[PATCH v9 0/5] arm64: Support perf event modifiers :G and :H

[PATCH v9 0/5] arm64: Support perf event modifiers :G and :H

[Andrew Murray]

This patchset provides support for perf event modifiers :G and :H which
allows for filtering of PMU events between host and guests when used
with KVM.

As the underlying hardware cannot distinguish between guest and host
context, the performance counters must be stopped and started upon
entry/exit to the guest. This is performed at EL2 in a way that
minimizes overhead and improves accuracy of recording events that only
occur in the requested context.

This has been tested with VHE and non-VHE kernels with a KVM guest.

Changes from v8:

 - Added additional comments
 - Fixed bisect build failure
 - Renamed cpu_ctxt variable to cpu_data

Changes from v7:

 - Added additional patch to encapsulate kvm_cpu_context in kvm_host_data

Changes from v6:

 - Move events_host/events_guest out of kvm_cpu_context

Changes from v5:

 - Tweak logic in use of kvm_set_pmu_events

Changes from v4:

 - Prevent unnecessary write_sysreg calls by improving
   __pmu_switch_to_xxx logic.

Changes from v3:

 - Remove confusing _only suffix from bitfields in kvm_cpu_context
 - Remove unnecessary condition when clearing event bits in disable
 - Simplify API of KVM accessors
 - Prevent unnecessary setting of pmcnten when guest/host events are
   the same.

Changes from v2:

 - Ensured that exclude_kernel works for guest
 - Removed unnecessary exclusion of EL2 with exclude_host on !VHE
 - Renamed kvm_clr_set_host_pmu_events to reflect args order
 - Added additional information to isb patch

Changes from v1:

 - Removed unnecessary exclusion of EL1 with exclude_guest on VHE
 - Removed unnecessary isb from existing perf_event.c driver
 - Folded perf_event.c patches together
 - Added additional information to last patch commit message


Andrew Murray (5):
  arm64: arm_pmu: remove unnecessary isb instruction
  arm64: KVM: encapsulate kvm_cpu_context in kvm_host_data
  arm64: KVM: add accessors to track guest/host only counters
  arm64: arm_pmu: Add support for exclude_host/exclude_guest attributes
  arm64: KVM: Enable support for :G/:H perf event modifiers

 arch/arm/include/asm/kvm_host.h   |  8 ++++--
 arch/arm64/include/asm/kvm_asm.h  |  4 +--
 arch/arm64/include/asm/kvm_host.h | 42 +++++++++++++++++++++++----
 arch/arm64/kernel/asm-offsets.c   |  2 +-
 arch/arm64/kernel/perf_event.c    | 54 +++++++++++++++++++++++++++++------
 arch/arm64/kvm/hyp/switch.c       | 60 +++++++++++++++++++++++++++++++++++++++
 virt/kvm/arm/arm.c                | 12 ++++----
 7 files changed, 159 insertions(+), 23 deletions(-)

-- 
2.7.4

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[PATCH v9 1/5] arm64: arm_pmu: remove unnecessary isb instruction

[Andrew Murray]

The armv8pmu_enable_event_counter function issues an isb instruction
after enabling a pair of counters - this doesn't provide any value
and is inconsistent with the armv8pmu_disable_event_counter.

In any case armv8pmu_enable_event_counter is always called with the
PMU stopped. Starting the PMU with armv8pmu_start results in an isb
instruction being issued prior to writing to PMCR_EL0.

Let's remove the unnecessary isb instruction.

Signed-off-by: Andrew Murray <andrew.murray@arm.com>
Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Acked-by: Mark Rutland <mark.rutland@arm.com>
---
 arch/arm64/kernel/perf_event.c | 1 -
 1 file changed, 1 deletion(-)

diff --git a/arch/arm64/kernel/perf_event.c b/arch/arm64/kernel/perf_event.c
index 8e38d52..de564ae 100644
--- a/arch/arm64/kernel/perf_event.c
+++ b/arch/arm64/kernel/perf_event.c
@@ -652,7 +652,6 @@ static inline void armv8pmu_enable_event_counter(struct perf_event *event)
 	armv8pmu_enable_counter(idx);
 	if (armv8pmu_event_is_chained(event))
 		armv8pmu_enable_counter(idx - 1);
-	isb();
 }
 
 static inline int armv8pmu_disable_counter(int idx)
-- 
2.7.4


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[PATCH v9 2/5] arm64: KVM: encapsulate kvm_cpu_context in kvm_host_data

[Andrew Murray]

The virt/arm core allocates a kvm_cpu_context_t percpu, at present this is
a typedef to kvm_cpu_context and is used to store host cpu context. The
kvm_cpu_context structure is also used elsewhere to hold vcpu context.
In order to use the percpu to hold additional future host information we
encapsulate kvm_cpu_context in a new structure and rename the typedef and
percpu to match.

