* [PATCH V2 4/5] ara virt interface of perf to support kvm guest os statistics collection in guest os
@ 2010-06-21 9:31 Zhang, Yanmin
2010-06-22 8:24 ` Jes Sorensen
0 siblings, 1 reply; 3+ messages in thread
From: Zhang, Yanmin @ 2010-06-21 9:31 UTC (permalink / raw)
To: LKML, kvm, Avi Kivity
Cc: Ingo Molnar, Fr??d??ric Weisbecker, Arnaldo Carvalho de Melo,
Cyrill Gorcunov, Lin Ming, Sheng Yang, Marcelo Tosatti,
oerg Roedel, Jes Sorensen, Gleb Natapov, Zachary Amsden,
zhiteng.huang, tim.c.chen
The 4th patch is to implement para virt perf at guest side.
Signed-off-by: Zhang Yanmin <yanmin_zhang@linux.intel.com>
---
--- linux-2.6_tip0620/arch/x86/Kconfig 2010-06-21 15:19:39.180999849 +0800
+++ linux-2.6_tip0620perfkvm/arch/x86/Kconfig 2010-06-21 15:21:39.309999849 +0800
@@ -552,6 +552,14 @@ config KVM_GUEST
This option enables various optimizations for running under the KVM
hypervisor.
+config KVM_PERF
+ bool "KVM Guest perf support"
+ select PARAVIRT
+ select PERF_EVENT
+ ---help---
+ This option enables various optimizations for running perf in
+ guest os under the KVM hypervisor.
+
source "arch/x86/lguest/Kconfig"
config PARAVIRT
--- linux-2.6_tip0620/arch/x86/kernel/cpu/perf_event.c 2010-06-21 15:19:39.964999849 +0800
+++ linux-2.6_tip0620perfkvm/arch/x86/kernel/cpu/perf_event.c 2010-06-21 16:44:36.602999849 +0800
@@ -25,6 +25,7 @@
#include <linux/highmem.h>
#include <linux/cpu.h>
#include <linux/bitops.h>
+#include <linux/kvm_para.h>
#include <asm/apic.h>
#include <asm/stacktrace.h>
@@ -583,10 +584,20 @@ static void x86_pmu_disable_all(void)
}
}
+#ifdef CONFIG_KVM_PERF
+static int kvm_hw_perf_enable(void);
+static int kvm_hw_perf_disable(void);
+#endif
+
void hw_perf_disable(void)
{
struct cpu_hw_events *cpuc = &__get_cpu_var(cpu_hw_events);
+#ifdef CONFIG_KVM_PERF
+ if (!kvm_hw_perf_disable())
+ return;
+#endif
+
if (!x86_pmu_initialized())
return;
@@ -810,6 +821,11 @@ void hw_perf_enable(void)
struct hw_perf_event *hwc;
int i, added = cpuc->n_added;
+#ifdef CONFIG_KVM_PERF
+ if (!kvm_hw_perf_enable())
+ return;
+#endif
+
if (!x86_pmu_initialized())
return;
@@ -1264,6 +1280,7 @@ x86_get_event_constraints(struct cpu_hw_
#include "perf_event_intel_lbr.c"
#include "perf_event_intel_ds.c"
#include "perf_event_intel.c"
+#include "perf_event_kvm.c"
static int __cpuinit
x86_pmu_notifier(struct notifier_block *self, unsigned long action, void *hcpu)
@@ -1317,6 +1334,11 @@ void __init init_hw_perf_events(void)
pr_info("Performance Events: ");
+#ifdef CONFIG_KVM_PERF
+ if (!kvm_init_hw_perf_events())
+ return;
+#endif
+
switch (boot_cpu_data.x86_vendor) {
case X86_VENDOR_INTEL:
err = intel_pmu_init();
@@ -1541,6 +1563,13 @@ const struct pmu *hw_perf_event_init(str
const struct pmu *tmp;
int err;
+#ifdef CONFIG_KVM_PERF
