diff mbox

[v2,2/2] ARM/ARM64: KVM: Forward PSCI SYSTEM_OFF and SYSTEM_RESET to user space

Message ID 1386864747-29006-6-git-send-email-anup.patel@linaro.org
State New
Headers show

Commit Message

Anup Patel Dec. 12, 2013, 4:12 p.m. UTC
The PSCI SYSTEM_OFF and SYSTEM_RESET functions are system-level
functions hence cannot be fully emulated by the in-kernel PSCI
emulation code.

To tackle this, we forward PSCI SYSTEM_OFF and SYSTEM_RESET function
calls from vcpu to user space (i.e. QEMU or KVMTOOL) via kvm_run
structure using KVM_EXIT_SYSTEM_EVENT exit reasons.

Signed-off-by: Anup Patel <anup.patel@linaro.org>
Signed-off-by: Pranavkumar Sawargaonkar <pranavkumar@linaro.org>
---
 arch/arm/include/asm/kvm_psci.h   |    2 +-
 arch/arm/include/uapi/asm/kvm.h   |    2 ++
 arch/arm/kvm/handle_exit.c        |   13 +++++++---
 arch/arm/kvm/psci.c               |   48 ++++++++++++++++++++++++++++++-------
 arch/arm64/include/asm/kvm_psci.h |    2 +-
 arch/arm64/include/uapi/asm/kvm.h |    2 ++
 arch/arm64/kvm/handle_exit.c      |   12 +++++++---
 7 files changed, 65 insertions(+), 16 deletions(-)

Comments

Christoffer Dall Dec. 13, 2013, 8:08 p.m. UTC | #1
On Thu, Dec 12, 2013 at 09:42:27PM +0530, Anup Patel wrote:
> The PSCI SYSTEM_OFF and SYSTEM_RESET functions are system-level
> functions hence cannot be fully emulated by the in-kernel PSCI
> emulation code.
> 
> To tackle this, we forward PSCI SYSTEM_OFF and SYSTEM_RESET function
> calls from vcpu to user space (i.e. QEMU or KVMTOOL) via kvm_run
> structure using KVM_EXIT_SYSTEM_EVENT exit reasons.
> 
> Signed-off-by: Anup Patel <anup.patel@linaro.org>
> Signed-off-by: Pranavkumar Sawargaonkar <pranavkumar@linaro.org>
> ---
>  arch/arm/include/asm/kvm_psci.h   |    2 +-
>  arch/arm/include/uapi/asm/kvm.h   |    2 ++
>  arch/arm/kvm/handle_exit.c        |   13 +++++++---
>  arch/arm/kvm/psci.c               |   48 ++++++++++++++++++++++++++++++-------
>  arch/arm64/include/asm/kvm_psci.h |    2 +-
>  arch/arm64/include/uapi/asm/kvm.h |    2 ++
>  arch/arm64/kvm/handle_exit.c      |   12 +++++++---
>  7 files changed, 65 insertions(+), 16 deletions(-)
> 
> diff --git a/arch/arm/include/asm/kvm_psci.h b/arch/arm/include/asm/kvm_psci.h
> index 9a83d98..992d7f1 100644
> --- a/arch/arm/include/asm/kvm_psci.h
> +++ b/arch/arm/include/asm/kvm_psci.h
> @@ -18,6 +18,6 @@
>  #ifndef __ARM_KVM_PSCI_H__
>  #define __ARM_KVM_PSCI_H__
>  
> -bool kvm_psci_call(struct kvm_vcpu *vcpu);
> +int kvm_psci_call(struct kvm_vcpu *vcpu);
>  
>  #endif /* __ARM_KVM_PSCI_H__ */
> diff --git a/arch/arm/include/uapi/asm/kvm.h b/arch/arm/include/uapi/asm/kvm.h
> index c498b60..f4de20c 100644
> --- a/arch/arm/include/uapi/asm/kvm.h
> +++ b/arch/arm/include/uapi/asm/kvm.h
> @@ -172,6 +172,8 @@ struct kvm_arch_memory_slot {
>  #define KVM_PSCI_FN_CPU_OFF		KVM_PSCI_FN(1)
>  #define KVM_PSCI_FN_CPU_ON		KVM_PSCI_FN(2)
>  #define KVM_PSCI_FN_MIGRATE		KVM_PSCI_FN(3)
> +#define KVM_PSCI_FN_SYSTEM_OFF		KVM_PSCI_FN(4)
> +#define KVM_PSCI_FN_SYSTEM_RESET	KVM_PSCI_FN(5)
>  
>  #define KVM_PSCI_RET_SUCCESS		0
>  #define KVM_PSCI_RET_NI			((unsigned long)-1)
> diff --git a/arch/arm/kvm/handle_exit.c b/arch/arm/kvm/handle_exit.c
> index a920790..c3f0e72 100644
> --- a/arch/arm/kvm/handle_exit.c
> +++ b/arch/arm/kvm/handle_exit.c
> @@ -40,14 +40,21 @@ static int handle_svc_hyp(struct kvm_vcpu *vcpu, struct kvm_run *run)
>  
>  static int handle_hvc(struct kvm_vcpu *vcpu, struct kvm_run *run)
>  {
> +	int ret;
> +
>  	trace_kvm_hvc(*vcpu_pc(vcpu), *vcpu_reg(vcpu, 0),
>  		      kvm_vcpu_hvc_get_imm(vcpu));
>  
> -	if (kvm_psci_call(vcpu))
> +	ret = kvm_psci_call(vcpu);
> +	if (ret >= 0)
> +		return ret;
> +	else if (ret == -EINVAL) {
> +		kvm_inject_undefined(vcpu);
>  		return 1;
> +	}
> +
> +	return ret;