Signed-off-by: Andrew Murray <andrew.murray@arm.com>
---
 arch/arm/include/asm/kvm_host.h   |  8 ++++++--
 arch/arm64/include/asm/kvm_asm.h  |  4 ++--
 arch/arm64/include/asm/kvm_host.h | 14 +++++++++-----
 arch/arm64/kernel/asm-offsets.c   |  2 +-
 virt/kvm/arm/arm.c                | 12 +++++++-----
 5 files changed, 25 insertions(+), 15 deletions(-)

diff --git a/arch/arm/include/asm/kvm_host.h b/arch/arm/include/asm/kvm_host.h
index 79906ce..71645ba 100644
--- a/arch/arm/include/asm/kvm_host.h
+++ b/arch/arm/include/asm/kvm_host.h
@@ -145,7 +145,11 @@ struct kvm_cpu_context {
 	u32 cp15[NR_CP15_REGS];
 };
 
-typedef struct kvm_cpu_context kvm_cpu_context_t;
+struct kvm_host_data {
+	struct kvm_cpu_context host_ctxt;
+};
+
+typedef struct kvm_host_data kvm_host_data_t;
 
 struct kvm_vcpu_arch {
 	struct kvm_cpu_context ctxt;
@@ -163,7 +167,7 @@ struct kvm_vcpu_arch {
 	struct kvm_vcpu_fault_info fault;
 
 	/* Host FP context */
-	kvm_cpu_context_t *host_cpu_context;
+	struct kvm_cpu_context *host_cpu_context;
 
 	/* VGIC state */
 	struct vgic_cpu vgic_cpu;
diff --git a/arch/arm64/include/asm/kvm_asm.h b/arch/arm64/include/asm/kvm_asm.h
index 102b5a5..6a9bfd4 100644
--- a/arch/arm64/include/asm/kvm_asm.h
+++ b/arch/arm64/include/asm/kvm_asm.h
@@ -102,12 +102,12 @@ extern u32 __init_stage2_translation(void);
 .endm
 
 .macro get_host_ctxt reg, tmp
-	hyp_adr_this_cpu \reg, kvm_host_cpu_state, \tmp
+	hyp_adr_this_cpu \reg, kvm_host_data, \tmp
 .endm
 
 .macro get_vcpu_ptr vcpu, ctxt
 	get_host_ctxt \ctxt, \vcpu
-	ldr	\vcpu, [\ctxt, #HOST_CONTEXT_VCPU]
+	ldr	\vcpu, [\ctxt, #HOST_DATA_VCPU]
 	kern_hyp_va	\vcpu
 .endm
 
diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h
index 1550192..9ab4b13 100644
--- a/arch/arm64/include/asm/kvm_host.h
+++ b/arch/arm64/include/asm/kvm_host.h
@@ -205,7 +205,11 @@ struct kvm_cpu_context {
 	struct kvm_vcpu *__hyp_running_vcpu;
 };
 
-typedef struct kvm_cpu_context kvm_cpu_context_t;
+struct kvm_host_data {
+	struct kvm_cpu_context host_ctxt;
+};
+
+typedef struct kvm_host_data kvm_host_data_t;
 
 struct kvm_vcpu_arch {
 	struct kvm_cpu_context ctxt;
@@ -241,7 +245,7 @@ struct kvm_vcpu_arch {
 	struct kvm_guest_debug_arch external_debug_state;
 
 	/* Pointer to host CPU context */
-	kvm_cpu_context_t *host_cpu_context;
+	struct kvm_cpu_context *host_cpu_context;
 
 	struct thread_info *host_thread_info;	/* hyp VA */
 	struct user_fpsimd_state *host_fpsimd_state;	/* hyp VA */
@@ -387,7 +391,7 @@ void kvm_set_sei_esr(struct kvm_vcpu *vcpu, u64 syndrome);
 
 struct kvm_vcpu *kvm_mpidr_to_vcpu(struct kvm *kvm, unsigned long mpidr);
 
-DECLARE_PER_CPU(kvm_cpu_context_t, kvm_host_cpu_state);
+DECLARE_PER_CPU(kvm_host_data_t, kvm_host_data);
 
 void __kvm_enable_ssbs(void);
 
@@ -400,8 +404,8 @@ static inline void __cpu_init_hyp_mode(phys_addr_t pgd_ptr,
 	 * kernel's mapping to the linear mapping, and store it in tpidr_el2
 	 * so that we can use adr_l to access per-cpu variables in EL2.
 	 */
-	u64 tpidr_el2 = ((u64)this_cpu_ptr(&kvm_host_cpu_state) -
-			 (u64)kvm_ksym_ref(kvm_host_cpu_state));
+	u64 tpidr_el2 = ((u64)this_cpu_ptr(&kvm_host_data) -
+			 (u64)kvm_ksym_ref(kvm_host_data));
 