+ if (kvm_para_available()) {
+ tmp = kvm_hw_perf_event_init(event);
+ return tmp;
+ }
+#endif
+
err = __hw_perf_event_init(event);
if (!err) {
/*
--- linux-2.6_tip0620/arch/x86/kernel/cpu/perf_event_kvm.c 1970-01-01 08:00:00.000000000 +0800
+++ linux-2.6_tip0620perfkvm/arch/x86/kernel/cpu/perf_event_kvm.c 2010-06-21 16:44:56.735999849 +0800
@@ -0,0 +1,426 @@
+/*
+ * Performance events
+ *
+ * Copyright (C) 2010 Intel Corporation
+ * Zhang Yanmin <yanmin.zhang@intel.com>
+ *
+ * For licencing details see kernel-base/COPYING
+ */
+
+#ifdef CONFIG_KVM_PERF
+
+static atomic_t guest_perf_id; /*Global id counter per guest os*/
+
+static inline int get_new_perf_event_id(void)
+{
+ return atomic_inc_return(&guest_perf_id);
+}
+
+#ifdef CONFIG_X86_LOCAL_APIC
+
+static bool kvm_reserve_pmc_hardware(void)
+{
+ if (nmi_watchdog == NMI_LOCAL_APIC)
+ disable_lapic_nmi_watchdog();
+
+ return true;
+}
+
+static void kvm_release_pmc_hardware(void)
+{
+ if (nmi_watchdog == NMI_LOCAL_APIC)
+ enable_lapic_nmi_watchdog();
+}
+
+#else
+
+static bool kvm_reserve_pmc_hardware(void) { return true; }
+static void kvm_release_pmc_hardware(void) {}
+
+#endif
+
+static void kvm_hw_perf_event_destroy(struct perf_event *event)
+{
+ struct guest_perf_shadow *shadow = event->guest_perf_shadow;
+
+ BUG_ON(!shadow);
+ kvm_hypercall2(KVM_PERF_OP, KVM_PERF_OP_CLOSE, shadow->id);
+
+ kfree(shadow);
+ event->guest_perf_shadow = NULL;
+
+ if (atomic_dec_and_mutex_lock(&active_events, &pmc_reserve_mutex)) {
+ kvm_release_pmc_hardware();
+ mutex_unlock(&pmc_reserve_mutex);
+ }
+}
+
+/* The guest might also run as a host */
+static int check_ontop_guest_overflow(struct perf_event *event, int overflows)
+{
+ struct host_perf_shadow *host_shadow = event->host_perf_shadow;
+ if (!host_shadow)
+ return 0;
+
+ if (perf_guest_cbs)
+ perf_guest_cbs->copy_event_to_shadow(event, overflows);
+
+ return 1;
+}
+
+static int
+check_event_overflow(struct perf_event *event, struct pt_regs *regs)
+{
+ struct perf_sample_data data;
+ struct guest_perf_shadow *guest_shadow = event->guest_perf_shadow;
+ s32 overflows;
+ int i;
+ int handled = 0;
+
+ local64_set(&event->count, guest_shadow->counter.count);
+
+again:
+ overflows = atomic_read(&guest_shadow->counter.overflows);
+ if (atomic_cmpxchg(&guest_shadow->counter.overflows, overflows, 0) !=
+ overflows)
+ goto again;
+
+ if (check_ontop_guest_overflow(event, overflows)) {
+ handled = 1;
+ return handled;
+ }
+
+ for (i = 0; i < overflows; i++) {
+ perf_sample_data_init(&data, 0);
+
+ data.period = event->hw.last_period;
+
+ if (event->overflow_handler)
+ event->overflow_handler(event, 1, &data, regs);
+ else
+
+ perf_event_output(event, 1, &data, regs);
+
+ handled++;
+ }
+
+ return handled;
+}
