Introduce a new PMU named 'kvm-hv' inside a new module named 'kvm-hv-pmu' to report Book3s kvm-hv specific performance counters. This will expose KVM-HV specific performance attributes to user-space via kernel's PMU infrastructure and would enableusers to monitor active kvm-hv based guests.
The patch creates necessary scaffolding to for the new PMU callbacks and introduces the new kernel module name 'kvm-hv-pmu' which is built with CONFIG_KVM_BOOK3S_HV_PMU. The patch doesn't introduce any perf-events yet, which will be introduced in later patches Signed-off-by: Vaibhav Jain <vaib...@linux.ibm.com> --- Changelog v3->v4: * Introduced a new kernel module named 'kmv-hv-pmu' to host the new PMU instead of building the as part of KVM-HV module. [ Maddy ] * Moved the code from arch/powerpc/kvm to arch/powerpc/perf [ Atheera ] * Added a new config named KVM_BOOK3S_HV_PMU to arch/powerpc/kvm/Kconfig v2->v3: * Fixed a build warning reported by kernel build robot. Link: https://lore.kernel.org/oe-kbuild-all/202501171030.3x0gqw8g-...@intel.com v1->v2: * Fixed an issue of kvm-hv not loading on baremetal kvm [Gautam] --- arch/powerpc/kvm/Kconfig | 13 ++++ arch/powerpc/perf/Makefile | 2 + arch/powerpc/perf/kvm-hv-pmu.c | 138 +++++++++++++++++++++++++++++++++ 3 files changed, 153 insertions(+) create mode 100644 arch/powerpc/perf/kvm-hv-pmu.c diff --git a/arch/powerpc/kvm/Kconfig b/arch/powerpc/kvm/Kconfig index dbfdc126bf14..5f0ce19e7e27 100644 --- a/arch/powerpc/kvm/Kconfig +++ b/arch/powerpc/kvm/Kconfig @@ -83,6 +83,7 @@ config KVM_BOOK3S_64_HV depends on KVM_BOOK3S_64 && PPC_POWERNV select KVM_BOOK3S_HV_POSSIBLE select KVM_GENERIC_MMU_NOTIFIER + select KVM_BOOK3S_HV_PMU select CMA help Support running unmodified book3s_64 guest kernels in @@ -171,6 +172,18 @@ config KVM_BOOK3S_HV_NESTED_PMU_WORKAROUND those buggy L1s which saves the L2 state, at the cost of performance in all nested-capable guest entry/exit. +config KVM_BOOK3S_HV_PMU + tristate "Hypervisor Perf events for KVM Book3s-HV" + depends on KVM_BOOK3S_64_HV && HV_PERF_CTRS + help + Enable Book3s-HV Hypervisor Perf events PMU named 'kvm-hv'. These + Perf events give an overview of hypervisor performance overall + instead of a specific guests. Currently the PMU reports + L0-Hypervisor stats on a kvm-hv enabled PSeries LPAR like: + * Total/Used Guest-Heap + * Total/Used Guest Page-table Memory + * Total amount of Guest Page-table Memory reclaimed + config KVM_BOOKE_HV bool diff --git a/arch/powerpc/perf/Makefile b/arch/powerpc/perf/Makefile index ac2cf58d62db..7f53fcb7495a 100644 --- a/arch/powerpc/perf/Makefile +++ b/arch/powerpc/perf/Makefile @@ -18,6 +18,8 @@ obj-$(CONFIG_HV_PERF_CTRS) += hv-24x7.o hv-gpci.o hv-common.o obj-$(CONFIG_VPA_PMU) += vpa-pmu.o +obj-$(CONFIG_KVM_BOOK3S_HV_PMU) += kvm-hv-pmu.o + obj-$(CONFIG_PPC_8xx) += 8xx-pmu.o obj-$(CONFIG_PPC64) += $(obj64-y) diff --git a/arch/powerpc/perf/kvm-hv-pmu.c b/arch/powerpc/perf/kvm-hv-pmu.c new file mode 100644 index 000000000000..c154f54e09e2 --- /dev/null +++ b/arch/powerpc/perf/kvm-hv-pmu.c @@ -0,0 +1,138 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Description: PMUs specific to running nested KVM-HV guests + * on Book3S processors (specifically POWER9 and later). + */ + +#define pr_fmt(fmt) "kvmppc-pmu: " fmt + +#include "asm-generic/local64.h" +#include <linux/kernel.h> +#include <linux/errno.h> +#include <linux/ratelimit.h> +#include <linux/kvm_host.h> +#include <linux/gfp_types.h> +#include <linux/pgtable.h> +#include <linux/perf_event.h> +#include <linux/spinlock_types.h> +#include <linux/spinlock.h> + +#include <asm/types.h> +#include <asm/kvm_ppc.h> +#include <asm/kvm_book3s.h> +#include <asm/mmu.h> +#include <asm/pgalloc.h> +#include <asm/pte-walk.h> +#include <asm/reg.h> +#include <asm/plpar_wrappers.h> +#include <asm/firmware.h> + +enum kvmppc_pmu_eventid { + KVMPPC_EVENT_MAX, +}; + +static struct attribute *kvmppc_pmu_events_attr[] = { + NULL, +}; + +static const struct attribute_group kvmppc_pmu_events_group = { + .name = "events", + .attrs = kvmppc_pmu_events_attr, +}; + +PMU_FORMAT_ATTR(event, "config:0"); +static struct attribute *kvmppc_pmu_format_attr[] = { + &format_attr_event.attr, + NULL, +}; + +static struct attribute_group kvmppc_pmu_format_group = { + .name = "format", + .attrs = kvmppc_pmu_format_attr, +}; + +static const struct attribute_group *kvmppc_pmu_attr_groups[] = { + &kvmppc_pmu_events_group, + &kvmppc_pmu_format_group, + NULL, +}; + +static int kvmppc_pmu_event_init(struct perf_event *event) +{ + unsigned int config = event->attr.config; + + pr_debug("%s: Event(%p) id=%llu cpu=%x on_cpu=%x config=%u", + __func__, event, event->id, event->cpu, + event->oncpu, config); + + if (event->attr.type != event->pmu->type) + return -ENOENT; + + if (config >= KVMPPC_EVENT_MAX) + return -EINVAL; + + local64_set(&event->hw.prev_count, 0); + local64_set(&event->count, 0); + + return 0; +} + +static void kvmppc_pmu_del(struct perf_event *event, int flags) +{ +} + +static int kvmppc_pmu_add(struct perf_event *event, int flags) +{ + return 0; +} + +static void kvmppc_pmu_read(struct perf_event *event) +{ +} + +/* L1 wide counters PMU */ +static struct pmu kvmppc_pmu = { + .module = THIS_MODULE, + .task_ctx_nr = perf_sw_context, + .name = "kvm-hv", + .event_init = kvmppc_pmu_event_init, + .add = kvmppc_pmu_add, + .del = kvmppc_pmu_del, + .read = kvmppc_pmu_read, + .attr_groups = kvmppc_pmu_attr_groups, + .type = -1, +}; + +static int __init kvmppc_register_pmu(void) +{ + int rc = -EOPNOTSUPP; + + /* only support events for nestedv2 right now */ + if (kvmhv_is_nestedv2()) { + /* Setup done now register the PMU */ + pr_info("Registering kvm-hv pmu"); + + /* Register only if we arent already registered */ + rc = (kvmppc_pmu.type == -1) ? + perf_pmu_register(&kvmppc_pmu, kvmppc_pmu.name, + -1) : 0; + } + + return rc; +} + +static void __exit kvmppc_unregister_pmu(void) +{ + if (kvmhv_is_nestedv2()) { + if (kvmppc_pmu.type != -1) + perf_pmu_unregister(&kvmppc_pmu); + + pr_info("kvmhv_pmu unregistered.\n"); + } +} + +module_init(kvmppc_register_pmu); +module_exit(kvmppc_unregister_pmu); +MODULE_DESCRIPTION("KVM PPC Book3s-hv PMU"); +MODULE_AUTHOR("Vaibhav Jain <vaib...@linux.ibm.com>"); +MODULE_LICENSE("GPL"); -- 2.48.1