 	/*
 	 * Call initialization code, and switch to the full blown HYP code.
diff --git a/arch/arm64/kernel/asm-offsets.c b/arch/arm64/kernel/asm-offsets.c
index 323aeb5..cb968ff 100644
--- a/arch/arm64/kernel/asm-offsets.c
+++ b/arch/arm64/kernel/asm-offsets.c
@@ -142,7 +142,7 @@ int main(void)
   DEFINE(CPU_FP_REGS,		offsetof(struct kvm_regs, fp_regs));
   DEFINE(VCPU_FPEXC32_EL2,	offsetof(struct kvm_vcpu, arch.ctxt.sys_regs[FPEXC32_EL2]));
   DEFINE(VCPU_HOST_CONTEXT,	offsetof(struct kvm_vcpu, arch.host_cpu_context));
-  DEFINE(HOST_CONTEXT_VCPU,	offsetof(struct kvm_cpu_context, __hyp_running_vcpu));
+  DEFINE(HOST_DATA_VCPU,	offsetof(struct kvm_host_data, host_ctxt.__hyp_running_vcpu));
 #endif
 #ifdef CONFIG_CPU_PM
   DEFINE(CPU_SUSPEND_SZ,	sizeof(struct cpu_suspend_ctx));
diff --git a/virt/kvm/arm/arm.c b/virt/kvm/arm/arm.c
index 150c8a6..160ab30 100644
--- a/virt/kvm/arm/arm.c
+++ b/virt/kvm/arm/arm.c
@@ -56,7 +56,7 @@
 __asm__(".arch_extension	virt");
 #endif
 
-DEFINE_PER_CPU(kvm_cpu_context_t, kvm_host_cpu_state);
+DEFINE_PER_CPU(kvm_host_data_t, kvm_host_data);
 static DEFINE_PER_CPU(unsigned long, kvm_arm_hyp_stack_page);
 
 /* Per-CPU variable containing the currently running vcpu. */
@@ -361,8 +361,10 @@ int kvm_arch_vcpu_init(struct kvm_vcpu *vcpu)
 void kvm_arch_vcpu_load(struct kvm_vcpu *vcpu, int cpu)
 {
 	int *last_ran;
+	kvm_host_data_t *cpu_data;
 
 	last_ran = this_cpu_ptr(vcpu->kvm->arch.last_vcpu_ran);
+	cpu_data = this_cpu_ptr(&kvm_host_data);
 
 	/*
 	 * We might get preempted before the vCPU actually runs, but
@@ -374,7 +376,7 @@ void kvm_arch_vcpu_load(struct kvm_vcpu *vcpu, int cpu)
 	}
 
 	vcpu->cpu = cpu;
-	vcpu->arch.host_cpu_context = this_cpu_ptr(&kvm_host_cpu_state);
+	vcpu->arch.host_cpu_context = &cpu_data->host_ctxt;
 
 	kvm_arm_set_running_vcpu(vcpu);
 	kvm_vgic_load(vcpu);
@@ -1547,10 +1549,10 @@ static int init_hyp_mode(void)
 	}
 
 	for_each_possible_cpu(cpu) {
-		kvm_cpu_context_t *cpu_ctxt;
+		kvm_host_data_t *cpu_data;
 
-		cpu_ctxt = per_cpu_ptr(&kvm_host_cpu_state, cpu);
-		err = create_hyp_mappings(cpu_ctxt, cpu_ctxt + 1, PAGE_HYP);
+		cpu_data = per_cpu_ptr(&kvm_host_data, cpu);
+		err = create_hyp_mappings(cpu_data, cpu_data + 1, PAGE_HYP);
 
 		if (err) {
 			kvm_err("Cannot map host CPU state: %d\n", err);
-- 
2.7.4


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Re: [PATCH v9 2/5] arm64: KVM: encapsulate kvm_cpu_context in kvm_host_data

[Suzuki K Poulose]

Hi Andrew,

On 07/01/2019 14:41, Andrew Murray wrote:
> The virt/arm core allocates a kvm_cpu_context_t percpu, at present this is
> a typedef to kvm_cpu_context and is used to store host cpu context. The
> kvm_cpu_context structure is also used elsewhere to hold vcpu context.
> In order to use the percpu to hold additional future host information we
> encapsulate kvm_cpu_context in a new structure and rename the typedef and
> percpu to match.
> 
> Signed-off-by: Andrew Murray <andrew.murray@arm.com>
> ---
>   arch/arm/include/asm/kvm_host.h   |  8 ++++++--
>   arch/arm64/include/asm/kvm_asm.h  |  4 ++--
>   arch/arm64/include/asm/kvm_host.h | 14 +++++++++-----
>   arch/arm64/kernel/asm-offsets.c   |  2 +-
>   virt/kvm/arm/arm.c                | 12 +++++++-----
>   5 files changed, 25 insertions(+), 15 deletions(-)
> 
> diff --git a/arch/arm/include/asm/kvm_host.h b/arch/arm/include/asm/kvm_host.h
> index 79906ce..71645ba 100644
> --- a/arch/arm/include/asm/kvm_host.h
> +++ b/arch/arm/include/asm/kvm_host.h
> @@ -145,7 +145,11 @@ struct kvm_cpu_context {
>   	u32 cp15[NR_CP15_REGS];
>   };
>   
> -typedef struct kvm_cpu_context kvm_cpu_context_t;
> +struct kvm_host_data {
> +	struct kvm_cpu_context host_ctxt;
> +};
> +
> +typedef struct kvm_host_data kvm_host_data_t;
>   
>   struct kvm_vcpu_arch {
>   	struct kvm_cpu_context ctxt;
> @@ -163,7 +167,7 @@ struct kvm_vcpu_arch {
>   	struct kvm_vcpu_fault_info fault;
>   
>   	/* Host FP context */
> -	kvm_cpu_context_t *host_cpu_context;
> +	struct kvm_cpu_context *host_cpu_context;
>   
>   	/* VGIC state */
>   	struct vgic_cpu vgic_cpu;
> diff --git a/arch/arm64/include/asm/kvm_asm.h b/arch/arm64/include/asm/kvm_asm.h
> index 102b5a5..6a9bfd4 100644
> --- a/arch/arm64/include/asm/kvm_asm.h
> +++ b/arch/arm64/include/asm/kvm_asm.h
> @@ -102,12 +102,12 @@ extern u32 __init_stage2_translation(void);
>   .endm
>   
>   .macro get_host_ctxt reg, tmp
> -	hyp_adr_this_cpu \reg, kvm_host_cpu_state, \tmp
> +	hyp_adr_this_cpu \reg, kvm_host_data, \tmp
>   .endm

