CoreSight February 2024

coresight@lists.linaro.org

7 participants
33 discussions

Re: [PATCH V4 00/11] perf/core: Add ability for an event to "pause" or "resume" AUX area tracing

by James Clark

On 31/01/2024 16:53, Ian Rogers wrote: > On Mon, Jan 29, 2024 at 4:49 AM Adrian Hunter <adrian.hunter(a)intel.com> wrote: >> >> On 11/01/24 10:19, Adrian Hunter wrote: >>> Hi >>> >>> Hardware traces, such as instruction traces, can produce a vast amount of >>> trace data, so being able to reduce tracing to more specific circumstances >>> can be useful. >>> >>> The ability to pause or resume tracing when another event happens, can do >>> that. >>> >>> These patches add such a facilty and show how it would work for Intel >>> Processor Trace. >>> >>> Maintainers of other AUX area tracing implementations are requested to >>> consider if this is something they might employ and then whether or not >>> the ABI would work for them. >>> >>> Changes to perf tools are now (since V4) fleshed out. >>> >>> >>> Changes in V4: >>> >>> perf/core: Add aux_pause, aux_resume, aux_start_paused >>> Rename aux_output_cfg -> aux_action >>> Reorder aux_action bits from: >>> aux_pause, aux_resume, aux_start_paused >>> to: >>> aux_start_paused, aux_pause, aux_resume >>> Fix aux_action bits __u64 -> __u32 >>> >>> coresight: Have a stab at support for pause / resume >>> Dropped >>> >>> perf tools >>> All new patches >>> >>> Changes in RFC V3: >>> >>> coresight: Have a stab at support for pause / resume >>> 'mode' -> 'flags' so it at least compiles >>> >>> Changes in RFC V2: >>> >>> Use ->stop() / ->start() instead of ->pause_resume() >>> Move aux_start_paused bit into aux_output_cfg >>> Tighten up when Intel PT pause / resume is allowed >>> Add an example of how it might work for CoreSight >> >> Any more comments? > > I think the tools side looks good. The parsing changes match the > existing style. I wonder if it wouldn't be better to handle the valid > strings (pause, resume, etc.) in the lexer rather than a separate > parse function, but the pattern used matches the existing one. You can > have my Acked-by on the tools changes, although the subtleties of ARM > PMUs makes me somewhat nervous in this regard. > > Thanks, > Ian Acked-by: James Clark <james.clark(a)arm.com> I will get round to adding the Coresight support at some point. I checked the new parsing in this version and it seems to work ok.