Wouldn't

ret = kvm_psci_call(vcpu);
if (ret == -EINVAL) {
	kvm_inject_undefined(vcpu);
	return 1;
}

return ret;

be simpler?

also, minor nit, but I think according to the CodingStyle if you have
single statements in if cases, but they are part of a larger if
statement with alternative clauses that use curly-brackets to
encapsulate multiple statements, then you should use curly braces around
the single-line statement as well...

>  
> -	kvm_inject_undefined(vcpu);
> -	return 1;
>  }
>  
>  static int handle_smc(struct kvm_vcpu *vcpu, struct kvm_run *run)
> diff --git a/arch/arm/kvm/psci.c b/arch/arm/kvm/psci.c
> index 0881bf1..8e246d6 100644
> --- a/arch/arm/kvm/psci.c
> +++ b/arch/arm/kvm/psci.c
> @@ -84,18 +84,41 @@ static unsigned long kvm_psci_vcpu_on(struct kvm_vcpu *source_vcpu)
>  	return KVM_PSCI_RET_SUCCESS;
>  }
>  
> +static inline void kvm_prepare_system_event(struct kvm_vcpu *vcpu, u32 type)
> +{
> +	memset(&vcpu->run->system_event, 0, sizeof(vcpu->run->system_event));
> +	vcpu->run->system_event.type = type;
> +	vcpu->run->exit_reason = KVM_EXIT_SYSTEM_EVENT;
> +}
> +
> +static void kvm_psci_system_off(struct kvm_vcpu *vcpu)
> +{
> +	kvm_prepare_system_event(vcpu, KVM_SYSTEM_EVENT_SHUTDOWN);
> +}
> +
> +static void kvm_psci_system_reset(struct kvm_vcpu *vcpu)
> +{
> +	kvm_prepare_system_event(vcpu, KVM_SYSTEM_EVENT_RESET);
> +}
> +
>  /**
>   * kvm_psci_call - handle PSCI call if r0 value is in range
>   * @vcpu: Pointer to the VCPU struct
>   *
>   * Handle PSCI calls from guests through traps from HVC instructions.
> - * The calling convention is similar to SMC calls to the secure world where
> - * the function number is placed in r0 and this function returns true if the
> - * function number specified in r0 is withing the PSCI range, and false
> - * otherwise.
> + * The calling convention is similar to SMC calls to the secure world
> + * where the function number is placed in r0 and function number

the function number

> + * specified in r0 is withing the PSCI range.

this reads a little funny now.  I think you can get rid of everything
after the first mention of r0 (cut from "and function number...") since
you explain that in the error codes below.

> + *
> + * This function returns: > 0 (success), 0 (success but exit to user
> + * space), and < 0 (errors)

you could use @return: instead of "This function returns", but I'm not
sure if anyone actually cares.