minor nit: We now load "kvm_host_data" instead of the host_ctxt here,
even though they both are same. Do we need to make this explicitly load
the address of the host_ctxt member to make sure this doesn't break
with future changes to the structure ?
i.e,
	add	\reg, \reg, #HOST_DATA_CONTEXT

Otherwise,

Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com>

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Re: [PATCH v9 2/5] arm64: KVM: encapsulate kvm_cpu_context in kvm_host_data

[Andrew Murray]

On Thu, Jan 10, 2019 at 11:36:01AM +0000, Suzuki K Poulose wrote:
> Hi Andrew,
> 
> On 07/01/2019 14:41, Andrew Murray wrote:
> > The virt/arm core allocates a kvm_cpu_context_t percpu, at present this is
> > a typedef to kvm_cpu_context and is used to store host cpu context. The
> > kvm_cpu_context structure is also used elsewhere to hold vcpu context.
> > In order to use the percpu to hold additional future host information we
> > encapsulate kvm_cpu_context in a new structure and rename the typedef and
> > percpu to match.
> > 
> > Signed-off-by: Andrew Murray <andrew.murray@arm.com>
> > ---
> >   arch/arm/include/asm/kvm_host.h   |  8 ++++++--
> >   arch/arm64/include/asm/kvm_asm.h  |  4 ++--
> >   arch/arm64/include/asm/kvm_host.h | 14 +++++++++-----
> >   arch/arm64/kernel/asm-offsets.c   |  2 +-
> >   virt/kvm/arm/arm.c                | 12 +++++++-----
> >   5 files changed, 25 insertions(+), 15 deletions(-)
> > 
> > diff --git a/arch/arm/include/asm/kvm_host.h b/arch/arm/include/asm/kvm_host.h
> > index 79906ce..71645ba 100644
> > --- a/arch/arm/include/asm/kvm_host.h
> > +++ b/arch/arm/include/asm/kvm_host.h
> > @@ -145,7 +145,11 @@ struct kvm_cpu_context {
> >   	u32 cp15[NR_CP15_REGS];
> >   };
> > -typedef struct kvm_cpu_context kvm_cpu_context_t;
> > +struct kvm_host_data {
> > +	struct kvm_cpu_context host_ctxt;
> > +};
> > +
> > +typedef struct kvm_host_data kvm_host_data_t;
> >   struct kvm_vcpu_arch {
> >   	struct kvm_cpu_context ctxt;
> > @@ -163,7 +167,7 @@ struct kvm_vcpu_arch {
> >   	struct kvm_vcpu_fault_info fault;
> >   	/* Host FP context */
> > -	kvm_cpu_context_t *host_cpu_context;
> > +	struct kvm_cpu_context *host_cpu_context;
> >   	/* VGIC state */
> >   	struct vgic_cpu vgic_cpu;
> > diff --git a/arch/arm64/include/asm/kvm_asm.h b/arch/arm64/include/asm/kvm_asm.h
> > index 102b5a5..6a9bfd4 100644
> > --- a/arch/arm64/include/asm/kvm_asm.h
> > +++ b/arch/arm64/include/asm/kvm_asm.h
> > @@ -102,12 +102,12 @@ extern u32 __init_stage2_translation(void);
> >   .endm
> >   .macro get_host_ctxt reg, tmp
> > -	hyp_adr_this_cpu \reg, kvm_host_cpu_state, \tmp
> > +	hyp_adr_this_cpu \reg, kvm_host_data, \tmp
> >   .endm
> 
> minor nit: We now load "kvm_host_data" instead of the host_ctxt here,
> even though they both are same. Do we need to make this explicitly load
> the address of the host_ctxt member to make sure this doesn't break
> with future changes to the structure ?
> i.e,
> 	add	\reg, \reg, #HOST_DATA_CONTEXT
> 
> Otherwise,
> 
> Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com>

Thanks for spotting this.

