[PATCH v2 8/8] arm64: kvm: Check support for AArch32 for 32bit guests

2016-02-25 Thread Suzuki K Poulose 
Add a check to make sure the system supports AArch32 state
before initialising a 32bit guest.

Cc: Christoffer Dall 
Cc: Marc Zyngier 
Cc: kvmarm@lists.cs.columbia.edu
Signed-off-by: Suzuki K Poulose 

---

I really wanted to pass kvm_vcpu down to the helpers. But then, I can't
define the arch specific helper in asm/kvm_host.h due to lack of kvm_vcpu's
definition yet:

 In file included from include/linux/kvm_host.h:35:0,
  from arch/arm64/kernel/asm-offsets.c:24:
 ./arch/arm64/include/asm/kvm_host.h: In function 
‘kvm_arch_vcpu_validate_features’:
 ./arch/arm64/include/asm/kvm_host.h:344:48: error: dereferencing pointer to 
incomplete type
   return  !test_bit(KVM_ARM_VCPU_EL1_32BIT, vcpu->arch.features) ||
---
 arch/arm/include/asm/kvm_host.h   |5 +
 arch/arm/kvm/arm.c|3 +++
 arch/arm64/include/asm/kvm_host.h |8 
 3 files changed, 16 insertions(+)

diff --git a/arch/arm/include/asm/kvm_host.h b/arch/arm/include/asm/kvm_host.h
index f9f2779..945c23a 100644
--- a/arch/arm/include/asm/kvm_host.h
+++ b/arch/arm/include/asm/kvm_host.h
@@ -238,6 +238,11 @@ static inline void kvm_arch_sync_events(struct kvm *kvm) {}
 static inline void kvm_arch_vcpu_uninit(struct kvm_vcpu *vcpu) {}
 static inline void kvm_arch_sched_in(struct kvm_vcpu *vcpu, int cpu) {}
 
+static inline bool kvm_arch_vcpu_validate_features(struct kvm_vcpu_arch 
*arch_vcpu)
+{
+   return true;
+}
+
 static inline void kvm_arm_init_debug(void) {}
 static inline void kvm_arm_setup_debug(struct kvm_vcpu *vcpu) {}
 static inline void kvm_arm_clear_debug(struct kvm_vcpu *vcpu) {}
diff --git a/arch/arm/kvm/arm.c b/arch/arm/kvm/arm.c
index dda1959..fc4ea37 100644
--- a/arch/arm/kvm/arm.c
+++ b/arch/arm/kvm/arm.c
@@ -787,6 +787,9 @@ static int kvm_vcpu_set_target(struct kvm_vcpu *vcpu,
set_bit(i, vcpu->arch.features);
}
 
+   if (!kvm_arch_vcpu_validate_features(&vcpu->arch))
+   return -EINVAL;
+
vcpu->arch.target = phys_target;
 
/* Now we know what it is, we can reset it. */
diff --git a/arch/arm64/include/asm/kvm_host.h 
b/arch/arm64/include/asm/kvm_host.h
index 689d4c9..9d60a6c 100644
--- a/arch/arm64/include/asm/kvm_host.h
+++ b/arch/arm64/include/asm/kvm_host.h
@@ -24,6 +24,8 @@
 
 #include 
 #include 
+#include 
+#include 
 #include 
 #include 
 
@@ -338,6 +340,12 @@ static inline void kvm_arch_sync_events(struct kvm *kvm) {}
 static inline void kvm_arch_vcpu_uninit(struct kvm_vcpu *vcpu) {}
 static inline void kvm_arch_sched_in(struct kvm_vcpu *vcpu, int cpu) {}
 
+static inline bool kvm_arch_vcpu_validate_features(struct kvm_vcpu_arch 
*arch_vcpu)
+{
+   return  !test_bit(KVM_ARM_VCPU_EL1_32BIT, arch_vcpu->features) ||
+   system_supports_32bit_el0();
+}
+
 void kvm_arm_init_debug(void);
 void kvm_arm_setup_debug(struct kvm_vcpu *vcpu);
 void kvm_arm_clear_debug(struct kvm_vcpu *vcpu);
-- 
1.7.9.5

