On 2015/12/1 2:22, Marc Zyngier wrote:
> On Fri, 30 Oct 2015 14:22:00 +0800
> Shannon Zhao <zhaoshenglong@xxxxxxxxxx> wrote:
>
>> From: Shannon Zhao <shannon.zhao@xxxxxxxxxx>
>>
>> When calling perf_event_create_kernel_counter to create perf_event,
>> assign a overflow handler. Then when perf event overflows, set
>> irq_pending and call kvm_vcpu_kick() to sync the interrupt.
>>
>> Signed-off-by: Shannon Zhao <shannon.zhao@xxxxxxxxxx>
>> ---
>> arch/arm/kvm/arm.c | 4 +++
>> include/kvm/arm_pmu.h | 4 +++
>> virt/kvm/arm/pmu.c | 76 ++++++++++++++++++++++++++++++++++++++++++++++++++-
>> 3 files changed, 83 insertions(+), 1 deletion(-)
>>
>> diff --git a/arch/arm/kvm/arm.c b/arch/arm/kvm/arm.c
>> index 78b2869..9c0fec4 100644
>> --- a/arch/arm/kvm/arm.c
>> +++ b/arch/arm/kvm/arm.c
>> @@ -28,6 +28,7 @@
>> #include <linux/sched.h>
>> #include <linux/kvm.h>
>> #include <trace/events/kvm.h>
>> +#include <kvm/arm_pmu.h>
>>
>> #define CREATE_TRACE_POINTS
>> #include "trace.h"
>> @@ -551,6 +552,7 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu, struct kvm_run *run)
>>
>> if (ret <= 0 || need_new_vmid_gen(vcpu->kvm)) {
>> local_irq_enable();
>> + kvm_pmu_sync_hwstate(vcpu);
>
> This is very weird. Are you only injecting interrupts when a signal is
> pending? I don't understand how this works...
>
>> kvm_vgic_sync_hwstate(vcpu);
>> preempt_enable();
>> kvm_timer_sync_hwstate(vcpu);
>> @@ -598,6 +600,8 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu, struct kvm_run *run)
>> kvm_guest_exit();
>> trace_kvm_exit(kvm_vcpu_trap_get_class(vcpu), *vcpu_pc(vcpu));
>>
>> + kvm_pmu_post_sync_hwstate(vcpu);
>> +
>> kvm_vgic_sync_hwstate(vcpu);
>>
>> preempt_enable();
>> diff --git a/include/kvm/arm_pmu.h b/include/kvm/arm_pmu.h
>> index acd025a..5e7f943 100644
>> --- a/include/kvm/arm_pmu.h
>> +++ b/include/kvm/arm_pmu.h
>> @@ -39,6 +39,8 @@ struct kvm_pmu {
>> };
>>
>> #ifdef CONFIG_KVM_ARM_PMU
>> +void kvm_pmu_sync_hwstate(struct kvm_vcpu *vcpu);
>> +void kvm_pmu_post_sync_hwstate(struct kvm_vcpu *vcpu);
>
> Please follow the current terminology: _flush_ on VM entry, _sync_ on
> VM exit.
>
Hi Marc,
Is below patch the right way for this?