+
+static int
+kvm_check_event_overflow(struct pt_regs *regs)
+{
+ struct cpu_hw_events *cpuc = &__get_cpu_var(cpu_hw_events);
+ struct perf_event *event;
+ int i, max_count;
+ int handled = 0;
+
+ max_count = X86_PMC_IDX_MAX;
+ for (i = 0; i < max_count; i++) {
+ event = cpuc->event_list[i];
+ if (event)
+ handled += check_event_overflow(event, regs);
+ }
+ return handled;
+}
+
+static DEFINE_PER_CPU(int, kvm_nmi_entered);
+
+static int kvm_x86_pmu_handle_irq(struct pt_regs *regs)
+{
+ int handled = 0;
+
+ if (percpu_read(kvm_nmi_entered))
+ return 0;
+
+ percpu_write(kvm_nmi_entered, 1);
+
+ handled = kvm_check_event_overflow(regs);
+ if (handled)
+ inc_irq_stat(apic_perf_irqs);
+
+ percpu_write(kvm_nmi_entered, 0);
+
+ return handled;
+}
+
+static int __kprobes
+kvm_perf_event_nmi_handler(struct notifier_block *self,
+ unsigned long cmd, void *__args)
+{
+ struct die_args *args = __args;
+ struct pt_regs *regs;
+
+ if (!atomic_read(&active_events))
+ return NOTIFY_DONE;
+
+ switch (cmd) {
+ case DIE_NMI:
+ case DIE_NMI_IPI:
+ break;
+
+ default:
+ return NOTIFY_DONE;
+ }
+
+ regs = args->regs;
+
+ kvm_x86_pmu_handle_irq(regs);
+
+ return NOTIFY_STOP;
+}
+
+static __read_mostly struct notifier_block kvm_perf_event_nmi_notifier = {
+ .notifier_call = kvm_perf_event_nmi_handler,
+ .next = NULL,
+ .priority = 1
+};
+
+static int kvm_add_event(struct perf_event *event)
+{
+ int i, max_count;
+ unsigned long flags;
+ struct cpu_hw_events *cpuc = &__get_cpu_var(cpu_hw_events);
+ int ret = -1;
+
+ local_irq_save(flags);
+ max_count = X86_PMC_IDX_MAX;
+
+ if (cpuc->n_events >= max_count) {
+ local_irq_restore(flags);
+ return -ENOSPC;
+ }
+ for (i = 0; i < max_count; i++) {
+ if (cpuc->event_list[i] == NULL) {
+ cpuc->event_list[i] = event;
+ cpuc->n_events++;
+ ret = 0;
+ break;
+ }
+ }
+ local_irq_restore(flags);
+ return ret;
+}
+
+static int kvm_del_event(struct perf_event *event)
+{
+ int i, max_count;
+ unsigned long flags;
+ struct cpu_hw_events *cpuc = &__get_cpu_var(cpu_hw_events);
+ int ret = -1;
+
+ local_irq_save(flags);
+ max_count = X86_PMC_IDX_MAX;
+ for (i = 0; i < max_count; i++) {
+ if (cpuc->event_list[i] == event) {
+ cpuc->event_list[i] = NULL;
+ cpuc->n_events--;
+ ret = 0;
+ break;
+ }
+ }
+ local_irq_restore(flags);
+ return ret;
+}
+
+static int kvm_pmu_enable(struct perf_event *event)
+{
+ int ret;
+ struct guest_perf_shadow *shadow = event->guest_perf_shadow;
+
+ if (kvm_add_event(event))
+ return -1;
+
+ ret = kvm_hypercall2(KVM_PERF_OP, KVM_PERF_OP_ENABLE, shadow->id);
+ return ret;
+}
+
+static void kvm_pmu_disable(struct perf_event *event)
+{
+ struct guest_perf_shadow *shadow = event->guest_perf_shadow;
+ kvm_hypercall2(KVM_PERF_OP, KVM_PERF_OP_DISABLE, shadow->id);