3 months, 1 week

[PATCH v4 2/7] arm64: KVM: Use shared area to pass PMU event state to hypervisor

by James Clark

Currently the state of the PMU events is copied into the VCPU struct before every VCPU run. This isn't scalable if more data for other features needs to be added too. So make a writable area that's shared between the host and the hypervisor to store this state. Normal per-cpu constructs can't be used because although the framework exists for the host to write to the hypervisor's per-cpu structs, this only works until the protection is enabled. And for the other way around, no framework exists for the hypervisor to access the host's size and layout of per-cpu data. Instead of making a new framework for the hypervisor to access the host's per-cpu data that would only be used once, just define the new shared area as an array with NR_CPUS elements. This also reduces the amount of sharing that needs to be done, because unlike this array, the per-cpu data isn't contiguous. Signed-off-by: James Clark <james.clark(a)arm.com> --- arch/arm64/include/asm/kvm_host.h | 8 ++++++++ arch/arm64/kernel/image-vars.h | 1 + arch/arm64/kvm/arm.c | 16 ++++++++++++++-- arch/arm64/kvm/hyp/nvhe/setup.c | 11 +++++++++++ arch/arm64/kvm/hyp/nvhe/switch.c | 9 +++++++-- arch/arm64/kvm/pmu.c | 4 +--- include/kvm/arm_pmu.h | 17 ----------------- 7 files changed, 42 insertions(+), 24 deletions(-) diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h index 824f29f04916..93d38ad257ed 100644 --- a/arch/arm64/include/asm/kvm_host.h +++ b/arch/arm64/include/asm/kvm_host.h @@ -466,6 +466,14 @@ struct kvm_cpu_context { struct kvm_vcpu *__hyp_running_vcpu; }; +struct kvm_host_global_state { + struct kvm_pmu_events { + u32 events_host; + u32 events_guest; + } pmu_events; +} ____cacheline_aligned; +extern struct kvm_host_global_state kvm_host_global_state[NR_CPUS]; + struct kvm_host_data { struct kvm_cpu_context host_ctxt; }; diff --git a/arch/arm64/kernel/image-vars.h b/arch/arm64/kernel/image-vars.h index 119ca121b5f8..1a9dbb02bb4a 100644 --- a/arch/arm64/kernel/image-vars.h +++ b/arch/arm64/kernel/image-vars.h @@ -59,6 +59,7 @@ KVM_NVHE_ALIAS(alt_cb_patch_nops); /* Global kernel state accessed by nVHE hyp code. */ KVM_NVHE_ALIAS(kvm_vgic_global_state); +KVM_NVHE_ALIAS(kvm_host_global_state); /* Kernel symbols used to call panic() from nVHE hyp code (via ERET). */ KVM_NVHE_ALIAS(nvhe_hyp_panic_handler); diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c index 4796104c4471..bd6b2eda5f4f 100644 --- a/arch/arm64/kvm/arm.c +++ b/arch/arm64/kvm/arm.c @@ -47,6 +47,20 @@ static enum kvm_mode kvm_mode = KVM_MODE_DEFAULT; +/* + * Host state that isn't associated with any VCPU, but will affect any VCPU + * running on a host CPU in the future. This remains writable from the host and + * readable in the hyp. + * + * PER_CPU constructs aren't compatible between the hypervisor and the host so + * just define it as a NR_CPUS array. DECLARE_KVM_NVHE_PER_CPU works in both + * places, but not after the hypervisor protection is initialised. After that, + * kvm_arm_hyp_percpu_base isn't accessible from the host, so even if the + * kvm_host_global_state struct was shared with the host, the per-cpu offset + * can't be calculated without sharing even more data with the host. + */ +struct kvm_host_global_state kvm_host_global_state[NR_CPUS]; + DECLARE_KVM_HYP_PER_CPU(unsigned long, kvm_hyp_vector); DEFINE_PER_CPU(unsigned long, kvm_arm_hyp_stack_page); @@ -1016,8 +1030,6 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu) kvm_vgic_flush_hwstate(vcpu); - kvm_pmu_update_vcpu_events(vcpu); - /* * Ensure we set