> + *
> + * Errors:
> + * -EINVAL: Unrecognized PSCI function
>   */
> -bool kvm_psci_call(struct kvm_vcpu *vcpu)
> +int kvm_psci_call(struct kvm_vcpu *vcpu)
>  {
> +	int ret = 1;
>  	unsigned long psci_fn = *vcpu_reg(vcpu, 0) & ~((u32) 0);
>  	unsigned long val;
>  
> @@ -111,11 +134,20 @@ bool kvm_psci_call(struct kvm_vcpu *vcpu)
>  	case KVM_PSCI_FN_MIGRATE:
>  		val = KVM_PSCI_RET_NI;
>  		break;
> -
> +	case KVM_PSCI_FN_SYSTEM_OFF:
> +		kvm_psci_system_off(vcpu);
> +		val = KVM_PSCI_RET_SUCCESS;
> +		ret = 0;
> +		break;
> +	case KVM_PSCI_FN_SYSTEM_RESET:
> +		kvm_psci_system_reset(vcpu);
> +		val = KVM_PSCI_RET_SUCCESS;
> +		ret = 0;
> +		break;
>  	default:
> -		return false;
> +		return -EINVAL;
>  	}
>  
>  	*vcpu_reg(vcpu, 0) = val;
> -	return true;
> +	return ret;
>  }
> diff --git a/arch/arm64/include/asm/kvm_psci.h b/arch/arm64/include/asm/kvm_psci.h
> index e301a48..9bd0ee8 100644
> --- a/arch/arm64/include/asm/kvm_psci.h
> +++ b/arch/arm64/include/asm/kvm_psci.h
> @@ -18,6 +18,6 @@
>  #ifndef __ARM64_KVM_PSCI_H__
>  #define __ARM64_KVM_PSCI_H__
>  
> -bool kvm_psci_call(struct kvm_vcpu *vcpu);
> +int kvm_psci_call(struct kvm_vcpu *vcpu);
>  
>  #endif /* __ARM64_KVM_PSCI_H__ */
> diff --git a/arch/arm64/include/uapi/asm/kvm.h b/arch/arm64/include/uapi/asm/kvm.h
> index d9f026b..f678902 100644
> --- a/arch/arm64/include/uapi/asm/kvm.h
> +++ b/arch/arm64/include/uapi/asm/kvm.h
> @@ -158,6 +158,8 @@ struct kvm_arch_memory_slot {
>  #define KVM_PSCI_FN_CPU_OFF		KVM_PSCI_FN(1)
>  #define KVM_PSCI_FN_CPU_ON		KVM_PSCI_FN(2)
>  #define KVM_PSCI_FN_MIGRATE		KVM_PSCI_FN(3)
> +#define KVM_PSCI_FN_SYSTEM_OFF		KVM_PSCI_FN(4)
> +#define KVM_PSCI_FN_SYSTEM_RESET	KVM_PSCI_FN(5)
>  
>  #define KVM_PSCI_RET_SUCCESS		0
>  #define KVM_PSCI_RET_NI			((unsigned long)-1)
> diff --git a/arch/arm64/kvm/handle_exit.c b/arch/arm64/kvm/handle_exit.c
> index df84d7b..e382eb8 100644
> --- a/arch/arm64/kvm/handle_exit.c
> +++ b/arch/arm64/kvm/handle_exit.c
> @@ -30,11 +30,17 @@ typedef int (*exit_handle_fn)(struct kvm_vcpu *, struct kvm_run *);
>  
>  static int handle_hvc(struct kvm_vcpu *vcpu, struct kvm_run *run)
>  {
> -	if (kvm_psci_call(vcpu))
> +	int ret;
> +
> +	ret = kvm_psci_call(vcpu);
> +	if (ret >= 0)
> +		return ret;
> +	else if (ret == -EINVAL) {
> +		kvm_inject_undefined(vcpu);
>  		return 1;
> +	}
>  
> -	kvm_inject_undefined(vcpu);
> -	return 1;
> +	return ret;

same as above.

>  }
>  
>  static int handle_smc(struct kvm_vcpu *vcpu, struct kvm_run *run)
> -- 
> 1.7.9.5
> 

Aside from the code formatting and commenting above, it looks pretty
good to me.