+ local64_set(&event->count, shadow->counter.count);
+ kvm_del_event(event);
+}
+
+static void kvm_pmu_read(struct perf_event *event)
+{
+ int ret;
+ struct guest_perf_shadow *shadow = event->guest_perf_shadow;
+ ret = kvm_hypercall2(KVM_PERF_OP, KVM_PERF_OP_READ, shadow->id);
+ if (!ret)
+ local64_set(&event->count, shadow->counter.count);
+ return;
+}
+
+static void kvm_pmu_unthrottle(struct perf_event *event)
+{
+ return;
+}
+
+static const struct pmu kvm_pmu = {
+ .enable = kvm_pmu_enable,
+ .disable = kvm_pmu_disable,
+ .start = kvm_pmu_enable,
+ .stop = kvm_pmu_disable,
+ .read = kvm_pmu_read,
+ .unthrottle = kvm_pmu_unthrottle,
+};
+
+static int kvm_default_x86_handle_irq(struct pt_regs *regs)
+{
+ return 1;
+}
+
+int __init kvm_init_hw_perf_events(void)
+{
+ if (!kvm_para_available())
+ return -1;
+
+ x86_pmu.handle_irq = kvm_default_x86_handle_irq;
+
+ pr_cont("KVM PARA PMU driver.\n");
+ register_die_notifier(&kvm_perf_event_nmi_notifier);
+
+ return 0;
+}
+
+static __u64 kvm_get_pte_phys(void *virt_addr)
+{
+ __u64 pte_phys;
+
+#ifdef CONFIG_HIGHPTE
+ struct page *page;
+ unsigned long dst = (unsigned long) virt_addr;
+
+ page = kmap_atomic_to_page(virt_addr);
+ pte_phys = page_to_pfn(page);
+ pte_phys <<= PAGE_SHIFT;
+ pte_phys += (dst & ~(PAGE_MASK));
+#else
+ pte_phys = (unsigned long)__pa(virt_addr);
+#endif
+ return pte_phys;
+}
+
+static int __kvm_hw_perf_event_init(struct perf_event *event)
+{
+ int err;
+ unsigned long result;
+ __u64 param_addr;
+ struct guest_perf_shadow *shadow = NULL;
+ struct guest_perf_event_param guest_param;
+ struct guest_perf_attr *attr = NULL;
+
+ err = 0;
+
+ attr = kzalloc(sizeof(*attr), GFP_KERNEL);
+ if (!attr) {
+ err = -ENOMEM;
+ goto out;
+ }
+
+ shadow = kzalloc(sizeof(*shadow), GFP_KERNEL);
+ if (!shadow) {
+ err = -ENOMEM;
+ goto out;
+ }
+
+ shadow->id = get_new_perf_event_id();
+ event->guest_perf_shadow = shadow;
+
+ if (!atomic_inc_not_zero(&active_events)) {
+ mutex_lock(&pmc_reserve_mutex);
+ if (atomic_read(&active_events) == 0) {
+ if (!kvm_reserve_pmc_hardware())
+ err = -EBUSY;
+ }
+ if (!err)
+ atomic_inc(&active_events);
+ mutex_unlock(&pmc_reserve_mutex);
+ if (err)
+ goto out;
+ }
+
+ event->destroy = kvm_hw_perf_event_destroy;
+ attr->type = event->attr.type;
+ attr->config = event->attr.config;
+ attr->sample_period = event->attr.sample_period;
+ attr->read_format = event->attr.read_format;
+ attr->flags = event->attr.flags;
+ attr->bp_type = event->attr.bp_type;
+ attr->bp_addr = event->attr.bp_addr;
+ attr->bp_len = event->attr.bp_len;
+
+ guest_param.id = shadow->id;
+ guest_param.attr_addr = kvm_get_pte_phys(attr);
+ guest_param.guest_event_addr = kvm_get_pte_phys(&shadow->counter);
+ param_addr = kvm_get_pte_phys(&guest_param);