mode to IN_GUEST_MODE after we disable * interrupts and before the final VCPU requests check. diff --git a/arch/arm64/kvm/hyp/nvhe/setup.c b/arch/arm64/kvm/hyp/nvhe/setup.c index b5452e58c49a..3e45cc10ba96 100644 --- a/arch/arm64/kvm/hyp/nvhe/setup.c +++ b/arch/arm64/kvm/hyp/nvhe/setup.c @@ -159,6 +159,17 @@ static int recreate_hyp_mappings(phys_addr_t phys, unsigned long size, if (ret) return ret; + /* + * Similar to kvm_vgic_global_state, but this one remains writable by + * the host rather than read-only. Used to store per-cpu state about the + * host that isn't associated with any particular VCPU. + */ + prot = pkvm_mkstate(KVM_PGTABLE_PROT_RW, PKVM_PAGE_SHARED_OWNED); + ret = pkvm_create_mappings(&kvm_host_global_state, + &kvm_host_global_state + 1, prot); + if (ret) + return ret; + ret = create_hyp_debug_uart_mapping(); if (ret) return ret; diff --git a/arch/arm64/kvm/hyp/nvhe/switch.c b/arch/arm64/kvm/hyp/nvhe/switch.c index c50f8459e4fc..89147a9dc38c 100644 --- a/arch/arm64/kvm/hyp/nvhe/switch.c +++ b/arch/arm64/kvm/hyp/nvhe/switch.c @@ -130,13 +130,18 @@ static void __hyp_vgic_restore_state(struct kvm_vcpu *vcpu) } } +static struct kvm_pmu_events *kvm_nvhe_get_pmu_events(struct kvm_vcpu *vcpu) +{ + return &kvm_host_global_state[vcpu->cpu].pmu_events; +} + /* * Disable host events, enable guest events */ #ifdef CONFIG_HW_PERF_EVENTS static bool __pmu_switch_to_guest(struct kvm_vcpu *vcpu) { - struct kvm_pmu_events *pmu = &vcpu->arch.pmu.events; + struct kvm_pmu_events *pmu = kvm_nvhe_get_pmu_events(vcpu); if (pmu->events_host) write_sysreg(pmu->events_host, pmcntenclr_el0); @@ -152,7 +157,7 @@ static bool __pmu_switch_to_guest(struct kvm_vcpu *vcpu) */ static void __pmu_switch_to_host(struct kvm_vcpu *vcpu) { - struct kvm_pmu_events *pmu = &vcpu->arch.pmu.events; + struct kvm_pmu_events *pmu = kvm_nvhe_get_pmu_events(vcpu); if (pmu->events_guest) write_sysreg(pmu->events_guest, pmcntenclr_el0); diff --git a/arch/arm64/kvm/pmu.c b/arch/arm64/kvm/pmu.c index a243934c5568..136d5c6c1916 100644 --- a/arch/arm64/kvm/pmu.c +++ b/arch/arm64/kvm/pmu.c @@ -6,8 +6,6 @@ #include <linux/kvm_host.h> #include <linux/perf_event.h> -static DEFINE_PER_CPU(struct kvm_pmu_events, kvm_pmu_events); - /* * Given the perf event attributes and system type, determine * if we are going to need to switch counters at guest entry/exit. @@ -28,7 +26,7 @@ static bool kvm_pmu_switch_needed(struct perf_event_attr *attr) struct kvm_pmu_events *kvm_get_pmu_events(void) { - return this_cpu_ptr(&kvm_pmu_events); + return &kvm_host_global_state[smp_processor_id()].pmu_events; } /* diff --git a/include/kvm/arm_pmu.h b/include/kvm/arm_pmu.h index 4b9d8fb393a8..71a835970ab5 100644 --- a/include/kvm/arm_pmu.h +++ b/include/kvm/arm_pmu.h @@ -18,14 +18,8 @@ struct kvm_pmc { struct perf_event *perf_event; }; -struct kvm_pmu_events { - u32 events_host; - u32 events_guest; -}; - struct kvm_pmu { struct irq_work overflow_work; - struct kvm_pmu_events events; struct kvm_pmc pmc[ARMV8_PMU_MAX_COUNTERS]; int irq_num; bool created; @@ -79,17 +73,6 @@ void kvm_vcpu_pmu_resync_el0(void); #define kvm_vcpu_has_pmu(vcpu) \ (vcpu_has_feature(vcpu, KVM_ARM_VCPU_PMU_V3)) -/* - * Updates the vcpu's view of the pmu events for this cpu. - * Must be called before every vcpu run after disabling interrupts, to ensure - * that an interrupt cannot fire and update the structure. - */ -#define kvm_pmu_update_vcpu_events(vcpu) \ - do { \ - if (!has_vhe() && kvm_vcpu_has_pmu(vcpu)) \ - vcpu->arch.pmu.events = *kvm_get_pmu_events(); \ - } while (0) - /* * Evaluates as true when emulating PMUv3p5, and false otherwise. */ -- 2.34.1