diff --git a/arch/arm/kvm/arm.c b/arch/arm/kvm/arm.c
index 78b2869..84008d1 100644
--- a/arch/arm/kvm/arm.c
+++ b/arch/arm/kvm/arm.c
@@ -28,6 +28,7 @@
#include <linux/sched.h>
#include <linux/kvm.h>
#include <trace/events/kvm.h>
+#include <kvm/arm_pmu.h>
#define CREATE_TRACE_POINTS
#include "trace.h"
@@ -531,6 +532,8 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu,
struct kvm_run *run)
*/
kvm_timer_flush_hwstate(vcpu);
+ kvm_pmu_flush_hwstate(vcpu);
+
/*
* Preparing the interrupts to be injected also
* involves poking the GIC, which must be done in a
@@ -554,6 +557,7 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu,
struct kvm_run *run)
kvm_vgic_sync_hwstate(vcpu);
preempt_enable();
kvm_timer_sync_hwstate(vcpu);
+ kvm_pmu_sync_hwstate(vcpu);
continue;
}
@@ -604,6 +608,8 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu,
struct kvm_run *run)
kvm_timer_sync_hwstate(vcpu);
+ kvm_pmu_sync_hwstate(vcpu);
+
ret = handle_exit(vcpu, run, ret);
}
diff --git a/include/kvm/arm_pmu.h b/include/kvm/arm_pmu.h
index 47bbd43..edfe4e5 100644
--- a/include/kvm/arm_pmu.h
+++ b/include/kvm/arm_pmu.h
@@ -41,6 +41,8 @@ struct kvm_pmu {
};
#ifdef CONFIG_KVM_ARM_PMU
+void kvm_pmu_flush_hwstate(struct kvm_vcpu *vcpu);
+void kvm_pmu_sync_hwstate(struct kvm_vcpu *vcpu);
unsigned long kvm_pmu_get_counter_value(struct kvm_vcpu *vcpu, u32
select_idx);
void kvm_pmu_disable_counter(struct kvm_vcpu *vcpu, u32 val);
void kvm_pmu_enable_counter(struct kvm_vcpu *vcpu, u32 val, bool
all_enable);
@@ -51,6 +53,8 @@ void kvm_pmu_set_counter_event_type(struct kvm_vcpu
*vcpu, u32 data,
u32 select_idx);
void kvm_pmu_handle_pmcr(struct kvm_vcpu *vcpu, u32 val);
#else
+void kvm_pmu_flush_hwstate(struct kvm_vcpu *vcpu) {}
+void kvm_pmu_sync_hwstate(struct kvm_vcpu *vcpu) {}
unsigned long kvm_pmu_get_counter_value(struct kvm_vcpu *vcpu, u32
select_idx)
{
return 0;
diff --git a/virt/kvm/arm/pmu.c b/virt/kvm/arm/pmu.c
index 15cac45..9aad2f7 100644
--- a/virt/kvm/arm/pmu.c
+++ b/virt/kvm/arm/pmu.c
@@ -21,6 +21,7 @@
#include <linux/perf_event.h>
#include <asm/kvm_emulate.h>
#include <kvm/arm_pmu.h>
+#include <kvm/arm_vgic.h>
/**
* kvm_pmu_get_counter_value - get PMU counter value
@@ -79,6 +80,78 @@ static void kvm_pmu_stop_counter(struct kvm_pmc *pmc)
}
/**
+ * kvm_pmu_flush_hwstate - flush pmu state to cpu
+ * @vcpu: The vcpu pointer
+ *
+ * Inject virtual PMU IRQ if IRQ is pending for this cpu.
+ */
+void kvm_pmu_flush_hwstate(struct kvm_vcpu *vcpu)
+{
+ struct kvm_pmu *pmu = &vcpu->arch.pmu;
+ u32 overflow;
+
+ if (!vcpu_mode_is_32bit(vcpu))
+ overflow = vcpu_sys_reg(vcpu, PMOVSSET_EL0);
+ else
+ overflow = vcpu_cp15(vcpu, c9_PMOVSSET);
+
+ if ((pmu->irq_pending || overflow != 0) && (pmu->irq_num != -1))
+ kvm_vgic_inject_irq(vcpu->kvm, vcpu->vcpu_id,
pmu->irq_num, 1);
+
+ pmu->irq_pending = false;
+}
+
+/**
+ * kvm_pmu_sync_hwstate - sync pmu state for cpu
+ * @vcpu: The vcpu pointer
+ *
+ * Inject virtual PMU IRQ if IRQ is pending for this cpu when back from
guest.
+ */
+void kvm_pmu_sync_hwstate(struct kvm_vcpu *vcpu)
+{
+ struct kvm_pmu *pmu = &vcpu->arch.pmu;
+
+ if (pmu->irq_pending && (pmu->irq_num != -1))
+ kvm_vgic_inject_irq(vcpu->kvm, vcpu->vcpu_id,
pmu->irq_num, 1);
+
+ pmu->irq_pending = false;
+}
--
Shannon
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