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Re: [PATCH v2 8/8] arm64: kvm: Check support for AArch32 for 32bit guests

2016-03-02 Thread Marc Zyngier 
On 25/02/16 09:52, Suzuki K Poulose wrote:
> Add a check to make sure the system supports AArch32 state
> before initialising a 32bit guest.
> 
> Cc: Christoffer Dall 
> Cc: Marc Zyngier 
> Cc: kvmarm@lists.cs.columbia.edu
> Signed-off-by: Suzuki K Poulose 
> 
> ---
> 
> I really wanted to pass kvm_vcpu down to the helpers. But then, I can't
> define the arch specific helper in asm/kvm_host.h due to lack of kvm_vcpu's
> definition yet:
> 
>  In file included from include/linux/kvm_host.h:35:0,
>   from arch/arm64/kernel/asm-offsets.c:24:
>  ./arch/arm64/include/asm/kvm_host.h: In function 
> ‘kvm_arch_vcpu_validate_features’:
>  ./arch/arm64/include/asm/kvm_host.h:344:48: error: dereferencing pointer to 
> incomplete type
>return  !test_bit(KVM_ARM_VCPU_EL1_32BIT, vcpu->arch.features) ||

Why don't you just have the prototype in kvm_host.h, and move the actual
implementation to something like guest.c? But I think there is a better
approach, see below.

> ---
>  arch/arm/include/asm/kvm_host.h   |5 +
>  arch/arm/kvm/arm.c|3 +++
>  arch/arm64/include/asm/kvm_host.h |8 
>  3 files changed, 16 insertions(+)
> 
> diff --git a/arch/arm/include/asm/kvm_host.h b/arch/arm/include/asm/kvm_host.h
> index f9f2779..945c23a 100644
> --- a/arch/arm/include/asm/kvm_host.h
> +++ b/arch/arm/include/asm/kvm_host.h
> @@ -238,6 +238,11 @@ static inline void kvm_arch_sync_events(struct kvm *kvm) 
> {}
>  static inline void kvm_arch_vcpu_uninit(struct kvm_vcpu *vcpu) {}
>  static inline void kvm_arch_sched_in(struct kvm_vcpu *vcpu, int cpu) {}
>  
> +static inline bool kvm_arch_vcpu_validate_features(struct kvm_vcpu_arch 
> *arch_vcpu)
> +{
> + return true;
> +}
> +
>  static inline void kvm_arm_init_debug(void) {}
>  static inline void kvm_arm_setup_debug(struct kvm_vcpu *vcpu) {}
>  static inline void kvm_arm_clear_debug(struct kvm_vcpu *vcpu) {}
> diff --git a/arch/arm/kvm/arm.c b/arch/arm/kvm/arm.c
> index dda1959..fc4ea37 100644
> --- a/arch/arm/kvm/arm.c
> +++ b/arch/arm/kvm/arm.c
> @@ -787,6 +787,9 @@ static int kvm_vcpu_set_target(struct kvm_vcpu *vcpu,
>   set_bit(i, vcpu->arch.features);
>   }
>  
> + if (!kvm_arch_vcpu_validate_features(&vcpu->arch))
> + return -EINVAL;
> +
>   vcpu->arch.target = phys_target;
>  
>   /* Now we know what it is, we can reset it. */
> diff --git a/arch/arm64/include/asm/kvm_host.h 
> b/arch/arm64/include/asm/kvm_host.h
> index 689d4c9..9d60a6c 100644
> --- a/arch/arm64/include/asm/kvm_host.h
> +++ b/arch/arm64/include/asm/kvm_host.h
> @@ -24,6 +24,8 @@
>  
>  #include 
>  #include 
> +#include 
> +#include 
>  #include 
>  #include 
>  
> @@ -338,6 +340,12 @@ static inline void kvm_arch_sync_events(struct kvm *kvm) 
> {}
>  static inline void kvm_arch_vcpu_uninit(struct kvm_vcpu *vcpu) {}
>  static inline void kvm_arch_sched_in(struct kvm_vcpu *vcpu, int cpu) {}
>  
> +static inline bool kvm_arch_vcpu_validate_features(struct kvm_vcpu_arch 
> *arch_vcpu)
> +{
> + return  !test_bit(KVM_ARM_VCPU_EL1_32BIT, arch_vcpu->features) ||
> + system_supports_32bit_el0();
> +}
> +

This is really convoluted (it took me 5 minutes staring at the
expression and remembering that AArch32 EL1 implies AArch32 EL0 to get it).

