diff mbox series

[v2,2/2] riscv: KVM: add basic support for host vs guest profiling

Message ID 7eb3e1a8fc9f9aa0340a6a1fb88a127b767480ea.1723518282.git.zhouquan@iscas.ac.cn (mailing list archive)
State New, archived
Headers show
Series riscv: Add perf support to collect KVM guest statistics from host side | expand

Commit Message

Quan Zhou Aug. 13, 2024, 1:24 p.m. UTC 
From: Quan Zhou <zhouquan@iscas.ac.cn>

For the information collected on the host side, we need to
identify which data originates from the guest and record
these events separately, this can be achieved by having
KVM register perf callbacks.

Signed-off-by: Quan Zhou <zhouquan@iscas.ac.cn>
---
 arch/riscv/include/asm/kvm_host.h |  5 +++++
 arch/riscv/kvm/Kconfig            |  1 +
 arch/riscv/kvm/main.c             | 12 ++++++++++--
 arch/riscv/kvm/vcpu.c             |  7 +++++++
 4 files changed, 23 insertions(+), 2 deletions(-)

Comments

Andrew Jones Aug. 21, 2024, 12:51 p.m. UTC | #1 
On Tue, Aug 13, 2024 at 09:24:10PM GMT, zhouquan@iscas.ac.cn wrote:
> From: Quan Zhou <zhouquan@iscas.ac.cn>
> 
> For the information collected on the host side, we need to
> identify which data originates from the guest and record
> these events separately, this can be achieved by having
> KVM register perf callbacks.
> 
> Signed-off-by: Quan Zhou <zhouquan@iscas.ac.cn>
> ---
>  arch/riscv/include/asm/kvm_host.h |  5 +++++
>  arch/riscv/kvm/Kconfig            |  1 +
>  arch/riscv/kvm/main.c             | 12 ++++++++++--
>  arch/riscv/kvm/vcpu.c             |  7 +++++++
>  4 files changed, 23 insertions(+), 2 deletions(-)
> 
> diff --git a/arch/riscv/include/asm/kvm_host.h b/arch/riscv/include/asm/kvm_host.h
> index 2e2254fd2a2a..d2350b08a3f4 100644
> --- a/arch/riscv/include/asm/kvm_host.h
> +++ b/arch/riscv/include/asm/kvm_host.h
> @@ -286,6 +286,11 @@ struct kvm_vcpu_arch {
>  	} sta;
>  };
>

Let's add the same comment here that arm64 has unless you determine
that 'any event that arrives while a vCPU is loaded is considered to be
"in guest"' is not true for riscv.