-Christoffer
diff mbox

Patch

diff --git a/arch/arm/include/asm/kvm_psci.h b/arch/arm/include/asm/kvm_psci.h
index 9a83d98..992d7f1 100644
--- a/arch/arm/include/asm/kvm_psci.h
+++ b/arch/arm/include/asm/kvm_psci.h
@@ -18,6 +18,6 @@ 
 #ifndef __ARM_KVM_PSCI_H__
 #define __ARM_KVM_PSCI_H__
 
-bool kvm_psci_call(struct kvm_vcpu *vcpu);
+int kvm_psci_call(struct kvm_vcpu *vcpu);
 
 #endif /* __ARM_KVM_PSCI_H__ */
diff --git a/arch/arm/include/uapi/asm/kvm.h b/arch/arm/include/uapi/asm/kvm.h
index c498b60..f4de20c 100644
--- a/arch/arm/include/uapi/asm/kvm.h
+++ b/arch/arm/include/uapi/asm/kvm.h
@@ -172,6 +172,8 @@  struct kvm_arch_memory_slot {
 #define KVM_PSCI_FN_CPU_OFF		KVM_PSCI_FN(1)
 #define KVM_PSCI_FN_CPU_ON		KVM_PSCI_FN(2)
 #define KVM_PSCI_FN_MIGRATE		KVM_PSCI_FN(3)
+#define KVM_PSCI_FN_SYSTEM_OFF		KVM_PSCI_FN(4)
+#define KVM_PSCI_FN_SYSTEM_RESET	KVM_PSCI_FN(5)
 
 #define KVM_PSCI_RET_SUCCESS		0
 #define KVM_PSCI_RET_NI			((unsigned long)-1)
diff --git a/arch/arm/kvm/handle_exit.c b/arch/arm/kvm/handle_exit.c
index a920790..c3f0e72 100644
--- a/arch/arm/kvm/handle_exit.c
+++ b/arch/arm/kvm/handle_exit.c
@@ -40,14 +40,21 @@  static int handle_svc_hyp(struct kvm_vcpu *vcpu, struct kvm_run *run)
 
 static int handle_hvc(struct kvm_vcpu *vcpu, struct kvm_run *run)
 {
+	int ret;
+
 	trace_kvm_hvc(*vcpu_pc(vcpu), *vcpu_reg(vcpu, 0),
 		      kvm_vcpu_hvc_get_imm(vcpu));
 
-	if (kvm_psci_call(vcpu))
+	ret = kvm_psci_call(vcpu);
+	if (ret >= 0)
+		return ret;
+	else if (ret == -EINVAL) {
+		kvm_inject_undefined(vcpu);
 		return 1;
+	}
+
+	return ret;
 
-	kvm_inject_undefined(vcpu);
-	return 1;
 }
 
 static int handle_smc(struct kvm_vcpu *vcpu, struct kvm_run *run)
diff --git a/arch/arm/kvm/psci.c b/arch/arm/kvm/psci.c
index 0881bf1..8e246d6 100644
--- a/arch/arm/kvm/psci.c
+++ b/arch/arm/kvm/psci.c
@@ -84,18 +84,41 @@  static unsigned long kvm_psci_vcpu_on(struct kvm_vcpu *source_vcpu)
 	return KVM_PSCI_RET_SUCCESS;
 }
 
+static inline void kvm_prepare_system_event(struct kvm_vcpu *vcpu, u32 type)
+{
+	memset(&vcpu->run->system_event, 0, sizeof(vcpu->run->system_event));
+	vcpu->run->system_event.type = type;
+	vcpu->run->exit_reason = KVM_EXIT_SYSTEM_EVENT;
+}
+
+static void kvm_psci_system_off(struct kvm_vcpu *vcpu)
+{
+	kvm_prepare_system_event(vcpu, KVM_SYSTEM_EVENT_SHUTDOWN);
+}
+
+static void kvm_psci_system_reset(struct kvm_vcpu *vcpu)
+{
+	kvm_prepare_system_event(vcpu, KVM_SYSTEM_EVENT_RESET);
+}
+
 /**
  * kvm_psci_call - handle PSCI call if r0 value is in range
  * @vcpu: Pointer to the VCPU struct
  *
  * Handle PSCI calls from guests through traps from HVC instructions.
- * The calling convention is similar to SMC calls to the secure world where
- * the function number is placed in r0 and this function returns true if the
- * function number specified in r0 is withing the PSCI range, and false
- * otherwise.
+ * The calling convention is similar to SMC calls to the secure world
+ * where the function number is placed in r0 and function number
+ * specified in r0 is withing the PSCI range.
+ *
+ * This function returns: > 0 (success), 0 (success but exit to user
+ * space), and < 0 (errors)
+ *
+ * Errors:
+ * -EINVAL: Unrecognized PSCI function
  */
-bool kvm_psci_call(struct kvm_vcpu *vcpu)
+int kvm_psci_call(struct kvm_vcpu *vcpu)
 {
+	int ret = 1;
 	unsigned long psci_fn = *vcpu_reg(vcpu, 0) & ~((u32) 0);
 	unsigned long val;
 