Are you happy for me to add the Reviewed-by tag if I squash in the following?

diff --git a/arch/arm64/include/asm/kvm_asm.h b/arch/arm64/include/asm/kvm_asm.h
index 6a9bfd4..f182d13 100644
--- a/arch/arm64/include/asm/kvm_asm.h
+++ b/arch/arm64/include/asm/kvm_asm.h
@@ -103,11 +103,12 @@ extern u32 __init_stage2_translation(void);
 
 .macro get_host_ctxt reg, tmp
        hyp_adr_this_cpu \reg, kvm_host_data, \tmp
+       add     \reg, \reg, #HOST_DATA_CONTEXT
 .endm
 
 .macro get_vcpu_ptr vcpu, ctxt
        get_host_ctxt \ctxt, \vcpu
-       ldr     \vcpu, [\ctxt, #HOST_DATA_VCPU]
+       ldr     \vcpu, [\ctxt, #HOST_CONTEXT_VCPU]
        kern_hyp_va     \vcpu
 .endm
 
diff --git a/arch/arm64/kernel/asm-offsets.c b/arch/arm64/kernel/asm-offsets.c
index cb968ff..0deddfb 100644
--- a/arch/arm64/kernel/asm-offsets.c
+++ b/arch/arm64/kernel/asm-offsets.c
@@ -142,7 +142,8 @@ int main(void)
   DEFINE(CPU_FP_REGS,          offsetof(struct kvm_regs, fp_regs));
   DEFINE(VCPU_FPEXC32_EL2,     offsetof(struct kvm_vcpu, arch.ctxt.sys_regs[FPEXC32_EL2]));
   DEFINE(VCPU_HOST_CONTEXT,    offsetof(struct kvm_vcpu, arch.host_cpu_context));
-  DEFINE(HOST_DATA_VCPU,       offsetof(struct kvm_host_data, host_ctxt.__hyp_running_vcpu));
+  DEFINE(HOST_CONTEXT_VCPU,    offsetof(struct kvm_cpu_context, __hyp_running_vcpu));
+  DEFINE(HOST_DATA_CONTEXT,    offsetof(struct kvm_host_data, host_ctxt));
 #endif
 #ifdef CONFIG_CPU_PM
   DEFINE(CPU_SUSPEND_SZ,       sizeof(struct cpu_suspend_ctx));


Thanks,

Andrew Murray

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Re: [PATCH v9 2/5] arm64: KVM: encapsulate kvm_cpu_context in kvm_host_data

[Suzuki K Poulose]

On 10/01/2019 15:16, Andrew Murray wrote:
> On Thu, Jan 10, 2019 at 11:36:01AM +0000, Suzuki K Poulose wrote:
>> Hi Andrew,
>>
>> On 07/01/2019 14:41, Andrew Murray wrote:
>>> The virt/arm core allocates a kvm_cpu_context_t percpu, at present this is
>>> a typedef to kvm_cpu_context and is used to store host cpu context. The
>>> kvm_cpu_context structure is also used elsewhere to hold vcpu context.
>>> In order to use the percpu to hold additional future host information we
>>> encapsulate kvm_cpu_context in a new structure and rename the typedef and
>>> percpu to match.
>>>
>>> Signed-off-by: Andrew Murray <andrew.murray@arm.com>
>>> ---
>>>    arch/arm/include/asm/kvm_host.h   |  8 ++++++--
>>>    arch/arm64/include/asm/kvm_asm.h  |  4 ++--
>>>    arch/arm64/include/asm/kvm_host.h | 14 +++++++++-----
>>>    arch/arm64/kernel/asm-offsets.c   |  2 +-
>>>    virt/kvm/arm/arm.c                | 12 +++++++-----
>>>    5 files changed, 25 insertions(+), 15 deletions(-)
>>>
>>> diff --git a/arch/arm/include/asm/kvm_host.h b/arch/arm/include/asm/kvm_host.h
>>> index 79906ce..71645ba 100644
>>> --- a/arch/arm/include/asm/kvm_host.h
>>> +++ b/arch/arm/include/asm/kvm_host.h
>>> @@ -145,7 +145,11 @@ struct kvm_cpu_context {
>>>    	u32 cp15[NR_CP15_REGS];
>>>    };
>>> -typedef struct kvm_cpu_context kvm_cpu_context_t;
>>> +struct kvm_host_data {
>>> +	struct kvm_cpu_context host_ctxt;
>>> +};
>>> +
>>> +typedef struct kvm_host_data kvm_host_data_t;
>>>    struct kvm_vcpu_arch {
>>>    	struct kvm_cpu_context ctxt;
>>> @@ -163,7 +167,7 @@ struct kvm_vcpu_arch {
>>>    	struct kvm_vcpu_fault_info fault;
>>>    	/* Host FP context */
>>> -	kvm_cpu_context_t *host_cpu_context;
>>> +	struct kvm_cpu_context *host_cpu_context;
>>>    	/* VGIC state */
>>>    	struct vgic_cpu vgic_cpu;
>>> diff --git a/arch/arm64/include/asm/kvm_asm.h b/arch/arm64/include/asm/kvm_asm.h
>>> index 102b5a5..6a9bfd4 100644
>>> --- a/arch/arm64/include/asm/kvm_asm.h
>>> +++ b/arch/arm64/include/asm/kvm_asm.h
>>> @@ -102,12 +102,12 @@ extern u32 __init_stage2_translation(void);
>>>    .endm
>>>    .macro get_host_ctxt reg, tmp
>>> -	hyp_adr_this_cpu \reg, kvm_host_cpu_state, \tmp
>>> +	hyp_adr_this_cpu \reg, kvm_host_data, \tmp
>>>    .endm
>>
>> minor nit: We now load "kvm_host_data" instead of the host_ctxt here,
>> even though they both are same. Do we need to make this explicitly load
>> the address of the host_ctxt member to make sure this doesn't break
>> with future changes to the structure ?
>> i.e,
>> 	add	\reg, \reg, #HOST_DATA_CONTEXT
>>
>> Otherwise,
>>
>> Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com>
> 
> Thanks for spotting this.
> 
> Are you happy for me to add the Reviewed-by tag if I squash in the following?