> +static inline bool kvm_arch_pmi_in_guest(struct kvm_vcpu *vcpu)
> +{
> +	return IS_ENABLED(CONFIG_GUEST_PERF_EVENTS) && !!vcpu;
> +}
> +
>  static inline void kvm_arch_sync_events(struct kvm *kvm) {}
>  
>  #define KVM_RISCV_GSTAGE_TLB_MIN_ORDER		12
> diff --git a/arch/riscv/kvm/Kconfig b/arch/riscv/kvm/Kconfig
> index 26d1727f0550..0c3cbb0915ff 100644
> --- a/arch/riscv/kvm/Kconfig
> +++ b/arch/riscv/kvm/Kconfig
> @@ -32,6 +32,7 @@ config KVM
>  	select KVM_XFER_TO_GUEST_WORK
>  	select KVM_GENERIC_MMU_NOTIFIER
>  	select SCHED_INFO
> +	select GUEST_PERF_EVENTS if PERF_EVENTS
>  	help
>  	  Support hosting virtualized guest machines.
>  
> diff --git a/arch/riscv/kvm/main.c b/arch/riscv/kvm/main.c
> index bab2ec34cd87..734b48d8f6dd 100644
> --- a/arch/riscv/kvm/main.c
> +++ b/arch/riscv/kvm/main.c
> @@ -51,6 +51,12 @@ void kvm_arch_hardware_disable(void)
>  	csr_write(CSR_HIDELEG, 0);
>  }
>  
> +static void kvm_riscv_teardown(void)
> +{
> +	kvm_riscv_aia_exit();
> +	kvm_unregister_perf_callbacks();
> +}
> +
>  static int __init riscv_kvm_init(void)
>  {
>  	int rc;
> @@ -105,9 +111,11 @@ static int __init riscv_kvm_init(void)
>  		kvm_info("AIA available with %d guest external interrupts\n",
>  			 kvm_riscv_aia_nr_hgei);
>  
> +	kvm_register_perf_callbacks(NULL);
> +
>  	rc = kvm_init(sizeof(struct kvm_vcpu), 0, THIS_MODULE);
>  	if (rc) {
> -		kvm_riscv_aia_exit();
> +		kvm_riscv_teardown();
>  		return rc;
>  	}
>  
> @@ -117,7 +125,7 @@ module_init(riscv_kvm_init);
>  
>  static void __exit riscv_kvm_exit(void)
>  {
> -	kvm_riscv_aia_exit();
> +	kvm_riscv_teardown();
>  
>  	kvm_exit();
>  }
> diff --git a/arch/riscv/kvm/vcpu.c b/arch/riscv/kvm/vcpu.c
> index 8d7d381737ee..e8ffb3456898 100644
> --- a/arch/riscv/kvm/vcpu.c
> +++ b/arch/riscv/kvm/vcpu.c
> @@ -226,6 +226,13 @@ bool kvm_arch_vcpu_in_kernel(struct kvm_vcpu *vcpu)
>  	return (vcpu->arch.guest_context.sstatus & SR_SPP) ? true : false;
>  }
>  
> +#ifdef CONFIG_GUEST_PERF_EVENTS
> +unsigned long kvm_arch_vcpu_get_ip(struct kvm_vcpu *vcpu)
> +{
> +	return vcpu->arch.guest_context.sepc;
> +}
> +#endif
> +
>  vm_fault_t kvm_arch_vcpu_fault(struct kvm_vcpu *vcpu, struct vm_fault *vmf)
>  {
>  	return VM_FAULT_SIGBUS;
> -- 
> 2.34.1
>

Thanks,
drew
Quan Zhou Aug. 22, 2024, 6:42 a.m. UTC | #2 
On 2024/8/21 20:51, Andrew Jones wrote:
> On Tue, Aug 13, 2024 at 09:24:10PM GMT, zhouquan@iscas.ac.cn wrote:
>> From: Quan Zhou <zhouquan@iscas.ac.cn>
>>
>> For the information collected on the host side, we need to
>> identify which data originates from the guest and record
>> these events separately, this can be achieved by having
>> KVM register perf callbacks.
>>
>> Signed-off-by: Quan Zhou <zhouquan@iscas.ac.cn>
>> ---
>>   arch/riscv/include/asm/kvm_host.h |  5 +++++
>>   arch/riscv/kvm/Kconfig            |  1 +
>>   arch/riscv/kvm/main.c             | 12 ++++++++++--
>>   arch/riscv/kvm/vcpu.c             |  7 +++++++
>>   4 files changed, 23 insertions(+), 2 deletions(-)
>>
>> diff --git a/arch/riscv/include/asm/kvm_host.h b/arch/riscv/include/asm/kvm_host.h
>> index 2e2254fd2a2a..d2350b08a3f4 100644
>> --- a/arch/riscv/include/asm/kvm_host.h
>> +++ b/arch/riscv/include/asm/kvm_host.h
>> @@ -286,6 +286,11 @@ struct kvm_vcpu_arch {
>>   	} sta;
>>   };
>>
> 
> Let's add the same comment here that arm64 has unless you determine
> that 'any event that arrives while a vCPU is loaded is considered to be
> "in guest"' is not true for riscv.
> 

Ok, i will add this comment to clarify the point.