Now, we already have kvm_reset_vcpu() that validates AArch32 support. It
would probably be better to move things there. Thoughts?

>  void kvm_arm_init_debug(void);
>  void kvm_arm_setup_debug(struct kvm_vcpu *vcpu);
>  void kvm_arm_clear_debug(struct kvm_vcpu *vcpu);
> 

Thanks,

M.
-- 
Jazz is not dead. It just smells funny...
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Re: [PATCH v2 8/8] arm64: kvm: Check support for AArch32 for 32bit guests

2016-03-02 Thread Suzuki K. Poulose 

On 02/03/16 09:08, Marc Zyngier wrote:

On 25/02/16 09:52, Suzuki K Poulose wrote:



I really wanted to pass kvm_vcpu down to the helpers. But then, I can't
define the arch specific helper in asm/kvm_host.h due to lack of kvm_vcpu's
definition yet:

  In file included from include/linux/kvm_host.h:35:0,
   from arch/arm64/kernel/asm-offsets.c:24:
  ./arch/arm64/include/asm/kvm_host.h: In function 
‘kvm_arch_vcpu_validate_features’:
  ./arch/arm64/include/asm/kvm_host.h:344:48: error: dereferencing pointer to 
incomplete type
return  !test_bit(KVM_ARM_VCPU_EL1_32BIT, vcpu->arch.features) ||


Why don't you just have the prototype in kvm_host.h, and move the actual
implementation to something like guest.c? But I think there is a better
approach, see below.


I thought it would better be a static inline. But, the GCC can do that, silly 
me :)



This is really convoluted (it took me 5 minutes staring at the
expression and remembering that AArch32 EL1 implies AArch32 EL0 to get it).

Now, we already have kvm_reset_vcpu() that validates AArch32 support. It
would probably be better to move things there. Thoughts?


Definitely. I overlooked the function name to do something
specific to resetting the CPU than doing some checks :(.
I will respin it.

Cheers
Suzuki
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Re: [PATCH v2 8/8] arm64: kvm: Check support for AArch32 for 32bit guests

2016-03-14 Thread Suzuki K. Poulose 

On 02/03/16 09:08, Marc Zyngier wrote:

On 25/02/16 09:52, Suzuki K Poulose wrote:

Add a check to make sure the system supports AArch32 state
before initialising a 32bit guest.

Cc: Christoffer Dall 
Cc: Marc Zyngier 
Cc: kvmarm@lists.cs.columbia.edu
Signed-off-by: Suzuki K Poulose 


...


@@ -338,6 +340,12 @@ static inline void kvm_arch_sync_events(struct kvm *kvm) {}
  static inline void kvm_arch_vcpu_uninit(struct kvm_vcpu *vcpu) {}
  static inline void kvm_arch_sched_in(struct kvm_vcpu *vcpu, int cpu) {}

+static inline bool kvm_arch_vcpu_validate_features(struct kvm_vcpu_arch 
*arch_vcpu)
+{
+   return  !test_bit(KVM_ARM_VCPU_EL1_32BIT, arch_vcpu->features) ||
+   system_supports_32bit_el0();
+}
+


This is really convoluted (it took me 5 minutes staring at the
expression and remembering that AArch32 EL1 implies AArch32 EL0 to get it).

Now, we already have kvm_reset_vcpu() that validates AArch32 support. It
would probably be better to move things there. Thoughts?


I think we can leave the kvm bits as it is now, discarding this patch, as
we already do the right thing. Also system_supports_32bit_el0() doesn't
guarantee system_supports_32bit_el1(). The negation and converse are
both true though.

i.e,

!32bit_el0_support => !32bit_el1_support
  &
32bit_el1_support => 32bit_el0_support

Thanks
Suzuki

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