@@ -111,11 +134,20 @@  bool kvm_psci_call(struct kvm_vcpu *vcpu)
 	case KVM_PSCI_FN_MIGRATE:
 		val = KVM_PSCI_RET_NI;
 		break;
-
+	case KVM_PSCI_FN_SYSTEM_OFF:
+		kvm_psci_system_off(vcpu);
+		val = KVM_PSCI_RET_SUCCESS;
+		ret = 0;
+		break;
+	case KVM_PSCI_FN_SYSTEM_RESET:
+		kvm_psci_system_reset(vcpu);
+		val = KVM_PSCI_RET_SUCCESS;
+		ret = 0;
+		break;
 	default:
-		return false;
+		return -EINVAL;
 	}
 
 	*vcpu_reg(vcpu, 0) = val;
-	return true;
+	return ret;
 }
diff --git a/arch/arm64/include/asm/kvm_psci.h b/arch/arm64/include/asm/kvm_psci.h
index e301a48..9bd0ee8 100644
--- a/arch/arm64/include/asm/kvm_psci.h
+++ b/arch/arm64/include/asm/kvm_psci.h
@@ -18,6 +18,6 @@ 
 #ifndef __ARM64_KVM_PSCI_H__
 #define __ARM64_KVM_PSCI_H__
 
-bool kvm_psci_call(struct kvm_vcpu *vcpu);
+int kvm_psci_call(struct kvm_vcpu *vcpu);
 
 #endif /* __ARM64_KVM_PSCI_H__ */
diff --git a/arch/arm64/include/uapi/asm/kvm.h b/arch/arm64/include/uapi/asm/kvm.h
index d9f026b..f678902 100644
--- a/arch/arm64/include/uapi/asm/kvm.h
+++ b/arch/arm64/include/uapi/asm/kvm.h
@@ -158,6 +158,8 @@  struct kvm_arch_memory_slot {
 #define KVM_PSCI_FN_CPU_OFF		KVM_PSCI_FN(1)
 #define KVM_PSCI_FN_CPU_ON		KVM_PSCI_FN(2)
 #define KVM_PSCI_FN_MIGRATE		KVM_PSCI_FN(3)
+#define KVM_PSCI_FN_SYSTEM_OFF		KVM_PSCI_FN(4)
+#define KVM_PSCI_FN_SYSTEM_RESET	KVM_PSCI_FN(5)
 
 #define KVM_PSCI_RET_SUCCESS		0
 #define KVM_PSCI_RET_NI			((unsigned long)-1)
diff --git a/arch/arm64/kvm/handle_exit.c b/arch/arm64/kvm/handle_exit.c
index df84d7b..e382eb8 100644
--- a/arch/arm64/kvm/handle_exit.c
+++ b/arch/arm64/kvm/handle_exit.c
@@ -30,11 +30,17 @@  typedef int (*exit_handle_fn)(struct kvm_vcpu *, struct kvm_run *);
 
 static int handle_hvc(struct kvm_vcpu *vcpu, struct kvm_run *run)
 {
-	if (kvm_psci_call(vcpu))
+	int ret;
+
+	ret = kvm_psci_call(vcpu);
+	if (ret >= 0)
+		return ret;
+	else if (ret == -EINVAL) {
+		kvm_inject_undefined(vcpu);
 		return 1;
+	}
 
-	kvm_inject_undefined(vcpu);
-	return 1;
+	return ret;
 }
 
 static int handle_smc(struct kvm_vcpu *vcpu, struct kvm_run *run)