Thanks,
Quan

>> +static inline bool kvm_arch_pmi_in_guest(struct kvm_vcpu *vcpu)
>> +{
>> +	return IS_ENABLED(CONFIG_GUEST_PERF_EVENTS) && !!vcpu;
>> +}
>> +
>>   static inline void kvm_arch_sync_events(struct kvm *kvm) {}
>>   
>>   #define KVM_RISCV_GSTAGE_TLB_MIN_ORDER		12
>> diff --git a/arch/riscv/kvm/Kconfig b/arch/riscv/kvm/Kconfig
>> index 26d1727f0550..0c3cbb0915ff 100644
>> --- a/arch/riscv/kvm/Kconfig
>> +++ b/arch/riscv/kvm/Kconfig
>> @@ -32,6 +32,7 @@ config KVM
>>   	select KVM_XFER_TO_GUEST_WORK
>>   	select KVM_GENERIC_MMU_NOTIFIER
>>   	select SCHED_INFO
>> +	select GUEST_PERF_EVENTS if PERF_EVENTS
>>   	help
>>   	  Support hosting virtualized guest machines.
>>   
>> diff --git a/arch/riscv/kvm/main.c b/arch/riscv/kvm/main.c
>> index bab2ec34cd87..734b48d8f6dd 100644
>> --- a/arch/riscv/kvm/main.c
>> +++ b/arch/riscv/kvm/main.c
>> @@ -51,6 +51,12 @@ void kvm_arch_hardware_disable(void)
>>   	csr_write(CSR_HIDELEG, 0);
>>   }
>>   
>> +static void kvm_riscv_teardown(void)
>> +{
>> +	kvm_riscv_aia_exit();
>> +	kvm_unregister_perf_callbacks();
>> +}
>> +
>>   static int __init riscv_kvm_init(void)
>>   {
>>   	int rc;
>> @@ -105,9 +111,11 @@ static int __init riscv_kvm_init(void)
>>   		kvm_info("AIA available with %d guest external interrupts\n",
>>   			 kvm_riscv_aia_nr_hgei);
>>   
>> +	kvm_register_perf_callbacks(NULL);
>> +
>>   	rc = kvm_init(sizeof(struct kvm_vcpu), 0, THIS_MODULE);
>>   	if (rc) {
>> -		kvm_riscv_aia_exit();
>> +		kvm_riscv_teardown();
>>   		return rc;
>>   	}
>>   
>> @@ -117,7 +125,7 @@ module_init(riscv_kvm_init);
>>   
>>   static void __exit riscv_kvm_exit(void)
>>   {
>> -	kvm_riscv_aia_exit();
>> +	kvm_riscv_teardown();
>>   
>>   	kvm_exit();
>>   }
>> diff --git a/arch/riscv/kvm/vcpu.c b/arch/riscv/kvm/vcpu.c
>> index 8d7d381737ee..e8ffb3456898 100644
>> --- a/arch/riscv/kvm/vcpu.c
>> +++ b/arch/riscv/kvm/vcpu.c
>> @@ -226,6 +226,13 @@ bool kvm_arch_vcpu_in_kernel(struct kvm_vcpu *vcpu)
>>   	return (vcpu->arch.guest_context.sstatus & SR_SPP) ? true : false;
>>   }
>>   
>> +#ifdef CONFIG_GUEST_PERF_EVENTS
>> +unsigned long kvm_arch_vcpu_get_ip(struct kvm_vcpu *vcpu)
>> +{
>> +	return vcpu->arch.guest_context.sepc;
>> +}
>> +#endif
>> +
>>   vm_fault_t kvm_arch_vcpu_fault(struct kvm_vcpu *vcpu, struct vm_fault *vmf)
>>   {
>>   	return VM_FAULT_SIGBUS;
>> -- 
>> 2.34.1
>>
> 
> Thanks,
> drew
diff mbox series