Yes, that looks fine to me.

Cheers
Suzuki

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[PATCH v9 3/5] arm64: KVM: add accessors to track guest/host only counters

[Andrew Murray]

In order to effeciently enable/disable guest/host only perf counters
at guest entry/exit we add bitfields to kvm_cpu_context for guest and
host events as well as accessors for updating them.

Signed-off-by: Andrew Murray <andrew.murray@arm.com>
Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com>
---
 arch/arm64/include/asm/kvm_host.h | 28 ++++++++++++++++++++++++++++
 1 file changed, 28 insertions(+)

diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h
index 9ab4b13..50f9d4c 100644
--- a/arch/arm64/include/asm/kvm_host.h
+++ b/arch/arm64/include/asm/kvm_host.h
@@ -205,8 +205,14 @@ struct kvm_cpu_context {
 	struct kvm_vcpu *__hyp_running_vcpu;
 };
 
+struct kvm_pmu_events {
+	u32 events_host;
+	u32 events_guest;
+};
+
 struct kvm_host_data {
 	struct kvm_cpu_context host_ctxt;
+	struct kvm_pmu_events pmu_events;
 };
 
 typedef struct kvm_host_data kvm_host_data_t;
@@ -471,11 +477,33 @@ void kvm_arch_vcpu_load_fp(struct kvm_vcpu *vcpu);
 void kvm_arch_vcpu_ctxsync_fp(struct kvm_vcpu *vcpu);
 void kvm_arch_vcpu_put_fp(struct kvm_vcpu *vcpu);
 
+#define KVM_PMU_EVENTS_HOST	1
+#define KVM_PMU_EVENTS_GUEST	2
+
 #ifdef CONFIG_KVM /* Avoid conflicts with core headers if CONFIG_KVM=n */
 static inline int kvm_arch_vcpu_run_pid_change(struct kvm_vcpu *vcpu)
 {
 	return kvm_arch_vcpu_run_map_fp(vcpu);
 }
+static inline void kvm_set_pmu_events(u32 set, int flags)
+{
+	struct kvm_host_data *ctx = this_cpu_ptr(&kvm_host_data);
+
+	if (flags & KVM_PMU_EVENTS_HOST)
+		ctx->pmu_events.events_host |= set;
+	if (flags & KVM_PMU_EVENTS_GUEST)
+		ctx->pmu_events.events_guest |= set;
+}
+static inline void kvm_clr_pmu_events(u32 clr)
+{
+	struct kvm_host_data *ctx = this_cpu_ptr(&kvm_host_data);
+
+	ctx->pmu_events.events_host &= ~clr;
+	ctx->pmu_events.events_guest &= ~clr;
+}
+#else
+static inline void kvm_set_pmu_events(u32 set, int flags) {}
+static inline void kvm_clr_pmu_events(u32 clr) {}
 #endif
 
 static inline void kvm_arm_vhe_guest_enter(void)
-- 
2.7.4


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[PATCH v9 4/5] arm64: arm_pmu: Add support for exclude_host/exclude_guest attributes

[Andrew Murray]

Add support for the :G and :H attributes in perf by handling the
exclude_host/exclude_guest event attributes.

We notify KVM of counters that we wish to be enabled or disabled on
guest entry/exit and thus defer from starting or stopping :G events
as per the events exclude_host attribute.

With both VHE and non-VHE we switch the counters between host/guest
at EL2. We are able to eliminate counters counting host events on
the boundaries of guest entry/exit when using :G by filtering out
EL2 for exclude_host. However when using :H unless exclude_hv is set
on non-VHE then there is a small blackout window at the guest
entry/exit where host events are not captured.

