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.
> 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);
> @@ -49,6 +51,8 @@ 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_sync_hwstate(struct kvm_vcpu *vcpu) {}
> +void kvm_pmu_post_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 11d1bfb..6d48d9a 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
> @@ -69,6 +70,78 @@ static void kvm_pmu_stop_counter(struct kvm_pmc *pmc)
> }
>
> /**
> + * kvm_pmu_sync_hwstate - sync pmu state for cpu
> + * @vcpu: The vcpu pointer
> + *
> + * Inject virtual PMU IRQ if IRQ is pending for this cpu.
> + */
> +void kvm_pmu_sync_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_post_sync_hwstate - post 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_post_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;
> +}
> +
> +/**
> + * When perf event overflows, set irq_pending and call kvm_vcpu_kick() to inject
> + * the interrupt.
> + */
> +static void kvm_pmu_perf_overflow(struct perf_event *perf_event,
> + struct perf_sample_data *data,
> + struct pt_regs *regs)
> +{
> + struct kvm_pmc *pmc = perf_event->overflow_handler_context;
> + struct kvm_vcpu *vcpu = pmc->vcpu;
> + struct kvm_pmu *pmu = &vcpu->arch.pmu;
> + int idx = pmc->idx;
> +
> + if (!vcpu_mode_is_32bit(vcpu)) {
> + if ((vcpu_sys_reg(vcpu, PMINTENSET_EL1) >> idx) & 0x1) {
> + __set_bit(idx,
> + (unsigned long *)&vcpu_sys_reg(vcpu, PMOVSSET_EL0));
> + __set_bit(idx,
> + (unsigned long *)&vcpu_sys_reg(vcpu, PMOVSCLR_EL0));
> + pmu->irq_pending = true;
> + kvm_vcpu_kick(vcpu);
> + }
> + } else {
> + if ((vcpu_cp15(vcpu, c9_PMINTENSET) >> idx) & 0x1) {
> + __set_bit(idx,
> + (unsigned long *)&vcpu_cp15(vcpu, c9_PMOVSSET));
> + __set_bit(idx,
> + (unsigned long *)&vcpu_cp15(vcpu, c9_PMOVSCLR));
> + pmu->irq_pending = true;
> + kvm_vcpu_kick(vcpu);
There is some obvious code factorization that can be done here.
> + }
> + }
> +}
> +
> +/**
> * kvm_pmu_enable_counter - enable selected PMU counter
> * @vcpu: The vcpu pointer
> * @val: the value guest writes to PMCNTENSET register
> @@ -293,7 +366,8 @@ void kvm_pmu_set_counter_event_type(struct kvm_vcpu *vcpu, u32 data,
> /* The initial sample period (overflow count) of an event. */
> attr.sample_period = (-counter) & pmc->bitmask;
>
> - event = perf_event_create_kernel_counter(&attr, -1, current, NULL, pmc);
> + event = perf_event_create_kernel_counter(&attr, -1, current,
> + kvm_pmu_perf_overflow, pmc);
> if (IS_ERR(event)) {
> printk_once("kvm: pmu event creation failed %ld\n",
> PTR_ERR(event));
Thanks,
M.
--
Jazz is not dead. It just smells funny.
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