | 413 ++++++++++++++++++ net/core/gro.c | 7 +- net/core/netdev-genl-gen.c | 19 + net/core/netdev-genl-gen.h | 2 + net/core/netdev-genl.c | 123 ++++++ net/core/page_pool.c | 362 +++++++++------- net/core/skbuff.c | 110 ++++- net/core/sock.c | 61 +++ net/ipv4/tcp.c | 257 ++++++++++- net/ipv4/tcp_input.c | 13 +- net/ipv4/tcp_ipv4.c | 9 + net/ipv4/tcp_output.c | 5 +- net/packet/af_packet.c | 4 +- tools/include/uapi/linux/netdev.h | 19 + tools/testing/selftests/net/.gitignore | 1 + tools/testing/selftests/net/Makefile | 5 + tools/testing/selftests/net/ncdevmem.c | 546 ++++++++++++++++++++++++ 42 files changed, 2764 insertions(+), 270 deletions(-) create mode 100644 Documentation/networking/devmem.rst create mode 100644 include/net/devmem.h create mode 100644 net/core/devmem.c create mode 100644 tools/testing/selftests/net/ncdevmem.c -- 2.44.0.rc1.240.g4c46232300-goog

1 month

10
72
0 0

[PATCH 0/2] tracing/selftests: Verbosity improvements to KTAP output

by Mark Brown

This series aims to improve the usability of the ftrace selftests when running as part of the kselftest runner, mainly for use with automated systems. It fixes the output of verbose mode when run in KTAP output mode and then enables verbose mode by default when invoked from the kselftest runner so that the diagnostic information is there by default when run in automated systems. I've split this into two patches in case there is a concern with one part but not the other, especially given the verbosity of the verbose output when it triggers. Signed-off-by: Mark Brown <broonie(a)kernel.org> --- Mark Brown (2): tracing/selftests: Support log output when generating KTAP output tracing/selftests: Default to verbose mode when running in kselftest tools/testing/selftests/ftrace/ftracetest | 8 +++++++- tools/testing/selftests/ftrace/ftracetest-ktap | 2 +- 2 files changed, 8 insertions(+), 2 deletions(-) --- base-commit: 4cece764965020c22cff7665b18a012006359095 change-id: 20240319-kselftest-ftrace-ktap-verbose-72e37957e213 Best regards, -- Mark Brown <broonie(a)kernel.org>

1 month

5
8
0 0

[PATCH bpf-next v5 0/6] sleepable bpf_timer (was: allow HID-BPF to do device IOs)

by Benjamin Tissoires

New version of the sleepable bpf_timer code, without the HID changes, as they can now go through the HID tree indepandantly. For reference, the use cases I have in mind: --- Basically, I need to be able to defer a HID-BPF program for the following reasons (from the aforementioned patch): 1. defer an event: Sometimes we receive an out of proximity event, but the device can not be trusted enough, and we need to ensure that we won't receive another one in the following n milliseconds. So we need to wait those n milliseconds, and eventually re-inject that event in the stack. 2. inject new events in reaction to one given event: We might want to transform one given event into several. This is the case for macro keys where a single key press is supposed to send a sequence of key presses. But this could also be used to patch a faulty behavior, if a device forgets to send a release event. 3. communicate with the device in reaction to one event: We might want to communicate back to the device after a given event. For example a device might send us an event saying that it came back from sleeping state and needs to be re-initialized. Currently we can achieve that by keeping a userspace program around, raise a bpf event, and let that userspace program inject the events and commands. However, we are just keeping that program alive as a daemon for just scheduling commands. There is no logic in it, so it doesn't really justify an actual userspace wakeup. So a kernel workqueue seems simpler to handle. bpf_timers are currently running in a soft IRQ context, this patch series implements a sleppable context for them. Cheers, Benjamin To: Alexei Starovoitov <ast(a)kernel.org> To: Daniel Borkmann <daniel(a)iogearbox.net> To: Andrii Nakryiko <andrii(a)kernel.org> To: Martin KaFai Lau <martin.lau(a)linux.dev> To: Eduard Zingerman <eddyz87(a)gmail.com> To: Song Liu <song(a)kernel.org> To: Yonghong Song <yonghong.song(a)linux.dev> To: John Fastabend <john.fastabend(a)gmail.com> To: KP Singh <kpsingh(a)kernel.org> To: Stanislav Fomichev <sdf(a)google.com> To: Hao Luo <haoluo(a)google.com> To: Jiri Olsa <jolsa(a)kernel.org> To: Mykola Lysenko <mykolal(a)fb.com> To: Shuah Khan <shuah(a)kernel.org> Cc: Benjamin Tissoires <bentiss(a)kernel.org> Cc: <bpf(a)vger.kernel.org> Cc: <linux-kernel(a)vger.kernel.org> Cc: <linux-kselftest(a)vger.kernel.org> --- Changes in v5: - took various reviews into account - rewrote the tests to be separated to not have a uggly include - Link to v4: https://lore.kernel.org/r/20240315-hid-bpf-sleepable-v4-0-5658f2540564@kern… Changes in v4: - dropped the HID changes, they can go independently from bpf-core - addressed Alexei's and Eduard's remarks - added selftests - Link to v3: https://lore.kernel.org/r/20240221-hid-bpf-sleepable-v3-0-1fb378ca6301@kern… Changes in v3: - fixed the crash from v2 - changed the API to have only BPF_F_TIMER_SLEEPABLE for bpf_timer_start() - split the new kfuncs/verifier patch into several sub-patches, for easier reviews - Link to v2: https://lore.kernel.org/r/20240214-hid-bpf-sleepable-v2-0-5756b054724d@kern… Changes in v2: - make use of bpf_timer (and dropped the custom HID handling) - implemented bpf_timer_set_sleepable_cb as a kfunc - still not implemented global subprogs - no sleepable bpf_timer selftests yet - Link to v1: https://lore.kernel.org/r/20240209-hid-bpf-sleepable-v1-0-4cc895b5adbd@kern… --- Benjamin Tissoires (6): bpf/helpers: introduce sleepable bpf_timers bpf/verifier: add bpf_timer as a kfunc capable type bpf/helpers: introduce bpf_timer_set_sleepable_cb() kfunc bpf/helpers: mark the callback of bpf_timer_set_sleepable_cb() as sleepable tools: sync include/uapi/linux/bpf.h selftests/bpf: add sleepable timer tests include/linux/bpf_verifier.h | 1 + include/uapi/linux/bpf.h | 4 + kernel/bpf/helpers.c | 132 ++++++++++++++- kernel/bpf/verifier.c | 96 ++++++++++- tools/include/uapi/linux/bpf.h | 4 + tools/testing/selftests/bpf/bpf_experimental.h | 5 + .../selftests/bpf/bpf_testmod/bpf_testmod.c | 5 + .../selftests/bpf/bpf_testmod/bpf_testmod_kfunc.h | 1 + tools/testing/selftests/bpf/prog_tests/timer.c | 34 ++++ .../testing/selftests/bpf/progs/timer_sleepable.c | 185 +++++++++++++++++++++ 10 files changed, 458 insertions(+), 9 deletions(-) --- base-commit: 9187210eee7d87eea37b45ea93454a88681894a4 change-id: 20240205-hid-bpf-sleepable-c01260fd91c4 Best regards, -- Benjamin Tissoires <bentiss(a)kernel.org>

1 month

5
26
0 0

2024

2023

2022

2021

2020

2019

2018

2017

Linux-kselftest-mirror March 2024