Patch

diff --git a/arch/riscv/include/asm/kvm_host.h b/arch/riscv/include/asm/kvm_host.h
index 2e2254fd2a2a..d2350b08a3f4 100644
--- a/arch/riscv/include/asm/kvm_host.h
+++ b/arch/riscv/include/asm/kvm_host.h
@@ -286,6 +286,11 @@  struct kvm_vcpu_arch {
 	} sta;
 };
 
+static inline bool kvm_arch_pmi_in_guest(struct kvm_vcpu *vcpu)
+{
+	return IS_ENABLED(CONFIG_GUEST_PERF_EVENTS) && !!vcpu;
+}
+
 static inline void kvm_arch_sync_events(struct kvm *kvm) {}
 
 #define KVM_RISCV_GSTAGE_TLB_MIN_ORDER		12
diff --git a/arch/riscv/kvm/Kconfig b/arch/riscv/kvm/Kconfig
index 26d1727f0550..0c3cbb0915ff 100644
--- a/arch/riscv/kvm/Kconfig
+++ b/arch/riscv/kvm/Kconfig
@@ -32,6 +32,7 @@  config KVM
 	select KVM_XFER_TO_GUEST_WORK
 	select KVM_GENERIC_MMU_NOTIFIER
 	select SCHED_INFO
+	select GUEST_PERF_EVENTS if PERF_EVENTS
 	help
 	  Support hosting virtualized guest machines.
 
diff --git a/arch/riscv/kvm/main.c b/arch/riscv/kvm/main.c
index bab2ec34cd87..734b48d8f6dd 100644
--- a/arch/riscv/kvm/main.c
+++ b/arch/riscv/kvm/main.c
@@ -51,6 +51,12 @@  void kvm_arch_hardware_disable(void)
 	csr_write(CSR_HIDELEG, 0);
 }
 
+static void kvm_riscv_teardown(void)
+{
+	kvm_riscv_aia_exit();
+	kvm_unregister_perf_callbacks();
+}
+
 static int __init riscv_kvm_init(void)
 {
 	int rc;
@@ -105,9 +111,11 @@  static int __init riscv_kvm_init(void)
 		kvm_info("AIA available with %d guest external interrupts\n",
 			 kvm_riscv_aia_nr_hgei);
 
+	kvm_register_perf_callbacks(NULL);
+
 	rc = kvm_init(sizeof(struct kvm_vcpu), 0, THIS_MODULE);
 	if (rc) {
-		kvm_riscv_aia_exit();
+		kvm_riscv_teardown();
 		return rc;
 	}
 
@@ -117,7 +125,7 @@  module_init(riscv_kvm_init);
 
 static void __exit riscv_kvm_exit(void)
 {
-	kvm_riscv_aia_exit();
+	kvm_riscv_teardown();
 
 	kvm_exit();
 }
diff --git a/arch/riscv/kvm/vcpu.c b/arch/riscv/kvm/vcpu.c
index 8d7d381737ee..e8ffb3456898 100644
--- a/arch/riscv/kvm/vcpu.c
+++ b/arch/riscv/kvm/vcpu.c
@@ -226,6 +226,13 @@  bool kvm_arch_vcpu_in_kernel(struct kvm_vcpu *vcpu)
 	return (vcpu->arch.guest_context.sstatus & SR_SPP) ? true : false;
 }
 
+#ifdef CONFIG_GUEST_PERF_EVENTS
+unsigned long kvm_arch_vcpu_get_ip(struct kvm_vcpu *vcpu)
+{
+	return vcpu->arch.guest_context.sepc;
+}
+#endif
+
 vm_fault_t kvm_arch_vcpu_fault(struct kvm_vcpu *vcpu, struct vm_fault *vmf)
 {
 	return VM_FAULT_SIGBUS;