Introduce a new PMU named 'kvm-hv' 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 enable
users to monitor active kvm-hv based guests.
The patch creates necessary scaffolding to for the new PMU callbacks and
introduces two new exports kvmppc_{,un}register_pmu() that are called from
kvm-hv init and exit function to perform initialize and cleanup for the
'kvm-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
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/include/asm/kvm_book3s.h | 20 ++++
arch/powerpc/kvm/Makefile | 6 ++
arch/powerpc/kvm/book3s_hv.c | 9 ++
arch/powerpc/kvm/book3s_hv_pmu.c | 133 ++++++++++++++++++++++++++
4 files changed, 168 insertions(+)
create mode 100644 arch/powerpc/kvm/book3s_hv_pmu.c
diff --git a/arch/powerpc/include/asm/kvm_book3s.h
b/arch/powerpc/include/asm/kvm_book3s.h
index e1ff291ba891..7a7854c65ebb 100644
--- a/arch/powerpc/include/asm/kvm_book3s.h
+++ b/arch/powerpc/include/asm/kvm_book3s.h
@@ -348,6 +348,26 @@ static inline bool kvmhv_is_nestedv1(void)
#endif
+/* kvm-ppc pmu registration */
+#if IS_ENABLED(CONFIG_KVM_BOOK3S_64_HV)
+#ifdef CONFIG_PERF_EVENTS
+int kvmppc_register_pmu(void);
+void kvmppc_unregister_pmu(void);
+
+#else
+
+static inline int kvmppc_register_pmu(void)
+{
+ return 0;
+}
+
+static inline void kvmppc_unregister_pmu(void)
+{
+ /* do nothing */
+}
+#endif /* CONFIG_PERF_EVENTS */
+#endif /* CONFIG_KVM_BOOK3S_64_HV */
+
int __kvmhv_nestedv2_reload_ptregs(struct kvm_vcpu *vcpu, struct pt_regs
*regs);
int __kvmhv_nestedv2_mark_dirty_ptregs(struct kvm_vcpu *vcpu, struct pt_regs
*regs);
int __kvmhv_nestedv2_mark_dirty(struct kvm_vcpu *vcpu, u16 iden);
diff --git a/arch/powerpc/kvm/Makefile b/arch/powerpc/kvm/Makefile
index 4bd9d1230869..7645307ff277 100644
--- a/arch/powerpc/kvm/Makefile
+++ b/arch/powerpc/kvm/Makefile
@@ -92,6 +92,12 @@ kvm-book3s_64-builtin-objs-$(CONFIG_KVM_BOOK3S_64_HANDLER)
+= \
$(kvm-book3s_64-builtin-tm-objs-y) \
$(kvm-book3s_64-builtin-xics-objs-y)
+# enable kvm_hv perf events
+ifdef CONFIG_PERF_EVENTS
+kvm-book3s_64-builtin-objs-$(CONFIG_KVM_BOOK3S_64_HANDLER) += \
+ book3s_hv_pmu.o
+endif
+
obj-$(CONFIG_GUEST_STATE_BUFFER_TEST) += test-guest-state-buffer.o
endif
diff --git a/arch/powerpc/kvm/book3s_hv.c b/arch/powerpc/kvm/book3s_hv.c
index 25429905ae90..6365b8126574 100644
--- a/arch/powerpc/kvm/book3s_hv.c
+++ b/arch/powerpc/kvm/book3s_hv.c
@@ -6662,6 +6662,14 @@ static int kvmppc_book3s_init_hv(void)
return r;
}
+ r = kvmppc_register_pmu();
+ if (r == -EOPNOTSUPP) {
+ pr_info("KVM-HV: PMU not supported %d\n", r);
+ } else if (r) {
+ pr_err("KVM-HV: Unable to register PMUs %d\n", r);
+ goto err;
+ }
+
kvm_ops_hv.owner = THIS_MODULE;
kvmppc_hv_ops = &kvm_ops_hv;
@@ -6676,6 +6684,7 @@ static int kvmppc_book3s_init_hv(void)
static void kvmppc_book3s_exit_hv(void)
{
+ kvmppc_unregister_pmu();
kvmppc_uvmem_free();
kvmppc_free_host_rm_ops();
if (kvmppc_radix_possible())
diff --git a/arch/powerpc/kvm/book3s_hv_pmu.c b/arch/powerpc/kvm/book3s_hv_pmu.c
new file mode 100644
index 000000000000..8c6ed30b7654
--- /dev/null
+++ b/arch/powerpc/kvm/book3s_hv_pmu.c
@@ -0,0 +1,133 @@
+// 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 = {
+ .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,
+};
+
+int 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;
+}
+EXPORT_SYMBOL_GPL(kvmppc_register_pmu);
+
+void kvmppc_unregister_pmu(void)
+{
+ if (kvmhv_is_nestedv2()) {
+ if (kvmppc_pmu.type != -1)
+ perf_pmu_unregister(&kvmppc_pmu);
+
+ pr_info("kvmhv_pmu unregistered.\n");
+ }
+}
+EXPORT_SYMBOL_GPL(kvmppc_unregister_pmu);
--
2.48.1