+ result = kvm_hypercall3(KVM_PERF_OP, KVM_PERF_OP_OPEN,
+ (unsigned long) param_addr, param_addr >> 32);
+
+ if (result)
+ err = result;
+
+out:
+ if (err && shadow) {
+ kfree(shadow);
+ event->guest_perf_shadow = NULL;
+ }
+ kfree(attr);
+
+ return err;
+}
+
+const struct pmu *kvm_hw_perf_event_init(struct perf_event *event)
+{
+ int err;
+
+ if (!kvm_para_has_feature(KVM_FEATURE_PV_PERF))
+ return ERR_PTR(-ENOSYS);
+
+ err = __kvm_hw_perf_event_init(event);
+ if (err)
+ return ERR_PTR(err);
+
+ return &kvm_pmu;
+}
+
+static int kvm_hw_perf_enable(void)
+{
+ struct cpu_hw_events *cpuc = &__get_cpu_var(cpu_hw_events);
+
+ if (!kvm_para_available())
+ return -1;
+
+ if (cpuc->enabled)
+ return 0;
+
+ if (cpuc->n_added)
+ cpuc->n_added = 0;
+
+ cpuc->enabled = 1;
+ barrier();
+
+ return 0;
+}
+
+static int kvm_hw_perf_disable(void)
+{
+ struct cpu_hw_events *cpuc = &__get_cpu_var(cpu_hw_events);
+
+ if (!kvm_para_available())
+ return -1;
+
+ if (!cpuc->enabled)
+ return 0;
+
+ cpuc->n_added = 0;
+ cpuc->enabled = 0;
+ barrier();
+
+ return 0;
+}
+
+#endif
+
--- linux-2.6_tip0620/Documentation/kvm/cpuid.txt 2010-06-21 15:19:26.199999849 +0800
+++ linux-2.6_tip0620perfkvm/Documentation/kvm/cpuid.txt 2010-06-21 15:21:39.312999849 +0800
@@ -36,6 +36,9 @@ KVM_FEATURE_MMU_OP ||
KVM_FEATURE_CLOCKSOURCE2 || 3 || kvmclock available at msrs
|| || 0x4b564d00 and 0x4b564d01
------------------------------------------------------------------------------
+KVM_FEATURE_PV_PERF || 4 || kvm paravirt perf event
+ || || available
+------------------------------------------------------------------------------
KVM_FEATURE_CLOCKSOURCE_STABLE_BIT || 24 || host will warn if no guest-side
|| || per-cpu warps are expected in
|| || kvmclock.
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH V2 4/5] ara virt interface of perf to support kvm guest os statistics collection in guest os
2010-06-21 9:31 [PATCH V2 4/5] ara virt interface of perf to support kvm guest os statistics collection in guest os Zhang, Yanmin
@ 2010-06-22 8:24 ` Jes Sorensen
2010-06-22 9:10 ` Zhang, Yanmin
0 siblings, 1 reply; 3+ messages in thread
From: Jes Sorensen @ 2010-06-22 8:24 UTC (permalink / raw)
To: Zhang, Yanmin
Cc: LKML, kvm, Avi Kivity, Ingo Molnar, Fr??d??ric Weisbecker,
Arnaldo Carvalho de Melo, Cyrill Gorcunov, Lin Ming, Sheng Yang,
Marcelo Tosatti, oerg Roedel, Gleb Natapov, Zachary Amsden,
zhiteng.huang, tim.c.chen
On 06/21/10 11:31, Zhang, Yanmin wrote:
> @@ -583,10 +584,20 @@ static void x86_pmu_disable_all(void)
> }
> }
>
> +#ifdef CONFIG_KVM_PERF
> +static int kvm_hw_perf_enable(void);
> +static int kvm_hw_perf_disable(void);
> +#endif
Please put these prototypes into a header ... and create dummy stubs for
them when CONFIG_KVM_PERF is not set.