Signed-off-by: Andrew Murray <andrew.murray@arm.com>
Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com>
---
 arch/arm64/kernel/perf_event.c | 53 ++++++++++++++++++++++++++++++++++++------
 1 file changed, 46 insertions(+), 7 deletions(-)

diff --git a/arch/arm64/kernel/perf_event.c b/arch/arm64/kernel/perf_event.c
index de564ae..64dde86 100644
--- a/arch/arm64/kernel/perf_event.c
+++ b/arch/arm64/kernel/perf_event.c
@@ -26,6 +26,7 @@
 
 #include <linux/acpi.h>
 #include <linux/clocksource.h>
+#include <linux/kvm_host.h>
 #include <linux/of.h>
 #include <linux/perf/arm_pmu.h>
 #include <linux/platform_device.h>
@@ -647,11 +648,27 @@ static inline int armv8pmu_enable_counter(int idx)
 
 static inline void armv8pmu_enable_event_counter(struct perf_event *event)
 {
+	struct perf_event_attr *attr = &event->attr;
 	int idx = event->hw.idx;
+	int flags = 0;
+	u32 counter_bits = BIT(ARMV8_IDX_TO_COUNTER(idx));
 
-	armv8pmu_enable_counter(idx);
 	if (armv8pmu_event_is_chained(event))
-		armv8pmu_enable_counter(idx - 1);
+		counter_bits |= BIT(ARMV8_IDX_TO_COUNTER(idx - 1));
+
+	if (!attr->exclude_host)
+		flags |= KVM_PMU_EVENTS_HOST;
+	if (!attr->exclude_guest)
+		flags |= KVM_PMU_EVENTS_GUEST;
+
+	kvm_set_pmu_events(counter_bits, flags);
+
+	/* We rely on the hypervisor switch code to enable guest counters */
+	if (!attr->exclude_host) {
+		armv8pmu_enable_counter(idx);
+		if (armv8pmu_event_is_chained(event))
+			armv8pmu_enable_counter(idx - 1);
+	}
 }
 
 static inline int armv8pmu_disable_counter(int idx)
@@ -664,11 +681,21 @@ static inline int armv8pmu_disable_counter(int idx)
 static inline void armv8pmu_disable_event_counter(struct perf_event *event)
 {
 	struct hw_perf_event *hwc = &event->hw;
+	struct perf_event_attr *attr = &event->attr;
 	int idx = hwc->idx;
+	u32 counter_bits = BIT(ARMV8_IDX_TO_COUNTER(idx));
 
 	if (armv8pmu_event_is_chained(event))
-		armv8pmu_disable_counter(idx - 1);
-	armv8pmu_disable_counter(idx);
+		counter_bits |= BIT(ARMV8_IDX_TO_COUNTER(idx - 1));
+
+	kvm_clr_pmu_events(counter_bits);
+
+	/* We rely on the hypervisor switch code to disable guest counters */
+	if (!attr->exclude_host) {
+		if (armv8pmu_event_is_chained(event))
+			armv8pmu_disable_counter(idx - 1);
+		armv8pmu_disable_counter(idx);
+	}
 }
 
 static inline int armv8pmu_enable_intens(int idx)
@@ -943,16 +970,25 @@ static int armv8pmu_set_event_filter(struct hw_perf_event *event,
 	 * Therefore we ignore exclude_hv in this configuration, since
 	 * there's no hypervisor to sample anyway. This is consistent
 	 * with other architectures (x86 and Power).
+	 *
+	 * To eliminate counting host events on the boundaries of
+	 * guest entry/exit we ensure EL2 is not included in hyp mode
+	 * with !exclude_host.
 	 */
 	if (is_kernel_in_hyp_mode()) {
-		if (!attr->exclude_kernel)
+		if (!attr->exclude_kernel && !attr->exclude_host)
 			config_base |= ARMV8_PMU_INCLUDE_EL2;
 	} else {
-		if (attr->exclude_kernel)
-			config_base |= ARMV8_PMU_EXCLUDE_EL1;
 		if (!attr->exclude_hv)
 			config_base |= ARMV8_PMU_INCLUDE_EL2;
 	}
+
+	/*
+	 * Filter out !VHE kernels and guest kernels
+	 */
+	if (attr->exclude_kernel)
+		config_base |= ARMV8_PMU_EXCLUDE_EL1;
+
 	if (attr->exclude_user)
 		config_base |= ARMV8_PMU_EXCLUDE_EL0;
 
@@ -976,6 +1012,9 @@ static void armv8pmu_reset(void *info)
 		armv8pmu_disable_intens(idx);
 	}
 
+	/* Clear the counters we flip at guest entry/exit */
+	kvm_clr_pmu_events(U32_MAX);
+
 	/*
 	 * Initialize & Reset PMNC. Request overflow interrupt for
 	 * 64 bit cycle counter but cheat in armv8pmu_write_counter().
-- 
2.7.4


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[PATCH v9 5/5] arm64: KVM: Enable support for :G/:H perf event modifiers

[Andrew Murray]

Enable/disable event counters as appropriate when entering and exiting
the guest to enable support for guest or host only event counting.