3 months, 1 week

[PATCH v5 00/10] Add support to configure TPDM CMB subunit

by Tao Zhang

Introduction of TPDM CMB(Continuous Multi Bit) subunit CMB subunit is responsible for creating a dataset element, and is also optionally responsible for packing it to fit multiple elements on a single ATB transfer if possible in the configuration. The TPDM Core Datapath requests timestamps be stored by the TPDA and then delivering ATB sized data (depending on ATB width and element size, this could be smaller or larger than a dataset element) to the ATB Mast FSM. The CMB makes trace elements in two modes. In �continuous� mode, every valid data cycle creates an element. In �trace on change� mode, when valid data changes on the bus, a trace element is created. In continuous mode, all cycles where this condition is true create trace elements. In trace on change mode, a data element is only when the previously sampled input is different from the current sampled input. The CMB subunit must be configured prior to enablement. This series adds support for TPDM to configure the configure CMB subunit. Once this series patches are applied properly, the new tpdm nodes for should be observed at the tpdm path /sys/bus/coresight/devices/tpdm* which supports CMB subunit. e.g. root@qemuarm64:/sys/devices/platform/soc@0/684c000.tpdm/tpdm0# ls -l -rw-r--r-- 1 root root 4096 Jan 1 00:00 cmb_mode drwxr-xr-x 2 root root 0 Jan 1 00:00 cmb_msr drwxr-xr-x 2 root root 0 Jan 1 00:00 cmb_patt drwxr-xr-x 2 root root 0 Jan 1 00:00 cmb_trig_patt -rw-r--r-- 1 root root 4096 Jan 1 00:00 cmb_trig_ts -rw-r--r-- 1 root root 4096 Jan 1 00:00 cmb_ts_all drwxr-xr-x 2 root root 0 Jan 1 00:00 connections drwxr-xr-x 2 root root 0 Jan 1 00:00 dsb_edge drwxr-xr-x 2 root root 0 Jan 1 00:00 dsb_msr drwxr-xr-x 2 root root 0 Jan 1 00:00 dsb_patt drwxr-xr-x 2 root root 0 Jan 1 00:00 dsb_trig_patt -rw-r--r-- 1 root root 4096 Jan 1 00:00 enable_source --w------- 1 root root 4096 Jan 1 00:00 integration_test drwxr-xr-x 2 root root 0 Ja? 1 00:00 power --w------- 1 root root 4096 Jan 1 00:00 reset_dataset lrwxrwxrwx 1 root root 0 Apr 5 2021 subsystem -> ../../../../../bus/coresight -rw-r--r-- 1 root root 4096 Apr 5 2021 uevent -r--r--r-- 1 root root 4096 Jan 1 00:00 waiting_for_supplier We can use the commands are similar to the below to configure the TPDMs which support CMB subunit. Enable coresight sink first. echo 1 > /sys/bus/coresight/devices/tmc_etf0/enable_sink echo 1 > /sys/bus/coresight/devices/tpdm0/reset_dataset echo 1 > /sys/bus/coresight/devices/tpdm0/cmb_mode echo 1 > /sys/bus/coresight/devices/tpdm0/cmb_patt/enable_ts echo 0xFFFFFFFF > /sys/bus/coresight/devices/tpdm0/cmb_patt/tpmr0 echo 0 > /sys/bus/coresight/devices/tpdm0/cmb_trig_ts echo 0xFFFFFFFF > /sys/bus/coresight/devices/tpdm0/cmb_trig_patt/xpr1 echo 1 > /sys/bus/coresight/devices/tpdm0/enable_source codelinaro link: https://git.codelinaro.org/clo/linux-kernel/coresight/-/commits/tpdm-cmb-v5 Changes in V5: 1. Return directly to refine the process of "tpdm_enable_dsb" and "tpdm_disable_dsb" if the TPDM does not support DSB dataset. -- Suzuki K Poulose 2. Change the new property name from "qcom,cmb-element-size" to "qcom,cmb-element-bits". And update the property name to the new tpdm example which supports the CMB dataset. -- Krzysztof 3. Drop unnecessary () around the drvdata member access in patch#5. -- Suzuki K Poulose 4. Replace the error code "-EEXIST" with the port number in detecting multiple TPDMs on one input port. In patch#5. -- Suzuki K Poulose 5. Due to the modification of the new property name, the searched property name was changed from "qcom,cmb-element-size" to "qcom,cmb-element-bits". In patch#5. 