> void hw_perf_disable(void)
> {
> struct cpu_hw_events *cpuc = &__get_cpu_var(cpu_hw_events);
>
> +#ifdef CONFIG_KVM_PERF
> + if (!kvm_hw_perf_disable())
> + return;
> +#endif
If you stub them out we can avoid all the ugly #ifdefs
> @@ -810,6 +821,11 @@ void hw_perf_enable(void)
> struct hw_perf_event *hwc;
> int i, added = cpuc->n_added;
>
> +#ifdef CONFIG_KVM_PERF
> + if (!kvm_hw_perf_enable())
> + return;
> +#endif
and here....
> @@ -1317,6 +1334,11 @@ void __init init_hw_perf_events(void)
>
> pr_info("Performance Events: ");
>
> +#ifdef CONFIG_KVM_PERF
> + if (!kvm_init_hw_perf_events())
> + return;
> +#endif
and again here :)
Cheers,
Jes
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH V2 4/5] ara virt interface of perf to support kvm guest os statistics collection in guest os
2010-06-22 8:24 ` Jes Sorensen
@ 2010-06-22 9:10 ` Zhang, Yanmin
0 siblings, 0 replies; 3+ messages in thread
From: Zhang, Yanmin @ 2010-06-22 9:10 UTC (permalink / raw)
To: Jes Sorensen
Cc: LKML, kvm, Avi Kivity, Ingo Molnar, Fr??d??ric Weisbecker,
Arnaldo Carvalho de Melo, Cyrill Gorcunov, Lin Ming, Sheng Yang,
Marcelo Tosatti, oerg Roedel, Gleb Natapov, Zachary Amsden,
zhiteng.huang, tim.c.chen, Peter Zijlstra
On Tue, 2010-06-22 at 10:24 +0200, Jes Sorensen wrote:
> On 06/21/10 11:31, Zhang, Yanmin wrote:
> > @@ -583,10 +584,20 @@ static void x86_pmu_disable_all(void)
> > }
> > }
> >
> > +#ifdef CONFIG_KVM_PERF
> > +static int kvm_hw_perf_enable(void);
> > +static int kvm_hw_perf_disable(void);
> > +#endif
>
> Please put these prototypes into a header ... and create dummy stubs for
> them when CONFIG_KVM_PERF is not set.
Ok. I just didn't want to touch too much generic codes of perf.
>
> > void hw_perf_disable(void)
> > {
> > struct cpu_hw_events *cpuc = &__get_cpu_var(cpu_hw_events);
> >
> > +#ifdef CONFIG_KVM_PERF
> > + if (!kvm_hw_perf_disable())
> > + return;
> > +#endif
>
> If you stub them out we can avoid all the ugly #ifdefs
Ok.
>
> > @@ -810,6 +821,11 @@ void hw_perf_enable(void)
> > struct hw_perf_event *hwc;
> > int i, added = cpuc->n_added;
> >
> > +#ifdef CONFIG_KVM_PERF
> > + if (!kvm_hw_perf_enable())
> > + return;
> > +#endif
>
> and here....
Ok.
>
> > @@ -1317,6 +1334,11 @@ void __init init_hw_perf_events(void)
> >
> > pr_info("Performance Events: ");
> >
> > +#ifdef CONFIG_KVM_PERF
> > + if (!kvm_init_hw_perf_events())
> > + return;
> > +#endif
>
> and again here :)
Ok. Peter is working out a couple of patches to support multiple PMU. His patches
change pmu difition and we might move some into the callbacks. That will become
much clearer.
Yanmin
^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2010-06-22 9:10 UTC | newest]
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2010-06-21 9:31 [PATCH V2 4/5] ara virt interface of perf to support kvm guest os statistics collection in guest os Zhang, Yanmin
2010-06-22 8:24 ` Jes Sorensen
2010-06-22 9:10 ` Zhang, Yanmin
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