@@ -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
+ 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
@@ -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)
new file mode 100644
@@ -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()) {
+ /* Register the pmu */
+ rc = perf_pmu_register(&kvmppc_pmu, kvmppc_pmu.name, -1);
+ if (rc)
+ goto out;
+
+ pr_info("Registered kvm-hv pmu");
+ }
+
+out:
+ 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 <vaibhav@linux.ibm.com>");
+MODULE_LICENSE("GPL");
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 <vaibhav@linux.ibm.com> --- Changelog v4->v5: * Fixed a kismet warning reported by build-robot by removing dependency to CONFIG_HV_PERF_CTRS https://lore.kernel.org/oe-kbuild-all/202502280218.Jdd4jjlZ-lkp@intel.com/ * Removed a redundant check in kvmppc_register_pmu() [ Atheera ] 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-lkp@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