6. Replace the judgement "tpdm_has_cmb_dataset(drvdata)" with "drvdata->cmb" in the function "tpdm_reset_datasets". In patch#6. -- Suzuki K Poulose 7. Drop unnecessary () around kstrtoul() in the function "cmb_mode_store". In patch#6. -- Suzuki K Poulose 8. Update the date and the kernel version in the Document. -- Suzuki K Poulose 9. Initialize the return value to "-EINVAL" and remove the unnecessary code in the function "enable_ts_show". In patch#8. -- Suzuki K Poulose 10. Replace spin lock/unlock with guard(spinlock). In patch#8. -- Suzuki K Poulose 11. Drop _rw from the macro "tpdm_patt_enable_ts_rw". In patch#8. -- Suzuki K Poulose Changes in V4: 1. Replace spin lock/unlock to avoid forgetting to unlock when the function exits. -- Suzuki K Poulose 2. Move the helper "tpdm_has_dsb_dataset" to the header file. -- Suzuki K Poulose 3. Fix the incorrect property of the sample in the documents. -- James Clark 4. Clear the dsb/cmb element size directly in the clear helper. -- Suzuki K Poulose 5. Correct the comment of "tpdm_read_element_size". -- Suzuki K Poulose 6. Call the helper "tpdm_has_dsb/cmb_dataset" in TPDA driver to check what dataset the TPDM supports. -- Suzuki K Poulose 7. Refine the dsb/cmb dataset support check in enable/disable functions. -- Suzuki K Poulose 8. Get rid of redundant code in function "set_cmb_tier". -- Suzuki K Poulose 9. Since one SysFs file should follow "one value", use "dev_ext_attribute" to instead of the previous "enable_ts" Sysfs file approach. -- Suzuki K Poulose 10. Change the kernel version to 6.9 for the MSR related SysFs file. -- James Clark 11. Refine the function "tpdm_simple_dataset_store". -- Suzuki K Poulose Changes in V3: 1. Add 8-bit support to the description in the TPDM devicetree document. -- Rob Herring 2. Change how the result is produced in "tpdm_read_element_size". -- James Clark 3. Calling "tpdm_clear_element_size" at the beginning of "tpda_enable_port". -- James Clark 4. Use "dsb_esize" and "cmb_esize" to determine whether multiple TPDMs are detected on a TPDA input port in "tpda_get_element_size". -- James Clark 5. Modify the judgment logic in "tpda_enable_port". -- James Clark 6. Add more description of "cmb_mode" to TPDM SysFS document. -- James Clark Changes in V2: 1. Optimizate and modify this patch series based on the patch series "Add support to configure TPDM CMB subunit". 2. Modify the functions that read the element size of DSB/CMB in TPDA driver. Tao Zhang (10): coresight-tpdm: Optimize the store function of tpdm simple dataset coresight-tpdm: Optimize the useage of tpdm_has_dsb_dataset dt-bindings: arm: qcom,coresight-tpdm: Add support for CMB element size coresight-tpdm: Add CMB dataset support coresight-tpda: Add support to configure CMB element coresight-tpdm: Add support to configure CMB coresight-tpdm: Add pattern registers support for CMB coresight-tpdm: Add timestamp control register support for the CMB dt-bindings: arm: qcom,coresight-tpdm: Add support for TPDM CMB MSR register coresight-tpdm: Add msr register support for CMB .../testing/sysfs-bus-coresight-devices-tpdm | 87 ++++ .../bindings/arm/qcom,coresight-tpdm.yaml | 35 ++ drivers/hwtracing/coresight/coresight-tpda.c | 123 +++-- drivers/hwtracing/coresight/coresight-tpda.h | 6 + drivers/hwtracing/coresight/coresight-tpdm.c | 455 ++++++++++++++++-- drivers/hwtracing/coresight/coresight-tpdm.h | 113 +++++ 6 files changed, 727 insertions(+), 92 deletions(-) -- 2.17.1

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CoreSight February 2024