For both VHE and non-VHE we switch the counters between host/guest at
EL2. EL2 is filtered out by the PMU when we are using the :G modifier.

The PMU may be on when we change which counters are enabled however
we avoid adding an isb as we instead rely on existing context
synchronisation events: the isb in kvm_arm_vhe_guest_exit for VHE and
the eret from the hvc in kvm_call_hyp.

Signed-off-by: Andrew Murray <andrew.murray@arm.com>
Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com>
---
 arch/arm64/kvm/hyp/switch.c | 60 +++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 60 insertions(+)

diff --git a/arch/arm64/kvm/hyp/switch.c b/arch/arm64/kvm/hyp/switch.c
index d496ef5..bec6521 100644
--- a/arch/arm64/kvm/hyp/switch.c
+++ b/arch/arm64/kvm/hyp/switch.c
@@ -373,6 +373,54 @@ static bool __hyp_text __hyp_switch_fpsimd(struct kvm_vcpu *vcpu)
 	return true;
 }
 
+static bool __hyp_text __pmu_switch_to_guest(struct kvm_cpu_context *host_ctxt)
+{
+	struct kvm_host_data *host;
+	struct kvm_pmu_events *pmu;
+	u32 clr, set;
+
+	host = container_of(host_ctxt, struct kvm_host_data, host_ctxt);
+	pmu = &host->pmu_events;
+
+	/* We can potentially avoid a sysreg write by only changing bits that
+	 * differ between the guest/host. E.g. where events are enabled in
+	 * both guest and host
+	 */
+	clr = pmu->events_host & ~pmu->events_guest;
+	set = pmu->events_guest & ~pmu->events_host;
+
+	if (clr)
+		write_sysreg(clr, pmcntenclr_el0);
+
+	if (set)
+		write_sysreg(set, pmcntenset_el0);
+
+	return (clr || set);
+}
+
+static void __hyp_text __pmu_switch_to_host(struct kvm_cpu_context *host_ctxt)
+{
+	struct kvm_host_data *host;
+	struct kvm_pmu_events *pmu;
+	u32 clr, set;
+
+	host = container_of(host_ctxt, struct kvm_host_data, host_ctxt);
+	pmu = &host->pmu_events;
+
+	/* We can potentially avoid a sysreg write by only changing bits that
+	 * differ between the guest/host. E.g. where events are enabled in
+	 * both guest and host
+	 */
+	clr = pmu->events_guest & ~pmu->events_host;
+	set = pmu->events_host & ~pmu->events_guest;
+
+	if (clr)
+		write_sysreg(clr, pmcntenclr_el0);
+
+	if (set)
+		write_sysreg(set, pmcntenset_el0);
+}
+
 /*
  * Return true when we were able to fixup the guest exit and should return to
  * the guest, false when we should restore the host state and return to the
@@ -488,12 +536,15 @@ int kvm_vcpu_run_vhe(struct kvm_vcpu *vcpu)
 {
 	struct kvm_cpu_context *host_ctxt;
 	struct kvm_cpu_context *guest_ctxt;
+	bool pmu_switch_needed;
 	u64 exit_code;
 
 	host_ctxt = vcpu->arch.host_cpu_context;
 	host_ctxt->__hyp_running_vcpu = vcpu;
 	guest_ctxt = &vcpu->arch.ctxt;
 
+	pmu_switch_needed = __pmu_switch_to_guest(host_ctxt);
+
 	sysreg_save_host_state_vhe(host_ctxt);
 
 	__activate_traps(vcpu);
@@ -524,6 +575,9 @@ int kvm_vcpu_run_vhe(struct kvm_vcpu *vcpu)
 
 	__debug_switch_to_host(vcpu);
 
+	if (pmu_switch_needed)
+		__pmu_switch_to_host(host_ctxt);
+
 	return exit_code;
 }
 
@@ -532,6 +586,7 @@ int __hyp_text __kvm_vcpu_run_nvhe(struct kvm_vcpu *vcpu)
 {
 	struct kvm_cpu_context *host_ctxt;
 	struct kvm_cpu_context *guest_ctxt;
+	bool pmu_switch_needed;
 	u64 exit_code;
 
 	vcpu = kern_hyp_va(vcpu);
@@ -540,6 +595,8 @@ int __hyp_text __kvm_vcpu_run_nvhe(struct kvm_vcpu *vcpu)
 	host_ctxt->__hyp_running_vcpu = vcpu;
 	guest_ctxt = &vcpu->arch.ctxt;
 
+	pmu_switch_needed = __pmu_switch_to_guest(host_ctxt);
+
 	__sysreg_save_state_nvhe(host_ctxt);
 
 	__activate_traps(vcpu);
@@ -586,6 +643,9 @@ int __hyp_text __kvm_vcpu_run_nvhe(struct kvm_vcpu *vcpu)
 	 */
 	__debug_switch_to_host(vcpu);
 
+	if (pmu_switch_needed)
+		__pmu_switch_to_host(host_ctxt);
+
 	return exit_code;
 }
 
-- 
2.7.4


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